Post by: Scott Van Den Elzen on May 02, 2007, 11:42:48 PM
So... I'm wondering about that... do the two arrays interfere with one another where frequencies overlap? How would you avoid that? For example, lets say a guitar part has a lot of 600Hz. At the same time, the vocal part hits a note right around there. Will there be cancellation and summation issues in the room as a result? Can someone help me understand why or why not?
I have 4 Yamaha Club V tops, (usually only use two, except some wide outdoor venues) and enough processing and power to run my vocals separately, and put one set of tops inside, and one set outside, or one on top upside-down. I guess it would be kinda like "aux fed vocals." This all has me sort of curious. Does anyone think it would be worth the extra effort to try this out? Has anyone here tried it with a smallish system?
Post by: Bennett Prescott on May 02, 2007, 11:47:23 PM
The problem with two separate arrays is only if you're running identical (or near identical) source material through them. Since Dave is using them for different stuff, no big deal, and the advantage of having each array work half as hard is no doubt significant.
While the two arrays will still interfere with each other on the occasions that they're both produce identical amounts of, say, 400Hz, this is much less destructive and much more pleasing to the ear than conventional box overlap phase issues.
Post by: Mike Summa on May 03, 2007, 12:14:19 AM
| Scott Van Den Elzen wrote on Wed, 02 May 2007 22:42 |
There was a post not too long ago about how Rat Sound is hanging a separate array on the RHCP tour for vocals, which allows for more clarity by not forcing the same cabs to produce too many simultaneous frequencies. (Correct me if I'm not summarizing that correctly.) |
Kind of reminds me of the Wall of Sound.
Post by: Scott Van Den Elzen on May 03, 2007, 12:21:32 AM
| Bennett Prescott wrote on Wed, 02 May 2007 20:47 |
While the two arrays will still interfere with each other on the occasions that they're both produce identical amounts of, say, 400Hz, this is much less destructive and much more pleasing to the ear than conventional box overlap phase issues. |
Are you saying that it works better specifically because it's arrays, or just because the program material is different?
So, if I understand the premise correctly, on the upside... reducing the complexity of the signal by splitting to two boxes means more headroom and less distortion. on the downside... when there is occasionally overlap in the program material, there can be detrimental interference between the boxes. That about right?
It seems like, if you're NOT saying that this works better with arrays than trap boxes, I might find some reasonable benefit to flipping one set of tops upside-down on top the other (reducinging interference concerns) and running vox through one and the rest through the other.
I may have to do some experimenting. It might enable me to cover more people with my existing rig, and it could certainly improve clarity, especially vocals.
Post by: Bennett Prescott on May 03, 2007, 12:21:52 AM
Post by: Scott Deeter on May 03, 2007, 12:25:42 AM
| Bennett Prescott wrote on Thu, 03 May 2007 00:21 |
Nooow you've gone and done it. |
Guess your along for another ride Bennett
I'll be watching from "behind" the railing......again also.
Post by: Bennett Prescott on May 03, 2007, 12:26:28 AM
The long and short of it is, if you can afford to carry twice the PA to every show, there are definite sound quality advantages to using one only for vocals. The interference that you will get is almost nonexistant compared to what exists when running identical signal to two overlapping speakers not designed for it (say, two generic 15"x2" arrayed flat) and I talk about it more as a textbook case so nobody thinks it goes away. It exists in the same way that any two sources reproducing the same frequency separated by more than a half wavelength or so will interfere... since the source material will be different between the two, however, the interference will be constantly changing and audibly insignificant, especially compared to the benefits of running the second PA.
Post by: Justice C. Bigler on May 03, 2007, 12:37:05 AM
Dual PA
I was at the RHCP show in Oklahoma City, but I can't really comment about how it sounded because I was off the stage right, listening to the side fills. Damn security wouldn't let me hang out at FOH while the show was running!
From where I was sitting, I couldn't hear the vocals very well, everything else sounded all right, but the vocals were pretty muddy from where I was.
Dave is also using a sub set up which he calls "Sub Cannons" which you can find HERE
EDIT: Here's the blog posts where Dave talks about setting this rig up and why he think it works better:
Dual PA 1
Dual PA 2
I'm not sure that you would get any practical benefit to using this set up with any but the biggest systems, in the biggest venues, at very high SPL levels.
Post by: Scott Deeter on May 03, 2007, 12:47:08 AM
| Scott Van Den Elzen wrote on Thu, 03 May 2007 00:21 |
I may have to do some experimenting. It might enable me to cover more people with my existing rig, and it could certainly improve clarity, especially vocals. |
| Bennett Prescott wrote on Thu, 03 May 2007 00:26 |
The long and short of it is, if you can afford to carry twice the PA to every show, there are definite sound quality advantages to using one only for vocals. |
Sorry, I feel the urge to add a thought on this now. Could it be possible you wouldn't need "twice" the PA. My thinking is using a 3-way Full range cab (maybe Bi-Amped) with no subs for vocals only, and maybe a 2-way mid/hi box with subs for the music/instument part?
Post by: Bennett Prescott on May 03, 2007, 12:52:26 AM
Post by: Jeff Davis on May 03, 2007, 03:42:39 AM
Post by: TrevorMilburn on May 03, 2007, 04:25:21 AM
Regards,
Trevor
Post by: Bennett Prescott on May 03, 2007, 10:02:29 AM
As for LCR vs. LR vs. Whatever you want to call what Dave's doing... it comes down to this, entirely: Is it worth the small but significant sound clarity advantage to you to carry 1.5 - 2x the PA, with all the attendant problems? For almost everyone, the answer is no.
Post by: Dave Dermont on May 03, 2007, 11:13:08 AM
I personally feel there would be little advantage gained from the extra effort, but hey, I have been wrong before.
I once used a PA where they had a couple Bose 802s on each side hooked up to the console's vocal submaster output. In this case, it was two totally different kinds of PA systems. It was an interesting exercise, the results were not horrible, but I'd still rather have one "proper" PA than two half-assed ones.
Please report back with your findings.
Post by: Deron Lucatorta on May 03, 2007, 11:47:03 AM
| Dave Dermont wrote on Thu, 03 May 2007 10:13 |
I'd still rather have one "proper" PA than two half-assed ones. |
I would have to second this....
Post by: Patrick Tracy on May 03, 2007, 01:37:55 PM
Post by: guy poindexter on May 03, 2007, 03:28:05 PM
Post by: Kyle Abel on May 03, 2007, 03:50:31 PM
However, if you were doing an install such as a church, where the pastor's voice would have it's own speakers, it might make sense to fly the vocals' speakers in the middle. I guess it depends on the application.
Post by: Bennett Prescott on May 03, 2007, 06:56:29 PM
| Deron Lucatorta wrote on Thu, 03 May 2007 11:47 | ||
|
Thirdeded.
Post by: Reid Hall on May 03, 2007, 07:07:41 PM
Two lav mic wearing actors singing a duet with thei noses almost touching would normally cause horrible phase problems, but if you run one into an "A"PA and on into a "B"PA, no problem. The sounds combine in the air and not the PA.
I am shure running vox in its own PA will produc similar advanages.
Post by: Dave Rat on May 03, 2007, 08:49:39 PM
Ok, here is the run down on the concept, advantages and common usages of the concept of the dual PA implementation.
First of all, the big advantage of the dual system is that it reduces the negative effects of the inherent and significant inter-modulation distortion (IM Distortion) in speaker systems. As far as running two half ass 'ed PA's vs one full PA, I run two full PA systems side by side.
The concept is based on something that monitor engineers have been doing on the upper touring levels for many years which is using separate wedges for vocals and instruments. If you are curious as whether the dual PA concept works, it is quite simple to try it with wedges. The fact that the advantages can be experienced with monitor wedges also addresses the inaccurate comment(s) that the concept only applies on a large scale.
For those that are unfamiliar with IM distortion, one aspect of it can be looked at as follows: Speakers are most efficient when the voice coil is centered in the gap and least efficient when the cone is fully extended or fully pulled back. This efficiency drop which manifests itself as a non linearity I.E. distortion, can be both electrical and mechanical and can be quite significant. When one frequency put the cone or diaphragm in motion and another tone is introduced, the two frequencies effect the efficiency that the other is being reproduced causing distortion. The dual PA not only reduces the complexity of the signals driving each of the speaker system, it also allows more line array speakers to be used to cover a given space therefore allowing a reduced level to be sent each speaker reducing mechanical and thermal compression. Furthermore, it allows for improved sight lines by reducing the need for excessively long line array "banana's" in room with raised seating on the sides.
To demonstrate the effects at home of IM distortion, take two wedges and run a low frequency tone into both and then talk into a mic that is also running into both wedges, while the tone is on at fairy high level. Now rewire so that the tone comes from one wedge and the vocal comes from the other wedge and listen again. The difference in vocal clarity is should be readily audible and dramatic in 2-way monitors and becomes more and more significant as volume is increased.
I did extensive testing of this phenomenon while developing the MicroWedges and attempting to avoid this phenomenon was the basis for the three way Rat Sound L-Wedges developed in the mid 80's.
With a three way monitor where the vocal radiates from the mid and high speakers and the tone is in the low speaker, the difference is minimal. To demonstrate the reduced but still existing IM distortion issue with a three way monitor, the tone would need to be at the lower end of the midrange driver's frequency range.
As far as the reference to the Wall of sound, yes, that design was considered in the concept and I am striving for the same advantages they were so many years ago. The difference is that now with the proliferation of line arrays, the opportunity to have two PA's side by side is now a reality. Thus there is room to implement a tourable and realistic multi system setup within the existing accepted rock touring paradigm.
My original concept was to have three PA's. One for vocals, one for guitar and one for bass and drums spread between. I built small scale mock up of the system and using past tour multi track recordings I did some testing which indicated that the majority of the advantages were realized when going from one PA to two systems and adding the third was much less dramatic.
The beauty of the dual setup is that I can switch from mixing into a single PA to a mixing into dual PA in real time during a real concert. It is not like "OK, maybe it sounded better yesterday" It is "listen to this and now listen to this! Do you hear the difference?"
Regarding comments about interference between the dual PA systems, just as placing a bass rig on stage next to a guitar rig on stage causes no interference issues because they are reproducing different signals, having a vocal Pa next to an instrument PA also causes no interference issues as I never run the same signals into both systems.
As far as budgeting all that gear, well, that is a tough one and Peppers have been touring with this dual rig for over year now and I would have lost my budgeting for it long ago if the difference was not so clearly stunning and so easily demonstrate able.
Now that is all hardware I am talking about. As far as my mixing abilities and whether any particular show sounded good or not, well, that is a separate issue and have at it, but that is unrelated to the technical angle regarding the effectiveness of utilizing a dual system.
Also, to clarify, I run Bass/Guitar, Toms and Cymbals to the outside stereo clusters and Vocals/Kick and Snare to the inside stereo clusters. The reasoning is that though the Kick and Snare will effect the vocals with some IM distortion, they are short burst signals so vocal intelligeablity wont be significantly diminished. The bass is mainly reproduced by the 15"s and 2"s in the outer clusters where as the guitar is more prominant in the 7" speakers. The tom toms are infrequent enough that the negative effects their signal has is a non issue.
I saw some links to the blog I have been writing on about the tour, and there is more info there if you do a search for "Sound Nerd Speak"
OK, I hope that opens a big huge can of worms and opinions!! I fully expect and have seen considerable resistance already from all but a few with open minds as of course I am clearly a bit of a crack pot for doing anything aside from the generic accepted ways of setting up PA's. For some strange reason a high percentage of sound humans seem to be dead set on doing their best to stick to the half a century old stereo paradigm while light systems now move and video has been created and sets designs come up with new and innovative contraptions, we sound people must stick to hanging a good old fashioned stereo PA, because, hey, that's the way it is done.
But what if? What if it really does sound better? What if the dual setup truly does improve clarity and I am not crazy? Hmmm, that would mean that the audience gets a better show, the bands gets better sound, the PA vendors get a bit more budget and we as sound engineers have more fun doing what we love to do. I must say I am having the most fun mixing that I have ever had in my 27 year career!!
Oh, and I also hope that credibility assigned to the opinions offered are directly proportional to the amount of testing and research that the opinionators have done to create up their stances.
Post by: Evan Kirkendall on May 03, 2007, 08:52:33 PM
Dave Rat's on PSW!!
Dude, you gotta be bored to be here.
Great post as always. I always enjoy reading your stuff!
Evan
Post by: Too Tall (Curtis H. List) on May 03, 2007, 10:29:44 PM
| Dave Rat wrote on Thu, 03 May 2007 20:49 |
Hello Hello Ok, here is the run down on the concept, advantages and common usages of the concept of the dual PA implementation. First of all, the big advantage of the dual system is that it reduces the negative effects of the inherent and significant inter-modulation distortion (IM Distortion) in speaker systems. As far as running two half ass 'ed PA's vs one full PA, I run two full PA systems side by side. Snip- |
Hi Dave,
Broadways have been doing this longer then I have been working IA gigs (late 70s).
They might have been doing it before The Dead used The Wall of Sound, but I don’t know that for sure.
Beyond IM distortion a separate speaker system can be deployed in different places to address the fact that the orchestra is in a different place and has a great deal more stage volume then vocals. The flexibility can be a huge advantage when you want to put more vocals in a dead spot you just point the vocal box over a bit without bringing more orchestra, which the spill from the pit is covering just fine.
Some of the people I have worked with that have been mixing plays for years are absolute masters at this. You have to give props to the sound designers too.
In what you are doing the vocals and “orchestra” are all in the same place so you don’t need the flexibility quite as much.
For IM distortion drivers/speaker design has come a long way. It has been a while since IM has been a “First order” problem. I measure IM on all the drivers and the final speaker with xover and it is very low as long as you stay away from the MI series driver or more to the point true “Guitar speakers”.
That said when you push drivers hard I would guess it gets worse.
If you hear an appreciable improvement in a live setting I applaud your effort. Compared to studio or high end Home Theater, Live Sound has always been more of a challenge to produce high quality sound (not that most of the Ipod MP3 users would notice through their $1.99 ear buds).
And in your case the SPL you are pushing makes every type of distortion more of a problem.
Cheers
Post by: Vince Byrne on May 04, 2007, 11:58:11 AM
| Dave Rat wrote on Thu, 03 May 2007 19:49 |
I fully expect and have seen considerable resistance already from all but a few with open minds as of course I am clearly a bit of a crack pot for doing anything aside from the generic accepted ways of setting up PA's. |
That's why they call it the "bleeding edge"...
The physics make sense. I can hear it with mons. I'll probably never be able to afford it with mains, but thanks for looking over the edge and sharing what you find there with us.
Peace,
Vince
Post by: John Roberts {JR} on May 04, 2007, 12:53:39 PM
I have given this some thought on a smaller scale for hifi reproduction. A dedicated vocal, drum/bass, and lead channel with dedicated and spatially located speaker systems could get us one step closer to that live band playing in our living room. For sound reinforcement what is the true goal? A live band 25' away from everybody in the audience, or one 50' tall kick drum on stage? Perhaps a little of both.
Live sound reinforcement often crosses the line and creates something more than just what's on stage. That's good if it good. Anybody who's ever done micro-SR where you just throw the vocals through a few plastic speakers on sticks knows that you can get some damn good sound by keeping all the sources discrete. Scaling this up to mega-SR surely has merit for those with the budget and capable of dealing with the logistics.
JR
Post by: Scott Van Den Elzen on May 04, 2007, 08:21:02 PM
| Evan Kirkendall wrote on Thu, 03 May 2007 17:52 |
Holy shit! Dave Rat's on PSW!! Dude, you gotta be bored to be here. Great post as always. I always enjoy reading your stuff! Evan |
I'll second that!
Dave, I can't tell you how cool it is that you chimed in on this thread! You've given me tons to think about, as is the case anytime I read what you write.
Post by: Scott Van Den Elzen on May 04, 2007, 08:22:45 PM
| Vince Byrne wrote on Fri, 04 May 2007 08:58 | ||
That's why they call it the "bleeding edge"... The physics make sense. I can hear it with mons. I'll probably never be able to afford it with mains, but thanks for looking over the edge and sharing what you find there with us. Peace, Vince |
A few comments are implying this is only meaningful on big rigs, or arrays. Why wouldn't I want to do this with my little 250 person rig? Will we all be doing it soon just like Aux Fed subs??
It seems like a relatively small thing -- what do I need? 1 more snake send from a sub group, a crossover (or not, depending on the system.) A couple amp channels, and two more top boxes (that I already have just sitting in the trailer for most gigs anyway.)
I'm definitely going to experiment. If it works as well as I think it may, it could noticably improve my sound. Seems like that might get me more business at better prices, making the extra rig and labor pay for itself, and enabling the business to expand.
No harm in trying.
Post by: Bob Leonard on May 04, 2007, 08:30:49 PM
| John Roberts {JR} wrote on Fri, 04 May 2007 12:53 |
I find sound reproduction and reinforcement critically flawed from the start so there's many flaws to attack and perhaps master. Even a perfect speaker will have Doppler distortion from combined sources in the same passband. To some lesser extent there's probably IM in free space too. Trying to squeeze everything into one speaker system is probably expecting too much from the best technology. I have given this some thought on a smaller scale for hifi reproduction. A dedicated vocal, drum/bass, and lead channel with dedicated and spatially located speaker systems could get us one step closer to that live band playing in our living room. For sound reinforcement what is the true goal? A live band 25' away from everybody in the audience, or one 50' tall kick drum on stage? Perhaps a little of both. Live sound reinforcement often crosses the line and creates something more than just what's on stage. That's good if it good. Anybody who's ever done micro-SR where you just throw the vocals through a few plastic speakers on sticks knows that you can get some damn good sound by keeping all the sources discrete. Scaling this up to mega-SR surely has merit for those with the budget and capable of dealing with the logistics. JR |
JR,
I have used this technique on a very small scale for about 12 years now. I've said many times that I suppliment my backline using MIDI systems from Roland to the tune of about 10K. The realism is dependent on the audio chain used to reproduce the MIDI samples, those being bass, drums, horns, violins, piano, you name it and depending on if I have a bass player or drummer in for the gig. So I run seperate audio chains for vocals, monitors and all backline instrumentation. The instrumentation audio chain ends up coming through BUS 1/2 into SRX 725s and a pair of 18" subs. Vocals are through the same board but through the main mix, a seperate audio chain and eventually into the speakers used for FOH. Depending on the gig that could be another pair of 725s, EV SX500+, TA15s or combo in some cases, and without subs for vocals. Lately, after a job request a few months ago, I have been placing everything BEHIND the band (wall of sound). I am totally blown away by the quality of the sound overall. There is no interaction between the systems and everything is distinctive and clear even when I hit the dance floor 40-50 feet away at 90-100Db. Does it get load on stage?? Sometimes, but never loader than the vocals. The biggest advantage is the near perfect mix the audience hears.
Spelling
Post by: Dan Brandesky on May 04, 2007, 08:47:06 PM
-Dan
Post by: Dave Rat on May 05, 2007, 12:28:05 AM
Post by: Dave Rat on May 05, 2007, 12:28:36 AM
Though there are parallels between the Broadway concept and the Dual PA in that both utilize separate systems, the primary advantage's gained and focus of the dual PA is on clarity improvement at higher volumes rather than eliminating comb filtering issues and sound source location. Therefore the implementation, configuration and signal matrixing is quite a different concept.
Post by: Phil Nulty on May 06, 2007, 09:10:40 AM
Having being to many peppers concerts before the switch and then getting to hear the dual pa in action in Philadelphia last year from FOH (thanks dave) i can say it is a gig all others will be judged on for me. I have yet to hear the clarity i heard that day.
I have only got one chance to try it out myself apart from testing at home. The extra workload was offset by the extra clarity of the gig. well worth the effort.
Thanks dave for pushing the boat that bit further.
just my 2 cent
phil
Post by: Michael 'Bink' Knowles on May 06, 2007, 09:31:11 AM
So: two PA systems pointing North. Two PA systems pointing West. Two PA systems pointing South. Or whatever. Something like that.
-Bink
Post by: Kemper Watson on May 06, 2007, 10:54:58 AM
| Phil Nulty wrote on Sun, 06 May 2007 09:10 |
FWIW Having being to many peppers concerts before the switch and then getting to hear the dual pa in action in Philadelphia last year from FOH (thanks dave) i can say it is a gig all others will be judged on for me. I have yet to hear the clarity i heard that day. I have only got one chance to try it out myself apart from testing at home. The extra workload was offset by the extra clarity of the gig. well worth the effort. Thanks dave for pushing the boat that bit further. just my 2 cent phil |
I met Dave here in Atlanta this past October and heard the dual PA at FOH(Thanks Dave). It is now what all other shows shall be judged. The clarity was amazing throughout the venue.
Post by: Tony "T" Tissot on May 06, 2007, 04:29:46 PM
| Too Tall (Curtis H. List) wrote on Thu, 03 May 2007 19:29 |
Broadways have been doing this longer then I have been working IA gigs (late 70s). |
And regionals as well - when the gear is available, and the on-stage mic complement is large enough.
Comb-filtering (proximity)
Classic capsule failure (i.e. the principles get both an "A" and a "B" channel on them.
Still a LCR right system typically - but with only the center duplicated.
Post by: Tony "T" Tissot on May 06, 2007, 04:36:40 PM
| John Roberts {JR} wrote on Fri, 04 May 2007 09:53 |
I find sound reproduction and reinforcement critically flawed from the start so there's many flaws to attack and perhaps master. Even a perfect speaker will have Doppler distortion from combined sources in the same passband. To some lesser extent there's probably IM in free space too. Trying to squeeze everything into one speaker system is probably expecting too much from the best technology. I have given this some thought on a smaller scale for hifi reproduction. A dedicated vocal, drum/bass, and lead channel with dedicated and spatially located speaker systems could get us one step closer to that live band playing in our living room. For sound reinforcement what is the true goal? A live band 25' away from everybody in the audience, or one 50' tall kick drum on stage? Perhaps a little of both. Live sound reinforcement often crosses the line and creates something more than just what's on stage. That's good if it good. Anybody who's ever done micro-SR where you just throw the vocals through a few plastic speakers on sticks knows that you can get some damn good sound by keeping all the sources discrete. Scaling this up to mega-SR surely has merit for those with the budget and capable of dealing with the logistics. JR |
Sounds eerily like Blose's justification for the Butt Sticks!
Post by: Allen (Alien) Craft on May 06, 2007, 06:59:48 PM
Clarity? you bet.
as mentioned in previous replies, there are phasing and combining aspects to be considered, but in general, this technique is effective.
Post by: Dave Rat on May 07, 2007, 06:56:36 PM
Conversely, the dual PA allows one system to carry vocals while the other reproduces none.
I guess it could be theoretically possible to use conventional stereo system with a dedicated center cluster that caries all the vocals but it would be quite challenging to achieve adequate vocal coverage off axis. Plus there would be time delay issues for the people off axis as the vocals would arrive 25 or so milliseconds late with a not so uncommon PA spread distance of 60 feet, like we tour with. Furthermore, due to volume drop with distance, it would be extremely complex if not impossible to achieve a consistent vocal to instrument level when relying on a center cluster for all vocal reproduction in an arena sized venue, due to the some of the audience's proximity to the main PA instrument clusters and distance from the 'flown high and middle' center cluster.
The key to the dual PA is having two systems in such close proximity to each other that their coverage pattern and output level within that coverage pattern is as close identical as possible.
Hence the reason that the existence of line arrays has created the opportunity to do something that before was not feasible on a large scale.
Post by: Scott MacAuley on May 08, 2007, 11:12:18 PM
Adding 4 cabs, 2 line arrayed with my main pa, two more on the other side. Vocals only. Will have to have some vocal in the mains. Will report back during the weekend. Should be interesting.
Post by: Pascal Pincosy on May 08, 2007, 11:43:44 PM
Post by: Steven Welwood on May 10, 2007, 12:54:32 AM
Regarding the implementation of the second PA, what is the best way separate them:
1)L-R (outer system):instruments
Mono/Center (inner system):vox, kick, & snare
2)L-R (outer):instruments
Aux (inner):vox
3)Left (outer):instruments
Right (inner):vox
4)other?
...or does it make much difference?
Question 2
Are the subs included in the separation, or can they be summed without losing clarity of the kick & bass?
Thanks.
Steven
[Edit for clarification (hopefully
)]
Post by: Scott Deeter on May 11, 2007, 12:36:22 AM
| Steven Welwood wrote on Thu, 10 May 2007 00:54 |
Question 1 Regarding the implementation of the second PA, what is the best way separate them: 1)L-R:instruments Mono/Center:vox, kick, & snare 2)L-R:instruments Aux:vox 3)Left:instruments Right:vox 4)other? Question 2 Are the subs included in the separation, or can they be summed without losing clarity of the kick & bass? Thanks. Steven |
Hi Steven,
I've been thinking about this "Dual PA" and how to implement it for the little guy (small PA). Using a small format mixer, I think you'd need a mixer with individual Main L & R faders or a mixer that has sub groups. The next question is do you need or want a Stereo PA. With Stereo, you'd need the extra channels to create the L & R for each vocal or instrument then.
My thoughts on a (small) "Mono" Dual PA system first. I'd bet you could get by with the Vocal PA using a 3-way cab ran Full Range passive, using an Eq (that has a HPF) and 1 amp ran in stereo mode (Stage L & R vocal cabs). The Instrument PA would consist of Mid-Hi cabs & Subs ran 2-way (Bi-Amped) using an Eq & xover with amps for tops & subs. I'm thinking for the Vocal PA you wouldn't need subs if you have a cab that covers the vocal range freq. response needed, most likely a 3-way cab that goes low enough plus giving clarity for the vocals. For the Instrument Mid-Hi cab, you could use the same 3-way cab (for matching power and cosmetic reasons) or a 2-way cab as you'll be using subs with the instrument PA running 2-way (Bi-Amped).
With the above set-up using a mixer that has separate L & R mains faders, simply choose which the vocals & instruments would be and pan the the channels L or R to match the PA intended. The signal routing for a dual PA would depend on the routing available on your mixer (of course
), and the possibilities could be a Mono Dual PA, Stereo Dual PA or a Dual Mono-Dual PA. I wont go into all the possibilities that could work as I believe most could come up with a solution to do it themselves.For the hell of it, I was looking at the Community Sonus cabs (again) with the 90 x 40 horns particularly the 3294 3-way 15" cab. From what I remember when asking about this cab awhile ago, it wouldn't array well in multiples due to the 90 degree horizontal horn, but as a 1 box a side will do ok. So my thoughts are to keep the fronts parallel with each other in a Dual PA set up. Am I on the right track in my thinking here?
http://www.community.chester.pa.us/files/specs/new/SONUS-329 4.pdf
Post by: Steven Welwood on May 11, 2007, 01:22:28 AM
We already have two complete systems, for a total of 4 3-way tops, and 4 subs, which we have been using just for more coverage. It's a bit more coverage than we really need right now, though, so I think the vocal clarity of the dual system approach would be worth shaving coverage off the chairs in the back corners
So . . . if I run the division--as suggested earlier in the thread--with vox, kick, and snare to the inside (on the mono channel), and the instruments on the outside (via L-R), where does that leave the subs?
Do I run the kick just to the inside sub, and the bass and floor tom just to the outside sub, or should I sum them to get all sub signals to all 4 subs? (The subs have summing inputs, so it wouldn't require summing at the board.)
Fronts of speakers in-line was how I understood the aiming should be (the way you have diagrammed), so the two lefts both cover the same area, and the two rights cover the same area.
Post by: Scott Van Den Elzen on May 11, 2007, 01:53:34 AM
Ideally you would be running subs off an aux so that only kick drum, bass, and keys would make it to the subs. There's no reason to match the full range boxes up with the subs.
I would recommend the aux fed subs pretty highly... I actually run this way for all my shows.
As far as splitting vox off to their own PA, that's all theoretical until I have a chance to use it at a real gig.
Post by: Scott Deeter on May 11, 2007, 02:50:17 AM
| Steven Welwood wrote on Fri, 11 May 2007 01:22 |
So . . . if I run the division--as suggested earlier in the thread--with vox, kick, and snare to the inside (on the mono channel), and the instruments on the outside (via L-R), where does that leave the subs? Do I run the kick just to the inside sub, and the bass and floor tom just to the outside sub, or should I sum them to get all sub signals to all 4 subs? (The subs have summing inputs, so it wouldn't require summing at the board.) |
Hmm, good question. Being that Mr. Rat is running 2 full blown PA's he can do that with no problem and I understand the thought in that mix configuration, with you having 4 subs, I'm guessing you run a pair stage L & R. So they have the coupling effect of each pair at least. If you run a pair a side and 1 sub is for kick and the other is for Bass & Floor tom, then you wouldn't get the coupling advantages. A possible way to go with the kick in the vocal PA, would be to center cluster the vocal subs in the middle and the Bass & Floor tom subs 1 each stage L & R. At least the Kick subs can couple, maybe that will be enough umph or maybe not.
Honestly, my first choice (with a small system) would be to try as I suggested with vocals only in 1 PA (a pair of 3-way tops). With doing this, the advantage in the Dual PA basically came up to get the vocals clearer anyway. The advantage of Aux fed subs is to clean up the mix also helping to make the vocals clearer (is that a word "clearer"?). So if the vocals are already separate from the instruments, maybe Aux fed subs wouldn't be needed.
I think in a small system you'd want as much umph out of the subs as you can get regarding the kick at least, so I'd hate to see you loose that in splitting them up between the Kick & Bass. In the Aux Fed system, Kick & Bass both go to the same subs anyway.
Ok, time to stop as I feel babble coming on
Post by: Steven Welwood on May 11, 2007, 01:47:02 PM
| Scott Deeter wrote on Fri, 11 May 2007 00:50 |
A possible way to go with the kick in the vocal PA, would be to center cluster the vocal subs in the middle and the Bass & Floor tom subs 1 each stage L & R. At least the Kick subs can couple, maybe that will be enough umph or maybe not. |
I would love to be able to center cluster the subs! Unfortunately, we use the subs as bases for the tops. However, I agree that with the vocals already separated out, it may not be necessary to separate the bottom end any more. And with our application (the hip hop side, at least), it's probably worth sacrificing a bit of low-end clarity to get a significant increase of thump!
I am running the subs L-R right now, but when we get a new board, I'll be able to aux-feed them.
Just one more question. The stage end of the snake is generally located by the drums, close to center, and I'm running active speakers & subs (for ease & quickness of setup time, and less equipment to haul around). The L & R channels are as simple as it gets, because they will only be going to 1 speaker each. The center channel and subs though, now require the same send to both sides. Should I split the sends at the snake to either side, or should I go from snake to one side, and daisy-chain to the other?
Post by: Dave Rat on May 11, 2007, 03:12:09 PM
I currently run instruments (guitar, bass, toms and cymbals) to the outer clusters and vocals, kick and snare to the inners. The theory is that guitars lean heavy on the midrange speakers while bass leans on the low speakers. Toms are dynamic enough not to cause blurring issues that are audible in that it is ok for them to step on bass and guitar during the short bursts they are hit. Cymbals lean mainly on the horns. For the inner clusters, vocals are clear and open and the short duration kick and snare hits will step on vocals but since kick and snare hits are short bursts spaced in time rather than consistent tones like guitar and bass can be, the K and S do not negatively impact intelligibility of the vox.
As far as inner vs outer, either way is fine, I chose vox/K/S to he inside but in situation where vox feedback is and issue, vox/K/S to the outside may be preferable.
Primarily the goal is to get the dual clusters so close together that they have identical coverage patterns and so it does not matter which cluster is used for what.
Post by: Dave Rat on May 11, 2007, 03:19:52 PM
I would love to hear about how well or not well it works in that application, if you try it. The way I look at it, the dual PA is just another tool to add to the sound "tool box" of solutions to optimize sound systems to venue/artist. Using the right tools for the job is the key to creativity and quality of the humans that setup and operate the systems.
Post by: Steven Welwood on May 11, 2007, 03:23:07 PM
Post by: Dave Rat on May 11, 2007, 03:24:02 PM
Post by: Mike Slay on May 12, 2007, 12:05:13 AM
Post by: Scott MacAuley on May 12, 2007, 05:02:03 AM
Small loud room. Holds 400 max. They want concert level sound for a Cumbia, Terra caliente etc band. Big group tomorrow as well. Dance floor 50x25 + 11' depth for stage.
The main stack is mono due to the layout of the room, 6x18 2x15 subs, 4x 12 mids (1kw ea), 4 horns. I flew 4 12 inch with horns 2 per side. Fed subs from left master, Mids/highs from right master crossed over at 120, and the 4 vocal cabs crossed over at 100 off of submaster 2, I also usually feed the dj system from subs 3/4 summed as a round the room fill at low volume.
31 band eqs on all, safety compressors on all.
At concert levels the vocal only cabs filled in very nicely.
Lots of control and clarity only attainable at lower volumes with a standard system.
I would say that in really loud small environments this idea should be implimented. It also allowed for nice round eq tweaking for the instruments to blow a hole for the vocals to sit in and eliminate painfull frequencies without having to tweak each instrument to death.
For normal mortal gigs whare you are running everything cool
it's probably not necessary. I need a bigger board..
Thanks for the suggestion.
Post by: Bob Leonard on May 12, 2007, 07:40:06 AM
| Dave Rat wrote on Fri, 11 May 2007 15:12 |
"The best way" is something that infinitely debatable so instead I will offer "a way" and the reasoning behind it. I currently run instruments (guitar, bass, toms and cymbals) to the outer clusters and vocals, kick and snare to the inners. The theory is that guitars lean heavy on the midrange speakers while bass leans on the low speakers. Toms are dynamic enough not to cause blurring issues that are audible in that it is ok for them to step on bass and guitar during the short bursts they are hit. Cymbals lean mainly on the horns. For the inner clusters, vocals are clear and open and the short duration kick and snare hits will step on vocals but since kick and snare hits are short bursts spaced in time rather than consistent tones like guitar and bass can be, the K and S do not negatively impact intelligibility of the vox. As far as inner vs outer, either way is fine, I chose vox/K/S to he inside but in situation where vox feedback is and issue, vox/K/S to the outside may be preferable. Primarily the goal is to get the dual clusters so close together that they have identical coverage patterns and so it does not matter which cluster is used for what. |
Dave Rat,
I had sent a PM last week, did you ever receive it?
Thanks,
BL
Post by: Too Tall (Curtis H. List) on May 12, 2007, 10:46:50 AM
| Dave Rat wrote on Mon, 07 May 2007 18:56 |
Center clusters can be useful. I have been touring with a center cluster as well that is vocal heavy in it's mix. Though the purpose of the center cluster is a bit different that the dual PA. Typically the center cluster augments vocals in room center and close but is not capable both logistically and acoustically to completely allow vocals to be removed from the mains system. Conversely, the dual PA allows one system to carry vocals while the other reproduces none. I guess it could be theoretically possible to use conventional stereo system with a dedicated center cluster that caries all the vocals but it would be quite challenging to achieve adequate vocal coverage off axis. Plus there would be time delay issues for the people off axis as the vocals would arrive 25 or so milliseconds late with a not so uncommon PA spread distance of 60 feet, like we tour with. Furthermore, due to volume drop with distance, it would be extremely complex if not impossible to achieve a consistent vocal to instrument level when relying on a center cluster for all vocal reproduction in an arena sized venue, due to the some of the audience's proximity to the main PA instrument clusters and distance from the 'flown high and middle' center cluster. |
You mentioned many of the problems. In addition if you try to reach the edges from the middle the reflection off the side wall is always a very acute angle causing most of the energy to bounce to the middle in one narrow angle. When you model this in Ulysses it is almost impossible to account for without moving or adding some boxes. adjusting levels and delays won't fix it.
Most if not all of the center clusters that cover the entire horizontal coverage are in fact “exploded” clusters where the boxes are spread out if not exactly L,C,R.
The only thing that allows them to be still called a “cluster” is they all receive the same signal.
| Dave Rat wrote on Mon, 07 May 2007 18:56 |
The key to the dual PA is having two systems in such close proximity to each other that their coverage pattern and output level within that coverage pattern is as close identical as possible. Hence the reason that the existence of line arrays has created the opportunity to do something that before was not feasible on a large scale. |
How does this work out when you bring in the accountant?
Is twice the PA only doing the same amount of work?
Or for the same room and crowd can you push the boxes harder with a dual PA and not need twice the number of boxes to do the same amount of work?
Is this a revenue neutral system or close to one?
If you needed 20 boxes to cover with a typical single PA, how many boxes with a dual PA?
BTW, thanks for spending all the time on this Dave.
Post by: Scott MacAuley on May 12, 2007, 06:17:18 PM
I tried it, I liked it, the clients liked it, the patrons liked it. Now I will work on incorporating it into the main system in a practical maner using top boxes strictly tailored for vocals within a ground stacked system as vocal enhancement.
Thanks Dave.
Post by: Dave Rat on May 12, 2007, 11:45:31 PM
Post by: Dave Rat on May 12, 2007, 11:50:38 PM
Post by: Langston Holland on May 12, 2007, 11:53:04 PM
| Dave wrote on Sat, 12 May 2007: |
cool cool. That is in line with my experience. In that with the dual rig I can slam the instrument rig if need be and still have mega clear vox. I ran into this in one arena where is was quite deep and a low cieling that forced short bananas. |
What concerns me here is that I understand what you said. Thanks for the fascinating instruction Prof. Rat! :)
Post by: Dave Rat on May 13, 2007, 12:14:34 AM
| Too Tall (Curtis H. List) wrote on Sat, 12 May 2007 15:46 |
How does this work out when you bring in the accountant? Is twice the PA only doing the same amount of work? Or for the same room and crowd can you push the boxes harder with a dual PA and not need twice the number of boxes to do the same amount of work? Is this a revenue neutral system or close to one? If you needed 20 boxes to cover with a typical single PA, how many boxes with a dual PA? BTW, thanks for spending all the time on this Dave. |
Well, the accountant is a challenge, as we know, regardless of the goals we attempt to achieve with our sonic endeavors. I am fortunate to have established significant trust and freedom over the more than 2 decades I have know/worked with the peppers so I can be a bit more adventurous than is typically common. That said, if I do not produce results, management very much enjoys putting me on the spot and I am held to very high expectations from many angles.
Yes, the extra boxes, trucking and labor does cost more yet in the big scheme of things, the extra cost is still fairly low compared to expenditures on hires video and lighting rigs. The way I see it, if we sound humans step out of our shell and \ take on some more adventurous sound system setups, we can start climbing out of the rut of being budgeted below lighting and video on major tours.
The dual hangs get a bit louder than the single hang system with the same coverage but not a lot louder. The primary gain is in clarity.
I currently only dual PA the main hangs but yes, a 10 per side system goes to a 20 per side system.
Post by: Vladimir Angelovski on May 13, 2007, 05:36:39 AM
Though I have read the "nerd sound speak" about dual PA on the Dave's blog, it is very interesting to see what other sound "humans" think about it and what are their questions on the subject.
Here's mine. Since I have 6 trap boxes per side, stacked three above three boxes what do you think about sending the Kick snare and vocals into the lower row and the rest of the band to the higher row of boxes?
Thanks,
Vlad
Post by: Eric Snodgrass on May 13, 2007, 09:40:53 AM
Post by: Scott Van Den Elzen on May 13, 2007, 10:09:14 AM
I'd be more inclined to use proper splay (which Vlad may already be doing) to get the boxes arraying properly, and try what he suggested -- splitting vox out top and bottom. That way coverage would be even between instruments and vocals.
Post by: Vladimir Angelovski on May 13, 2007, 10:42:34 AM
| Eric Snodgrass wrote on Sun, 13 May 2007 15:40 |
I don't know how well those boxes array or if there are any comb-filtering issues with that setup you pictured but I would be more inclined to put the vocals in the middle two boxes with the band in the outer and inner two boxes. That might help a bit with comb-filtering issues by sending different sources to the boxes that are next to each other in that setup. Someone in this thread earlier also mentioned turning upside-down the vocal speakers so the horns don't line up with the horns of the speakers next to them. This would be worth a try as well. |
I must agree with Scott on the coverage issue. As for the comb filtering, yes there is a little of it but it is audible only if I listen to the pink noise (you physicly can't have perfect seam betwwen two boxes)not with music. And these boxes array a loooot better than my previous rectangle boxes which I sold.
I also think that I would get much more pressure in the HF band if I turn the upper boxes upside down. The problem is that they have rubber feet on the bottom and rubbered holes on top that fit the feet from the upper ones. The whole stack is rock solid and if I try to turn them upside down they will slip. I can't tighten them with the ratchet strip because of their trapezoidal shape.
Great advices, guys. thanks a lot.
Vlad
Post by: Dave Rat on May 14, 2007, 12:42:36 AM
But, hey, does not hurt to give it a try and post your results.
Post by: Scott MacAuley on May 14, 2007, 12:25:08 PM
Group came from Playing a staduim in Orlando 4 hours earlier, drove to West Palm,
hopped on stage. Agents wide eyed response to the system by the third song... "WOAH!!", he wound up dancing near the stacks despite exaustion. Top 4 cabs with 5:1 comp on them vocals only, middle 4 cabs normal mix with slightly less vocal, aux fed subs. I will never play a little loud place without the vocals only setup again. They wanted clear concert levels....they got it.
Also saved my A^%& the night before. The KB player for the second band pulled up a curruped patch that send the sound of the battle for Mogadishu through the mids at whatever the loudest output of a yamaha keyboard is, toasting the 4 12in mids
off the CA12 before I could grab the fader. The guy's patch levels were all over the place. Toasted the DI as well. but the vocals and the show kept going. First time I've blown anything in years. Had to scramble up some 15 cabs for last night.
Post by: Scott Deeter on May 14, 2007, 02:41:13 PM
| Scott MacAuley wrote on Sat, 12 May 2007 05:02 |
The main stack is mono due to the layout of the room, 6x18 2x15 subs, 4x 12 mids (1kw ea), 4 horns. I flew 4 12 inch with horns 2 per side. Fed subs from left master, Mids/highs from right master crossed over at 120, and the 4 vocal cabs crossed over at 100 off of submaster 2, I also usually feed the dj system from subs 3/4 summed as a round the room fill at low volume. 31 band eqs on all, safety compressors on all. At concert levels the vocal only cabs filled in very nicely. Lots of control and clarity only attainable at lower volumes with a standard system. |
Scott,
That's great, you tried it, and you liked it. Maybe I'm not following correctly here, but where are you sending the Lows from the Vocal cabs cross point?
Post by: Patrick Tracy on May 14, 2007, 02:50:19 PM
| Scott Deeter wrote on Mon, 14 May 2007 12:41 | ||
Scott, That's great, you tried it, and you liked it. Maybe I'm not following correctly here, but where are you sending the Lows from the Vocal cabs cross point? |
I'll bet just like aux fed subs: nowhere.
Post by: Scott Deeter on May 14, 2007, 03:14:02 PM
| Patrick Tracy wrote on Mon, 14 May 2007 14:50 | ||||
I'll bet just like aux fed subs: nowhere. |
Hmm, maybe I should have asked "where are the lows from the vocal cabs cross point coming from?". Meaning what part of the system do you hear them from. The main system is crossed @ 120 and the vocals are crossed @ 100 (having 2 different low groups now). Better yet, how are the lows from the vocals implemented into the system? Scott, are you running subs for the vocal PA also?
Thanks Patrick, I thought I had a simple question, now I don't know how to ask it in the correct terms now.
Post by: Patrick Tracy on May 14, 2007, 05:09:59 PM
I realize you weren't asking me, but if you were this is how I'd do it, with subgroup fed subwoofers:
Subgroup 1: Vocals and perhaps whatever doesn't interfere such as kick and snare
Subgroup 2: Remaining instruments
Subgroup 3: Kick, bass, Hammond, maybe toms
Subgroup 1 to crossover 1, high out to vocal system
Subgroup 2 to crossover 2, high out to instrument system
Subgroup 3 to crossover 3, low out to subwoofer system
Subgroup numbers may be different in use, for example using pairs for stereo, and LF subgroup could be an aux send instead. I would shoot for having the first two groups sum to an ideal mono or stereo mix. I'd be tempted to get a surround controller to be able to adjust the overall volume with one knob.
Post by: Scott MacAuley on May 14, 2007, 09:56:17 PM
Vocal cabs are cut off at 100hz via another crossover. Sub-master 2 feeds the eq,comp,snake,BEh*&^ 1500, to 2 12"x1"horn cabs per side. I can assign vocals there by sending them through sub2. The main mid/high cabs are fed by master out right the subs by master out left. In this club I also have to feed the DJ booth for a little back fill from subs 3/4 summed so that that feed is not affected by panning something out of my subs. Exactly how I will implement this permanently I have not worked out yet. I used the vocal cabs to "ADD" to the main system
so some vocals were feeding my main mid and high tops because it was a small club and I needed to have a little vocal in there for those right in front of the main stack.
I know,
I know, 
I know, buy a bigger board with more auxes that I can still lift myself, I'm working on it.Trying to get my pics up.
No subs for the vocal cabs. Small PA, don't need them. What are
you going to put in them anyway? LF room tone? The difference in crossover points is my wacky imperfect idea since the vocals are the only thing feeding the vocal system I gave them a touch more warmth. The lows and mid/highs on the main system are crossed over using one side of a stereo crossover for each. The crossover points have to be set manually with an rta per channel for the perfectionists. For DJ only you can lower the xover point on the mids without changing the subs. Handy. It's a variation on the idea adapted to SMALL venues. In a DJ system adding subs to good full range cabs seems to work better than the traditional split of low/mid/high because of all the extra bass energy and number of speakers around the room.
The end result is a nicer sounding room. I borrowed Dave's Idea combined with this DJ concept and ADDED vocal only cabinets.
Less vocal in the mains as a psychological fill, most from the vocal only tops. Once again for a small venue.
I would suspect that with line arrays this could get very tricky,
I only deal with ground stacked or semi-flown stuff.
ADDED: The vocal clarity was unparralelled, the reverb clear.
A few people commented on this and how the vocals sounded exactly like the artist's records sound. That small club mushy sound was gone.
Dave.. What are the royalties for using this concept gonna cost me per show?
. Thanks for the concept.
Post by: Scott MacAuley on May 15, 2007, 07:59:17 AM
http://www.screamersusa.com/vocalstak
Don't flame me for imperfect placement. It was a test.
Small place for 500 people, no? You can see the acoustical nightmare the place is.
The ev1502er's to the right of the main stack were an emergency addition the night after due to the other band's F(*&G keyboard player. His patches were all extremely low, except ONE!.
In the 2-3 seconds it took to hear the blast, spot the clip light, and mute the channel, 4 1000w 12" mids were toasted despite compression, limiting, and on-board clip limiters.
The voice coils were burned completly around and in pieces.
Will post that on a new thread.
BTW. While rereading this thread I realized the article mentioned
RCHP
O.K. too fast, RHCP. Dumb Me just realized that was Red Hot Chili Peppers. Given RCHP's
I meant RHCP, sound, with the vocals so clear and upfront, coupled with the results I got in a small club, I'd say that would make a hell of a lot of sense! The vocals for Groupo Sonador have a very distinct sound with lots of reverb. The effect within the audience Sat and Sun was as if the vocals were truly flying around the room over the band while still very close and present with a physical body and presence of their own.Kind of a nice psychoacoustic aftereffect, even in mono.
That type of effect would certainly enhance the RHCP experience.
Fized my spalling miztake. Sorrie.
Post by: Scott Van Den Elzen on May 15, 2007, 03:10:44 PM
| Scott MacAuley wrote on Tue, 15 May 2007 04:59 |
... BTW. While rereading this thread I realized the article mentioned RCHP. Dumb Me just realized that was Red Hot Chili Peppers. Given RCHP's... |
RCHP?
Royal Canadian Hot Peppers?
Red California Highway Patrol?
Post by: Dave Rat on May 15, 2007, 03:29:41 PM
To be honest, I expected to see more reluctance to the dual PA concept on the board here and I expected to see a bunch of posts where people would go into detail about why it wont work or is a waste of time without actually trying it first, as I have experienced in the past.
Post by: Evan Kirkendall on May 15, 2007, 03:36:32 PM
Ive got a decent sized show coming up on Friday. I may try this concept as well... 2 RS220's per side, vox/drums in inner speakers, guitar/bass in outer.
Evan
Post by: Scott MacAuley on May 15, 2007, 04:46:02 PM
Since I tried it with the vocal cabs on top, it would be interesting to see how the side by side works. I believe in small venues the over the top configuration might work best because of the relative closeness of the audience to the stacks.
(Under 20 feet). Plus it keeps a screaming vocal from directly blasting them. Since our ears are more sensitive to side to side direction, more than up and down,I would have to agree that at close range the side by side configuration might be expected to be a little wierd. At working range I would think it would work fine. I did notice eq'ing vocals was much easier especially in the high range. I couldn't try it with drums in the vocal cabs because I didn't build them for that kind of abuse, so I'm curious how your test will turn out.
Thanks again Mr. Rat.
Post by: Winston Gamble on May 15, 2007, 05:20:18 PM
| Evan Kirkendall wrote on Tue, 15 May 2007 20:36 |
Hm... Ive got a decent sized show coming up on Friday. I may try this concept as well... 2 RS220's per side, vox/drums in inner speakers, guitar/bass in outer. Evan |
With just two speakers (60 degree?) per side, it seems any vocal clarity you gain may be negated by the loss of even coverage. Getting all the sounds to all the people would be the higher priority for me. Although this two PA technique sounds like just the thing to help all the small rigs I see with two or more 90 degree cabs per side arrayed in the proverbial "Wall of Mud".
Winston
Post by: Scott Van Den Elzen on May 15, 2007, 06:26:38 PM
| Winston Gamble wrote on Tue, 15 May 2007 14:20 | ||
With just two speakers (60 degree?) per side, it seems any vocal clarity you gain may be negated by the loss of even coverage. Getting all the sounds to all the people would be the higher priority for me... Winston |
I think it depends a lot on room dimensions. A lot of the sheds I play are long and narrow, and my 90 degree boxes are actually too wide -- causing more reflection from the side walls than I want. OTOH, when the room is wide, I like the 90s a lot better.
I think for weekend warriors, it's really all about being adaptive. You take the gear and room you have, and make them work together as best as possible. Nothing feels better than hearing "I've never heard it sound so good in this awful room. Great work."
I'm really looking forward to trying this out on Saturday. It took me a little time to get all the pieces together, but I'm ready to take a crack at it.
Post by: Tony "T" Tissot on May 15, 2007, 06:28:20 PM
| Quote: |
.. I expected to see more reluctance to the dual PA concept on the board .... |
au contraire.
I hope to have a similar rig in place for a 2-day Memorial day weekend festival.
We've done similar in theater, for different reasons, with the center channel. But I never put 2 and 2 together for R&R.
I am hoping for more apparent clarity at volume - (wonder what, if any, potential SPL gain? I suspect none - as that's not really the point - except what comes from being able to drive a bit harder.
This may prove to be the poor sound-man's way to array systems that are not designed to be arrayed?
Post by: Scott MacAuley on May 15, 2007, 06:49:45 PM
| Scott Van Den Elzen wrote on Tue, 15 May 2007 |
I think for weekend warriors, it's really all about being adaptive. You take the gear and room you have, and make them work together as best as possible. Nothing feels better than hearing "I've never heard it sound so good in this awful room. Great work." |
Well put! Applies to bread and butter gigs with bigger companies too!
Fixed.
Post by: Evan Kirkendall on May 15, 2007, 07:10:54 PM
Evan
Post by: Derek Williams on May 16, 2007, 06:15:41 AM
| Dave Rat wrote on Tue, 15 May 2007 20:29 |
I expected to see a bunch of posts where people would go into detail about why it wont work or is a waste of time without actually trying it first, as I have experienced in the past. |
I think that's a problem that we see a lot of in sound... There's so many Sound 'Engineers' who think that this stuff is black magic and not just physics. The amount of people who just do the same thing day in day out because 'It worked like this last time' is just amazing.
We're on the edge of something really exciting at the moment, for us lower-down-the-food-chain-sound-types we're just getting into the affordable digital boards and I must admit that I'm liking the ability to move an input into any of the outputs on the scene recall, among other things - there is going to be fun time ahead for the open minded that is
When the lampies moved from manual analog boards to the digital ones their jobs got really exciting and I can see us going that way too....
Back on topic....
I've always tried to use a seperate vocal PA whenever budget permits (I do musical theatre in Ireland - not much money!) and I must say that it's really satisfying to see one of the realy Big Boys using the same techniques, makes me think I'm doing something right
Post by: Scott MacAuley on May 16, 2007, 06:49:55 AM
I think the reason why the test worked so well for me was because I did not have drums in my vocal cabs due to their weaker components, drums went to the mains. This would also eliminate another set of subs on smaller systems. I'd keep that in mind if you are only running a couple of cabs per side.
This idea would probably also be interesting for a Satriani style gig as well as you could highlight the lead instrument
in it's own little crystal clear world. Hmmm.
I think the idea of mixing in the air rather than through the mixer may have been what Bose is trying to do with their pole type system as well. They suggest each player posses his/her own
unit. Very expensive and not possible for most of us these days.
It also wouldn't work well in a large venue such as a stadium, or for modern music or any high spl environment.
I think Dave's idea is a more realistic approach to this on a larger scale. Not having the drums in the vocal cabs might be the
practical approach for average one or two stack per side type gigs as you would only need high quality vocal range cabinets and can compress them more than the mains for metal or dance type shows similar to the original mastering process or the dreaded radio station compress it to hell sound. At the same time
you have the full powered, transient rich, gut wrenching less compressed music flying out of the mains which is what most people seem to want when they go to a modern live show.
Perhaps Dave has also discovered an answer to the unnatural surround sound at home problem that will make audiences happy.
I'm going to go play in my cave for a awhile and ...Shut up now
zzzzzttt,zzztt,,,... 
"It's AALIIVVEEEEE! Ah HA hA hA!"Post by: Marcus Baeumler on May 16, 2007, 05:06:43 PM
And also thanks for all posters here for chiming in with valuable ideas and of course to Dave for taking this budget approach serious.
Marcus
Post by: Patrick Tracy on May 17, 2007, 01:00:19 AM
| Scott MacAuley wrote on Wed, 16 May 2007 04:49 |
Perhaps Dave has also discovered an answer to the unnatural surround sound at home problem that will make audiences happy. |
5.1 surround mixes often have the dialog in the center channel and the other audio distributed among the four other speakers, both for positing the voices at the screen and for clarity. Then there's the LFE channel, the ".1", that usually has only the low frequencies of the mix. Much like dual P.A. with aux fed subs.
Post by: Scott MacAuley on May 20, 2007, 11:23:52 PM
Seriously working on permanent cabinets and console.
At this point I am going over the schematics for two boards I recently aquired to convert two buses for vocal only and subs.
One of them is an old monitor board with 18 buses to play with and I may graft an old A/H console's eq's into it as well to build a "small Format" FOH from hell console with both main eq's and monitor eq's, All sweepable. With 6 monitor feeds and 2 fx feeds. My Soundtracs FM may go up for sale soon.
Post by: Mark Coleman on September 04, 2007, 07:37:42 AM
| Derek Williams wrote on Wed, 16 May 2007 11:15 |
(I do musical theatre in Ireland - not much money!) |
I saw Riverdance in The Gaiety on Aug 25th. Whoever ran sound for that show alone deserves a year's salary.
I couldn't stop talking about it to my drummer. Crystal clear, punchy & tight, and plenty loud when the moments were right.
BTW, I was just convincing my WW band to let me try aux-fed subs. Now I have to start again with dual PA/aux-fed sub. It all makes so much sense, but try to convince someone with no interest in SR or PA? Forget it. All they hear is Charlie Brown's teacher.
How long before the pros are running "one-speaker-per-frequency" PAs?
Mark
Post by: Eric Steinberg on March 28, 2008, 07:55:00 PM
One of our rigs consists of Merlyn S2 cabs, which are bi-amp with a horn and (2) 10" woofers. My thought is to re-wire the 10's to seperate channels, and splitting vocals and instruments between the two. Everything would still have to go through the single horn, but all the discussion of speaker efficiency vs. clarity seems to be in regard to the woofers so maybe that wouldn't be such a big deal?
Obviously this is not ideal as compared to 2 completely separate cabs, but maybe still worth experimenting. The the single 10" will have a hard time accomplishing what the pair of them did when it comes to getting instruments loud, and this could be a critical flaw.
The other cab I had in mind (and I'm no gear snob so I only know about what I've worked with) is the QSC Wideline. They have dual 10's as well. In bi-amp mode, the 10's are in parallel. In tri-amp mode, one 10 does the lows and the other does the mids. So here's another cab where one could try splitting vox and instruments between the two identical woofers and avoid having to hang a whole 'nother PA.
Post by: Mac Kerr on March 28, 2008, 08:07:16 PM
| Eric Steinberg wrote on Fri, 28 March 2008 19:55 |
One of our rigs consists of Merlyn S2 cabs, which are bi-amp with a horn and (2) 10" woofers. My thought is to re-wire the 10's to seperate channels, and splitting vocals and instruments between the two. Everything would still have to go through the single horn, but all the discussion of speaker efficiency vs. clarity seems to be in regard to the woofers so maybe that wouldn't be such a big deal? |
Mac
Post by: Eric Steinberg on March 28, 2008, 08:14:00 PM
It's the small venues where there just isn't room for two stacks that I'd like to try this in, or in the case of the Wideline... when it's just not practical for rig points or money to hang two arrays.
Post by: SteveKirby on March 28, 2008, 08:18:10 PM
Would this be an aux fed midrange?
Post by: Eric Steinberg on March 28, 2008, 08:55:09 PM
I had assumed the worst IM was in the woofers because of Dave Rat's "50hz tone" example, but that was just an assumption on my part.
I guess the next question is... how long before somebody starts building cabs that have redundant drivers specifically for doing a dual PA in one unit?
Post by: Milt Hathaway on March 28, 2008, 09:19:17 PM
Post by: Mac Kerr on March 28, 2008, 09:45:21 PM
| Milt Hathaway wrote on Fri, 28 March 2008 21:19 |
overexcurt |
Mac
Post by: Milt Hathaway on March 28, 2008, 09:49:36 PM
| Mac Kerr wrote on Fri, 28 March 2008 20:45 | ||
Mac |
It is now.
Post by: Scott MacAuley on March 28, 2008, 11:21:42 PM
YOU ARE OUT OF YOUR MIND!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Wow there is someone crazier than ..ME!. Cool.
But seriously:
Having the two speakers in the same cabinet sharing the same airspace will not only cause all kinds of distortions but probably add mush and overtones to whatever signal you are feeding. It's just like a Porsche 944 engine, if the timing belt is slightly off the pistons and valves smash into each other destroying the entire engine because they share the same airspace. In Your double 10, they will be constantly interfering with each other. You will probably also have a VERY big loss in effeciency per speaker as you are destroying the advantages of having two drivers working together in the first place.
I understand your concept, however since you will still be sharing the same horn, even if you isolated each speaker in it's own chamber.....you'd still have big issues in the critical areas covered by the horn. For small stuff, simple two way cabs
are all you need with their own feed.
If you are trying to enhance the vocals the way I do, you don't even need a ton of power.
With a standard small PA, I then ADD more vocal using other cabinets, to what is already there. If I have to push hard
I can back down the vocals in the mix and push up the submaster that feeds the vocal exciters to rebalance keeping the vocals clear against a really loud band. Or pull down the mids and highs feed to the mains (I use aux subs), and leave the exciters alone. I also like that I can have different compression on the exciters versus the heavy protection compression on the mains.
I'm late for a show, I'll check back in a day or two.
Post by: Art Welter on March 28, 2008, 11:43:15 PM
Note that in the QSC wide line both 10" diameter low-frequency transducers are used to cover the lowest frequency range. One driver covers only low frequencies while the range of the other extends through the mid frequencies to the mid/high crossover point.
If you run those drivers as separate units, you will loose 6dB in the frequency range they were mutually coupled. That means you need approximately double the amount of cabinets to be where you were before, so you don’t save any space. As has already been pointed out, clarity and articulation comes from the upper harmonics, so you are simply wasting space, amplifiers, and processing doing the bizarre approach you suggest.
So, in response to “how long before somebody starts building cabs that have redundant drivers specifically for doing a dual PA in one unit?”
It is unlikely to ever happen unless the correct amount of drugs and money are applied to a cabinet builder that does not mind creating a fiasco, and is not afraid of brain overexcurt ing.
Art Welter
Post by: Stephen Payne on March 29, 2008, 10:11:39 AM
Also I have an idea for a poor mans version for small shows.
Single PA
Dual Mono
2 Full range cabs on each side over aux fed subs stacked.
Right channel to outboard tops.
Left channel to inboard tops.
Usual instruments Kick, Bass etc to subs via aux.
Vocals panned 1/2 left.
Other full range instruments 1/2 right.
The idea is that by sharing but not separating completely the assignments each might have more "space".
Any one ever try something like this?
Post by: Scott Van Den Elzen on March 29, 2008, 11:20:07 AM
| Stephen Payne wrote on Sat, 29 March 2008 07:11 |
I'm curious if the people who tried the 2 PA setup and liked it are still using it regularly. Also I have an idea for a poor mans version for small shows. Single PA Dual Mono 2 Full range cabs on each side over aux fed subs stacked. Right channel to outboard tops. Left channel to inboard tops. Usual instruments Kick, Bass etc to subs via aux. Vocals panned 1/2 left. Other full range instruments 1/2 right. The idea is that by sharing but not separating completely the assignments each might have more "space". Any one ever try something like this? |
I still use a separate channel for vocals on nearly all my gigs. And still love it. It's at least as helpful to clarity as aux fed subs has been.
Regarding the "kinda, sorta" method you described above, it sounds like a comb filtering mess to me.
The original concern I had about this method was overlap between the speakers at specific frequencies. I was assured by some of the experts here that as long as the source material was different, I wouldn't have a problem (they were right, of course). However, what you're describing would put the same source information in two different speakers that are side by side.
What you described seems like it has all the needed components, so why not just pan hard left and hard right, completely separating the mixes?
Post by: Milt Hathaway on March 29, 2008, 11:53:28 AM
| Stephen Payne wrote on Sat, 29 March 2008 09:11 |
Any one ever try something like this? |
If you run a dual PA system, you DO NOT want any signal going into both systems. You will have severe comb-filtering problems.
However I have run the dual PA setup a few times, when the gig/venue/act was appropriate:
This was for Gary P. Nunn in a long narrow outdoor area. I didn't need wide coverage, but I did want extremely clear vocals. It sounded incredible. I distributed signal the same way Dave Rat does: Vox and Kit on one system, everything else on the other. Those are standard old EV Deltamax cabinets, 15" + 2". Subs were on an aux. If I remember correctly, crowd was a little over 1000 people.
It makes a noticeable improvement in vocal clarity. I was amazed.
Post by: Stephen Payne on March 29, 2008, 12:24:59 PM
As far as comb filtering, I often see two over one stacks with exactly the same signal going to both so how would this be any worse? I guess totally different would be best.
Post by: Stephen Payne on March 29, 2008, 12:27:30 PM
| Milt Hathaway wrote on Sat, 29 March 2008 11:53 | ||
If you run a dual PA system, you DO NOT want any signal going into both systems. You will have severe comb-filtering problems. However I have run the dual PA setup a few times, when the gig/venue/act was appropriate: This was for Gary P. Nunn in a long narrow outdoor area. I didn't need wide coverage, but I did want extremely clear vocals. It sounded incredible. I distributed signal the same way Dave Rat does: Vox and Kit on one system, everything else on the other. Those are standard old EV Deltamax cabinets, 15" + 2". Subs were on an aux. If I remember correctly, crowd was a little over 1000 people. It makes a noticeable improvement in vocal clarity. I was amazed. |
NICE!
Very similar to what I had in mind.
BTW, what stands are those? I need some tall ones.
Post by: Bob Leonard on March 29, 2008, 07:13:12 PM
| Scott Van Den Elzen wrote on Sat, 29 March 2008 11:20 | ||
I still use a separate channel for vocals on nearly all my gigs. And still love it. It's at least as helpful to clarity as aux fed subs has been. Regarding the "kinda, sorta" method you described above, it sounds like a comb filtering mess to me. The original concern I had about this method was overlap between the speakers at specific frequencies. I was assured by some of the experts here that as long as the source material was different, I wouldn't have a problem (they were right, of course). However, what you're describing would put the same source information in two different speakers that are side by side. What you described seems like it has all the needed components, so why not just pan hard left and hard right, completely separating the mixes? |
I've run seperate audio paths for vocals and backline for over 12 years. With the exception of the board everything is seperate. Vocals use the board main out and the backline uses BUS 1/2. Vocals get the SRX722s and the backline get's the SRX725s and subs. I wouldn't change it for the world, and I think the best feature when running like this is the ability to EQ the vocal path independently from the instrumentation.
Post by: Grant Conklin on March 29, 2008, 11:51:20 PM
| Bob Leonard wrote on Fri, 04 May 2007 19:30 |
... I have been placing everything BEHIND the band (wall of sound). I am totally blown away by the quality of the sound overall. There is no interaction between the systems and everything is distinctive and clear even when I hit the dance floor 40-50 feet away at 90-100Db. Does it get load on stage?? Sometimes, but never loader than the vocals. The biggest advantage is the near perfect mix the audience hears. |
Crap - someone beat me to it! I thought I had an original idea
BTW - just reading through this thread for the first time. 5 pages to go.I've been meaning to experiment with the idea of "band only" mains behind the band in effort to get stage volumes under control. Tried it for the first time in sound check tonight. So far, it's all I hoped it would be. The band can hear everything they need to hear without monitors. Vocal monitors have vocals only. The "front" mains are delayed to the "rear mains," (as are the subs) and are currently "vocals only," but I could put a little band in the front if the rear mains became overbearing.
I'm going to keep working on this experiment, and at some point I'll start a thread w/ my findings.
Thanks,
Grant
Post by: Art Welter on March 30, 2008, 12:15:39 AM
You said:
"band only" mains behind the band but I could put a little band in the front if the rear mains became overbearing."
OK, the band mains are overbearing, you now add them in the front (vocal) PA. What t.f. are you trying to do?
Post by: Rob Spence on March 30, 2008, 01:17:27 AM
Post by: Tim Padrick on March 30, 2008, 06:31:36 AM
| Art Welter wrote on Sat, 29 March 2008 23:15 |
Grant, You said: "band only" mains behind the band but I could put a little band in the front if the rear mains became overbearing." OK, the band mains are overbearing, you now add them in the front (vocal) PA. What t.f. are you trying to do? |
I think he meant band PA is too loud on stage, so back it down a bit, then put some band in the vocal PA to make up the difference out front.
Unless you can get the band PA quite wide (well outside the players), I'd think it would always be too loud on stage. When it's 95dBA at FOH, it's way too loud for me on the dance floor. If the PA was behind the band, I certainly would not want to be on stage.
Post by: Grant Conklin on March 30, 2008, 08:58:51 AM
| Tim Padrick wrote on Sun, 30 March 2008 05:31 | ||
I think he meant band PA is too loud on stage, so back it down a bit, then put some band in the vocal PA to make up the difference out front. |
You got it right Tim. I'm not really doing it for the reasons that Dave Rat separates band / vocals, although the benefits of that are welcome. Most bands even in "tame" settings don't realize how loud their monitors are, so the concept is to replace them w/ mains that actually face the audience. It's just an experiment. I have 6 rs220 cabs, and this event only requires 2 out front, so I left 2 at home, and brought 2 extra for the band.
Grant
Post by: Bob Leonard on March 30, 2008, 10:48:56 AM
| Tim Padrick wrote on Sun, 30 March 2008 06:31 | ||
I think he meant band PA is too loud on stage, so back it down a bit, then put some band in the vocal PA to make up the difference out front. Unless you can get the band PA quite wide (well outside the players), I'd think it would always be too loud on stage. When it's 95dBA at FOH, it's way too loud for me on the dance floor. If the PA was behind the band, I certainly would not want to be on stage. |
Tim,
Spot on. The only problem we ever have is the loudness if we can't get the speakers spread far enough apart or if the stage is very shallow. Usually though a smaller stage means a smaller room so in most cases it evens out. Working wider stages is best as you seem to always end up inside the speakers projected sound path. Almost like being inside a cone of silence.
There is one venue that I was asked to work as a benefit last year that scared us and I posted looking for some tips, though unfortunately we had to pass it off to another band. We worked it this year and everything worked out fine. In this case the venue wanted nothing out front, even monitors. We fought for the monitors and won, but everything else was behind us. In this case the seperate vocal path saved our ass and the SPL was just over 90db at 50' in a 100x100 foot room. It was after we got into the gig it became apparent as to why they wanted the stage clean. It was like a parade of sports stars and local TV celebrities walking across the stage. We had a great time, received lot's of compliments about the sound and performance, and picked up 6 more gigs including the same gig next year and a request to consider becoming the house band. This gig also taught me something else about the SRX725 and 722s. The projected pattern is much more focused than I had thought.
Post by: Eric Reese on March 31, 2008, 10:26:13 AM
| Grant Conklin wrote on Sun, 30 March 2008 07:58 | ||||
You got it right Tim. I'm not really doing it for the reasons that Dave Rat separates band / vocals, although the benefits of that are welcome. Most bands even in "tame" settings don't realize how loud their monitors are, so the concept is to replace them w/ mains that actually face the audience. It's just an experiment. I have 6 rs220 cabs, and this event only requires 2 out front, so I left 2 at home, and brought 2 extra for the band. Grant |
Just Curious, what about the the band mix bleed into the vocal mics? Or did I miss something?
Post by: Grant Conklin on March 31, 2008, 10:53:25 AM
I used my idea for real yesterday at a church service. It worked very well - bleed seems to always be a problem with loud bands, no matter what the setup. In this situation, the vocalists had to be close to the drums, and the platform was very crowded. The singers had to stand diagonally to the speakers behind them, so that probably helped some. I got compliments from both band and people in the audience - much more than usual. There's only one band member in question, and the only only "feedback" she gave me was a blank stare when I commented on my experiment. I need to find out what her experience was.
I'd say the jury is still out for me, but it's an experiment I'll try again in other settings.
Thanks,
Grant
Post by: Scott MacAuley on March 31, 2008, 07:30:34 PM
I'm still using this setup every weekend. It's a very satisfying feeling to see the look on the competition's faces. Especially after they've spent 20 grand or more on their system and insist mine must be a piece of crap. Whell it is, but finely tuned!.
I have found that when placing the stacks side by side it is better to have the vocals only in their own stack. When stacking the vocal cabs on top (preferred)I can put vocals in both without any issues.
Some of the patrons at one club I work apparently ask if I am there running sound before they pay to get in. Interesting.
On the back wall PA.
For my own band, we use a lot of electronics. I use analog modeling guitar rigs, electric drums, and a modeling bass rig.
We're using side located floor monitors but I've been toying with the idea of a multi feed backline PA and timing the mains to that. The problem is stage depth in small clubs. How would you time A diagonally placed speaker stack to the mains?
Roughly the center of the stack to the front of the mains perhaps?
Post by: Grant Conklin on March 31, 2008, 10:03:56 PM
| Scott MacAuley wrote on Mon, 31 March 2008 18:30 |
...the idea of a multi feed backline PA and timing the mains to that. The problem is stage depth in small clubs. How would you time A diagonally placed speaker stack to the mains? Roughly the center of the stack to the front of the mains perhaps? |
As with any delay, it's an average for the audience. Another labster (chime in if you wish) recently told me of a simple way to align subs, and it should work for delays as well:
Feed a signal tone to both sets of speakers. (in the case of a subwoofer, use the crossover frequency) Flip the phase on the speaker you wish to delay, and then adjust the delay until the sound is weakest. Flip the phase back, and you should be good to go, at least time-wise. You might experiment with different frequencies, or perhaps some noise.
Thanks,
Grant
Post by: Scott MacAuley on April 01, 2008, 08:17:00 AM
Here's a trick I use ALOT!. This is for those walk in gigs where you are using a house system or if you don't have other boxes.
Since you are probably stuck with a standard 3 way PA you don't have aux fed subs or exciters. You certainly don't want to rewire
the house pa, but plenty of guys try! BAD IDEA.
Whip up a little rack with a 2 way or 3way analog crossover and whatever other toys you might need. Usually compressors or your favorite FX. Make sure you have both patch insert cables and regular lines for it.
Patch the crossover into the submaster insert, or the submaster out and re enter it into either a return or spare input. Cut the lows around 100 or so for normal mortals. That is now your vocal master channel. You can cut the highs as well (with a 3 way) to solve some 8k and up issues. This way you do not have to kill the lows with limited eq and you can even toss a compressor for safety and smoothness after the crossover. Send all the vocals to that submaster, not the mains and then send the processed vocals to the mains. In really bad limited cases you can at least insert the crossover/comp into the lead vocal channel. That's where a stereo crossover is handy as you could handle two vocals if you have to. Works like a champ. Allows those crazy singers that like to cruise the audience (like me), freedom, and you sanity. If you are really really limited the behringer 4 ch active DI has balanced inputs and could probably be used as a
mic pre that would not be noiser than most cheap boards today.
You could then send up to 4 vocal mics to your handirack from the snake and then into a house mixer that doesn't have submasters or inserts. A 4 ch mic pre would be better.
You might get too much walk in work though.
I hope this helps somebody else's headaches too.
Cheers