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Title: Single-18" Subwoofers
Post by: [x] on August 30, 2004, 09:41:52 AM
Hi. I am a member of a Christian organization here at Purdue University. Currently, the sound guy is looking for some new subwoofers and mains. I have recommended that since he is going to use subwoofers, he should switch to mains that have 12" woofers for greater midrange clarity. I wanted to go and build him a new system (since I have a good deal of experience designing and building speakers for hi-fi as well as a fair knowledge of what is different about designing a pro sound speaker system) but he was not very receptive to the idea. But I have been given the task of searching out potential candidates on the internet and comparing them side-by-side to see which one will provide the best value. So far, here are the models I have lined up:

JBL JRX118S
JBL MP418S
JBL SR4718X
Yorkville LS608
Yamaha SW118V

BHFProfessional SXP118
>>This is a subwoofer of my own design, which uses a Selenium WPU1807QCF woofer. I'm including it in the comparison just to show how what I could do compares to what they'll spend on a commercial product.

Are there any other really good single-18" subwoofers I have missed? Please let me know so I can have the most complete comparison possible.
Title: Re: Single-18" Subwoofers
Post by: Mac Kerr on August 30, 2004, 11:52:30 AM
What is the music the sub will be used with? What is the rest of the system it will have to integrate with? What kind of venue will it be expected to fill? Will it have to be moved around? Are there size or weight constraints? What is the magic of a single 18"?

If you want a complete informed answer, ask a complete, informed question.

Are any of those you chose great subs? No. Will they suffice in some instances? Yes.

If you think bass only comes out of 18" drivers check out the LAB Subwoofer forum. Also check out the EAW SBX220. The LAB Sub is a dual 12" horn loaded sub that goes WAY lower than any of these and gets louder and is less distorted by design. The SBX220 is a dual 12" front loaded compact sub that goes lower and gets louder than any of your choices.

Mac Kerr
Title: Re: Single-18" Subwoofers
Post by: [x] on August 30, 2004, 12:21:19 PM
The room is a large lecture hall seating over 400 people. The music is basically contemporary Christian music played by our worship band, plus some stuff from CD, DVD, and VHS sources. The bass guitar and the kick drum will also be fed through the system. With all these considerations in mind, I wanted to build for them a pair of double-18" subwoofers using that Selenium driver I said earlier. I know that for this application, we really need dual 18s to get great sound, or a good bass horn like the LAB. Our sound guy doesn't really place all that much stock in what I have to say, though, especially when what I say is necessary costs more or is more complicated to do than what he thinks is necessary. He's not a professional sound guy, though. He also said that home-built products are not suitable for this application because they are not backed by any warranty, and they are difficult to insure, though my friend's father, who is in charge of sound equipment for Keynote Communications, the music ministry arm of our Christian organization (Campus Crusade for Christ) has many enclosures that were built by them. The Selenium woofers I wanted to use were backed by a 5-year limited warranty, and I gave him all these reasons whyt what I would build him would be superior for the price but he wouldn't budge. He wants single 18" woofers on each side, and he wants a reputable name. That's why I am researching single-18" subs for him.

Transportation is a big concern. Right now, we have a pickup bed to work with. I think they need a covered trailer, but we have a very limited budget. Our current subwoofers are Peavey dual-15" in bandpass enclosures. They are very boomy and indistinct, which led our sound guy to the conclusion that the room was being "overpowered" by them, which is why he wants to step backwards to single 18s when we buy new subs. I think that idea is dumb, dumb, dumb, but as I said before, our sound guy doesn't really place that much stock in what I have to say. The reason why the room seems to sound so bad is because the mains we were using are Crate brand, with cheap 15" woofers and made from 1/2" particleboard material with no inner bracing, thus boomy, indistinct midbass, further exacerbated by the subwoofers' poor transient decay and majorly not-flat frequency response. I have advised him that our new mains need to use 12s instead of 15s for better midrange clarity, and that they need to have better build quality. He said that made sense.

If I could get some expert opinions saying that we need dual 18" bins instead of single-18s, and that a home-built project really is not as bad as he says it is, then perhaps I could get our sound guy to change his mind.

Addendum - yes, I do realize that bass does not only come out of 18" woofers. It's all in the driver's design and the enclosure's loading, and the SBX220 is just an example of that. However, I fear that anything from EAW is just going to be out and out too expensive even for consideration.
Title: Re: Single-18" Subwoofers
Post by: Kevin Maxwell AKA TheMAXX on August 30, 2004, 01:13:13 PM
I have had to work with equipment that wasn’t the best and I make it sound the best that I can. Are you or this other guy capable of that? Are you trying to take it to the next level? Have you gotten the most out of the equipment you now have? It sounds like you don’t have the money to do it properly. So you are going to spend some money one way (yours) or the other (his) and maybe still not be what everyone is looking for.

From what you have said regarding construction it sounds like you might make some nice sturdy home made cabinets. If you are capable of doing that, how about making a LAB sub for them? And if you are really confident of your capabilities offer them a money back guarantee. If they don’t like it they don’t pay you.  

What are you using for a crossover / DSP now and how is everything feed. What amps (how much power) are being used and how? Are you using what is called Aux fed subs? Do you know what that is?

If the guy in charge is open to it can you find someone to come over and show you how to get the most out of what you have now? And then you can figure out where to go from there.

Does the guy in charge think that he knows everything? If he does (know it all) just tell him if he needs any help to call and then just walk away.
Title: Re: Single-18" Subwoofers
Post by: Dave Rickard on August 30, 2004, 01:28:27 PM
Hi Rory,

I replied to your question on the PE board.  If you have decided on Selenium, then also consider the 18SW1P.  Again, model the Peavey 18 Low Rider, you'll find it very similar to the SW1P.

daver
Title: Re: Single-18" Subwoofers
Post by: [x] on August 30, 2004, 02:36:47 PM
The reason I'm so stuck on this particular Selenium driver is that it's inexpensive, but seems very durable, with the power handling and the bass extension that's most appropriate for our application. The other Selenium sub is significantly more expensive. I haven't researched the price of the Peavey Low Rider 18 but our sound guy doesn't think Peavey has a very good reputation. This sub doesn't need to go ocean-deep, just deep enough to provide the power from the kick drum and the bass. It needs to be efficient and loud, fill the room appropriately, and last a long time.

Right now, we have a DBX DriveRack PA that is taking care of the room EQ and crossover functions. We used a real-time analyzer to make sure that the EQ was set properly for the room. The sub amp is a big 400w/channel Peavey which looks like it's almost as old as I am. It weighs a ton. As far as I know, our subs are not fed from an Aux Send. That is something to try, just to clean stuff up a bit. Wouldn't that make it a bit more complicated to cross over? We use a dbx DriveRack and that handles all the crossover stuff as well as the room EQ. So we basically get to choose between having room correction, adjustable crossovers, and real-time analysis, and keeping the vocals out of the subs.

I don't want to build a LAB sub because those are extremely complicated and we'll never use those in big enough numbers to realize their full potential, like the recommended 4/side. In addition, I don't know how their size compares to the dual-18" bin that I've designed.
Title: Re: Single-18" Subwoofers
Post by: Dave Rickard on August 30, 2004, 03:45:49 PM
http://srforums.prosoundweb.com/index.php/m/7113/503/?SQ=69b 12b2b9843cbffb587a13fcd37d6ea

may help with some answers.  

What impressed me about the Low Rider was the nearly identical specs to the big Selenium at a very affordable, locally available, price.  My local Peavey guy quoted me $175.  Run that past your sound guy.

Also, 400 watts seems pretty small for a sub amp.

Good luck,
daver
Title: Re: Single-18" Subwoofers
Post by: Kevin Maxwell AKA TheMAXX on August 30, 2004, 04:42:53 PM
I have used some of the other DBX DriveRack units but not the PA version. So I don’t know if you can easily do “Aux fed subs” with a DRPA. With some of the other units I use 1 input for the subs and the other for the rest of the house speakers (mono system) including font fills and delay. I wish the DR260 would let you route the RTA mic input as a 3erd in for subs. I usually feed the subs from a matrix or from the right out (and use the left for house) and leave the auxes open for other things.

When you say “We used a real-time analyzer to make sure that the EQ was set properly for the room.” That kind of puts up a big red flag in my mind. Was it just an RTA or something more sophisticated? How was it used?

400 watts seems kind of small to me for a sub amp if you really want a lot of kick.

Do you have one of these subs that you have designed to try it out with the rest of this system? I personally would shy away from something home made unless it was proven to me that it was better. Now I used to work with proprietary speaker cabinets made by a sound company that I used to do some freelance work for and they were a very nice design. And in the right hands they sounded great. But there is a bit of a difference between home made and proprietary boxes. These same people tried to make a trap box but they gave up because they could never get it to sound the way they wanted it to.

What is wrong with the present subs? Is it the design, the construction, the components the implementation or and or all of these things? Can you fix them cheaper then buying new? We all like new things but it isn’t always necessary.  
BTW I also have worked with some nice subs that weren’t 18s. I have never heard the LAB sub (I would love to) but I think the multiples would probably knock down the size room you are talking about. I know that is an exaggeration but my point is I don’t think you want that much kick for your application. Maybe someone who has some experience with them could tell you how many you would need for your applications.
Title: Re: Single-18" Subwoofers
Post by: [x] on August 30, 2004, 07:24:42 PM
I have a lot of experience designing homemade cabinets for my hi-fi projects. I have all the tools, and experience with both MDF and Plywood, and I understand the latter is better for pro audio because it is lighter and easier to carry. I have computerized design simulation tools for both enclosures AND crossovers.

I'm going to advise our sound guy that unless he is prepared to spend $1,000-2,000 on the subs, that he'd better just forget it and stick with what we have and just get some better main speakers.
Title: Re: Single-18" Subwoofers
Post by: Brian Adams on August 30, 2004, 11:59:19 PM
I don't own a Driverack, but one of the main differences between the DRPA and the 260 is that the DRPA is stereo, but not individually controllable.  If you change the EQ on one channel, it changes the other.  The 260 has independent channels.  Apparently.  So, the 260 is the only one that would work for aux fed subs.

BTW, I use Yorkville LS800P's, and I love them.  I don't know how they would work in your specific situation, but they're perfect for medium sized clubs (150-300).
Title: Re: Single-18" Subwoofers
Post by: Grayson Rech on August 31, 2004, 08:44:15 AM
If someone ask me to research subs and didn't like what I had to say or found out then I would wash my hands of matter if I wasn't the one in first step with whoever is placing the money down.  If this guy knows so much then he should have no trouble tackling this issue.  If he just happens to be in a higher position than you and isn't qualified enough to perform his job then in this instance I would speak with whoever is next up the ladder to address concerns.  The key reason is because it sounds like he's already figured out a plan regardless of your findings and with what would work best and when things go sour after money has been spent watch your back for I wouldn't want to be the one he points to as a fall guy . . . perks of the job of being a manager.  Best of luck to you, you have quite a "sound superior" to deal with.  As for subs and what not, perhaps a demo from another rig (rent, borrow, convince a local store for a test before you buy) will shed some light on what is "needed" and what is the "myth".  

. . . and I say unto thee shazbot!
Hoob
Title: Re: Single-18" Subwoofers
Post by: Bill Horn on August 31, 2004, 10:27:51 AM
 OK I'm reading between the lines a bit here...

It sounds like the church is replacing all FOH boxes? The decision to get rid of the Crate tops ( I hope) has been made? If so, I would hold off on a sub decision for now. Get used to the sound of your new tops...whatever they are they're going to sound better than what you have, and since sonic information that defines kick and bass as such comes from frequencies above 100 Hz your new tops may actually clean up the apparent mud from your subs somewhat.

Now...area you offering to donate your time in constructing the subs, or are you in business...essentially in competition with commercially built products? If the latter is true, you need to drop the matter of homemade cabs and abide by the decision of the church. If it's the former, build a couple and donate them, or keep ownership and let the praise band use them for free and consider it as part of your tithe.

I've built all the cabs my club band uses myself...four 18's, four tops, all the monitors...but I didn't charge the band for them (they're mine of course). I get asked to build cabs for people all the time, but politely decline because once I figure in my time the cost will be pretty close to a commercial product, and their resale value would be almost nothing. But I've let my church borrow whatever I can help them with when they need it.
Title: Re: Single-18" Subwoofers
Post by: Chip Prendergast on August 31, 2004, 10:33:21 AM
I am currently constructing dual 18" using the Peavey Low Rider.  I never even gave Peavey any thoughts but after seeing how many people on this board rave about the QW18 I checked into the drivers and found them for $179 ea at www.8thstreet.com.  That's pretty cheap.  When I ran the design through software I come up with no overexcursion at 1700 watts and 133 dB at 45 Hz.  Should have this finished in a week or so.

People on here are quick to say build a LAB sub and I looked into it.  For me cutting all the pieces with the many different angles and such is way beyond my woodworking experience or tools.

Speaking of Selenium (I checked them out and the Peaveys blow them away in software design)but they had some interesting horn loaded 12" mid/hi box plans (but same problem cutting all the pieces).

Title: Re: Single-18" Subwoofers
Post by: [x] on August 31, 2004, 10:59:11 AM
Money's always tight, and we've decided that we need to go ahead and replace our FOH boxes because we think that will do us more good than the sub upgrade at this time.

What do people here think about the JBL MPRO MP412 cabs? Or would we be wasting our time with those as compared to JBL SR4722X tops? Again, the primary consideration here is how much bang for the buck we can get.
Title: Re: Single-18" Subwoofers
Post by: bo putnam on August 31, 2004, 12:15:10 PM
BHFProfessional wrote on Mon, 30 August 2004 09:21

Transportation is a big concern. Right now, we have a pickup bed to work with. I think they need a covered trailer, but we have a very limited budget. Our current subwoofers are Peavey dual-15" in bandpass enclosures. They are very boomy and indistinct, which led our sound guy to the conclusion that the room was being "overpowered" by them, which is why he wants to step backwards to single 18s when we buy new subs. I think that idea is dumb, dumb, dumb, but as I said before, our sound guy doesn't really place that much stock in what I have to say. The reason why the room seems to sound so bad is because the mains we were using are Crate brand, with cheap 15" woofers and made from 1/2" particleboard material with no inner bracing, thus boomy, indistinct midbass, further exacerbated by the subwoofers' poor transient decay and majorly not-flat frequency response.


You might look into the EV Eliminator subs.  They are a single transverse mounted 18-in that many have real good luck with.  Paired with either EV's Eliminator Mains (15-in 2-way) or even better the EV QRx 115/75 main (better 15-in 2-way) are superb combos on a budget and space-restricted.  I would strongly suggest you go to the Ashly XR-1001 stereo 2-way crossover - it's flexibility really brings out the optimum crossover point and character to the response curve.  Check them out: http://www.ashly.com/product/xr-series.htm  Your audience will be very, very appreciative.  I concur with the potential boomy-ness of dual-subs - they can easily overpower / outweigh small rigs.  

BHFProfessional wrote on Mon, 30 August 2004 09:21

I have advised him that our new mains need to use 12s instead of 15s for better midrange clarity, and that they need to have better build quality. He said that made sense.


I do not agree with that - just MO.  You can get excellent voicing with the right transducer / cabinet combo.  Staying with EV here, their Ring Mode Decoupling (RMD) cabinet design minimizes standing waves (feedback) and has great voicing / clarity.  I think overall your frustration is a combination of transducer and  poor cabinet design.  
Title: Re: Single-18" Subwoofers
Post by: yam4000vca Jim Gould on August 31, 2004, 02:35:05 PM
I am trying to sort this thread out in my head as it has covered a lot of ground.
First good call as to replacing the Crate mains boxes with something else. Subs are nice but the main boxes here are more important.
You say the word bang for the buck. That is good but then you mention JBL. I think JBL is a good product but for you I think there are several other brands that would give you more bang for the buck. Peavey,Yorkville Community come into my mind as being better than JBL in the leauge you are in. At least the lower lines of JBL. It is not fair to compare the lower lines to the SRX which in my mind is where JBL starts but still a bit pricey for many.
You also state that you have built many hifi projects. That has given you SOME background but the things that matter in a box for live or pretty different in several ways. You also mention the word extension. I am not sure what exact frequency you are tryng to obtain live but it is probably lower than what really matters in this case.
In general I prefer a 12 above an 18 in a 3way system. That is my preference and not meant to mean that 15s can not work too.
I think one of the main things that you can do to sort all this out is to forget about the real time part of the DriveRack and bring in someone that really knows to optimize the whole system for you.
There are many ways to do this but I do think with the proper set up you may be suprised what your current subs can do.
Title: Re: Single-18" Subwoofers
Post by: [x] on August 31, 2004, 08:44:29 PM
Well, as far as tops go, which do you think would mate the best with our dual-15" Peavey subs? I am looking for something that will do great in the midrange and not suck away all our budget for music stuff. I think that a two-way 12" cabinet would be the best balance with the dual-15's down below handling bass duty. I'm looking for something that can go loud without being fatiguing, since a large part of what the PA is amplifying is voice. The room is a large lecture hall with a balcony that sometimes gets filled, and about 400 seats.

Suppose I'm considering the MPro MP412 cabinet. What other models from other manufacturers would you suggest that I look at as a better alternative, while staying under $650 per box? (The MPros are $579 from Sweetwater.) Again, there will be acoustic and electrified instruments, drums, vocals, and voice being carried by these, and a Peavey Dual-15" subwoofer enclosure will be handling bass below 250 Hz, so that's how they fit into the system.
Title: Re: Single-18" Subwoofers
Post by: bo putnam on August 31, 2004, 10:12:37 PM
BHFProfessional wrote on Tue, 31 August 2004 17:44

I think that a two-way 12" cabinet would be the best balance with the dual-15's down below handling bass duty.

I don't find size-comparisons (i.e., 12's vs 15's mains), per se, particularly compelling.  What matters is frequency response, efficiency and remaining "linear", or flat as possible.  I see no issue with paring 15-in 2-ways with dual 15-subs.  What matters more is how / where you are crossing over to the "mains", what control you have over the bi-amped configuration, and the linearity of the "mains".  

What is your crossover?  What is your crossover point?  What are the slopes?  

If you use the subs to merely do sub work, i.e., below say 70-90Hz, you will want more support from the mains.  I have used dual 18-in subs crossed at ~150Hz, paired with 15-in 2-ways and have VERY good results.  It's all in the control provided by the crossover.  

Most of your applications don't seem to need dual subs, IMO, but go your own way.  I think a single 18 might be sufficient, based upon the locations I've used same-same.  But I don't use the cabinet brands you are using - their response and your experience will be quite different.  
Title: Re: Single-18" Subwoofers
Post by: bo putnam on August 31, 2004, 10:16:58 PM
BHFProfessional wrote on Tue, 31 August 2004 17:44

a Peavey Dual-15" subwoofer enclosure will be handling bass below 250 Hz, so that's how they fit into the system.

Oh, wait a minute.  I re-read your post.  I think that high a crossover might be problematic.  It might contribute to "boomyness".  I would be interested in the impressions you get from a lower xover point, -24dB/octave slopes, and handing more off to the mains.  250Hz is well within the Second Decade, right in the vocal range, and any notch/peak at the crossover point will suck.
Title: Re: Single-18" Subwoofers
Post by: [x] on August 31, 2004, 10:36:13 PM
I have spun off a new topic, "Choosing Main Speakers", because the topic of this discussion os no longer about subwoofers, but main speakers.
Title: Second Decade
Post by: bo putnam on August 31, 2004, 11:06:45 PM
Title: Second Decade
Post by: bo putnam on August 31, 2004, 11:12:50 PM
Before closing, albeit even temporarily, I thought I'd harp on the Second Decade.

The so-called "Second Decade" is the range that commonly troubles live sound applications - it is the range where fundamental frequencies and related harmonics conspire to ruin attempts at feedback-free, clear live sound. This is a notoriously difficult range to "tame". It is right in the center of the vocal range, and is where acoustic guitars and other sources can very effectively be fattened or thinned. In short, it is critical.  If at all possible, I would avoid a bi-amp crossover in that range, JMO.

index.php/fa/426/0/
Title: Re: Single-18" Subwoofers
Post by: Tim Padrick on August 31, 2004, 11:51:58 PM
Tops: JBL MP412.  Above that, the Yorkville U15.  Both very good sounding boxes.

Sub: Peavey QW218.  A single 2x18 box will be a lot better value than a pair of 1x18 boxes, because it costs almost as much to build the little box as it does the big one.  A centrally located 2x18 will do a lot better (in most situations) than left & right 1x18s (http://www.padrick.net/LiveSound/SubwooferInfo.htm)

Make sure you have plenty of power (rule of thumb is that the amp should be rated 2x the continuous rating of the speaker).