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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Subwoofer Forum => Topic started by: Mark J Snyder on December 19, 2012, 04:45:13 AM
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Ok so after going over everything and talking about ideas with ppl I will be working with I've come up with a criteria that should make my decision about a system fairly limited it looks.
1 - Must be dual 18 reflex cabinets
2 - Runs off of one 20A preferably and if not then two 20A. No 30A.
3 - Still in production.
4 - $14,000 budget for speakers and amps.
Some top picks I've seen so far:
DB Tech S20
RCF TTS36a - If they can be found at that price point.
EAW SB1000z - Still sticking this one in here cause it's low power requirement. I could keep and use a Powersoft Digam5000 to power them well.
JBL STX828s
Bold 218 - Is the wild card - It's wild card status is due to it not being a widely recognised name and a new company
Thought's on these and any others I could look at would be greatly appreciated. The system will get alot of bass heavy EDM as well as live rock and jam bands. Probably more so the DJ stuff, tho I'm trying to break out of that more.
Thanks -Mark
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1 - Must be dual 18 reflex cabinets
Just curious: why?
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Ok so after going over everything and talking about ideas with ppl I will be working with I've come up with a criteria that should make my decision about a system fairly limited it looks.
1 - Must be dual 18 reflex cabinets
2 - Runs off of one 20A preferably and if not then two 20A. No 30A.
3 - Still in production.
4 - $14,000 budget for speakers and amps.
Some top picks I've seen so far:
DB Tech S20
RCF TTS36a - If they can be found at that price point.
EAW SB1000z - Still sticking this one in here cause it's low power requirement. I could keep and use a Powersoft Digam5000 to power them well.
JBL STX828s
Bold 218 - Is the wild card - It's wild card status is due to it not being a widely recognised name and a new company
Thought's on these and any others I could look at would be greatly appreciated. The system will get alot of bass heavy EDM as well as live rock and jam bands. Probably more so the DJ stuff, tho I'm trying to break out of that more.
Thanks -Mark
You are looking at this the wrong way. It sounds like you are saying-I need a car that has 300 HP. Without looking at your real needs. How much carrying capacity do you need? Are you carrying around 6 kids? Are you racing on the weekends and so forth. A single spec (300HP or 2x18")) doesn't give any useful information.
What you SHOULD be asking is "What subs do you recommend that I can get amps and speakers for that will produce a certain SPL at a certain freq." And does sound quality count? Just because it is loud-does it produce the "sound" that you are looking for?
You have a budget (at least it is a decent size for the amount of current you plan on using)-but do not state how loud or how low it needs to go.
You say EDM, therefore I would recommend something that gets to 30 or 35Hz at a minimum- SOLID. NOT just a simple number on a spec sheet. Look at the ACTUAL response curves and you will find that many cabinets that state -3dB @35Hz are actually a lot lower than that (often as much as -10dB at that freq).
Why does it have to be a 2x18" sub? What if something else could give you better performance with a different size driver? Is there something "magical" about a 2x18" that you must have?
You also mention being able to run off of a particular power circuit. How many you can run GREATLY depends on the type of music-amount of compression used and so forth.
You can run more cabinets off of a single outlet doing rock than you can EDM.
It is also not so much "how many can you run" but what SPL can you achieve off of a single circuit.
In order to get something that will "fill your needs", you need to look a bit harder at your "real" needs and don't limit yourself to just the driver size and quantity.
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1 - Must be dual 18 reflex cabinets
we recently rented 4 Martin WS218x for a high profile show. The specs are impressive at 105 sensitivity. they are using the same B&C 18 driver as our Xyons. Worth checking into if you are set on reflex cabs... and they rattled my teeth as well... smaart was showing a solid 35Hz and the powersofts had best impulse.
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As usual, Ivan, you pretty much nailed everything.
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we recently rented 4 Martin WS218x for a high profile show. The specs are impressive at 105 sensitivity. they are using the same B&C 18 driver as our Xyons. Worth checking into if you are set on reflex cabs... and they rattled my teeth as well... smaart was showing a solid 35Hz and the powersofts had best impulse.
105db out of any double 18 is a pure fiction.
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105db out of any double 18 is a pure fiction.
Depends on what freq you are talking about.
I know one famous manufacturer who claims 108dB from a front loaded 2x18". Of course that is around 1800Hz, so exactly not the "sub or bass" range, but it IS truthful.
The cabinet WILL produce that SPL-just not in a range that you want to use it. In the bass it is quite a bit lower.
And my car gets 90 mile per gallon easily. As long as I am going down a long hill and don't use the accelerator.
It all depends on where the data comes from-how it is used by the marketing dept and so forth.
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You are looking at this the wrong way. It sounds like you are saying-I need a car that has 300 HP. Without looking at your real needs. How much carrying capacity do you need? Are you carrying around 6 kids? Are you racing on the weekends and so forth. A single spec (300HP or 2x18")) doesn't give any useful information.
What you SHOULD be asking is "What subs do you recommend that I can get amps and speakers for that will produce a certain SPL at a certain freq." And does sound quality count? Just because it is loud-does it produce the "sound" that you are looking for?
You have a budget (at least it is a decent size for the amount of current you plan on using)-but do not state how loud or how low it needs to go.
You say EDM, therefore I would recommend something that gets to 30 or 35Hz at a minimum- SOLID. NOT just a simple number on a spec sheet. Look at the ACTUAL response curves and you will find that many cabinets that state -3dB @35Hz are actually a lot lower than that (often as much as -10dB at that freq).
Why does it have to be a 2x18" sub? What if something else could give you better performance with a different size driver? Is there something "magical" about a 2x18" that you must have?
You also mention being able to run off of a particular power circuit. How many you can run GREATLY depends on the type of music-amount of compression used and so forth.
You can run more cabinets off of a single outlet doing rock than you can EDM.
It is also not so much "how many can you run" but what SPL can you achieve off of a single circuit.
In order to get something that will "fill your needs", you need to look a bit harder at your "real" needs and don't limit yourself to just the driver size and quantity.
I can't say what SPL at a certain freq because I just don't know how I'd come up with a figure like that. Maybe you can help me figure that out first? I gave the Xyon as a target for SPL and Yes sound quality is important, more so than SPL I'd say but both are important of course.
How low? Again I don't have any particular number in mind 30-35Hz I certainly agree on that. I had 4 LA400's and tho not super loud I was constantly told by ppl it was the lowest sounding system they had heard. If I could get the same performance but with more SPL I'd be in a good spot. I used EAW's reccomended processor settings and their UX8800. HPF is 30Hz 12db BW.
I don't know what else to tell you guys other than give examples of what's being used by others in my area.
Why a dual 18 reflex? Well I would like to be able to combine with other cabinets myself and friends have to take on bigger rooms. I have 4 SB850's (old shallow ones) for example. Yes this isn't nessissarily going to sound so good but it's what it takes to get the job done sometimes and for what those gigs are nobody is going to complain about sound quality anyways.
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I can't say what SPL at a certain freq because I just don't know how I'd come up with a figure like that. Maybe you can help me figure that out first? I gave the Xyon as a target for SPL and Yes sound quality is important, more so than SPL I'd say but both are important of course.
How low? Again I don't have any particular number in mind 30-35Hz I certainly agree on that. I had 4 LA400's and tho not super loud I was constantly told by ppl it was the lowest sounding system they had heard. If I could get the same performance but with more SPL I'd be in a good spot. I used EAW's reccomended processor settings and their UX8800. HPF is 30Hz 12db BW.
I don't know what else to tell you guys other than give examples of what's being used by others in my area.
Why a dual 18 reflex? Well I would like to be able to combine with other cabinets myself and friends have to take on bigger rooms. I have 4 SB850's (old shallow ones) for example. Yes this isn't nessissarily going to sound so good but it's what it takes to get the job done sometimes and for what those gigs are nobody is going to complain about sound quality anyways.
Of the products you listed-only the SB850 has any actual freq response graphs. And to get an idea of what the real freq response is-you need to look at the unprocessed response-NOT the processed response.
Any sub can appear to go lower if you boost the low end. But you have to subtract that level from the max output.
You might try contacting the manufacturers to see if you can get a copy of the unprocessed freq response of the cabinets you are interested in.
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Of the products you listed-only the SB850 has any actual freq response graphs. And to get an idea of what the real freq response is-you need to look at the unprocessed response-NOT the processed response.
Any sub can appear to go lower if you boost the low end. But you have to subtract that level from the max output.
You might try contacting the manufacturers to see if you can get a copy of the unprocessed freq response of the cabinets you are interested in.
Man I'm not saying your trying to do me wrong or anything but your answers I feel are just making this over complicated or getting me nowhere. You said look at graphs and not just numbers and now say the graphs are wrong to look at unless I request the unprocessed ones. You say to come up with a target spl at a certain freq and that I may not nessisarily need overly powerful amps to achieve this. I get that, but being this a touring system I may not OWN 135db at 35Hz or whatever outside when I do indoors at a medium sized venue. Do I need amps capable of driving to the limits? No but it's better to have and turn down then not have when it may be needed. I tend to ignore numbers almost completely and go with opinions from ppl who have used the gear and how it compares because the numbers are just that only numbers that often reflect nothing in the real world.
Above and beyond all this my buddy who's helping me with this system is a Fullsail graduate and has been the Engineer on many large rigs one of his favorites being 32 KF850's per side. Now he's not so into going over gear like this that's why I came here but he keeps saying it doesn't matter so much what the system is capable of producing but rather how he will make it sound perceptively louder no matter what I buy.
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Above and beyond all this my buddy who's helping me with this system is a Fullsail graduate and has been the Engineer on many large rigs one of his favorites being 32 KF850's per side.
You just lost the last shred of whatever credibility you might have had.
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Just curious: why?
You want to double the power that PS Digam 5000 puts out per channel.
2X RMS is what you want. The EAW bin is rated at 700watts RMS per loudspeaker (2 per box).
The amp you listed puts out 750watts RMS per channel with an 8 ohm load.
Go for an amp that puts up closer to 1400wpc @8ohms. (with the EAW boxes)
Considering the price of the cabs and the Power soft amps your budget is limited.
However, you never stated how many boxes you wanted and how many amps you wanted.
Just pointing out that no matter what box you choose shoot for 2x the RMS rating for power.
Just to CMA here im gonna say make SURE you run a limiter as well. :)
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Above and beyond all this my buddy who's helping me with this system is a Fullsail graduate and has been the Engineer on many large rigs one of his favorites being 32 KF850's per side. Now he's not so into going over gear like this that's why I came here but he keeps saying it doesn't matter so much what the system is capable of producing but rather how he will make it sound perceptively louder no matter what I buy.
That explains a lot.
It's true that sometimes Ivan's explanations are a little over the top, but it's a rare day when his advice isn't on the money. There is an educational program for serious soundmen, and it's not at Fullsail. It's at Syn-Aud-Con (http://www.synaudcon.com/site/). Ivan has been through their courses. Several others here have as well. There are also training programs from almost all of the major manufacturers, all of these are available to anyone who wants to learn. Syn-Aud-Con costs real money, most of the rest are free. If you don't understand the implications of what Ivan has been saying, you might ask for an explanation, or do some research on your own to learn about it. Whining about the free help you are getting from experienced working professionals isn't going to get you far.
Mac
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Ok so after going over everything and talking about ideas with ppl I will be working with I've come up with a criteria that should make my decision about a system fairly limited it looks.
1 - Must be dual 18 reflex cabinets
2 - Runs off of one 20A preferably and if not then two 20A. No 30A.
3 - Still in production.
4 - $14,000 budget for speakers and amps.
Some top picks I've seen so far:
DB Tech S20
RCF TTS36a - If they can be found at that price point.
EAW SB1000z - Still sticking this one in here cause it's low power requirement. I could keep and use a Powersoft Digam5000 to power them well.
JBL STX828s
Bold 218 - Is the wild card - It's wild card status is due to it not being a widely recognised name and a new company
Thought's on these and any others I could look at would be greatly appreciated. The system will get alot of bass heavy EDM as well as live rock and jam bands. Probably more so the DJ stuff, tho I'm trying to break out of that more.
Thanks -Mark
If you want high output, drop the 2x18 and take a serious look at Danley. Yeah, they make dual 18s too, but the TH series is probably where you want to go with the budget you're talking about. Used, you can easily get TH115 cabinets for around $1,500 each. They're incredibly sensitive, so you can probably run a pile of them off 20A.
Cheers,
Randy Hyde
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I tend to ignore numbers almost completely and go with opinions from ppl who have used the gear and how it compares because the numbers are just that only numbers that often reflect nothing in the real world.
Above and beyond all this my buddy who's helping me with this system is a Fullsail graduate and has been the Engineer on many large rigs one of his favorites being 32 KF850's per side. Now he's not so into going over gear like this that's why I came here but he keeps saying it doesn't matter so much what the system is capable of producing but rather how he will make it sound perceptively louder no matter what I buy.
Yes the numbers can get stretched a bit by some manufacturers. However they get stretched A LOT MORE by people who don't under stand specs and how to read them.
Once you start to understand the numbers, what is achievable and so forth, then (and only then) can you start to be able to "read through" the specs and what might be achievable. Are the number believable (as stated earlier by Marjan)?
The people who don't understand what is going on (in any industry) are the ones who tend to dismiss the facts.
Opinions are great-but they have to be based on reality.
Accurate specs are a good way to start to compare products. Unless you have somebody who has done side by side comparisons with the products in question, then you have no basis to go on.
How do you tell who is correct when they say "ABC sub is da-bomb- believe me". You will often get these from people who have not actually heard the other ones. So they are basing their opinion on what? At least specs are a start. But agreed they don't tell the whole story. But they tell a lot more than an opinion.
For what it is worth- (and I am not trying to offend anybody on this board by this), but out of all of the full sail guys I have meet and worked with, only 2 were worth anything.
And those 2 would be good even if they didn't go to full sail. They are just that kind of person.
Nothing against full sail-but typically the people that I have meet think they know a lot more than they really do. I don't know if this comes from their character or the school.
Others experiences may be different.
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Opinions are great-but they have to be based on reality.
Accurate specs are a good way to start to compare products. Unless you have somebody who has done side by side comparisons with the products in question, then you have no basis to go on.
That's all I've been looking for is comparisons by ppl who have experienced these models. I'm not asking for direct answers of what to buy. A side by side comparison is not going to happen for me so how else do I get any idea but to ask those who have? Or at least heard each in use somewhere. When I first mentioned SB1000 I got alot of this that will beat it ect. I also got product A B here will outperform just about anything out there. Ok???
Sorry about earlier I'm overly stressed with this right now as I need to make a move on a purchase soon so even tho I agree I need to learn all the things I was told here I don't have the luxury of time to do so now. Will I someday? Yes I have lots of reading material and the motivation to learn.
As for Fullsail I know it doesn't have a good rep my buddy who went there said he's only gotten along with 1 other person who graduated from there and that he went for the piece of paper. I only wanted to state that he knows what he's talking about in some way you all might believe it. It's been 10 years since he graduated and in that time he engineered for a place in Florida that was an EAW house and he's worked on rigs from 850's to 750's to 760's. So I tend to believe he's got some good working knowlege.
The more I get into all this the more it's looking like there's not a terribly huge difference among the cabinets I've suggested and I'm just splitting hairs at this point. My buddy is telling me to worry less about what everything is capable of and just wait and see how he's going to make it sound bigger than it is. Understand my conflict here. I have him telling me one thing and you guys here another. Now not direct conflicts and he agrees with what I relay to him from here but also tells me it's less important that I'm thinking. I'm paying him some now but more later when the gigs come in and I can have him work with me. So the pressure's on we need to make money and sooner not later.
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That's all I've been looking for is comparisons by ppl who have experienced these models. I'm not asking for direct answers of what to buy. A side by side comparison is not going to happen for me so how else do I get any idea but to ask those who have? Or at least heard each in use somewhere. When I first mentioned SB1000 I got alot of this that will beat it ect. I also got product A B here will outperform just about anything out there. Ok???
Sorry about earlier I'm overly stressed with this right now as I need to make a move on a purchase soon so even tho I agree I need to learn all the things I was told here I don't have the luxury of time to do so now. Will I someday? Yes I have lots of reading material and the motivation to learn.
As for Fullsail I know it doesn't have a good rep my buddy who went there said he's only gotten along with 1 other person who graduated from there and that he went for the piece of paper. I only wanted to state that he knows what he's talking about in some way you all might believe it. It's been 10 years since he graduated and in that time he engineered for a place in Florida that was an EAW house and he's worked on rigs from 850's to 750's to 760's. So I tend to believe he's got some good working knowlege.
The more I get into all this the more it's looking like there's not a terribly huge difference among the cabinets I've suggested and I'm just splitting hairs at this point. My buddy is telling me to worry less about what everything is capable of and just wait and see how he's going to make it sound bigger than it is. Understand my conflict here. I have him telling me one thing and you guys here another. Now not direct conflicts and he agrees with what I relay to him from here but also tells me it's less important that I'm thinking. I'm paying him some now but more later when the gigs come in and I can have him work with me. So the pressure's on we need to make money and sooner not later.
Really? That is possible? He discovered the holly grail or something magical that all of us have no clue about it?
Dont get fooled with that kind of nonsense please.
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Really? That is possible? He discovered the holly grail or something magical that all of us have no clue about it?
Dont get fooled with that kind of nonsense please.
Agreed. When somebody make a comment like that, I ask for more SPECIFICS. What can HE do that others can't? WHAT is he going to adjust? And that statement is based on WHAT?
Sounds like a lot of "fluff"and over confidence (typical of most of the Full Sail graduates I have met) if you ask me-and he is con the OP.
In my opinion, getting a better tool would be a better approach, rather than listening to somebody who says "whatever you get I can make sound better". Better than what it is capable of?
I think we all are still waiting for an explanation about what is so special about a dual 18" sub. And nothing else is considered.
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we have "play time" often in the warehouse when there are free nights. Always doin side by sides. By far the lowest- the Xyons, by far the most efficient- the Danleys. We recently just had the Martins and were really impressed sound quality wise (as to why I suggested to check out). You have to figure what is most important to you. For me, past year I have used 4 Danley Minis and they have performed well in most all venues. I'm the "Weekend Warrior" and have been leaving the trailer behind and use an SUV only. Light and portable is most important to me. I'm sure you are familiar with Yankee Bootleggers in you area? Last month I had the Minis there, after the first song the DJ guy came to me and said: First where are the huge stacks of subs, I hear amazing lows but don't see any sub stacks, Second, Please turn it down the bar can't hear drink orders. My Minis may not go the lowest but they sure do put the "P" in punch.
I can let ya know when we have the next "play time"
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we have "play time" often in the warehouse when there are free nights. Always doin side by sides. By far the lowest- the Xyons, by far the most efficient- the Danleys. We recently just had the Martins and were really impressed sound quality wise (as to why I suggested to check out). You have to figure what is most important to you. For me, past year I have used 4 Danley Minis and they have performed well in most all venues. I'm the "Weekend Warrior" and have been leaving the trailer behind and use an SUV only. Light and portable is most important to me. I'm sure you are familiar with Yankee Bootleggers in you area? Last month I had the Minis there, after the first song the DJ guy came to me and said: First where are the huge stacks of subs, I hear amazing lows but don't see any sub stacks, Second, Please turn it down the bar can't hear drink orders. My Minis may not go the lowest but they sure do put the "P" in punch.
I can let ya know when we have the next "play time"
Just for clarification-the Danley TH minis in question have the highest low freq cutoff of any Danley products (all the others go lower) and the lowest sensitivity of any of the Danley Pro subs-this does not count the home theater subs-which go much lower and have a lower sensitivity.
So comparing a small single 12" to a much larger double 18" is a bit of stretch. The TH115 or Th118 would be a better cabinet to compare with 2x18"
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Agreed. When somebody make a comment like that, I ask for more SPECIFICS. What can HE do that others can't? WHAT is he going to adjust? And that statement is based on WHAT?
Sounds like a lot of "fluff"and over confidence (typical of most of the Full Sail graduates I have met) if you ask me-and he is con the OP.
In my opinion, getting a better tool would be a better approach, rather than listening to somebody who says "whatever you get I can make sound better". Better than what it is capable of?
I think we all are still waiting for an explanation about what is so special about a dual 18" sub. And nothing else is considered.
Ya I'm starting to see through what all he's been telling me as far as that type of stuff is concerned. The other thing he told me like that and I questioned immediatly was his suggestion to use 2 PRX635's for each side. He pointed out there trap boxes and said they could be arrayed as such and I think JBL also says this somewhere maybe. But ya he said the comb filtering wouldn't be a big problem and that your going to encounter comb filtering somewhere in almost every system which sure but from different points not within 1 single stack. I've never put two 90deg boxes beside eachother to see what exactly it would do. I know my LA325's can be touchy with arrangement and must be pointed straight out. When I first got them someone tried angling them inwards and before I got out front to hear it myself one stage hand with no experience or knowlege of sound what so ever said that sounds funny like that.
Why reflex cabinet's? Mostly because they can be combined with other cabinets avaliable for rent around here. Why 18's? I have no particular preference over a 21" driver other than I see big company's with huge stages sticking with 18's. Also I see them sticking with reflex cabinets so I figure theres a reason for that. Ya I'm not going to have anything near that size but maybe 12 cabinets is not so far away depending on how things go.
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Ya I'm starting to see through what all he's been telling me as far as that type of stuff is concerned. The other thing he told me like that and I questioned immediatly was his suggestion to use 2 PRX635's for each side. He pointed out there trap boxes and said they could be arrayed as such and I think JBL also says this somewhere maybe. But ya he said the comb filtering wouldn't be a big problem and that your going to encounter comb filtering somewhere in almost every system which sure but from different points not within 1 single stack. I've never put two 90deg boxes beside eachother to see what exactly it would do. I know my LA325's can be touchy with arrangement and must be pointed straight out. When I first got them someone tried angling them inwards and before I got out front to hear it myself one stage hand with no experience or knowlege of sound what so ever said that sounds funny like that.
Why reflex cabinet's? Mostly because they can be combined with other cabinets avaliable for rent around here. Why 18's? I have no particular preference over a 21" driver other than I see big company's with huge stages sticking with 18's. Also I see them sticking with reflex cabinets so I figure theres a reason for that. Ya I'm not going to have anything near that size but maybe 12 cabinets is not so far away depending on how things go.
A real easy test to see if any cabinet is arrayable is to put them in the array position and run some pink noise through them. You can get a pink noise file from many places or on the output of an RTA.
Then walk from one side to the other. Paying special attention to the area in the middle of the cabinets.
You can also do the same thing with a line array. Put pink noise through it and walk from front to back.
The swooshi swooshi sound you hear is combfiltering.
Yes it most often happens within a single cluster-but you can also get combfiltering between different clusters. The result is the same.
Even if you use front loaded ported cabinets together, that are different brands-with different tunings- you will end up with cancellations due to the different tunings. It does not matter if they use 18" drivers or not.
Even if it is the same 18" model number (not the same cabinet model), the tunings may be different as different manufacturers have a different idea of what is the best compromise.
How bad will it be? Not as bad as most make it out to be-but it will still be not as good as using all of the same model number.
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A real easy test to see if any cabinet is arrayable is to put them in the array position and run some pink noise through them. You can get a pink noise file from many places or on the output of an RTA.
Then walk from one side to the other. Paying special attention to the area in the middle of the cabinets.
You can also do the same thing with a line array. Put pink noise through it and walk from front to back.
The swooshi swooshi sound you hear is combfiltering.
Yes it most often happens within a single cluster-but you can also get combfiltering between different clusters. The result is the same.
Even if you use front loaded ported cabinets together, that are different brands-with different tunings- you will end up with cancellations due to the different tunings. It does not matter if they use 18" drivers or not.
Even if it is the same 18" model number (not the same cabinet model), the tunings may be different as different manufacturers have a different idea of what is the best compromise.
How bad will it be? Not as bad as most make it out to be-but it will still be not as good as using all of the same model number.
Ya I use Smaart and took the seminar when I got it. I run pink everytime I setup if I can. I know enough about comb filtering to know that's what it was when I heard that swooshi but not 100% sure how it affected the music as I couldn't hear any difference. The only places I've gotten comb filtering is between stacks when they are close and my 460s get it off axis where they trap together. The only thing I can notice is a drop in volume some where the boxes overlap. Maybe not very significant comb filtering? I'm giving myself homework tonight read through the chapters on comb filtering!
The gigs where I may need to add sub cabinets the sound quality isn't as much of a concern as spl is so it's an acceptable option.
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The other thing he told me like that and I questioned immediatly was his suggestion to use 2 PRX635's for each side. He pointed out there trap boxes and said they could be arrayed as such and I think JBL also says this somewhere maybe. But ya he said the comb filtering wouldn't be a big problem and that your going to encounter comb filtering somewhere in almost every system which sure but from different points not within 1 single stack. I've never put two 90deg boxes beside eachother to see what exactly it would do.
I'm actually running two PRX 625 cabinets side-by-side, per side, at a show I'm doing right now. Comb filtering isn't a problem (as a result of running four cabinets, versus two) as I run vocals through one cabinet and backline through the other (on each side).
That said, PRX series cabinets don't have the oomph for outdoor gigs in my opinion. My current gig is outdoors and the only thing saving my butt is the building that is about 100' in front of the stage (providing a reasonable reverberant field to get the volume up). I get 105 db at about 50' with no problem, but I'm not a big fan of the sound quality when I push it much beyond that.
I've tried to use the PRX 625 cabinets (which are about 4 dB louder than the PRX 635 cabs, according to the specs) in a free field, they don't work very well. Good indoor speakers, not my first choice for outdoors.
Cheers,
Randy Hyde
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Ya I use Smaart and took the seminar when I got it. I run pink everytime I setup if I can. I know enough about comb filtering to know that's what it was when I heard that swooshi but not 100% sure how it affected the music as I couldn't hear any difference. The only places I've gotten comb filtering is between stacks when they are close and my 460s get it off axis where they trap together. The only thing I can notice is a drop in volume some where the boxes overlap. Maybe not very significant comb filtering? I'm giving myself homework tonight read through the chapters on comb filtering!
The gigs where I may need to add sub cabinets the sound quality isn't as much of a concern as spl is so it's an acceptable option.
Regarding the issue of how bad is combfiltering-it really depends on the person listening.
To some people a little bit is quite annoying-while to others they might mot hear ) or recognize it.
Kind of like the flavor of food or wine or how a car handles etc.
And to the people that aren't picky-it is not an issue. But to the more professional-it is a real problem that they are constantly looking to make it better.
And yes it can be subtle. And while the average person may not say it is bad or an issue-if a system that did not have combfiltering was then played-they would recognize the new system as being clearer sounding.
Not that the combfilter system was bad-just that the one without is clearer.
Is that a big deal? depends on who is listening.
And if it is there-you WILL hear it-you may not recognize it as such. You won't hear the swooshi swooshi sound-but you will notice that the vocal lack clarity/openness, the timbre of the instruments is not as it should be, the attack of the percussive instruments is not a bright (due to the different arrival times which causes the issue in the first place) and so forth.
It comes down to your personal reference.
So to sum it up, people often talk about combfiltering. Is it this horrible thing that makes a system unusable? NO. But a system that doesn't have it sounds better.
The fewer number of speakers that can be used-the better it will sound-no matter how well the manufacturer say they array.
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The thing which can bite you worst when combining subs, even if they're nominally the same type (e.g. ported 18's) is that the phase response can vary quite a bit -- at certain frequencies, the two subs may be working against each other rather than with.
For kicks, I modeled two sub designs which wouldn't be outside the mainstream of what's out there. One uses an Eminence Omega Pro 18 in a small 4.5 ft^3 cab tuned to 48Hz (barely a subwoofer), and the other uses an RCF LF18X400 in an 8 ft^3 cab tuned to 35Hz. I've attached a chart with the calculated phase responses for each. Notice that at 45Hz, there are about 8 lines separating the two, which comes out to an 80 degree phase response difference. They're barely helping each other -- past 90 they're considered out of phase (that is, fighting each other). They're probably also aiming the bass off in some weird direction rather than where you want it.
It can be very hard to get different subs to play nicely together. Heck, sometimes it's hard to get things right with only one kind on hand. I think you'd be doing yourself a disservice by planning to mix-and-match. If you're planning to rely on augmenting yours with someone else's, your best bet is to buy what they've already got if it's a good choice, or start from scratch if it's not.
-Chris
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Comb-filtering is a major issue with systems that are used for more "stationary" audiences, and Ivan pretty much nailed it. I (possibly foolishly) don't worry too much about comb filtering in a dance-type situation, as much as I concentrate on focusing the sound on the dance floor, and some (if not most) club owners are in love with the "four corner" approach.
Since this is a live sound forum, I'd stick with the expertise of Ivan and the other guys here with extensive experience.
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I know enough about comb filtering to know that's what it was when I heard that swooshi but not 100% sure how it affected the music as I couldn't hear any difference.
Here's an example which may help illustrate it.
I once was helping a friend who had a rig with two mid-high speakers per side, each with a nominal 60O HF horn, but the boxes were tight packed so only had about 25-30O splay between them.
If you moved even half a metre to one side or the other, certain parts of the sound changed significantly - for example, the attack of the snare drum was noticeably reduced at some locations compared with others.
Now if you happened to be mixing (or EQing the rig) from one of the nulls, then you might end up trying to boost those frequencies to get the snare to sound right (which wouldn't be particularly successful even for that location anyway). But for other locations away from the nulls, that EQ would over-exaggerate the snare, making it obnoxiosly loud for everyone else.
In our case, we ended up living with the combing as the lesser of two evils (increasing the splay between boxes on each side would have significantly increased reflections from side walls), but we had to bear the combing in mind when EQing/mixing, and take care not to get caught out by it.
HTH,
David.
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Here is an example of a moment "when the light turned on" for me-regarding combfiltering.
There is a local venue (2500 seats) that I provided sound for all the time. I would take out a "4 stack a side" system. This was back in the pre line array days.
We got a call to do a wedding and the budget was small-and they only wanted to cover the dance floor.
So we took out 1 stack a side. Both my help and me noticed right away-when we played our "standard" setup songs-how much clearer the system sounded. It wasn't as loud-but sure did sound better.
Same venue-same physical setup-same speakers-just less of them.
From that point on-I used a few loudspeakers as I could to do the job.
Very rarely do you "pickup" on combfiltering as a specific "sound". But when you hear the sound without it-you QUICKLY realize how big a deal it can be.
You can easily play with this effect on the sound quality with a digital console. Just patch (or physically Y) a mic to 2 channels. bypass all compressors-eq etc. Set the input trim the same as well as the channel level.
Apply some input delay to one channel only. Start with 0ms delay and start increasing it. While listening to the sound, you can hear how it starts to "degrade" and become not as clear.
You can mute and unmute 1 channel (it doesn't matter which one) and hear the back and forth differences.
Yes the level will drop-but it is the sound quality you are interested in hearing.