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Old 13th September 2014, 10:20 PM   #1
blewett is offline blewett  United States
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Default vented/ported/sealed... design help

Hey everybody, I'm new to the forum and I'm trying to get information on enclosure designs for 18 in subs. I run a dance club with a rectangular dance floor that's about 1,000 sq. ft. I have 4 JBL JRX 125's that I'm flying, 4 EV 18's in single cabinets that are coupled, and 1 EAW LA 128Z all powered with Crown XTi series amps. I have changed the configuration a few times; stacked, staggered, corner loaded at each end of the room, and now I have them all corner loaded together at one end. Regardless of the configuration in this solid, concrete, rectangular room, I'm still finding dead spots and not getting the low end that my clientele are craving.

I'm looking to build an enclosure for all the subs to help get rid of my low end disappointment; whether it's 3 dual cabinets, 1 gigantic cabinet, or any other options that would work. Size isn't an issue and I'm pretty good and glueing stuff together. Any calculations that anyone has, or pictures of enclosures that could help with inspiration would be greatly appreciated.

I am running a dance club that plays a lot of electronic music with that super low, feel it in your chest, bass. I'm trying to create the best dance club possible. We all know that if it sounds like crap and you get listening fatigue, you can't (and don't want to) stay on the dance floor shaking your booty.

Thanks for your time and any/all help or advise anyone has.
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Old 13th September 2014, 11:03 PM   #2
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The cabinets have little to do with your issues with even bass thruout the room, that is all on the room. You need careful woofer placement to even things out. Toole's Sound Reproduction has a thorough section on the subject and should be your 1st investment towards sorting your issues.

dave
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Old 13th September 2014, 11:28 PM   #3
tb46 is offline tb46  United States
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Default Not quite enough information. :-)

Hi blewett,

"...4 EV 18's in single cabinets..."

Are these all the same drivers? Model number? T/S parameters? Xmax? Would you consider building something like two (big) dual driver tapped horns using these drivers (provided they look promising)? What's your general budget?

Here is a design that might apply: Gjallerhorn

You may want to do a little measuring to see what you are shooting for, e.g.: the JBL JRX 125's don't have much (any?) low end, so they would give you your general music SPL. If that's loud enough you could use that value as a target level to see how much you need to add at the sub level.

And, what Dave said:
Multiple Small Subs - Geddes Approach

Regards,
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Last edited by tb46; 13th September 2014 at 11:31 PM.
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Old 14th September 2014, 12:45 AM   #4
blewett is offline blewett  United States
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Dave and Oliver, I have moved the subs from corner to corner, staggered along the big main wall, everything short of flying them (which would be -8 db or something. lol) We used to have a big vented box that was slotted in the middle, the sub itself was in the slot with the cones pushing air into the box. We called her Bertha, she was around 65in tall, 50in wide, and 30in deep. (If my description of how she was built doesn't make sense, I can do a rough drawing and upload it.) She died and that is when we got the EAW to replace her, since then it just has not been the same. Cancelation zones aside, we just haven't been able to reproduce the low end that we once had.

When it comes to drivers one of our "expert" DJ's that thought they knew everything, got into my office and turned the limiter up to something like +15 and actually fried the EAW's before they were even 2 weeks old. I've been taking my blown subs to Around the Sound in Seattle, WA to be repaired; cool old guy, super knowledgable, and does a great job with re-coning and fixing fried coils. 2 of the EV's are ELX 118 passive subs and the other 2 EV's are older generation T-18's, they load from the front through the grate and face up. The boxes are at least 10 years old, air is blowing through the 1/4" jack in the back and they just don't sound as good as they used to. I don't know if all the mixed matched equipment could be causing cancelation and if we put everything in the same enclosures if it would help uniform and tighten our low end up. When it comes to space and money, there is a fair amount of both for this project.

Thanks to both of you for responding, any information and direction I can get is greatly appreciated.

-Kemmeth
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Old 14th September 2014, 01:16 AM   #5
rayma is offline rayma  United States
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Quote:
Originally Posted by planet10 View Post
The cabinets have little to do with your issues with even bass thruout the room, that is all on the room. You need careful woofer placement to even things out. Toole's Sound Reproduction has a thorough section on the subject and should be your 1st investment towards sorting your issues.
Yes, this is definitely your problem, not the speakers themselves.
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Old 14th September 2014, 03:43 PM   #6
TBTL is offline TBTL  Netherlands
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Do you have a drawing of the room layout?
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Old 14th September 2014, 04:06 PM   #7
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You run a club?
You have DJs that are allowed to play with your limiters?
You want the best sound "in the world" ?

I strongly advice you go to some professional sound company in your area in order to get a fast and solid solution.... Running a club is about making money (or losing the club if you donīt make any), you should not risk anything by trying to gain knowlege in an internetforum - this is fun, but takes too much time.. Obviously, you are at the very beginning of learning abot pro-audio. Get some local help. Some guys that can move some gear in the club, show you how what is done, how room problems can be dealt with, what amount of money has to be spend to acheive which result...

"The best club" will be very relative afterwards, but you will have your problems solved
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Old 14th September 2014, 04:31 PM   #8
tb46 is offline tb46  United States
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Hi blewett,

Well, obviously Sabbelbacke makes a very valid point, but anyway....

Your description of the condition of the assorted subs makes me wonder if it's just the room. The ELX 118 are bass reflex designs, and the T18 is not quite a tapped horn or scoop, and both designs aren't much below 50Hz. Your reconed EAW LA 128Z are, well, reconed, so they may be up to spec or even better, who knows? But it's another bass reflex design w/ ports that look like they would choke at low frequencies and high levels. The JBL JRX 125's don't add much to the low end, actually you would want to keep the low end out of them.

Big Bertha sounds like a nice size subwoofer, so you could contemplate building a dual 18" tapped horn for the very low end. Maybe something similar to the dual 12" DTS-10 just wider, e.g.: 60" x 48" x 24" (I'm just using this as an example, you don't want to just copy any design that was intended for a different driver):

Danley DTS-10 "Super Spud" DIY kit - AVS Forum

You could have your re-coner test the drivers in your EV T-18's for their T/S parameters. From that a test box could be designed to give this a try. Naturally, if your budget is sufficient I'd still recommend the Gjallerhorn (see link in Post #3), or maybe the Othorn: The Othorn tapped horn

But, you'll need at least one of these cheap SPL meters:

New Digital Sound Pressure Level Meter Tester Decibel Noise Measure 30 130 DB | eBay

Then, stick your EAW's in a corner, power them up w/ 1/3 octave warble tones, and get an idea what the SPL(s) is around the room @ different ranges.

A sketch of your layout wouldn't hurt either.

Regards,
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Old 14th September 2014, 10:15 PM   #9
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No sub that goes to 30 hz (or really you're missing the strong 38-42 band, that's the physicality you're missing) is your problem. If I were you I would either order t60's, build t60's (see billfitzmaurice.info for more info) or if you're feeling adventurous you can try turning your existing drivers into single fold tapped horns, seeing as you have size at your disposal it is really easy to come up with a low compression ratio horn with low 30's hz extension(i spectrum analyze club edm on a daily basis, what you need is strong 35 hz extension) i have come up with two designs that are catered to that extension but they both require a specific (alpine sws or swe series) driver. The same can be built with B&C drivers but I don't have that kind of money. You need a horn to really hit those low notes at max output because most pa subs just aren't designed to go that low. If you can figure out the driver I the subs you have I'll come up with a recommended design for free or let you know that it doesn't model well if that's the case. Feel free to message me if you'd like to know more about a custom design. I could even cad out a design if necessary but we can talk about that if it comes to it.
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Old 14th September 2014, 10:54 PM   #10
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Quote:
Originally Posted by blewett View Post
Dave and Oliver, I have moved the subs from corner to corner, staggered along the big main wall, everything short of flying them (which would be -8 db or something. lol) We used to have a big vented box that was slotted in the middle, the sub itself was in the slot with the cones pushing air into the box. We called her Bertha, she was around 65in tall, 50in wide, and 30in deep. (If my description of how she was built doesn't make sense, I can do a rough drawing and upload it.) She died and that is when we got the EAW to replace her, since then it just has not been the same. Cancelation zones aside, we just haven't been able to reproduce the low end that we once had.

When it comes to drivers one of our "expert" DJ's that thought they knew everything, got into my office and turned the limiter up to something like +15 and actually fried the EAW's before they were even 2 weeks old. I've been taking my blown subs to Around the Sound in Seattle, WA to be repaired; cool old guy, super knowledgable, and does a great job with re-coning and fixing fried coils. 2 of the EV's are ELX 118 passive subs and the other 2 EV's are older generation T-18's, they load from the front through the grate and face up. The boxes are at least 10 years old, air is blowing through the 1/4" jack in the back and they just don't sound as good as they used to. I don't know if all the mixed matched equipment could be causing cancelation and if we put everything in the same enclosures if it would help uniform and tighten our low end up. When it comes to space and money, there is a fair amount of both for this project.

Thanks to both of you for responding, any information and direction I can get is greatly appreciated.

-Kemmeth
Two things, if there is air flowing through a 1/4 inch jack than it was improperly designed or got damaged, fill that with epoxy, a plug, or PL as soon as possible as it leads to less low end and potential driver failure. Different designs have different phase response so yes, having different sub cabs and potential out of phase subs (did you check polarity when trying each of the locations?) could be part of the issue.
P.S. That ELX is -10 dB at 35 Hz and thus is a 50 Hz box --> This will not impress playing EDM. Trust me I have a 45 Hz FLH and even that leaves me with considerable amounts of "missing bass". I since built a 25 Hz FLH and thus know what it should have sounded like. In a club sub 30 hz is pointless if not downright dangerous (neighbor complaints from really low notes can be issues) but the power band from 32-42 or so really makes a difference.

Commercial options I know of that could fix your bass issue tend to run 2k per sub (the Dual stx jbl is one option). The boxes I would suggest building run about $550 per box in parts (2 quad 12 driver cabs would absolutely deck a club, we're talking 120 dB in the middle of the room down to 32 Hz kind of loud)
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