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12" in a 36x24 (Read 4494 times)
8bit-ash
Ex Member



12" in a 36x24
04/22/06 at 20:31:27
 
hi,  this is my first post.  I've pondered these designs for ages and after recommendation thought it about time I build a WO.

I've measured out a 36 x 24 wo for 12" drivers.  the rear chamber seems as though its gonna be a pretty tight squeeze Undecided  with a limited volume in comparison to some of the pics i've browsed on the forum .

has anyone else built a 36 x 24 12" with some decent success?

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60ndown
Ex Member



Re: 12" in a 36x24
Reply #1 - 04/23/06 at 01:32:12
 
[quote author=8bit-ash  link=1145737888/0#0 date=1145734287]hi,  this is my first post.  I've pondered these designs for ages and after recommendation thought it about time I build a WO.

I've measured out a 36 x 24 wo for 12" drivers.  the rear chamber seems as though its gonna be a pretty tight squeeze Undecided  with a limited volume in comparison to some of the pics i've browsed on the forum .

has anyone else built a 36 x 24 12" with some decent success?

[/quote]
its been done many times with sucsess and a few with dissapointment. read all the post you can on building the wo (for 12s) and then build it useing your best guesswork.... or get some 10s and be guarenteed sucsess?
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« Last Edit: 04/23/06 at 01:32:41 by 60ndown »  
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Zygi
Ex Member



Re: 12" in a 36x24
Reply #2 - 04/23/06 at 03:32:19
 
OR.....Go for the gusto and build a 12X36X36, you'll be glad you did.
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gexter
Ex Member



Re: 12" in a 36x24
Reply #3 - 04/23/06 at 04:18:39
 
Ditto

The only reason I build small boxes is space limitations. Its better to free up the space and go for the WO 36 x 36

if you can that is.
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« Last Edit: 04/23/06 at 04:19:11 by gexter »  
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8bit-ash
Ex Member



Re: 12" in a 36x24
Reply #4 - 04/23/06 at 06:48:07
 
hi, thanks for the replys.  The reason for the small box is limited space, and the reason for the 12"'s is the limited number of 10's with a decent spec.
I wanna stay away from car drivers and go pro audio, I've read nearly every post on the forum twice but cant find anywhere a recommended driver parameter list.  Is there one kicking about anywhere.
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Adrian D.
Ex Member



Re: 12" in a 36x24
Reply #5 - 04/23/06 at 07:14:17
 
pa subs generally 'demand' big boxes, well, atleast bigger than any car subs would demand.
you have to model a perfect 4th order bandpass for your sub, and DECREASE the size of the sealed chamber in the wo until it matches the size of the sealed chamber of the 'perfect 4th order'.
you can look into decware's 10" sub offers. the dhm pro is geared more towards spl (and pa). the other high spl option is the dhm 108.  
you want to use the wo for pa ?
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« Last Edit: 04/23/06 at 07:16:53 by adi_ro »  
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8bit-ash
Ex Member



Re: 12" in a 36x24
Reply #6 - 04/23/06 at 11:14:44
 
hi,  its mainly for the back of my vw t4 day van.  but I also want to be able to pull it out when we go off into the middle of nowhere for little partys.
If I like the design I was going to make  some of the bigger version to play sub under my kick bins for PA use.

Cheers for the link to the drivers, I'm in the Uk so postage will prob be a bit much.  I'll see if I can find a 10" driver with a similar spec over here.

One last thing, when it comes to modeling the rear chamber how do I go about it in winisd?  I've only ever designed ported boxes in it.

I opened a 4th order bandpass design but wasnt sure what to set the tuning port size/length and front chamber too so that I could work out the rear chamber.
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Adrian D.
Ex Member



Re: 12" in a 36x24
Reply #7 - 04/23/06 at 13:01:45
 
not sure about designing boxes  :-/ i guess you have to put the params in winisd (make sure you have the pro vers) and then design a 4th order, without changing anyting...
i'm also from europe, but that won't stop me from ordering a sub  from the usa Kiss.
if you're in UK, you can try www.bladeice.com for re subs, but they're kinda pricy. pick up any good 10 sub. try pioneer or infinity. if i managed to find re audio, adire audio, pioneer, infinity and jbl in romania, i'm sure you too can find those in the uk, and even more Grin
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gexter
Ex Member



Re: 12" in a 36x24
Reply #8 - 04/23/06 at 13:17:22
 

If I was going to use a bigger driver like the 12 I would match the driver volume up and shrink the compression chamber/ increase the sealed chamber.
just slide the baffle board. The WO is pretty forgiving but don't go to far if you need more sealed volume.
You could add polyester fill to the sealed area but don't pack it. accustic fiberglass is suppossed to be better.
If your driver is flipped so it faces into the sealed area I use fiberglass screening to keep it away from the the driver.


have fun and good luck..
by the way Zygi is part of the Decware team.

EDIT: post edited because of lack of intelligence and sleep

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« Last Edit: 04/30/06 at 15:07:21 by gexter »  
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Adrian D.
Ex Member



Re: 12" in a 36x24
Reply #9 - 04/23/06 at 14:16:59
 
wo = ported ?  :-/ Undecided Undecided
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gexter
Ex Member



Re: 12" in a 36x24
Reply #10 - 04/23/06 at 14:30:25
 
My bad!
Previous post EDITED

Thanks Adrian.
Trying to remember what I was thinking at the time. I think I was remembering an article I read on the simularities of the Horn and the ported box on the driver.

I had something else on my mind.. and I was trying to do two things as once..
Must have been a acid flashback from the early 70's

The WO is a simply a 4th order bandpass enclosure with a modified mouth.



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« Last Edit: 04/30/06 at 15:10:57 by gexter »  
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60ndown
Ex Member



Re: 12" in a 36x24
Reply #11 - 04/23/06 at 14:44:31
 
[quote author=8bit-ash  link=1145737888/0#4 date=1145771287]hi, thanks for the replys.  The reason for the small box is limited space, and the reason for the 12"'s is the limited number of 10's with a decent spec.
I wanna stay away from car drivers and go pro audio, I've read nearly every post on the forum twice but cant find anywhere a recommended driver parameter list.  Is there one kicking about anywhere.
[/quote]

i dont see why you have to stay away from car drivers? lots of 10" drivers have great specks these days.

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-462

60 quid each, 120 notes gets you 1200 wrms of 10 inch bass masness Cheesy
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8bit-ash
Ex Member



Re: 12" in a 36x24
Reply #12 - 04/23/06 at 15:24:35
 
i've just found car drivers to be a bit boom boom in the past. and their sensitivity is alway way down on PA drivers.  Maybe I should just give some a try.

What does reducing the compression chamber do to the characteristics of  the box?

Also i'm still unsure of how to model a 4th order BP for a WO in Winisd pro.  If anyone can give me an idiots guide i'd be greatful.
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Adrian D.
Ex Member



Re: 12" in a 36x24
Reply #13 - 04/23/06 at 15:51:38
 
oh, but same size pa subs don't go as low as car subs. and  my infinity ref 1040w in a db-10 is the proof that they can sound tight.
i guess the guide is pretty accurate, but i've read that you can model the wo as a 40hz tuned 4th order.
guide (not the 40hz tune version) :
step 1 :

step 2 :

step 3 :

rl-i > rs-hf  :-*
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« Last Edit: 04/23/06 at 15:57:07 by adi_ro »  
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DirtDawg
Ex Member



Re: 12" in a 36x24
Reply #14 - 04/23/06 at 15:56:32
 
[quote author=60ndown  link=1145737888/0#11 date=1145799871]

i dont see why you have to stay away from car drivers? lots of 10" drivers have great specks these days.

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-462

60 quid each, 120 notes gets you 1200 wrms of 10 inch bass masness Cheesy [/quote]

That's not a bad looking driver, but the 84dB sensitivity puts me off a little. Notice it's a 4 ohm driver rated at 2.83v. Subtract 3dB to compare with 1W on an 8 ohm driver. You will need a large part of that 600 Watt power rating to get a big sound out of it.

Good point about the 10" Pro drivers Adrian. Most Pros consider a 10" to be a mid driver, not a subwoofer.
I'm not against car subs at all. In fact, I have 4 WOs in service on friends' PA systems using car subs and they sound really good for their size.
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« Last Edit: 04/23/06 at 16:01:44 by DirtDawg »  
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J_Rock
Ex Member



Re: 12" in a 36x24
Reply #15 - 04/23/06 at 16:12:50
 
If I were you, dl winISD pro from linear team.

Plug in the driver parameters in the correct order(look in help tutorial)

Pick the driver that models best in a 40hz 4th order enclosure with chamber sizes equal or smaller than the 24 x 36 WO.

As a rule I don't exclude one type of woofer from anything I do, i just choose the best one I can afford.

~side note~
Those daytons are nice, I just got a pair of the high fidelity 10s in a trade for some cabinets, lower power handling than the HO, but higher sensitivity and larger Xmax makes them my choice:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-460
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Adrian D.
Ex Member



Re: 12" in a 36x24
Reply #16 - 04/23/06 at 16:17:32
 
JRock, are you gonna give'em a try in a db or a wo ?
8bit-ash, if you are considering the daytons, inform yourself about the taxes because they can be pretty heavy.
EDIT :
gex, jet's modded wos are similar to ported boxes.
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« Last Edit: 04/23/06 at 16:20:59 by adi_ro »  
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8bit-ash
Ex Member



Re: 12" in a 36x24
Reply #17 - 04/23/06 at 16:43:32
 
Yep i've had troubles finding a 10" pro audio driver up to doing the job.  Infact I havnt found one.  
Another reason for wanting to use a 12" was because someone I know was able to make me up a couple to order that have a very nice spec.

So for winisd  I calculate the front chamber by measuring the volume of the front WO chamber which i think is about 19l on the 24" version.  then set the tuning to 45hz. Do I leave the port info alone?
Then work out the best rear chamber.
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Adrian D.
Ex Member



Re: 12" in a 36x24
Reply #18 - 04/23/06 at 16:53:01
 
you have to look only at the SEALED chambers. the front chamber on the wo is the "compression" chamber.
just sim a 4th order, tuned @ 40hz, and write down the size of the sealed chamber. then compare it to the sealed chamber on the wo
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« Last Edit: 04/23/06 at 16:54:36 by adi_ro »  
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8bit-ash
Ex Member



Re: 12" in a 36x24
Reply #19 - 04/23/06 at 19:15:29
 
cool.  tried that with an alpine type r, eminence omega pro and kappa pro and i'm not impressed with the graph on any of them.   Guess i'll just have to make the thing and see what happens.
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Adrian D.
Ex Member



Re: 12" in a 36x24
Reply #20 - 04/24/06 at 04:57:43
 
bulid the thing, put 2 good 10s in it, throw decent power in and forget about it Kiss
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8bit-ash
Ex Member



Re: 12" in a 36x24
Reply #21 - 04/25/06 at 14:22:33
 
one more quick question for the resident WO experts before I go choppin wood.

I cut the inside panels 14" as originally I was gonna fit 12's.  Since its a 24" version i'm building would it be possible to increase the sealed chamber and front chamber by leaving the panels 14" for a 10" driver,  but tapering the horn mouth down to 12"?  
Effectively would that mean that the only difference is a shorter horn. Or does this also mess up the suitable volume of the horn?
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Adrian D.
Ex Member



Re: 12" in a 36x24
Reply #22 - 04/25/06 at 14:31:58
 
all i can say is that steve said not to move the baffle back because the box would get boomy. this would mean a decrease in the sealed volume and an increase in the compression chamber.
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Jet-Lee
Ex Member



Re: 12" in a 36x24
Reply #23 - 04/25/06 at 14:39:58
 
[quote author=Adrian D.  link=1145737888/15#16 date=1145805452]EDIT :
gex, jet's modded wos are similar to ported boxes. [/quote]
Yup. That's how they were modeled in WinISD. They performed great, over their replacements. Expecting bigger numbers in the future, with only power modifications.

8bit-ash, be sure to post pics of the build!
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8bit-ash
Ex Member



Re: 12" in a 36x24
Reply #24 - 04/25/06 at 18:08:59
 




cut the mitres this evening.  nice and easy as they were nearly all the same.

Its still 15" tall at the mo so need to decide tonight if i'm gonna cut it down for 10's or risk it and try 12's ???

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J_Rock
Ex Member



Re: 12" in a 36x24
Reply #25 - 04/26/06 at 00:57:51
 
If youwant to cut it down, just cut everything to 12 inches instead of 14.

unless you want 12s with a 10" horn.  In which case, just slam em in there you can fit mot 12s in a 12 x 12 piece, since the cutouts are generally 10.5 or so.
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