dual 12" monster subwoofer enclosure - Page 2 - AVS Forum | Home Theater Discussions And Reviews
Baselworld is only a few weeks away. Getting the latest news is easy, Click Here for info on how to join the Watchuseek.com newsletter list. Follow our team for updates featuring event coverage, new product unveilings, watch industry news & more!


Forum Jump: 
 
Thread Tools
Old 07-27-2013, 03:23 PM
AVS Special Member
 
Mrkazador's Avatar
 
Join Date: Jun 2005
Posts: 4,128
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 186 Post(s)
Liked: 341
Quote:
Originally Posted by mike d263 View Post

http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-467

i think i will be using a pair of these on 1200 watts a side.
ported they want less than 1.5 cubes says the website.

 

You could do 1.5cu ft tuned to 25hz with 700w. The problem you're going to run into is the port. To keep air velocity (chuffing) down you will need at a minimum two 3 x 38.25" round ports. You could do a single 3.5" port 25" long but the power has to be decreased to about 300w.


_______________________________

DIY Sound Group: Information and Tips
Mrkazador is offline  
Sponsored Links
Advertisement
 
Old 07-27-2013, 04:48 PM - Thread Starter
Member
 
mike d263's Avatar
 
Join Date: May 2012
Posts: 55
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
what is chuffing? never heard anyone use that term before.
i like to have a some head room on my subs. i do under stand over driving a speaker. i dont have to use a really small box i could do 2.25 to 2.5 per side.
if you where building the boxes with the size limits i have what would you do. i really dont want a sealed box. i have 2 10's in the correct size box sealed on they are rated for 500 each. om my peavy PV 8.5c
they sound good but i can tell around 30 hz they fall off.
mike d263 is offline  
Old 07-27-2013, 05:00 PM
AVS Special Member
 
Jay1's Avatar
 
Join Date: Aug 2002
Location: West Valley, AZ
Posts: 4,525
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 231 Post(s)
Liked: 214
Chuffing aka port velocity is to high, and audible wind noise is easily heard. It also means the port output is compressing, and your sub functions like a sealed box with a massive air leak.

The passive radiator suggestion that I previously posted details for is how you properly build a high output compact bass reflex enclosure
Jay1 is offline  
Old 07-27-2013, 05:01 PM
Senior Member
 
Rebel975's Avatar
 
Join Date: Mar 2013
Posts: 410
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 84
It's the sound of the air leaving the port. You have to keep port velocity (the speed of air going through the port) under a certain amount or it becomes audible.
Rebel975 is offline  
Old 07-27-2013, 05:54 PM - Thread Starter
Member
 
mike d263's Avatar
 
Join Date: May 2012
Posts: 55
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
oh port turbulence got you .

sorry if i sound ignorant to all this there are some things that i know and lot i dont. but all of you have been awsome in helping me figure this out !!!
so thanks for the input so far.
mike d263 is offline  
Old 07-28-2013, 06:10 AM - Thread Starter
Member
 
mike d263's Avatar
 
Join Date: May 2012
Posts: 55
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Hey jay i was looking at you PR build. that looks easy enough.

So if i where to do the PR's with the dayton HO12 dvc (the dual voice coil is need to get the peak power from the amp)
what size would i need to make the box?
Is placement of the PR and woofer important?
could i fire the woofer out front and the PR down?
mike d263 is offline  
Old 07-28-2013, 10:14 AM
AVS Special Member
 
Jay1's Avatar
 
Join Date: Aug 2002
Location: West Valley, AZ
Posts: 4,525
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 231 Post(s)
Liked: 214
Quote:
Originally Posted by mike d263 View Post

Hey jay i was looking at you PR build. that looks easy enough.

So if i where to do the PR's with the dayton HO12 dvc (the dual voice coil is need to get the peak power from the amp)
what size would i need to make the box?
Is placement of the PR and woofer important?
could i fire the woofer out front and the PR down?

Yes a PR build is simple, there are some considerations you have to make. You need two of the PR's, placed on opposing sides of the cabinet. With a small, light cabinet, the large excursion from the PR will cause your cabinet to rock and wobble if two arent placed on opposing sides to cancel out the effects. You also should not up/down fire a PR because it will sag, and reduce the amount of excursion available. You can down fire the active driver, or set it up like my build.

With a pair of the CSS APR 12's in each cabinet, here's both 1.5 ft3 and 2 ft3. The PR's require all of the mass they're supplied with (900g) added, so changing cabinet volume tweaks tuning.



The bigger box gets about 3hz lower, but the smaller box is stronger down to 26hz.

With a 20hz high pass filter in place on either of these you actually could handle 1200 watts without bottoming anything. If you do not plan on using a high pass filter do no watch of listen to anything with content below 20hz. This is a requirement for any bass reflex design, a filter is needed below the box tuning point.
Jay1 is offline  
Old 07-28-2013, 01:21 PM - Thread Starter
Member
 
mike d263's Avatar
 
Join Date: May 2012
Posts: 55
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
do i have to use the PR that you linked me too of can i use the dayton ones? if i add the cost of 2 PR per cab i go way over my budget.
mike d263 is offline  
Old 07-28-2013, 01:33 PM
AVS Special Member
 
Jay1's Avatar
 
Join Date: Aug 2002
Location: West Valley, AZ
Posts: 4,525
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 231 Post(s)
Liked: 214
Yes that is the downside to PRs (cost). The Dayton one's will not get the job done, the css apr is required.
Jay1 is offline  
Old 07-28-2013, 03:41 PM
AVS Special Member
 
Jay1's Avatar
 
Join Date: Aug 2002
Location: West Valley, AZ
Posts: 4,525
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 231 Post(s)
Liked: 214
You could get away with the original "monster 12" drivers in a 2.5 ft3 box if you use the 12" CSS APR's.



550g mass added to each APR (that is 12 of the 45g discs that come with each APR), tunes the box to 22hz, F3 point is 32hz. You could always get creative and add 3 db of boost at 25hz to make up for the undersized box



No matter what, if you build a bass reflex (ported, passive radiator) box you need a high pass filter, most will have options for EQ, so applying a little boost should be an option. You have been mentioning a 1200 watt amp, what amp is it exactly?
Jay1 is offline  
Old 07-29-2013, 01:18 AM
AVS Special Member
 
flyng_fool's Avatar
 
Join Date: Aug 2009
Location: Frisco, TX
Posts: 3,861
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 182 Post(s)
Liked: 163
Quote:
Originally Posted by Jay1 View Post

Chuffing aka port velocity is to high, and audible wind noise is easily heard. It also means the port output is compressing, and your sub functions like a sealed box with a massive air leak.

The passive radiator suggestion that I previously posted details for is how you properly build a high output compact bass reflex enclosure
What about a slotted port? Aren't those much less susceptible to chuffing?

Television: Mitsubishi WD65737 DLP
Processor: Emotiva UMC-200
Amps: Carver AV 806x/Behringer EP4000
Mains: DCM TimeFrame 600 Center: AT 453C
Surrounds: AT 251.1 Sub: Danley DTS-10
Blu Ray: Panasonic DMP-BD655
flyng_fool is offline  
Old 07-29-2013, 06:58 AM
AVS Special Member
 
Jay1's Avatar
 
Join Date: Aug 2002
Location: West Valley, AZ
Posts: 4,525
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 231 Post(s)
Liked: 214
Quote:
Originally Posted by flyng_fool View Post

What about a slotted port? Aren't those much less susceptible to chuffing?

No, the cross area of the port is what's important. It is just easier to build a really long slot port that wraps around corners. When box size is a factor, you end up with a much larger box using a long slot.
Jay1 is offline  
Old 07-29-2013, 06:32 PM - Thread Starter
Member
 
mike d263's Avatar
 
Join Date: May 2012
Posts: 55
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Jay1 View Post

You have been mentioning a 1200 watt amp, what amp is it exactly?

The amp is a QSC RMX2450

i already gave the monster 12's back
i think i am going to go with daytons
build the correct box ported and tuned for 20hz and deal with my wife being mad about the sub box size. hell i cant hear her when i play my radio any way.
i call it my bitchy wife noise cancelling device biggrin.gif
mike d263 is offline  
 
Thread Tools


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off