Suggestions Creating Subwoofer Box(s) - 56 cuft available - Page 4 - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 19th January 2012, 04:00 PM   #31
tb46 is offline tb46  United States
diyAudio Member
 
Join Date: Jan 2006
Location: Texas
Hi bjorno,

The way I understand the OP, he wants very low bass for HT, and is very specific about the space requirements, including where to vent the boxes (Post #21). Naturally, when you shorten the length a lot of nice things happen (to a point) :-).

Regards,
__________________
Oliver
  Reply With Quote
Old 19th January 2012, 04:23 PM   #32
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by 2MuchRiceMakesMeSick View Post
An example is, I have an 130wrms pioneer SC-57 that barely powers my tang bands (100wrms). I recently purchased a measley '90w rms' qsc amp and I cannot turn the gain up more then 5-10% before bottoming out the TBs.

Will these subs really handle 500w rms of pro audio QSC amps?
I have not used the speakers you are planning to use, but I have tested lots of Lab 12 speakers with 400 watt sine waves (49 volts) with no damage, and (accidentally) put 120 volts of 60 Hz (about 3600 watts) into a BC18SW115-4 for several seconds three times in a row.
Josh Ricci has pushed (and occasionally exceeded) the level of speakers, but his testing shows the TC brand doing quite well at rated power.

Most amps do not perform well if voltage drops, at very high peak power (like 4000 watts output using 10 gauge wire) the peak may be reduced as much as 3 dB.

Input gain and potentiometer taper on pro amplifiers varies considerably, "5-10%" may be full output, or even clipping the amp.
Clipping an amplifier can result in a 3 dB (double the power) or more increase in average power.
Amps sound different when clipping, some amps clip softly and basically sound compressed, others make a sub sound like it is "bottoming out" or flapping.
I re-tested a small tapped horn that I had thought to be rather marginal with one amp with another, and found it was the amp, not the speaker that sounded bad as soon as the clip lights illuminated. The other amp allowed another 6 dB of usable peak output, even though rated for less than 3 dB more output.

Some pro amps use lots of current limiting (2 ohm output less than four ohm output) some use very little, which can completely change the way a sub with a few narrow low impedance dips sound.

When it comes to real speakers and music, amp ratings do not tell the whole story.
P.S. There are some QSC amps that sound quite good on bass, and some that don't, though that can be said about Crown and Crest too.
For low impedance, super efficient good sounding LF output, good $ to watt ratio, hard to beat Brian Oppegaard's SpeakerPower SP-4000.
Brian learned quite a bit over his years at QSC, and from his relationship with ICE.

Art Welter

Last edited by weltersys; 19th January 2012 at 04:33 PM.
  Reply With Quote
Old 25th January 2012, 09:13 AM   #33
bjorno is offline bjorno  Sweden
diyAudio Member
 
Join Date: Mar 2005
Location: Jacobsmountain
Send a message via MSN to bjorno
Hi,

FYI: Just posting a HR script of the picture in post#30:

b
Attached Files
File Type: txt 2xepic.txt (464 Bytes, 20 views)
  Reply With Quote
Old 6th February 2012, 10:12 PM   #34
diyAudio Member
 
Join Date: Oct 2011
Quote:
Originally Posted by tb46 View Post
Hi 2MuchRiceMakesMeSick,

Here ist a drawing for the 14"x19"x80" box. I did not work out the access panel detail, but otherwise everything is there. The frequency response shifted up a little bit, as the drawn dimensions are a little different from the first rough try at it, you also gain a few dB.

Let me know what questions pop up.

Regards,

I started looking at this today and long story short I need to build this strong so that it supports a mattress on top (150 lbs) me (200 lbs) + two girls (100 lbs each)

Is it possible to shorten the 19" width of the box by 1.5" (2 x 0.75) to help support the weight? any other suggestions to make this box strong to support the weight?
  Reply With Quote
Old 7th February 2012, 01:26 AM   #35
tb46 is offline tb46  United States
diyAudio Member
 
Join Date: Jan 2006
Location: Texas
Hi 2MuchRiceMakesMeSick,

"...possible to shorten the 19" width of the box by 1.5" (2 x 0.75) to help support the weight? any other suggestions to make this box strong..."

No problem to reduce the 19" dimension to 17.5". It actually smoothens out the response a little bit more. If you build the boxes from a decent quality plywood, and if you build the bracing as shown they should be plenty strong enough. Naturally, that depends somewhat on the usage.

Regards,
__________________
Oliver
  Reply With Quote
Old 7th February 2012, 05:20 AM   #36
diyAudio Member
 
Join Date: Feb 2004
Location: Los Angeles
I like QSC-good products from nice folks. As with all brands products range from highly sophisticated-QSC - PowerLight3 Amplifiers-to nice but more ordinary. Just beware that many pro amps run nondefeatable fans. Even with variable speed, these cannot be used in a really quiet room, they have to be put elsewhere.

If you really want the "best" sound quality, consider a sealed design. That just has the simplest transient response, period. All other designs exist to further other goals, generally increasing low frequency sensitivity and/or maximum SPL, plus maybe reduction of distortion at those frequencies. All the other designs incur worsened transient response, and if you look at the frequency response of the horns there are all kinds of response spikes. Above the passband they might be, but horn shapes are generally compromised for practicality. Ported or horn may "outperform" the sealed, but you have a lot of space and a big budget, so optimization is not a big concern.

I love horns, but if I had your application I'd probably consider just a wall of subwoofers loading each other. Maybe manifold-style a la Electro-Voice, or a slot-loaded kind of thing.

Plus, if you want very very very low frequencies without building your house around a horn, sealed may be the only way to do that. Ports big enough to tune down to like 10 Hz or something will probably have their own resonances.
  Reply With Quote
Old 7th February 2012, 02:57 PM   #37
tb46 is offline tb46  United States
diyAudio Member
 
Join Date: Jan 2006
Location: Texas
Hi,

I updated the drawing:

Regards,
Attached Files
File Type: pdf Epic_12in_Dual_14x17.5x80_dwg.pdf (44.4 KB, 35 views)
__________________
Oliver
  Reply With Quote
Old 9th February 2012, 03:15 PM   #38
diyAudio Member
 
Join Date: Oct 2011
Thanks for the update.

I was thinking about building 2 boxes (4 woofers) in the 80" version and the other 2 in the 64" version.

Any problems in doing this? Suggestions on why I wouldnt do this?
  Reply With Quote
Old 9th February 2012, 05:39 PM   #39
tb46 is offline tb46  United States
diyAudio Member
 
Join Date: Jan 2006
Location: Texas
Hi,

This is something you almost have to try out yourself. I would recommend to stay with one length for all four boxes. But, it may well work (it may even work well). I don't think you can easily simulate what this will do in your room with your specific enclosure location. I'll attach the-hastily done-comparisons of SPL and phase.

Regards,
Attached Images
File Type: jpg Epic_12_14x17.5x80_64_SPL.jpg (32.2 KB, 112 views)
File Type: jpg Epic_12_14x17.5x80_64_Phase.jpg (40.8 KB, 111 views)
__________________
Oliver

Last edited by tb46; 9th February 2012 at 05:42 PM.
  Reply With Quote
Old 9th February 2012, 09:41 PM   #40
diyAudio Member
 
Join Date: Oct 2011
I may just build 2 of each and test them. Then built another 2 of the ones I like the best. Is there any way I can get you to update the drawing with the shorter box design?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Can I do a Jordan Jx92S in a .75 cuft cabinet? stephenmarklay Full Range 9 21st December 2009 08:14 PM
Subwoofer box for a Xenon x10d2. Need Suggestions. Ornlu Subwoofers 3 23rd May 2005 07:32 AM
Please help creating subwoofer enclosure Lach O'Sullivan Subwoofers 13 8th September 2003 06:20 AM


New To Site? Need Help?

All times are GMT. The time now is 08:41 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2