Recommend a subwoofer design for my application: - 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 23rd December 2010, 01:20 AM   #1
cast55 is offline cast55  Canada
diyAudio Member
 
Join Date: Sep 2010
Default Recommend a subwoofer design for my application:

I am running an active cross three way stereo triamplified (six channel) system.

My bass cabinets are vented EBS3, each carrying one EVX-180B driven by one channel of a QSC PLX3102. These cabinets are nicely flat to 32 Hz, and do extend lower than that to some extent. I have disabled the 32 Hz "subsonic" filter on the QSC, and instead implemented a 48 dB/octave L-R active slope at 20 Hz to roll off the subsonics and prevent driver overexcursion - the natural roll-off of the driver is somewhat higher than this. So configured, I'm pretty happy with the way these cabinets sound for music and movies, however I am definitely missing something on the extreme low end, and I was hoping to augment this infrasonic-to-low-sonic range with an additional sub.

Ideally, I would like something that can keep up with my mains (which are well into 130+ dB), but which cover the bottom octaves only, crossed at 32 Hz on the upper end, and extending down to 16 Hz at minimum, and 8 Hz if at all feasible. The project will be DIY, and difficulty is not really an issue. My budget is not set in stone, but I am thinking about $1K for amplification and $800 - $1K for drivers/enclosure, maximum. Huge transmission lines are probably out because I only have 8' ceilings.

Suggestions?
  Reply With Quote
Old 23rd December 2010, 11:43 AM   #2
epa is offline epa  Netherlands
diyAudio Member
 
Join Date: Apr 2010
Location: amsterdam
Quote:
Originally Posted by cast55 View Post
I am running an active cross three way stereo triamplified (six channel) system.

My bass cabinets are vented EBS3, each carrying one EVX-180B driven by one channel of a QSC PLX3102. These cabinets are nicely flat to 32 Hz, and do extend lower than that to some extent. I have disabled the 32 Hz "subsonic" filter on the QSC, and instead implemented a 48 dB/octave L-R active slope at 20 Hz to roll off the subsonics and prevent driver overexcursion - the natural roll-off of the driver is somewhat higher than this. So configured, I'm pretty happy with the way these cabinets sound for music and movies, however I am definitely missing something on the extreme low end, and I was hoping to augment this infrasonic-to-low-sonic range with an additional sub.

Ideally, I would like something that can keep up with my mains (which are well into 130+ dB), but which cover the bottom octaves only, crossed at 32 Hz on the upper end, and extending down to 16 Hz at minimum, and 8 Hz if at all feasible. The project will be DIY, and difficulty is not really an issue. My budget is not set in stone, but I am thinking about $1K for amplification and $800 - $1K for drivers/enclosure, maximum. Huge transmission lines are probably out because I only have 8' ceilings.

Suggestions?
verry narrow band
@ what freq you x-over to the mids?
is it mayby possible to redesign the ev 18"?
tapped horn or tqtp should go lower ,130 db is a challenge.
  Reply With Quote
Old 23rd December 2010, 06:11 PM   #3
tb46 is offline tb46  United States
diyAudio Member
 
Join Date: Jan 2006
Location: Texas
Default 134dB @ 8Hz

How abut the Matterhorn? :-)

Regards,
__________________
Oliver
  Reply With Quote
Old 23rd December 2010, 06:44 PM   #4
cast55 is offline cast55  Canada
diyAudio Member
 
Join Date: Sep 2010
Quote:
Originally Posted by epa View Post
verry narrow band
@ what freq you x-over to the mids?
is it mayby possible to redesign the ev 18"?
tapped horn or tqtp should go lower ,130 db is a challenge.
As it stands, I am crossing over to my mids (18Sound 10M600 on one channel each of QSC PLX1802) at 254 Hz, and then to my highs (JBL 2441 compression drivers on 2382A horns, on a QSC PLX1104) at 2kHz.

This actually measures and sounds decent in the room; however, I am using more EQ than I like to do this - I think I might add a midbass between the EVX-180B and the 10M600 at some point to clean things up a little. That is looking long-term, though. I would prefer to focus on the portion of the spectrum which is missing entirely, which is the infrasonic and low sub range. I designed my bass cabs specifically for the EVX180B, and for their intended purpose, they work perfectly. High SPL, low distortion, and decent extension for that driver; however, they were designed for music / sound reinforcement, and not for theater / synthesized low frequency effects which is the material I am trying to address with the new sub.

Although a LFE cabinet which could reproduce the same SPL as the existing system would be ideal, I suppose this is unnecessary in consideration of the fact that I would never exhibit movies etc. at maximum SPL. That sort of power I only rarely use for sound reinforcement of material for which that sort of thing is expected.

What is tqtp?
  Reply With Quote
Old 23rd December 2010, 10:23 PM   #5
epa is offline epa  Netherlands
diyAudio Member
 
Join Date: Apr 2010
Location: amsterdam
Quote:
Originally Posted by cast55 View Post
As it stands, I am crossing over to my mids (18Sound 10M600 on one channel each of QSC PLX1802) at 254 Hz, and then to my highs (JBL 2441 compression drivers on 2382A horns, on a QSC PLX1104) at 2kHz.

This actually measures and sounds decent in the room; however, I am using more EQ than I like to do this - I think I might add a midbass between the EVX-180B and the 10M600 at some point to clean things up a little. That is looking long-term, though. I would prefer to focus on the portion of the spectrum which is missing entirely, which is the infrasonic and low sub range. I designed my bass cabs specifically for the EVX180B, and for their intended purpose, they work perfectly. High SPL, low distortion, and decent extension for that driver; however, they were designed for music / sound reinforcement, and not for theater / synthesized low frequency effects which is the material I am trying to address with the new sub.

Although a LFE cabinet which could reproduce the same SPL as the existing system would be ideal, I suppose this is unnecessary in consideration of the fact that I would never exhibit movies etc. at maximum SPL. That sort of power I only rarely use for sound reinforcement of material for which that sort of thing is expected.

What is tqtp?
sorry its tqwtp tapped quarter wave tapered pipe
  Reply With Quote
Old 24th December 2010, 01:40 PM   #6
epa is offline epa  Netherlands
diyAudio Member
 
Join Date: Apr 2010
Location: amsterdam
something like this

Click the image to open in full size.


bms 18 860
klik on the pic to enlarge,then klik bottem left to enlarge again

Last edited by epa; 24th December 2010 at 01:42 PM.
  Reply With Quote
Old 24th December 2010, 04:57 PM   #7
tb46 is offline tb46  United States
diyAudio Member
 
Join Date: Jan 2006
Location: Texas
Hi epa,

These designs need very solid corners to give the SPL indicated, maybe 2 x pi would be more appropriate? Two boxes with dual JBL GTO1214 in a DTS-10 style enclosure will also get there, with corner loading.

Regards,
__________________
Oliver

Last edited by tb46; 24th December 2010 at 05:02 PM.
  Reply With Quote
Old 24th December 2010, 11:36 PM   #8
epa is offline epa  Netherlands
diyAudio Member
 
Join Date: Apr 2010
Location: amsterdam
Quote:
Originally Posted by tb46 View Post
Hi epa,

These designs need very solid corners to give the SPL indicated, maybe 2 x pi would be more appropriate? Two boxes with dual JBL GTO1214 in a DTS-10 style enclosure will also get there, with corner loading.

Regards,
hi tb46
i propose of corner loading these anyway.
i was thinking of a single fold.
what do you mean by solid corners?
haven,t moddeled these jbl's yet
  Reply With Quote
Old 25th December 2010, 04:45 PM   #9
tb46 is offline tb46  United States
diyAudio Member
 
Join Date: Jan 2006
Location: Texas
Hi epa,

A corner in a basement build from concrete would qualify as solid, wouldn't it? Whereas 3/8" plaster board on metal wall studs spaced on 24" centers wouldn't. In the sub 30Hz frequency range sound has a tendency to just go through walls, and the corner effect disappears, you might not even get to 1 x Pi. Measurements would tell, but I would recommend modelling in 2 x Pi.

As to the JBLs, they are inexpensive, and Petter Persson already has done the basic work:

http://www.diyaudio.com/forums/subwo...n-2x12-th.html

Merry Christmas!

Regards,
__________________
Oliver
  Reply With Quote
Old 25th December 2010, 11:30 PM   #10
epa is offline epa  Netherlands
diyAudio Member
 
Join Date: Apr 2010
Location: amsterdam
Quote:
Originally Posted by tb46 View Post
Hi epa,

A corner in a basement build from concrete would qualify as solid, wouldn't it? Whereas 3/8" plaster board on metal wall studs spaced on 24" centers wouldn't. In the sub 30Hz frequency range sound has a tendency to just go through walls, and the corner effect disappears, you might not even get to 1 x Pi. Measurements would tell, but I would recommend modelling in 2 x Pi.

As to the JBLs, they are inexpensive, and Petter Persson already has done the basic work:

http://www.diyaudio.com/forums/subwo...n-2x12-th.html

Merry Christmas!

Regards,
ah i see ,i tought you meant the corners in the horn
that project looks verry promissing,ill look in to it tomorrow
tnx
  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
Recommend a 8" Subwoofer driver dannyjmf Subwoofers 30 13th August 2011 01:53 AM
Please recommend a 10" subwoofer okmat Subwoofers 18 7th May 2010 11:18 PM
Please recommend Subwoofer Driver mart34 Subwoofers 5 26th September 2008 12:07 AM
CT design trans application HugoR Tubes / Valves 1 18th October 2005 09:46 PM
Car subwoofer usage in PA application chriscam Subwoofers 8 29th July 2003 10:58 AM


New To Site? Need Help?

All times are GMT. The time now is 08:11 AM.


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