$500 DIY Subwoofer Challenge! - 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 16th January 2013, 11:24 PM   #31
jbell is offline jbell  United States
diyAudio Member
 
Join Date: Apr 2003
Location: .
yea I'm not sure what's up with the 4pi requirement... most interior subs are really loaded about 1pi. However the dual mcm ported cabinet satisfies the 'rules' and exceeds spl requirements by 3db... ON THE CHEAP.

Personally I'd go a bit more expensive and go passive radiator, not ported. Then you'll get some true deep HT rumbles out of it. No cheating involved.

Dayton 12" pr's are $20 each. Use a pair. Subs on the 'skinny' end, and a PR on each "side"

It's still only $200 per cabinet in parts. You could accomplish a pair under $500 and place them around the room to even out your modes.
  Reply With Quote
Old 16th January 2013, 11:30 PM   #32
diyAudio Member
 
Join Date: Feb 2004
Quote:
Originally Posted by jbell View Post
yea I'm not sure what's up with the 4pi requirement... most interior subs are really loaded about 1pi.
I know this, and if you want to convert it, be my guest. I'm just using it because of the sensitivity measurement of the bose is anechoic, which was used to calculate the criteria.
  Reply With Quote
Old 16th January 2013, 11:42 PM   #33
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by turbodawg View Post
4pi space is full space, free air, anechoic.....

Criteria for doubling size twice or 4x is as I provided above:
So you want people to test their home subs suspended several hundred feet in the air or in an anechoic chamber good down to 45 Hz ?

I get what you mean now for size:

1.15 cubic feet 106 dB at 45 Hz (Bose toy sub size, using inflated max SPL level)
2.3 cubic feet 109 dB at 45 Hz
4.6 cubic feet 112 dB at 45 Hz
9.2 cubic feet 115 dB at 45 Hz
18.4 cubic feet 118 dB at 45 Hz

So the Tub Sub at 12.57 cubic feet may still squeak in by that criteria, but no way am I renting a crane to prove it .
  Reply With Quote
Old 16th January 2013, 11:48 PM   #34
diyAudio Member
 
Join Date: Feb 2004
Quote:
Originally Posted by weltersys View Post
So you want people to test their home subs suspended several hundred feet in the air or in an anechoic chamber good down to 45 Hz ?

I get what you mean now for size:

1.15 cubic feet 106 dB at 45 Hz (Bose toy sub size, using inflated max SPL level)
2.3 cubic feet 109 dB at 45 Hz
4.6 cubic feet 112 dB at 45 Hz
9.2 cubic feet 115 dB at 45 Hz
18.4 cubic feet 118 dB at 45 Hz

So the Tub Sub at 12.57 cubic feet may still squeak in by that criteria, but no way am I renting a crane to prove it .
Modeling in 4pi in hornresp will be sufficient here.
  Reply With Quote
Old 17th January 2013, 12:16 AM   #35
jbell is offline jbell  United States
diyAudio Member
 
Join Date: Apr 2003
Location: .
Quote:
Originally Posted by turbodawg View Post
I know this, and if you want to convert it, be my guest. I'm just using it because of the sensitivity measurement of the bose is anechoic, which was used to calculate the criteria.
No offense intended...

And as far as real 4pi, and bose 4pi... well here's a clip from bose's own site.

Our anechoic chamber sits on springs, a room within a room, isolated from the rest of the Bose Research and Development facility. Inside, dense and meticulously arranged fiberglass wedges protrude from all angles. The 24" wedges absorb all sound above 100Hz,

I don't trust any 'chamber' results below 125hz, and in fact feel like bose 45hz measurements probably don't line up exactly with a modeling program like hornresp.

That said, +3db@45hz (minimum) from a pair of $30 drivers in the same size enclosure should flat out embarrass bose... and I think is sufficient for your 'challenge.'

To make it more compelling, you could build a quad of the subs, and add a PA amp, and still be under $500. That's 120db@45hz in 4pi space.

Last edited by jbell; 17th January 2013 at 12:27 AM.
  Reply With Quote
Old 17th January 2013, 12:25 AM   #36
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by turbodawg View Post
I think you'll find you're a bit off on the Dayton. Spec sheet calls for 800 wrms, not AES.

Dayton Audio RSS390HO-4 15" Reference HO Subwoofer 4 Ohm 295-469
I did not find any test protocol on the Dayton website, but find it hard to believe it would handle much more power than the larger voice coil Lab 15.

Like all the other Eminence product Parts Express misquotes the power rating of the Lab 15 as RMS, when Eminence clearly states the use of the EIA 426A noise source.

The EIA 426A noise source is used by most manufacturers, I'd think Dayton would use it too.
Go ahead and try putting an 800 watt sine wave in to your Dayton Audio RSS390HO-4 15" Reference HO Subwoofer and tell me what color smoke comes out.
Speaking of smoke, can you post the Bose anechoic chamber (above 100 Hz) frequency response of the toy sub?

Art
Attached Images
File Type: png EIA, RMS.png (384.0 KB, 379 views)

Last edited by weltersys; 17th January 2013 at 12:29 AM.
  Reply With Quote
Old 17th January 2013, 12:31 AM   #37
diyAudio Member
 
Join Date: Feb 2011
Location: Colorado, USA
24" wedges? Really? Hilarious. A Bose Wave Radio ready chamber. I've been locked in a real one. Not fun after a few minutes.
  Reply With Quote
Old 17th January 2013, 01:01 AM   #38
diyAudio Member
 
Join Date: Feb 2004
Running my existing model of the 15 HO, 3 cubes total tuned in the high 30's, I get 118 db with 55v (750w) in 4pi space. Can't get into it further tonight, need to focus on other projects.
  Reply With Quote
Old 17th January 2013, 03:02 PM   #39
diyAudio Member
 
Join Date: Feb 2004
Quote:
Originally Posted by jbell View Post
No offense intended...

And as far as real 4pi, and bose 4pi... well here's a clip from bose's own site.

Our anechoic chamber sits on springs, a room within a room, isolated from the rest of the Bose Research and Development facility. Inside, dense and meticulously arranged fiberglass wedges protrude from all angles. The 24" wedges absorb all sound above 100Hz,

I don't trust any 'chamber' results below 125hz, and in fact feel like bose 45hz measurements probably don't line up exactly with a modeling program like hornresp.

That said, +3db@45hz (minimum) from a pair of $30 drivers in the same size enclosure should flat out embarrass bose... and I think is sufficient for your 'challenge.'

To make it more compelling, you could build a quad of the subs, and add a PA amp, and still be under $500. That's 120db@45hz in 4pi space.
I pulled the 85 db/w/m figure as an anechoic measurement of the sat's from a website that claimed that it was an indy test. So the figures presented are a high side educated guess, purely a nominal figure for the sake of comparison. It would be interesting to see what one of these actually does with a 400w 45hz sine wave............LOL.

Last edited by turbodawg; 17th January 2013 at 03:04 PM.
  Reply With Quote
Old 17th January 2013, 04:11 PM   #40
DrDyna is offline DrDyna  United States
diyAudio Member
 
DrDyna's Avatar
 
Join Date: May 2007
Blog Entries: 3
Quote:
Originally Posted by turbodawg View Post
It would be interesting to see what one of these actually does with a 400w 45hz sine wave............LOL.
RAH TATATATATATATA *poof*
__________________
The best video in the world.
  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
DIY FM Tuner challenge cadmaniac Everything Else 28 16th January 2004 08:34 AM
subwoofer project challenge 2Bit Subwoofers 0 21st December 2003 03:41 AM
ULTIMATE subwoofer challenge... can you do it? kingfootga Subwoofers 105 8th December 2003 06:25 AM
Challenge: To build the best subwoofer for around AUD$500 viper073 Subwoofers 34 3rd December 2002 06:31 AM


New To Site? Need Help?

All times are GMT. The time now is 11:56 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