operation below fs - Page 2 - 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 28th August 2006, 07:59 AM   #11
diyAudio Member
 
paulspencer's Avatar
 
Join Date: Sep 2003
Location: Melbourne, Australia
Those are some great links.

After reading that Nousaine article, I do wonder why he doesn't consider horn loaded. My simulations indicated you could exceed 120 dB easily @ 20 Hz with two high excursion 12" drivers with much less power than all but the cheapest of plate amps. Required footprint is only about 2 x 0.5m with a large floor to ceiling box. Not that bad really. If I had room I would have done it by now.

When I was working on the design, another who had built a smaller bass horn suggested that it could go well below 20 Hz due to the corner expansion. Given a spare basement, you could also build some very large vented boxes or bandpass boxes to get high SPL @ 10 Hz if unhappy with the extension of the horn.

The horn could actually match the SPL of the IB on the low end, given the same number of drivers. Not that you would pull this off since the horn would be huge then with that many drivers.
  Reply With Quote
Old 31st August 2006, 10:08 PM   #12
diyAudio Member
 
kingdaddy's Avatar
 
Join Date: Mar 2002
Location: Fort Worth, Texas
I've played 7Hz test tones on my 4-18" Avalanche IB with no problem and still quite strong on the SPL, but the electronics brick wall there and as far as I know you wont find many combinations of electronics that wont stop you somewhere before 5Hz. Also if your looking for any measurements or want to do some real experimenting here I donít know how you would as I donít know of any test equipment readably available that will test anything accurately down this low. BTW, why?
__________________
http://kingdaddy.linaeum.com/
  Reply With Quote
Old 2nd September 2006, 04:18 PM   #13
Bogie is offline Bogie  United States
diyAudio Member
 
Join Date: Dec 2004
Location: St. Louis
It's fun to hack off the guys at the seismic lab?
  Reply With Quote
Old 3rd September 2006, 11:04 AM   #14
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
I have just downloaded Stig Tangen's article from post4.
Can I assume the content as gospel? or are there any corrections that I should account for?

22Hz performance from a driver with Fs=40Hz seems more than impressive!
__________________
regards Andrew T.
  Reply With Quote
Old 3rd September 2006, 02:32 PM   #15
diyAudio Member
 
Join Date: Jul 2006
The why is to experiement with infrasonics in music. This thread is a continuation of the Giant Subwoofer thread where this was first broached.

There are 3 pipe organs in the world that have the 64' octave, which has its lowest note, C at 8hz. Is that music, or is it a sound effect?

I am not sure, but I'd like to experiment . I think it is a fascinating subject. If its possible to go lower, OK.

Do you have a link for that 18" Avalanche? I tried to find that once and could not.
  Reply With Quote
Old 3rd September 2006, 06:08 PM   #16
qi is offline qi
diyAudio Member
 
Join Date: Oct 2003
Location: .
Quote:
Do you have a link for that 18" Avalanche?
Have you heard of GOOGLE?

I found it in like 30 seconds...

http://www.frappr.com/?a=photo&gid=3...sh_slideticker
  Reply With Quote
Old 3rd September 2006, 06:42 PM   #17
AKN is offline AKN  Sweden
No snake oil
diyAudio Member
 
AKN's Avatar
 
Join Date: Aug 2005
Location: In the middle of Sweden
Send a message via MSN to AKN
Quote:
Originally posted by AndrewT
Hi,
I have just downloaded Stig Tangen's article from post4.
Can I assume the content as gospel? or are there any corrections that I should account for?

22Hz performance from a driver with Fs=40Hz seems more than impressive!
He has active correction.

Quote:
"The first two sections are the equalizer. The two last 2nd order filters are in combination a 4th order Linkwitz-Riley filter"

The woofer he is using has Qtc around 0.3 so it is possible to have sufficient gain from BR. Tuning is also low. Resulting in a shelf response that he is EQing flat.

The site seems to have lost all pictures that backed up his article.

Edit:
Here's one sim i made with JBL 2226 in 220L box tuned to 22Hz. Not impossible to EQ flat.
Attached Images
File Type: jpg 2226_220l_22hz.jpg (47.7 KB, 311 views)
__________________
/ Anders
  Reply With Quote
Old 3rd September 2006, 07:36 PM   #18
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi 4fun,
thanks for the clarification.

What about mistakes or rose tinted glasses in the Stig article?
__________________
regards Andrew T.
  Reply With Quote
Old 5th September 2006, 04:38 AM   #19
diyAudio Member
 
Join Date: Jul 2006
qi, IB Cult? I don't know what to make of that. All those boxes with the back side of the woofer exposed? Are those Avalanche? I really never heard of that name and have not been able to find them.
  Reply With Quote
Old 5th September 2006, 04:47 AM   #20
Bogie is offline Bogie  United States
diyAudio Member
 
Join Date: Dec 2004
Location: St. Louis
Enough woofs, with enough surface area, and enough xmax, and with a little judicious equalization, you're there. Granted, with a single one, you're not going to be able to rumble loud, but you _can_ rumble... And when you get into the folks who build walls out of them, well...

The limiting factors are construction of the chamber (the listening room) and how much $$$ you can throw at it.
  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
CFB and A2 operation hemgjord Tubes / Valves 2 9th September 2008 10:42 PM
dcc salvage operation jaudio Digital Source 1 27th October 2006 12:24 PM
Balanced Operation gchrist Pass Labs 1 21st July 2003 01:23 PM
Class B operation ding Solid State 17 8th October 2001 05:37 AM


New To Site? Need Help?

All times are GMT. The time now is 12:06 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