Helmholtz Resonator Inside a Sealed Cabinet - Page 2 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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 18th September 2012, 07:07 PM   #11
diyAudio Member
 
bolserst's Avatar
 
Join Date: Jun 2005
Location: Fort Worth, Texas
Default Dahlquist DQ10 woofer enclosure with internal chambers

It's been a while since I looked at one, but I believe the woofer enclosure of the Dahlquist DQ10 had two internal damping chambers. They were made by boarding off ends of the enclosure leaving a small gap with one wall to make the rectangular vent openings. There was damping material in these damping chambers.
  Reply With Quote
Old 18th September 2012, 07:39 PM   #12
diyAudio Member
 
LafeEric's Avatar
 
Join Date: May 2010
Quote:
Originally Posted by Don Hills View Post
Try this:

Code:
...
  fs=37.6374Hz  |Mmd = 16.00g not recognised by AkAbak, fs calculated and used instead
  ...
Hi Don.

Hate to go OT a bit, but I have been struggling at times with AkAbak not accepting certain values, such as Mmd, and I was wondering if you could explain that a bit, and your workaround.
  Reply With Quote
Old 18th September 2012, 09:17 PM   #13
diyAudio Member
 
Join Date: May 2009
Location: Wellington
Quote:
Originally Posted by LafeEric View Post
Hi Don.

Hate to go OT a bit, but I have been struggling at times with AkAbak not accepting certain values, such as Mmd, and I was wondering if you could explain that a bit, and your workaround.
I didn't do the workaround - the AkAbak model I used as a starting point was an export from Hornresp, which does the conversion during the export. I haven't looked into it, I suspect Hornresp uses a different subset of driver parameters for calculations than AkAbak does.
  Reply With Quote
Old 18th September 2012, 09:24 PM   #14
T101 is offline T101  Bulgaria
diyAudio Member
 
Join Date: Mar 2010
Location: Sofia-Bulgaria
Now it got even more confusing. Don't look at me, I just copy-pasted and pushed a button.
The only suspicion I had, was why the dip has such small extent, I would expect something like half octave at least. For instance if Fb is 50 Hz, then it should be between 37.5 and 75 Hz.
  Reply With Quote
Old 18th September 2012, 09:25 PM   #15
diyAudio Member
 
Join Date: May 2009
Location: Wellington
I think that using resonators to take the "hump" out of high Qts driver responses is going to be problematic to implement. Standard Helmholtz resonators have too high a Q value, as you see in the results - a very narrow notch. (By the way, when working with bass units, I find it useful to reduce the frequency range of the AkAbak graphing function to, say, 200 Hz instead of 20 KHz.)

You might be able to lower the Q of the resonator by stuffing it, similar to the Dahlqist DQ10 speaker scheme mentioned by bolserst.

Maybe you could produce an AkAbak script for a driver and enclosure that you would like to reduce peaks in, and we can try some ideas on it. If you're not proficient with AkAbak, do it in Hornresp and export it, or do it in some other software and provide the driver parameters and box dimensions.
  Reply With Quote
Old 19th September 2012, 12:37 PM   #16
diyAudio Member
 
LafeEric's Avatar
 
Join Date: May 2010
Perhaps you could further reduce the Q by venting into your stuffed second chamber through a vario-vent.

Speaking of which - does anyone know how to describe a vario-vent in AkAbak? I suppose one would describe a duct with a modified impedance - not sure how that's done...
  Reply With Quote
Old 19th September 2012, 12:42 PM   #17
diyAudio Member
 
LafeEric's Avatar
 
Join Date: May 2010
Quote:
Originally Posted by Don Hills View Post
I didn't do the workaround - the AkAbak model I used as a starting point was an export from Hornresp, which does the conversion during the export. I haven't looked into it, I suspect Hornresp uses a different subset of driver parameters for calculations than AkAbak does.
To keep this from going any more off topic I am going to switch this over to this thread... Akabak Simulator
  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
formula for Q of Helmholtz resonator PeteMcK Everything Else 9 18th September 2012 02:12 PM
Soldering Inside A Cabinet DreadPirate Multi-Way 6 5th December 2010 09:21 PM
Cabinet brace act as helmholtz resonator? RyanW Multi-Way 17 2nd October 2007 11:08 PM
Dont want mr. Helmholtz in my sealed sub ! Coolin Subwoofers 18 14th October 2005 09:13 PM


New To Site? Need Help?

All times are GMT. The time now is 03:26 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