Group Delay? - 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 29th October 2001, 06:14 AM   #1
Ignite is offline Ignite  Canada
diyAudio Member
 
Join Date: Jul 2001
Location: Toronto, Ontario, Canada
Send a message via ICQ to Ignite
I'm considering the design of subwoofer for the mini home theatre in my bedroom area. I want the lowest bass possible in a 2-3cu ft max enclosure. The obvious choice here is the ACI SV10, as it has a huge xmax and doesn't need a lot of enclosure volume to play deep. In a ported enclosure of 2 cu ft with an Fb of 21Hz it plays impressively deep with an F3 of about 23Hz.



_BUT_ group delay reaches around 25ms at 20Hz in that alignment. Will this result in noticably 'loose' bass?

[Edited by Ignite on 10-29-2001 at 05:29 PM]
  Reply With Quote
Old 29th October 2001, 07:50 PM   #2
Super is offline Super  United States
diyAudio Member
 
Join Date: May 2001
Location: Connecticut
Send a message via AIM to Super
I believe that the Shiva drivers can be used in enclosures almost as small as 1 cu foot. Also have a look at Dayton's Titanic series of drivers. They have good output in relatively small sealed enclosures.
__________________
Bryan
  Reply With Quote
Old 29th October 2001, 11:29 PM   #3
diyAudio Member
 
Join Date: Oct 2001
Location: 5280'
There considerable disagreement regarding how audible bass GD is. It seems pretty safe that say that 25ms won't be audible at 20Hz.
  Reply With Quote
Old 8th November 2001, 08:29 AM   #4
diyAudio Member
 
Join Date: Oct 2001
Location: Netherlands
I think it is noticeable. 25ms delay means it sounds as if the speakers should be 340*0.025=8.5m moved to the back. 25ms is 180 degress for 20Hz, which is surely audible. It also depends on the top frequency of the sub.

__________________
DuFré
  Reply With Quote
Old 12th November 2001, 10:47 AM   #5
Warp Engineer
On Holiday
 
AudioFreak's Avatar
 
Join Date: Oct 2001
Location: Queensland, Australia
I too face this problem .... given the wild phase changes and group delays of a ported enclosure, would it be possible to make some kind of parametric EQ that could cancel most of this out?
  Reply With Quote
Old 13th November 2001, 04:29 AM   #6
Ignite is offline Ignite  Canada
diyAudio Member
 
Join Date: Jul 2001
Location: Toronto, Ontario, Canada
Send a message via ICQ to Ignite
Perhaps, but probably not.
The only way to eliminate group delay is to change the timing of output at certain frequencies... something I have never heard of being done aside from per-driver timing.

I've opted for the design I was talking about to have a sealed enclosure and equalize for deeper bass.
  Reply With Quote
Old 13th November 2001, 05:52 AM   #7
diyAudio Member
 
Join Date: Oct 2001
Location: 5280'
For those desiring more info on the GD topic here are a couple of references

Blauert, J. and Laws, P "Group Delay Distortions in Electroacoustical Systems"
Journal of the Acoustical Society of America
Volume 63, Number 5, pp. 1478-1483 (May 1978)

"The Differential Time-Delay Distortion and Differential Phase-Shift Distortion as Measures of Phase Linearity" by Marshall Leach,
JAES, Vol. 37, No.9, September 1989

  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
Audibility of group delay? toenail Multi-Way 64 9th December 2013 09:53 PM
Evil group delay phreeky82 Subwoofers 16 4th October 2007 12:26 PM
Group Delay Question 69stingray Multi-Way 12 1st November 2005 11:27 AM
Question about the group delay of this: BAM Multi-Way 1 23rd November 2003 05:07 PM
Group Delay............When Is Too Much Too Much? OMNIFEX Multi-Way 0 14th March 2003 07:30 AM


New To Site? Need Help?

All times are GMT. The time now is 01:07 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