Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Group Delay
Group Delay
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
Thread Tools Search this Thread
Old 4th January 2010, 02:52 PM   #1
pargon is offline pargon  Mexico
diyAudio Member
Join Date: Sep 2005
Default Group Delay

I am in the process of analyzing which of several LF drivers from the collection would be best in a Pass version of EL Pipe-o. Using WinISD the driver with the best extension of bass response also demonstrates the highest degree of group delay around 30Hz. How critical is this? Should a group delay number of 22ms around 30Hz disqualify this woofer? I can tune the box volume to minimize the group delay, but the low frequency gain drops accordingly. Advice around the web seems to be that increased "stuffing" of the tube will help. Thanks in advance for your advice.
  Reply With Quote
Old 4th January 2010, 05:10 PM   #2
WithTarragon is online now WithTarragon  United States
diyAudio Member
Join Date: Jun 2007
Well, we do not have enough information yet.
1. The estimate of 22 ms seems large, are you confident about that?
2. You should be more worried about the group delay around the crossover point.
3. What is the crossover point and how steeply is it crossed over?
4. What are the kind of cabinet are the main woofers in (sealed, vented, horn loaded, etc).
5. Is the proposed crossover going to be active or passive.
  Reply With Quote
Old 4th January 2010, 05:26 PM   #3
Iain McNeill is offline Iain McNeill  United Kingdom
diyAudio Moderator Emeritus
Iain McNeill's Avatar
Join Date: Oct 2007
Location: Santa Cruz, California
The group delay is a function of the driver resonant frequency and Q and the enclosure. If you want low group delay then you need to use a sealed box and a low Q (e.g. 0.5-0.7).

The El pipe-o is a transmission line speaker, open at the far end so I would guess that this rolls off at 24dB/octave and hence has higher group delay than an equivalent sealed design but others may have better info.
  Reply With Quote
Old 4th January 2010, 08:53 PM   #4
pargon is offline pargon  Mexico
diyAudio Member
Join Date: Sep 2005
Default Thanks for the response Herb man

#1 That's what the WinISD lists for the driver, in the recommended size box.
#2,3,5 Current plan is to use a passive line level xover from Marchand, in the 40Hz region, where the group delay is about 9ms, but with a very steep curve up as freq goes down to 30 and then back down
# 4 Bass reflex cab on 604's
Thanks for your interest and time,
  Reply With Quote
Old 5th January 2010, 05:44 PM   #5
Ron E is offline Ron E  United States
diyAudio Member
Ron E's Avatar
Join Date: Jun 2002
Location: USA, MN
one period at 30Hz is 33msec. 20msec, being less than a period or two, means no problem. Group delay is a much misunderstood concept that isn't very useful, for the most part.
Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan
Armaments, universal debt, and planned obsolescence--those are the three pillars of Western prosperity. Aldous Huxley
  Reply With Quote
Old 29th January 2010, 08:37 PM   #6
head_unit is offline head_unit  United States
diyAudio Member
Join Date: Feb 2004
Location: Los Angeles
If I understand correctly, you are extending the lows by making the enclosure kinda more resonant down there. More resonant = more group delay. But if it's just at very low frequencies, not a big worry.
  Reply With Quote


Group DelayHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Acceptable group delay mitchyz250f Multi-Way 43 28th November 2008 08:40 PM
Evil group delay phreeky82 Subwoofers 16 4th October 2007 01:26 PM
Group Delay Question 69stingray Multi-Way 12 1st November 2005 12:27 PM
Group Delay............When Is Too Much Too Much? OMNIFEX Multi-Way 0 14th March 2003 08:30 AM
Group Delay? Ignite Multi-Way 6 13th November 2001 06:52 AM

New To Site? Need Help?

All times are GMT. The time now is 05:07 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio