Can a delay circuit be beneficial between bass and mids? - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

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 8th February 2012, 08:17 PM   #1
diyAudio Member
 
Join Date: Sep 2007
Default Can a delay circuit be beneficial between bass and mids?

Still fine tuning my active bass/midrange xovers. Mids to tweeter is passive, and needs no adjustment. I wonder if using all-pass delay stages will provide any benefit to the bass/mid transition? I do not have a way to measure phase of the drivers. The xover is 4th order LR @ 220 for 8" woofers, 2nd order BW @ 300 for the 4" mids. Amplitude looks good on paper, but I can hear something in the lower mids that's not quite right. Horizontal difference is between one and two inches, vertical is 28" C-T-C between the two most spaced drivers, M-T-M-WW configuration.

Has anyone successfully used delay between midrange and woofer?

Peace,
Tom E
  Reply With Quote
Old 8th February 2012, 08:33 PM   #2
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Hi,

No, when your talking about 2" for wavelengths about 3-4ft.

Your problem might be related to lack of baffle step correction
and / or related to the mid units fundamental resonance, its
hard to say with full modelling details.

TBH your arrangements for BSC sound (sic) non-existen

Delay for bass to mid never, sometimes for mid to treble.

rgds, sreten.

http://sites.google.com/site/undefinition/diy (see if nothing else, the excellent FAQs)
http://techtalk.parts-express.com/sh...d.php?t=219617
http://www.zaphaudio.com
http://www.zaphaudio.com/ZA5/
http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://web.archive.org/web/200909021...esigningXO.htm
http://www.rjbaudio.com/
http://web.archive.org/web/200909022...ve99/Spkrbldg/
http://speakerdesignworks.com/
http://www.htguide.com/forum/showthread.php4?t=28655
http://www.deadwaxcafe.com/vzone/david/david.htm
http://www.troelsgravesen.dk/Diy_Lou...r_Projects.htm
http://www.humblehomemadehifi.com/download.html
http://www.quarter-wave.com/
http://www.frugal-horn.com/
http://www.linkwitzlab.com/
http://www.musicanddesign.com/

Great free SPICE Emulator : http://focus.ti.com/docs/toolsw/fold...t/tina-ti.html
__________________
There is nothing so practical as a really good theory - Ludwig Boltzmann
When your only tool is a hammer, every problem looks like a nail - Abraham Maslow

Last edited by sreten; 8th February 2012 at 08:37 PM.
  Reply With Quote
Old 8th February 2012, 10:12 PM   #3
diyAudio Member
 
Join Date: Dec 2003
Location: Orange County, CA
When I worked for a major pro audio speaker manufacturer we put a time delay of 83 micro seconds for every inch the LF driver's dust cap was forward of the MF driver's dust cap. And that has 83 micro Seconds delay for every inch in front of the HF driver's diaphram. We had the HF driver furthest back in the enclosure. So the way we made them was with no delay on the HF, delay on the MF and still more delay on the LF.

However, on home speakers, the LF is the furthest from the listener and the HF the closest. Therefore, one would delay the MF as needed and the HF a bit more.

The rule is 83 micro seconds per inch of front to rear separation between drivers.
__________________
Dan Fraser
  Reply With Quote
Old 9th February 2012, 01:10 PM   #4
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Quote:
Originally Posted by dmfraser View Post
When I worked for a major pro audio speaker manufacturer we put a time delay of 83 micro seconds for every inch the LF driver's dust cap was forward of the MF driver's dust cap. And that has 83 micro Seconds delay for every inch in front of the HF driver's diaphram. We had the HF driver furthest back in the enclosure. So the way we made them was with no delay on the HF, delay on the MF and still more delay on the LF.

However, on home speakers, the LF is the furthest from the listener and the HF the closest. Therefore, one would delay the MF as needed and the HF a bit more.

The rule is 83 micro seconds per inch of front to rear separation between drivers.
Hi, pointless and inaudible at a typical bass / mid x/o point, rgds, sreten.

Driver offsets in typical 2 way bass/mid & treble speaker can be
compensated by making the x/o (acoustic curves) assymetric.

The phase shifts at bass to mid x/o are far higher than 83uS, and
any assymetry in the acoustic responses (very likely) will cause
far higher delays than that caused by driver acoustic offsets.
The effective acoustic offset of a driver may not be the dust cap.
__________________
There is nothing so practical as a really good theory - Ludwig Boltzmann
When your only tool is a hammer, every problem looks like a nail - Abraham Maslow
  Reply With Quote
Old 9th February 2012, 06:02 PM   #5
diyAudio Member
 
Join Date: Sep 2007
Is there an active circuit that will compensate for the phase shift, or do you believe it is not audible and therefore not worth attempting? I am not as worried about the physical driver offset (because of the low xover frequency) as I am about the phase shift between LR4 and BW2 I am using. Perhaps my initial post was not clear.

Peace,
Tom E
  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
delay line settings to time-align DTS-10 tapped horn to mids & high drivers cyclecamper Subwoofers 4 20th April 2011 06:52 AM
Recomnbed woofers/Mids for punchy yet deep bass? xenu Multi-Way 14 21st April 2009 02:32 AM
Which aleph for the bass and mids? Selfmade Pass Labs 5 22nd July 2008 06:25 PM
Mids/Bass driver for TDL Fossil Multi-Way 2 14th February 2006 11:45 AM
Bass interference with mids fr0st Multi-Way 12 16th January 2003 09:36 PM


New To Site? Need Help?

All times are GMT. The time now is 08:02 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