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 5th December 2007, 07:09 PM   #1
diyAudio Member
 
Join Date: Nov 2004
Location: sk
Send a message via AIM to ocool_15 Send a message via Yahoo to ocool_15
Default Testing Harmonic Distortion in a enclosure

I realize most harmonic distortion testing is done on a infinite baffle but was wondering if the tests would be valid between drivers if done in the same enclosure.

F3 and QTC will vary with the different drivers. The Qtc varies from about .0703-1.07 in the test enclosure.

I have a 0.3 cu ft enclosure I can mount them in for testing and will build the proper enclosure once a driver is chosen.

I have a couple pairs of 6.5" and am looking at using a pair for midbass/bass duty for my moderate home theatre. Frequency response will be F3-120Hz.
  Reply With Quote
Old 5th December 2007, 10:49 PM   #2
MaVo is offline MaVo  Germany
diyAudio Member
 
Join Date: Jan 2006
Location: Herne
a closed volume generates its own distortion due to air compression. look at linkwitz site for details.
  Reply With Quote
Old 6th December 2007, 08:29 AM   #3
diyAudio Member
 
Join Date: May 2006
But also work as HPF for driver and reduce some HD in low end.
It will be interesting to look and compare behaviour HD loudspeakers in the enclosure and without it.
  Reply With Quote
Old 6th December 2007, 08:53 AM   #4
Ron E is online now Ron E  United States
diyAudio Member
 
Ron E's Avatar
 
Join Date: Jun 2002
Location: USA, MN
Default Re: Testing Harmonic Distortion in a enclosure

Quote:
Originally posted by ocool_15
I realize most harmonic distortion testing is done on a infinite baffle but was wondering if the tests would be valid between drivers if done in the same enclosure.
Just do it. The true test would be if they were each in the enclosure size you would use with them. I wouldn't agree that distortion tests are usually infinite baffle....

Quote:
Originally posted by MaVo
a closed volume generates its own distortion due to air compression. look at linkwitz site for details.
This is important only when the enclosure stiffness dominates and when the displacement volume of the driver exceeds 15% of the total volume. Otherwise the air spring is usually considerably more linear than the driver's own Cms.
__________________
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 6th December 2007, 12:52 PM   #5
diyAudio Member
 
Join Date: Nov 2004
Location: sk
Send a message via AIM to ocool_15 Send a message via Yahoo to ocool_15
Default Re: Re: Testing Harmonic Distortion in a enclosure

Quote:
Originally posted by Ron E

Just do it. The true test would be if they were each in the enclosure size you would use with them. I wouldn't agree that distortion tests are usually infinite baffle....
Since the systems Qtc and F3 will vary from each other and from their final alignment doesn't that make the information of limited or no use in their intended range( up to 120Hz)?

Would the comparison be accurate at frequencies well above the enclosures high pass filter effect like 250 Hz-20kHz?
  Reply With Quote
Old 6th December 2007, 12:53 PM   #6
ucla88 is offline ucla88  Tahiti
diyAudio Member
 
Join Date: Dec 2001
Location: rocklin, CA
See my dipole-monopole comparison graphs

See the posts for Sept 19th.

http://www.markk.claub.net/whats_new.htm

To be fair, this is a 4 vs 1 comparison and a host of changed variables. Nonetheless, the distortion pattern is clearly different for the open baffle vs the closed box.


Ideally, if you're going to use a driver in an open baffle configuration, that's the way you should test it. Same for the closed box. However, that's just not always practical. You should still be able to get a reasonable idea of driver nonlinearities as long as they are compared in the same way.
__________________
http://www.audioheuristics.org/ aka Mark's Speaker Page
  Reply With Quote
Old 6th December 2007, 11:25 PM   #7
Ron E is online now Ron E  United States
diyAudio Member
 
Ron E's Avatar
 
Join Date: Jun 2002
Location: USA, MN
Quote:
Originally posted by ucla88
See my dipole-monopole comparison graphs
Ideally, if you're going to use a driver in an open baffle configuration, that's the way you should test it. Same for the closed box.
Very interesting! Even order is what would typically be generated in an enclosure. It would be neat to see the test rerun with one driver in each enclosure at the same drive level, and perhaps in different sized closed boxes.
__________________
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

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
Harmonic Distortion In Maggies JimOfOakCreek Planars & Exotics 2 20th April 2008 04:04 AM
Why is distortion harmonic? dsavitsk Tubes / Valves 48 12th March 2008 02:49 AM
What effect does a TL have on harmonic distortion? owdi Multi-Way 0 26th April 2006 03:55 PM
second harmonic distortion tenderland Tubes / Valves 5 5th August 2004 11:29 AM
Non Linear Distortion testing - Harmonic Distortion JMB Multi-Way 0 20th July 2004 02:54 PM


New To Site? Need Help?

All times are GMT. The time now is 12:33 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