Go Back   Home > Forums > >

Software Tools SPICE, PCB CAD, speaker design and measurement software, calculators

Mic distance for driver measurements
Mic distance for driver measurements
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
Old 7th November 2009, 04:20 AM   #1
ted4412wilt is offline ted4412wilt  United States
diyAudio Member
Join Date: Jun 2006
Location: Columbia, MO
Default Mic distance for driver measurements

How far should I place my ECM8000 from a driver using STEPS for minimal problems from measurement room reflections? I assume this should change with frequency. I am using a Xenex 802. What level to measure without overdriving the mic or mixer? Advice for measurement techniques would be greatly appreciated. I will be measuring a North D25 tweeter to compare with the factory measurement paper to calibrate my mic. Also will be measuring drivers from 4" to 10". Thanks,
  Reply With Quote
Old 7th November 2009, 09:37 AM   #2
SY is offline SY  United States
diyAudio Moderator Emeritus
SY's Avatar
Join Date: Oct 2002
Location: Chicagoland
It depends on what you're measuring. If it's a woofer, you want that mike nearly touching the driver. That will get you information good to a few hundred Hertz. For midrange and treble measurements, the mike should be backed off a meter or so. You'll then start picking up reflections, but those can be windowed out (with a concomitant loss of information in the lower frequencies).

If you're going to do measurements, you'll find that Joe d'Appolito's book "Testing Loudspeakers" will be the best expenditure you could make. There's a lot of subtlety to the simple view I just gave you, and modern measurement methods will allow you to collect tons of incorrect data very efficiently if you're not aware of the basics.
"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."
  Reply With Quote
Old 17th December 2009, 12:58 AM   #3
tvrgeek is offline tvrgeek  United States
diyAudio Member
Join Date: Dec 2009
Location: North Carolinia/Piedmont
Found out the hard way chasing weird distortions you can't near-field a tweeter. I find about half a meter to be a good compromise between ambient noise and level. (tweeter mounted in a meter square baffle.) One meter, as SY says, is probably wise for a mid. Full systems I only test outside. I have never had much luck with the ground plane method Joe recommends. Do get and read his book.

Not sure about the overload capability of our 8000's, but my little Audio Buddy preamp drives me crazy. I have to set the gain to below the "signal detected" LED to keep it from breaking up. I need a much better mic preamp. VU meters would be nice.

You can not calibrate your mic. Send it off and have it done by a pro. Only about $50 bucks. It is not that far off to start with. You can calibrate your electrical path.
  Reply With Quote
Old 17th December 2009, 01:24 AM   #4
Joachim Gerhard is offline Joachim Gerhard  Germany
diyAudio Member
Joachim Gerhard's Avatar
Join Date: Mar 2009
unfortunately the beringer is not accurate and has big variety. i bought 5 and non of them worked to any precission. that would not be a problem if they delivered a correction file that could be implemented in modern soundcard measurement systems. i measure in 1m on tweeter axis 15 off outdours at good weather or in a big hall for best result. keep the speakers at least 2m from all surfaces. i recommend the Girardin Mic from Liberty instruments. i have 4 that work just fine since 4 years and they come with a correction file that makes them a clone of the AOC paciffic condenser.
  Reply With Quote
Old 17th December 2009, 03:27 AM   #5
planet10 is online now planet10  Canada
diyAudio Moderator
planet10's Avatar
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Mic distance for driver measurements
Neither the Beringer or the similar Dayton are very flat. Paying someone like Cross Spectrum to calibrate it is well worth the cost.

Stay safe. Stay home. Respect the 2m bubble.
  Reply With Quote
Old 17th December 2009, 08:35 PM   #6
tvrgeek is offline tvrgeek  United States
diyAudio Member
Join Date: Dec 2009
Location: North Carolinia/Piedmont
They are not THAT bad. Better than a home brew Panasonic capsule even with Sigfried's mod. They are dirt cheap. "Real" instrumentation mics cost 10 to 100 times as much and still need calibration. But absolutely, pay a lab to calibrate them.

PS. Makes you wonder how the cheap AVR auto calibration works with 50 cent mics, now doesn't it? Might explain why they don't work!
  Reply to this post


Mic distance for driver measurementsHide this!Advertise here!
Thread Tools

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
Measuring driver's acoustic centrer, voice coil distance wigginjs Multi-Way 2 3rd June 2007 03:21 AM
Duct-Driver distance question Tyimo Multi-Way 2 18th October 2006 05:44 PM
Distance between Woofer and Midrange driver LageB Multi-Way 9 21st August 2003 05:53 AM
driver distance requiring shielding timsch75 Multi-Way 3 3rd August 2003 06:13 PM
Any minimum distance from driver to port? Circlotron Multi-Way 4 27th December 2002 11:23 PM

New To Site? Need Help?

All times are GMT. The time now is 03:49 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Copyright ©1999-2021 diyAudio