Polar Response Measurement Jig ideas? - diyAudio
Go Back   Home > Forums > Design & Build > Equipment & Tools

Equipment & Tools From test equipment to hand tools

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 31st March 2011, 12:31 AM   #1
diyAudio Member
 
Join Date: Jan 2009
Location: Decatur, Al
Default Polar Response Measurement Jig ideas?

I'm going to build a jig of some sort - that could be as simple as tape on the floor or as complicated as a swivel setup - to take polars at various angles from 0 to 90 degrees, with (15* intervals). I'm trying to stay simple and one constraint is that the setup not cause reflections.

In my case, I need something that would allow me to move the mic around the wall I've built.

I've considered doing something that uses a swivel at the base of the IEC baffle I've built, attach it to the mic stand and simply move the mic stand in a circular pattern. I'd like to take it a step further, though, and make it adjustable in distance from the baffle/driver being tested for various reasons.

I was wondering if anyone here might have some suggestions and/or pictures of what their polar jigs look like that could help me get my blue sky imagination going. A trip to Lowe's always helps kick my brain in to gear, but it also kicks my wallet up about 5 notches too high.

Here's what the baffle looks like:

Click the image to open in full size.


Note, the above isn't completely final. I still have to determine final bracing. It's up just to get an idea of what else needs to be done. FWIW, since I took the picture above, I've added absorption panels to the ceiling. So far, I've got a flat impulse response on-axis out to 12ms.

Thanks,
Erin
  Reply With Quote
Old 31st March 2011, 03:17 AM   #2
diyAudio Member
 
Join Date: Jan 2009
Location: Decatur, Al
I'm sorry; it has been brought to my attention that what I'm calling polar response is not what I'm after. I'm simply after various degrees of off-axis response. Sorry for the mix up, guys.
  Reply With Quote
Old 2nd April 2011, 02:15 AM   #3
diyAudio Member
 
Join Date: Nov 2008
If you are trying to measure frequency response, not even MLS can get you there with your setup. Room (walls, ceiling, floor) reflections will interfere and make any measured result non-repeatable and therefore invalid. The board dimensions are far smaller than the ideal "infinite baffle" (1/4 wavelength). The mic should be at all times 1 meter from the sound source (that is not the front of the speaker but somewhere behind the dustcap).
The best I could do, on a limited budged, was to dig a big hole, speaker flush to ground, mounted on a sheet of MDF, facing up and the mic suspended from above.
Make sure it is not windy or raining that day!
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
Importance of vertical polar response dantheman Multi-Way 43 8th January 2010 05:28 PM
Polar Measurement setup thadman Multi-Way 7 7th June 2009 06:29 PM
Crossover Types and Polar Response? Tenson Multi-Way 7 26th January 2009 01:37 PM
Impedance measurement jig for SpeakerWorkshop Tenson Multi-Way 10 24th November 2007 10:56 PM
woofer in 2.5 way affecting polar response thadman Multi-Way 0 15th June 2007 04:49 PM


New To Site? Need Help?

All times are GMT. The time now is 04:09 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