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

PA Systems A forum for discussion of all parts of a sound reinforcement or DJ system: loudspeakers, mixers (desks) etc.

Cheap DIY PA System
Cheap DIY PA System
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 29th February 2012, 10:05 AM   #31
geraldfryjr is offline geraldfryjr  United States
diyAudio Member
Join Date: Feb 2008
Location: Jackson,michigan
Not sure,lduarte1973,
But you can check here maybe or give them a call.

MCM Electronics | Help Center - Shipping

  Reply With Quote
Old 29th February 2012, 06:41 PM   #32
geraldfryjr is offline geraldfryjr  United States
diyAudio Member
Join Date: Feb 2008
Location: Jackson,michigan
I did some more efficiency measurement and it was very hard to get some accurate figures using the calaculator.

I do get 118db at 500hz and 1000hz at 1 watt flush with the driver.
I have found that by entering the distances in feet seem to give a better reading than meters.
For instance if I have 118db at 1cm I also measure 112db at 10cm and not 98db like the calculator depict's. ???

So by using values of greater than .5 for my initial distance values for a measurement point I seem to get better results.

Therefore if I am getting 112.5 at .5 foot I do read about 106.5 1 foot, So in the calculator this works out and according to the calculator I should be getting 95.76db at 3.25 feet or 1 meter at a level of 1 watt.

This is much higher than the advertised figures for this driver at 89db.
I could tell when I first set the levels that 89db at one watt could not have been right!

Considering that I had just got done testing my little 8" sub that is rated at about 88.5db.

Being that I am using less than adequate anechoic conditions and my room is very cluttered, I manged to position the driver so that I could get a reading from 1 metter away.
I had verified the results at 500Hz and 1000Hz at about 95.4db at 1 watt with it sitting in its packaging box in order to help dampen the backwave at those frequencys.

Thanks for putting me up to this as the advertised figure of 89db did have me a little bummed out.
But now I am very very happy the the results !!!

Here are some pictures of the driver.

enjoy !!!!

Attached Images
File Type: jpg 1.jpg (87.2 KB, 212 views)
File Type: jpg 2.jpg (511.4 KB, 200 views)
File Type: jpg 3.jpg (153.0 KB, 160 views)
File Type: jpg 4.jpg (109.9 KB, 160 views)
File Type: jpg 5.jpg (83.8 KB, 151 views)
  Reply With Quote
Old 1st March 2012, 05:52 AM   #33
mdocod is offline mdocod  United States
diyAudio Member
Join Date: Dec 2011
Location: Black Forest, CO
Send a message via AIM to mdocod

You can't do a sensitivity test inside a room like that. Your mic is picking up not just the sound from the driver, but all of the room reflections and loading, giving you a ton of "fake" sensitivity data.
  Reply With Quote
Old 1st March 2012, 06:29 AM   #34
geraldfryjr is offline geraldfryjr  United States
diyAudio Member
Join Date: Feb 2008
Location: Jackson,michigan
Yes, I understand that it is not the most accurate,But the numbers do line up.
118db flush with the driver is a lot louder than any reflections, and, 112.5db at .5 foot to 106.5db at one foot is exactly right.
Therefore the 95.5 db at 39 inches also coincides with what the calculator comes up with as well.
I also used a distance of .5meters at 19.5 inches and 1meter at 39 inches and the results were the same.
I think that it is pretty close.

In that particular area of the room there is alot of diffraction going on and very little direct reflections although like I said "it is less than optimum".

I did try different frequency's as well to help combat the effect of possible reflections and the results were the same.

If the weather was permitting I would have done it outside.
When it does clear up I will redo this again just to see how far off it is.
I am in no hurry to get them mounted as the cabinet is buried in the garage at the moment and I want to do an accurate measurement once I get them mounted as well.


Last edited by geraldfryjr; 1st March 2012 at 06:37 AM.
  Reply With Quote


Cheap DIY PA SystemHide 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
DIY Line Array for Pa system - Driver Selection woodrowman Full Range 9 12th October 2016 04:14 PM
Cheap drivers in cheap O.B. system Moreorless Full Range 17 7th April 2013 03:55 PM
cheap DIY PA speakers for garage/shop? khaosman Multi-Way 6 12th September 2011 01:23 AM
Looking for a DIY PA system for my sons Garage Band airframe Instruments and Amps 24 30th June 2006 04:20 AM
Anyone have any ideas for cheap DIY satellite/sub system? mikejz84 Multi-Way 8 8th September 2003 03:00 AM

New To Site? Need Help?

All times are GMT. The time now is 12:46 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio