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Speaker Measurement Thread

Yes, excellent, thanks!
Do you think we should have another specifically for hardware?
We can mention what we are using in the way of hardware in the
other threads but for detailed reviews, discussion about noise and
performance. Ken started a thread with some measurements of
the ECM-8000 and MXL Mic pre for example.
 
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I'm jumping on this thread now that I have a PC and can actually use the measuring equipment...

Thanks to another AK member I am embarking on a magical mystery measuring tour...:smoke:

Next purchase is the test equipment (where is the emoticon for hemorrhaging money?)
 
Vaughn said:
I'm jumping on this thread now that I have a PC and can actually use the measuring equipment...

Thanks to another AK member I am embarking on a magical mystery measuring tour...:smoke:

Next purchase is the test equipment (where is the emoticon for hemorrhaging money?)
Click to expand...

Let us know when you get things set up and post some pics!! :D
 
Mine is very flat, so I didn't bother.

PeteB says the ART box has some issues, but I don't have drivers for the M-Audio on the lab computer, so I just ran with that, and it seems to be doing well enough.

When CLIO's back up (and doing wavelets :)), I'll be able to compare the results.

I see some others buying the M-Audio Mobile Pre rather than the Fast Track Pro; this'll all shake out in time.... :yes:

http://www.m-audio.com/products/en_us/MobilePreUSB.html
 
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Dayton Mic vs. ECM8000

I'm trying to gain confidence with my new Dayton measurement mic.

Here's the provided FR graph of the actual mic:
attachment.php


Here's a comparo between the Dayton and my ECM:
attachment.php


Purple is the Dayton.
Green is the ECM I have used for a while.

The Dayton is run with the cal file provided by PE for it (downloaded from PE site. Enter your serial #, get the cal file.)

The ECM is run with a generic cal file.

I use Fuzzmeasure.

For reference, this is a 6x6 EWave.

I don't know what anyone can tell me about this. Do you think the raw response in the provided FR graph is too far off to begin with? If so, I'll send it back and try again.

About my comparo measurements...in your opinion, is this the limitation of the low end mics? That they won't be consistent? Just accept that the cal file somebody else provides is good?

:dunno:
 

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Does the cal file from Dayton match the printed curve that came with the mic? I believe it's a text file so you can read the numbers if there's not a way for fuzzmeasure to plot it.

If you didn't use the cal file, it looks like your Dayton and ECM would match up to 7 kHz. Above there, from what I've read on other forums, it's a crap shoot as to what is correct. The outfit commonly used for calibration and Dayton do not agree, last time I reviewed this. Still, I think the Dayton correction is better than stock ECM with none.

I have two different models of CLIO mics, and they do not agree. Their charge for calibration is substantial, so I have not done that. The one I use best matches my ECM; I have not directly compared my Dayton but note that the cal file for it has such minimal corrections that with HOLMImpulse, I didn't even run the cal procedure and obtained results comparable to CLIO.

The whole deal gets this: :dunno:
 
In my opinion, there is not enough of a correlation between the provided graph and the cal file. See attached.

There is some correlation, but it does not seem to be swinging as much as would seem appropriate if you count the FR deviations on the provided graph.

:dunno: is right.
 

Attachments

Inverse null

Zilch, trying to get an awesomely deep inverse null on my KDT QSC waves, like you get, to ID the forward axis. Any tips?
 
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Simple calibrated rotary table for horiz. polars

For my polar measurements I use a simple rotary table sitting atop a pine board fitted with a 3/8 inch dowel.
Click on the link below for a picture of the turntable and pine board below it.
http://www.audiokarma.org/forums/showthread.php?p=3873140#post3873140

The table is available from MCM Electronics.
http://www.mcmelectronics.com/product/21-1935
It is 20 inch diameter and can take up to 200 lbs and comes with a 3/8 inch hole drilled dead center in its underside.

All one needs then is a 12 inch wide pine board about 16 inches long with a 3/8 inch dowel glued down in the center 10 inches from one end. Mark the end of the board with a line using a sharpie.

The outer edge of the MCM turntable can be marked with deg increments to suit the tester's needs. I used 0 deg., 30 deg., 45 deg and 60 deg. but more can be added. Simply calculate the distance from an arbitrary 0 deg. mark on the outer edge for each deg. increment you want. The circumference of the 20 inch turntable is 62.83 inches.
For example, for 30 deg from the zero mark, measure along the outer edge from the zero mark 30/360 X 62.83=5.23 inches. 45 deg would be 45/360 X 62.83=7.85 inches. Place marks at those locations with a sharpie.

After you've finished placing all the deg. marks along the edge of the turntable you plan to use, place it on top of the pine board so the dowel fits into the turntable's center hole and you're in business measuring polars. The marks on the edge of the turntable will line up with the mark on the edge of the pine board.
 
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