Soundcard and Mic for measuring.

[champ222]

Hi there, i know this has probably been asked a thousand times, already, i tried searching, but i got soooo many results!!

Could someone suggest a good soundcard and measurment microphone for measuring frequency responses etc?

price is an issue, but i dont mind spending a bit of money for good kit.

i currently have an audigy something or other, but ive had it ages, and didnt buy it with measuring in mind.

i have read of problems with the creative cards and some software, so it sounds like it would be easier and better to just get a soundcard which is more appropriate.

Thanks Guys

Andy

 

[champ222]

also, to measure t/s parameters too.

 

[soongsc]

I think if you go through the varous software providers web site such as PRAXIS, you should find some good recommendations and tips.

 

[mAJORD]

mic: if you don't want to stuff aorund making your own from panasonic inserts..

behringer ECM8000

you'll then need a preamp of some sort, any reasonable mic preamp with unbalanced outputs is fine. (unless you spend big and get a sound card with balanced I/o)

for a sound card, in all reality for measuring speaker response any 'reasonable' sound card will do. the THD and noise of say an audigy or similar will be negligable.

I use my EM-U 404. Something like this is, or one of the cheaper M-audio cards is more than adequete for speaker measurements, I use it as a source tho, and for measuring Amp THD.

 

[Ouroboros]

But don't forget, that if you use the ECM8000, your pre-amp needs to supply a 24 to 48V phantom power feed to th emic.

 

[champ222]

thanks for the replys guys, regarding mics, which would perform better? the ECM8000, or one made from the panasonic insert?

i have a mixer which has phantom power, so assuming the voltage is the correct level, that should be ok.

regarding the soundcard, i have read (admittedly not exhaustively) that the internal re-sampling done in th audigy can cause problems regarding measuremnts?

Thanks again

Andy

 

[soongsc]

thanks for the replys guys, regarding mics, which would perform better? the ECM8000, or one made from the panasonic insert?

i have a mixer which has phantom power, so assuming the voltage is the correct level, that should be ok.

regarding the soundcard, i have read (admittedly not exhaustively) that the internal re-sampling done in th audigy can cause problems regarding measuremnts?

Thanks again

Andy

The Panasonic uses less than 10 volts phantom power, so it's necessary to check what your mixer has to decide between EMC8000 or the panasonic.

If you look at the PRAXIS site, they explain in quite well that at 48K and 96K sampling, it should be okay. So as long as you don't use other sampling rates, it should work fine.

 

[champ222]

The Panasonic uses less than 10 volts phantom power, so it's necessary to check what your mixer has to decide between EMC8000 or the panasonic.

If you look at the PRAXIS site, they explain in quite well that at 48K and 96K sampling, it should be okay. So as long as you don't use other sampling rates, it should work fine.

Thats a good point, i'l check it out.

Thanks again.

 

[qwad]

😀 and dont forget no matter which mike you use you will need to have it calibarated to make any measurements you take meaningful😉 cheers TC

 

[champ222]

should they not be calibrated from new? with the view of then calibrating it again, once a year like most other test equipment?

any idea on prices for calibration?

Thanks mate

 

[Ouroboros]

if you pay £600 for a B&K 4133 mic plus PSU unit, then they come with a genuine individual calibration sheet, and in my experience of using them, the calibration doesn't change in decades!

Unfortunately, the WM61 capsules and low-cost measuring mics like the ECM800 (which pobably uses a WM61 or similar) do vary from unit to unit. To get each one with an individual calibration chart would hugely increase the cost.

I have no idea how much mic capsules like the WM61 vary with time. Perhaps if they hopld their performance for a few years it's worth paying to have a calibration run performed.

Unfortunately in my current job I no longer have access to the B&K kit I had in the old company or else I would be able to calibrate a mic for you.

 

[champ222]

Thanks for the reply.

thats a fair point, and as you say, its a shame you dont have access to the equipment any more.

oh well...

...any idea how "inaccurate" a EMC8000 is likely to be without calibration?

Thanks again.

 

[daatkins]

Evening Champ,
I ordered a calibrated Panasonic WM60 capsule from Kim Girardin (email address was kmgrdn@luminet.net in 2002) for about $20 and built my own preamp. The calibration file Kim supplied can be found here (the data columns are frequency, amplitude error, phase error):
http://www.apcl43.dsl.pipex.com/mic_cal.txt

As you can see, the mic is essentially flat to around 10KHz, down 1dB at 11KHz and 3dB at 22KHz. I've seen a calibration file for a WM61 capsule and the performance is slightly better than mine.

As Mister Ouroboros said, it is known that the ECM8000 uses either a WM60 or WM61 so expect no worse than -3dB at 20KHz. This performance is fine if your intended use is crossover design and measurements.

Nice one,
David.


Edit: I forgot to mention that Vikash sells mic pre-amp kits and the uncalibrated WM61A capsule:
http://www.madaboutsound.com/index.asp

 

[champ222]

Excellent,

thanks guys

 

[champ222]

Evening Champ,
I ordered a calibrated Panasonic WM60 capsule from Kim Girardin (email address was kmgrdn@luminet.net in 2002) for about $20 and built my own preamp. The calibration file Kim supplied can be found here (the data columns are frequency, amplitude error, phase error):
http://www.apcl43.dsl.pipex.com/mic_cal.txt

As you can see, the mic is essentially flat to around 10KHz, down 1dB at 11KHz and 3dB at 22KHz. I've seen a calibration file for a WM61 capsule and the performance is slightly better than mine.

As Mister Ouroboros said, it is known that the ECM8000 uses either a WM60 or WM61 so expect no worse than -3dB at 20KHz. This performance is fine if your intended use is crossover design and measurements.

Nice one,
David.


Edit: I forgot to mention that Vikash sells mic pre-amp kits and the uncalibrated WM61A capsule:
http://www.madaboutsound.com/index.asp

So can you use this calibration file with the software then? to ingore the errors in the response?

Thanks

 

[johnnyx]

I use a Kim Girardin mic too, and the response curve is very similar. I tried to get both curves up in Praxis to do a comparison, but it didn't want to do that, possibly because of the file types; text files. Shame, because that would give a definite answer. I suspect that using a file such as that from daatkins would reduce the error considerably; the difference between units being much less than the difference between one and none.
Another issue though is sensitivity, in mV/Pa, for absolute spl measurements. I suspect that the variation in this parameter is greater, unit to unit. The sensitivity of mine is 10.42 mV/Pa @1kHz.

 

[paologatto]

On this topic: http://purebits.com/miccomp.html

 

[Paul W]

Kim Girardin calibrated my ECM8000 for $35. This particular mic is -0/+2db 20-20k. A broad rise beginning around 5k, +2 from 10k-12k, and back down to +0.5 at 20k. Fairly close to the "average" curve Behringer supplies with the mic.

 

[Omnibob]

Hi Andy,
I use a Klark-Teknik 6051 mic into a M-Audio "Mobile Pre". I have a dell and use Smaart Live to test. I have used Spectra products but like the Smaart stuff. I have used the Earthworks M-30 mic as well and it works well. I did not like the Beringer mic as it had a hi freq. boot and in large rooms it was not as correct in its readings.

good luck

 

[Dan_E10]

Evening Champ,
As you can see, the mic is essentially flat to around 10KHz, down 1dB at 11KHz and 3dB at 22KHz. I've seen a calibration file for a WM61 capsule and the performance is slightly better than mine.

As Mister Ouroboros said, it is known that the ECM8000 uses either a WM60 or WM61 so expect no worse than -3dB at 20KHz. This performance is fine if your intended use is crossover design and measurements.
Mad About Sound | UK Loudspeaker, Audio Products and Components

I didn't realize the ECM8000 used the Panasonic capsules. According to Linkwitz, these capsules need to be modified to reduce distortion and are only "marginally" suitable as is. The ECM8000 seems pretty popular, even for distortion measurements. Anyone know if it's set up similar to Linkwitz recommendations? My calibrated mic that was included in LspLab2 finally died and now I need to replace it.
Dan