Home » Audio » Measurement » Calibration microphone help needed
Calibration microphone help needed [message #25273] Mon, 05 May 2008 10:21 Go to next message
Mr Vinyl is currently offline  Mr Vinyl
Messages: 407
Registered: May 2009
Illuminati (1st Degree)
Hi all,

I recently acquired a Marantz AX-1000 Audio Computer. It was made in 1991 and is among other things a digital room analyzer. Unfortunately the microphone that came with it (AKG C-460b) is long gone. Can someone recommend a replacement calibration microphone with a very flat frequency response? I don't mind spending some money but don't want to spend a fortune either. Maybe under $250 if that's possible? It needs to be flat from 40-16,000.

I was thinking of trying the Behringer ECM8000. It's only $50 but claims to be flat 20-20,000 +/- 1db. See link. Are these figures to be believed or is it like speaker specs?

Thanks in advance.
Mr Vinyl


Re: Calibration microphone help needed [message #25274 is a reply to message #25273] Tue, 06 May 2008 14:52 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

Behringer microphones use those little Panasonic "puck" condenser cartridges. They're very inexpensive, but they have very flat response curves. It's pretty amazing really, that these cheapo mics work so well.

You can get a microphone that's calibrated and they'll send you a file with the actual response curve for you to input into your measurement system. That way, it will compensate for any ripples in amplitude and phase response. But those pucks are so flat you can use them uncalibrated and get within a decibel.


Thanks Wayne, One more question if I may... [message #25275 is a reply to message #25274] Fri, 09 May 2008 15:53 Go to previous messageGo to next message
Mr Vinyl is currently offline  Mr Vinyl
Messages: 407
Registered: May 2009
Illuminati (1st Degree)
I purchased the Behringer but didn't realize that it was rated for 15V-48V My Marantz' microphone board is rated for 12V only. The Mic seems to work perfectly. Do you think this is affecting the frequency response of the Mic? In other words would the Mic still be flat as the specs say in your opinion? There is no way to turn off the phantom power supply in the Marantz.

Thanks for your opinion.
Chris

Hope you don't mind being my personal audio consultant

Re: Thanks Wayne, One more question if I may... [message #25278 is a reply to message #25275] Mon, 12 May 2008 12:46 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

That's a good question. I think I would ask Behringer directly. The link below has tabs for FAQ (Answers) and a direct contact (Ask a Question). Maybe fire off a question to them in the "Ask a Question" tab and see what they say about your microphone.

Please write back and let us know what they say. I'm sure others will run into this as well, because 5v and 12v supplies are common as well 15-30v.


Re: Thanks Wayne, One more question if I may... [message #25279 is a reply to message #25278] Tue, 13 May 2008 14:37 Go to previous messageGo to next message
Mr Vinyl is currently offline  Mr Vinyl
Messages: 407
Registered: May 2009
Illuminati (1st Degree)
Wayne,

You asked me to post Behringer's response so here it is. Unfortunately they weren't much help. Here is what they said:

Hi,
and thank you for writing to BEHRINGER technical support! You're correct, the ECM8000 is designed to be used with a phantom power source as low as 15V. We don't have any information regarding how the ECM8000 will function with less then 15V. It doesn't sound all that far off in theory, but basically it's not within the specified range of the mic that we know WILL work well.

Re: Thanks Wayne, One more question if I may... [message #25280 is a reply to message #25279] Tue, 13 May 2008 18:04 Go to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

Well, they are confirming it's below spec. So I think you should expect the possibility of a performance penalty.


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