# Galaxy CM-140 questions



## JimP (May 18, 2006)

I'm considering the Galaxy mic as an upgrade from using an ECM8000 and mixer. 

From what I've read, it sounds like I can connect the CM-140 directly into my sound card using a 3.5 mono plug. I will not need a mixer/phantom power supply/preamp with the CM-140....is that correct?

Since it furnishes its own power, does the 9 volt battery last a while (a few months) or is it a problem due to constant replacing? I understand this depends heavily on how much its used. As a hobbies who goes in burst with this calibration thing, I don't want to be replacing batteries each time I pull it out.

Does the CM-140 have a slot for a tripod screw for mounting?

Are the available calibration files from this site close enough or do these mics vary enough where they require to be sent off for an individual calibration.

Thanks in advance


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## tonyvdb (Sep 5, 2007)

JimP said:


> I'm considering the Galaxy mic as an upgrade from using an ECM8000 and mixer.


I would not consider it an upgrade however it is a good meter and does eliminate all the connection issues. 



> From what I've read, it sounds like I can connect the CM-140 directly into my sound card using a 3.5 mono plug. I will not need a mixer/phantom power supply/preamp with the CM-140....is that correct?


Yes that is right.



> Since it furnishes its own power, does the 9 volt battery last a while (a few months) or is it a problem due to constant replacing? I understand this depends heavily on how much its used. As a hobbies who goes in burst with this calibration thing, I don't want to be replacing batteries each time I pull it out.


 Ive had my same rechargeable 9v battery in the 140 for over 6 months and it still works fine.



> Does the CM-140 have a slot for a tripod screw for mounting?


Yes



> Are the available calibration files from this site close enough or do these mics vary enough where they require to be sent off for an individual calibration.


as long as your not rough on the 140 you should have no need to do any calibrations to it at all.


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## zero the hero (Feb 24, 2008)

is it really only good to 31.5hz?


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## tonyvdb (Sep 5, 2007)

No, once you use the calibration file with REW is goes much lower. Even without it is still usable to about 20Hz


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## Skwisgaar (May 31, 2010)

This thread is very old but it is the first thing that shows up on google.

I wanted to know if the AC output of the device is more suited to a line in or if it would work better with a microphone pre-amplifier.


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## tonyvdb (Sep 5, 2007)

The output of the CM140 is a line level signal.


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## LPS (Aug 14, 2009)

The Galaxy Check Mate CM-140 incoprate both A-weighting and C-weighting, but no linear setting, so this instrument will not not output a linear AC signal to your sound card through its output jack. If you intend to use the CM-140 to record /analyse the sound externally, you will need to take the A or C weighting into account, plus the microphone response (this is what the "calibration files" are for).

I made a quick comparaison test, measuring and analysing pink noise from a loudspeaker (same conditions, location...) using the CM-140, the ECM-8000 and a precision Bruel&Kjaer sound level meter. The CM-140 (which is a IEC 651 class 2 instrument) and the ECM8000, are good for their price...but, as you know, both need to be "calibrated". Using the available calibration files for both the CM-140 and the ECM8000, the remaining "errors" between those and the precision instrumentation I used as a reference were mostly within +/- 2 dB between 30 - 20KHz (+/- 1 dB between 50-4kHz), which is...good! My ECM-8000 response was in fact better than anticipated in the 10kHz region (less than the +5to6 dB anticipated). As I said, it was only a quick test, but the result I got is still a good indication of the CM-140 and ECM-8000 performance...(with 75-85 dB SPL signals). However, the "CM-140 solution" is not better than the "ECM-8000 solution"...


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## Skwisgaar (May 31, 2010)

If I used an ECM-8000 to record to a computer using a mic/PC interface, is there software that could calculate the SPL from the resultant wav file? 

It just occurred to me how ludicrous the notion of computing SPL from a digital file is. Nevermind the question. I do intend to get something for the PC with a mic input for an entirely unrelated purpose.


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