Clarification on reading SMD microphone frequency response

Thread Starter

Choon Kwang

Joined Jun 6, 2022
9
Hi,
I would like to seek clarification on the frequency response (Characteristic response) for a microphone, MWS-4013-603-OM | East Electronics (east-elec.com) I do not understand why there are 2 curves in the graph. Which is the one I should refer to? Comparing this microphone to a similar one, CMEJ-0413-42-SMT-TR | Electret Condenser Microphones | Microphones (cuidevices.com) , why does this microphone frequency response center at -40dB whereas the East Electronics MWS-4013-603-OM frequency response center around 0dB?
 

Audioguru again

Joined Oct 21, 2019
4,794
The first mic has a range for its frequency response. They do not throw away the lousy ones, instead they sell ones that have shrieking high frequencies or no high frequencies. They should throw away the ones that exceed +/-3dB and let sellers on ebay sell them. You might need to buy many from a real electronic parts distributor and test them to find a good one.
-40dB is its minimum sensitivity which is 1/100th the 1V reference. They do not say the typical or maximum sensitivity.

The second mic has no range for its frequency response but its typical curve looks good, some might sound awful. It has a range for its sensitivity.
 

Papabravo

Joined Feb 24, 2006
18,793
The first datasheet says the minimum sensitivity is -40 dB ± 3 dB, where 0 dB is the 1V/Pascal reference for converting SPL(Sound Pressure Level) to voltage. I think the chart has been normalized to that minimum sensitivity, and both devices have similar responses. I could be wrong however.
 

LowQCab

Joined Nov 6, 2012
2,171
They don't want to come right out and tell You about the poor quality of their products.
If a Spec-Sheet leaves out important information,
or provides questionable information,
I look elsewhere.

They should be damn proud to brag on how good their product is,
instead they're hoping you'll jump at the low price, and ignore the questions.

That criss-crossed Frequency Response Curve is completely bogus, and means nothing, ( except stay away ).
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Thread Starter

Choon Kwang

Joined Jun 6, 2022
9
The first datasheet says the minimum sensitivity is -40 dB ± 3 dB, where 0 dB is the 1V/Pascal reference for converting SPL(Sound Pressure Level) to voltage. I think the chart has been normalized to that minimum sensitivity, and both devices have similar responses. I could be wrong however.
I got a reply from East Electronics quite promptly. Indeed, the chart is normalized. The 2 curves show the UL and LL across the frequency range.
 

LowQCab

Joined Nov 6, 2012
2,171
What is the UL and the LL ?,
these are not common acronyms/abbreviations.
Sounds like something somebody made-up so as to "sound" "official".
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Papabravo

Joined Feb 24, 2006
18,793
What is the UL and the LL ?,
these are not common acronyms/abbreviations.
Sounds like something somebody made-up so as to "sound" "official".
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.
They are "highly technical" abbreviations for Upper Limit and Lower Limit. The actual response falls anywhere between those two with 99+% probability
 

Thread Starter

Choon Kwang

Joined Jun 6, 2022
9
What is the UL and the LL ?,
these are not common acronyms/abbreviations.
Sounds like something somebody made-up so as to "sound" "official".
.
.
.
Sorry, UL = upper limit, LL=lower limit. e.g at 3.5kHz, the expected response is within -6dB and +9dB from the rated sensitivity of mic, between -46dB and -31dB. I hope this clarifies.
 

Audioguru again

Joined Oct 21, 2019
4,794
Maybe all those cheap microphones are the failures and the few with a flat frequency response cost much more.
Usually a manufacturer throws away the failures then an ebay seller finds and sells them.
But cheap microphones are usually not tested, most are horrible and maybe a few are fairly good.
 
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