On 8/1/2018 4:25 PM,
wrote:
"FWIW, In the early '70s I was visiting a top level R&D lab in
Nashville. A tech was showing me some of their projects. One
was using a measurement mic. I was very small, about the size of a
cigarette filter. He said the freq response was very good but it was
worthless for audio recording. "
He could have been using one of these, or something similar from another
manufacturer:
http://www.mic-w.com/products.php?cid=46
As it's been pointed out here, small measurement mics typically have low
sensitivity, that is, significantly less output than a typical recording
mic for a given SPL. Recording mics need to work satisfactorily over a
very wide dynamic range (you want to capture the stick hitting the snare
drum and the tail end of the reverberation decay, a range of 80 to 90
dB), while a measurement mic is usually used over a much smaller dynamic
range, or at a single level for a single measurement. You wouldn't use
the same measurement mic to measure noise on an airport runway as you
would in a field on a quiet night.
So this begs the question: When and where(within the recording
and playback of music) is 'flat' important??
It's important in the signal chain, so that you can modify it
predictably if you choose to do so. Recording microphones are usually
designed with known frequency response peaks and dips that have proven
to be flattering or useful for particular sound sources. This is why a
mic that sounds good on a snare drum has a different frequency response
curve than a mic that sounds good on a male vocal. There's no reason why
you couldn't use a dead flat mic on either of those sources but it
wouldn't sound like you're accustomed to hearing those sources miked
with the usual mics.
You could make it sound more or less like a "sounds good on...." mic by
applying EQ, but since most of the "sounds good on..." mics are
directional, they have their unique off-axis frequency response curves,
and a measurement mic, which is typically omni, wouldn't be able to
accurately reproduce the off-axis response with simple EQ.
There's been a fair amount of work in microphone modeling in the past
few years, so now we have mics from, for example, Antelope Audio and
Steven Slate, that start out with a pretty flat, pretty omni mic and DSP
is used to create the phase shifts and resonances within a particular
"sounds good on..." mic to provide a reasonably good faith model.
But that's more than you want to know.
--
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http://mikeriversaudio.wordpress.com