Measuring microphone frequency response?
« on: August 10, 2019, 05:28:04 PM »
I'm interested in learning how to measure a microphone frequency response. My understanding is, and please correct me if I'm wrong, you use a measurement mic to measure pink noise, then use the mic in question, and compare the differences with a tool that allows that.

My actual question is, what sort of speaker/monitor systems are required. Could I use cheaper monitors like the JBL 305mkii? And would a small deadened room work as for as the measuring environment?


Khron

Re: Measuring microphone frequency response?
« Reply #1 on: August 10, 2019, 06:41:13 PM »
Sweeps should be good enough; pink noise is only useful for "long-term" measurements.

At least using REW, you place your speaker, somewhere in the middle of the room (in all three directions), in order to try to have obstacles / reflection points as far from the speaker as feasible, then run a measurement sweep.

(I sat a monitor on a small stool (~1.5ft / 40cm tall), in the middle of my bed in the bedroom, facing the (doorless) doorway in the corner of the room.)

You save that as a calibration file, and use that as a reference for the subsequent sweeps of the "device under test" mics.

Of course, you'll want to have the mic diaphragms as close to the original position of the measurement mic.
About half a metre to a metre (2-3ft) on-axis with the tweeter should be enough to get a full (enough) spectrum of the speaker, and not get too much proximity effect with cardioids.
« Last Edit: August 10, 2019, 06:44:46 PM by Khron »
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Re: Measuring microphone frequency response?
« Reply #2 on: August 12, 2019, 11:36:12 AM »
Sweeps should be good enough; pink noise is only useful for "long-term" measurements.

At least using REW, you place your speaker, somewhere in the middle of the room (in all three directions), in order to try to have obstacles / reflection points as far from the speaker as feasible, then run a measurement sweep.

(I sat a monitor on a small stool (~1.5ft / 40cm tall), in the middle of my bed in the bedroom, facing the (doorless) doorway in the corner of the room.)

You save that as a calibration file, and use that as a reference for the subsequent sweeps of the "device under test" mics.

Of course, you'll want to have the mic diaphragms as close to the original position of the measurement mic.
About half a metre to a metre (2-3ft) on-axis with the tweeter should be enough to get a full (enough) spectrum of the speaker, and not get too much proximity effect with cardioids.
Is there a good VST for Audacity or Reaper that works for measuring? Or does Room EQ Wizard do it well?

Khron

Re: Measuring microphone frequency response?
« Reply #3 on: August 12, 2019, 11:42:02 AM »
Why wouldn't REW be enough? :)
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Re: Measuring microphone frequency response?
« Reply #4 on: August 13, 2019, 02:03:36 AM »
Why wouldn't REW be enough? :)
I just haven't tried it yet, since I don't have a proper measurement mic, and it didn't want to work with my omni pattern on my LCT441. I'm gonna try it out with my Little Gem just for a reverb decay test. I still need to get myself a proper monitor (or pair) and a measurement mic. As well as treat my space.

Khron

Re: Measuring microphone frequency response?
« Reply #5 on: August 13, 2019, 04:45:24 AM »
"Didn't want to work"?  :o
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Re: Measuring microphone frequency response?
« Reply #6 on: August 13, 2019, 12:12:41 PM »
"Didn't want to work"?  :o
Couldn't detect it for whatever reason.

Khron

Re: Measuring microphone frequency response?
« Reply #7 on: August 13, 2019, 12:56:08 PM »
That sounds more like an audio routing / configuration issue.
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans


 

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