I want to get opinions on what kind of microphone we need to get accurate measurements?
This mean to get same result if we next 6 or 12 months later with different temperature in room.
As cheaper class 2 microphones deviate with time, humidity and temperature.
Some class 1 1/4" Microphones even having great initial calibration result will require continuous calibration over time for accurate results, which will bring costs up.
Some class 1 1/2" Microphones show stability of 250 year / dB.
Class 2 usually don't show temperature coefficients.
But some inexpensive Class 1 Microphones like BSWA MP215 /200GBP/ show:
Dependence on temperature: ±0.2 dB
Dependence on humidity: ±0.2 dB
Dependence on pressure: ±0.6 dB
So this is ±1dB which is quite substantial and cannot be count as close to accurate.
So lets have some graphs and food for thoughts:
In graph:
Class 2 NTI Audio - M4261 - 400GBP
Class 2 Sonarworks Xref 20 Microphone - one of better samples - 70GBP
Class 1 NTI Audio - M2211 - 940GBP
Also graph for deviation of Brüel & Kjær microphone deviations /taken from B&K presentation/:
I expected less deviations, which can go up to ±1dB at higher frequencies.
But even super expensive Neumann U87 is having quite a deviations acceptance: ±1dB over whole spectrum.
So which microphone do you see as one which will provide long term accurate results without need of continuous calibration?
This mean to get same result if we next 6 or 12 months later with different temperature in room.
As cheaper class 2 microphones deviate with time, humidity and temperature.
Some class 1 1/4" Microphones even having great initial calibration result will require continuous calibration over time for accurate results, which will bring costs up.
Some class 1 1/2" Microphones show stability of 250 year / dB.
Class 2 usually don't show temperature coefficients.
But some inexpensive Class 1 Microphones like BSWA MP215 /200GBP/ show:
Dependence on temperature: ±0.2 dB
Dependence on humidity: ±0.2 dB
Dependence on pressure: ±0.6 dB
So this is ±1dB which is quite substantial and cannot be count as close to accurate.
So lets have some graphs and food for thoughts:
In graph:
Class 2 NTI Audio - M4261 - 400GBP
Class 2 Sonarworks Xref 20 Microphone - one of better samples - 70GBP
Class 1 NTI Audio - M2211 - 940GBP
Also graph for deviation of Brüel & Kjær microphone deviations /taken from B&K presentation/:
I expected less deviations, which can go up to ±1dB at higher frequencies.
But even super expensive Neumann U87 is having quite a deviations acceptance: ±1dB over whole spectrum.
So which microphone do you see as one which will provide long term accurate results without need of continuous calibration?