How to auto correction stimulus voltage to driving speaker and microphone measuring sensitivity

[Sam.Huang]

I want to build a gadgets for auto correction stimulus voltage, reference as standard voice source output@1K 94dBSPL stimulus voltage 0.25V and microphone get sensitivity is -59.65dB.

Assuming as below:

output@1K 96dBSPL and microphone get sensitivity is(-59.65-(-2))=-57.65dB

output@1K 103dBSPL and microphone get sensitivity is(-59.65-(-9))=-50.65dB in principle calculated .

How to auto correction calculated stimulus voltage and considerate shift in those?

Thanks in advance!!

[Sam.Huang]

I have updated snapshot to your reference and what purpose for that.How to quickly coarse adjust voltage and slight adjust it.thanks!

[santo_13]

An alternative proven method for this Microphone testing problem is as follows,

• Characterize the speaker response by sweeping drive voltage, frequency and for each drive voltage + frequency capture the dB SPL from the microphone
• This sweep data will give you a 3D array of a lookup table (voltage vs frequency vs dB SPL)
• When you want to generate a known dB SPL, use this lookup table to match the dB SPL and frequency to derive the voltage you need to drive at (tip: use interpolation)

[Sam.Huang]

Hi Santhosh,

Thanks for your prompt relay,I have built a lookup table to dynamic selected stimulus voltage as snapshot_1,but how to created lookup table.

In the Project execution procedure as below:

   1)use standard voice source @94dBSPL 1K and microphone get sensitivity value is standard reference.----Done.

   2)as standard reference sensitivity @94dBSPL 1k infer stimulus voltage how much is properly.

You mention is right by lookup table,the point is how to created first by different frequency point and if PXI4461 AO0 direct drive speaker or not.

I'm looking forward you reply.It's import for me.

Thanks in advance!!