four channels measurements

[oliver]

Hi John,
Do you think it would be possible to have REW perform a simultaneous measurement on four channels, so as to measure the SPL and impedance of the connected driver at the same time, thus avoiding having to switch inputs and perform two measurements each time? Perhaps as an option for the paid version.

Thank you,

Oliver

 

[John Mulcahy]

In principle that may be possible with one extra channel for the mic input (so 3 input channels in total). The impedance measurement input provides access to the signal at the driver terminals so it should be possible to derive an SPL impulse response from that and the mic capture. It would require other internal changes to the way inputs are treated, however, so it is something I can add to the todo list for future consideration.

 

[oliver]

Thanks so much John, that would be really great and really helpful.
Oliver

 

[oliver]

Sorry, John,
I'll take this opportunity to ask another question: is there a way to save calibration presets for the microphone, which can be recalled as needed? I use an ear simulator with different test fixtures, so I have to recalibrate each time depending on the configuration used.
Thank you,
Oliver.

 

[John Mulcahy]

You could save the preferences after selecting and calibrating an input and reload the relevant preferences file as needed.

 

[oliver]

Hi John,
many thanks.
Is there a way to avoid restarting REW when loading a new preference file?

 

[John Mulcahy]

No, some preferences affect structures that are only generated at startup.

 

[oliver]

Is there a way to implement some sort of calibration preset in the future?
Thank you,
Oliver

 

[John Mulcahy]

Maybe, but a better route would be to use the API. Its purpose is to facilitate extension of REW's functionality, the /audio/input-cal endpoint allows calibration data to be read and written.

 

[oliver]

Hi John,
following your advice about using the API, I created a script with a small application and now I can choose both the input channel (I have several couplers) and the calibration based on the test fixture.
Thanks a lot.
Oliver