ANC Measurement?

[cdyao]

Does anyone use REW to measure ANC Headphone performance?
I've got a miniDSP EARS. I think maybe SPL measurement by sweep sine can be used.
Connect the speaker out to some noise speaker and measure the SPL on EARS with ANC headphone on.

 

[cimera]

Not done this but some thoughts of mine:
- You have to take multiple meassurements (without headphone, with headphone but without ANC, with headphone and ANC) to be able to distinguish between the effects of active and passive NC
- The result might be dependent on the position and angle of the speaker relativ to the setup in all directions especally in combination with reflections that might occure in your room
- The result might also be dependent on the used test signal as the ANC might be more effective on "longer" periodic signals then on e.g. noise
- Also the level of the test signal might have an impact
- ANC effectiveness might be a function of time. So you should take the average over multiple meassurements

Maybe you could try out some of the variations resulting from this. Would be really intersting i think.

 

[cdyao]

e result might be dependent on the position and angle of the speaker relativ to the setup in all directions especally in combination with reflections that might occure in your room

Thanks for the very helpful info.
I wonder if we can get the "delta value" (ANC on vs off) inside REW application.
Or we have to export the measurement result for offline processing?

 

[cimera]

- Load both meassurements in REW
- Click on the "All SPL" tab
- Click on "Control" and then on "Trace arithmetic"

- Select the meassurements you want to work with and the operation you want to apply to them

- Click on "Generate"
- You should see a new meassurement as a result

 

[cdyao]

- Load both meassurements in REW
- Click on the "All SPL" tab
- Click on "Control" and then on "Trace arithmetic"
View attachment 42571
- Select the meassurements you want to work with and the operation you want to apply to them
View attachment 42572
- Click on "Generate"
- You should see a new meassurement as a result

Thanks for the info.
I tried it and it should be "A over B" in the trace arithmetic since we need to get the power ratio between ANC on and ANC off. (Not subtraction)