"Couldn't change sample rate" error with zoom tac-2 soundcard


#1

Hi Jules,

A customer reported me an issue with his zoom tac-2 soundcard on macos. Whenever it is selected, he gets a "Couldn't change sample rate" error. With some luck I finally figured what is causing the issue:

        pa.mSelector = kAudioDevicePropertyNominalSampleRate;
        pa.mScope = kAudioObjectPropertyScopeWildcard;
        pa.mElement = kAudioObjectPropertyElementMaster;
        Float64 sr = newSampleRate;

        if (! OK (AudioObjectSetPropertyData (deviceID, &pa, 0, 0, sizeof (sr), &sr)))
        {
           error = "Couldn't change sample rate to " + String(sr) + " Hz";
        }

If I replace kAudioObjectPropertyScopeWildcard by kAudioObjectPropertyScopeGlobal , then the driver accepts the sample rate change. I don't know whether the driver should accept kAudioObjectPropertyScopeWildcard , but maybe you want to consider changing it to kAudioObjectPropertyScopeGlobal if you think that is safe and fine.

 


#2

Bizarre! Ok, thanks for the heads-up - yes, I'll change that. Presumably all other drivers must ignore that value, so I think it's a safe bet that changing it to global won't do any harm.