Identifying audio signatures with low frequency and on phones

[AliasIO]

Hi. Nice work on this, first of all. I realise this is an older project but I have a couple of questions.

Do you have any suggestions why the audio signature is no longer identified when the base frequency is lowered to the audible range?

Have you had any luck getting this to work on mobile devices? Currently on Chrome and Firefox on my Pixel 2 XL, it doesn't pick up on audio signatures either.

Thanks!

[khankuan]

I suspect there is a limitation on audio devices on how low sound can be detected.

For mobile devices, there is a chance that noise cancellation on the phone kicked in for other method of emitting sound waves.

@jonongjs thoughts?

[AliasIO]

By low frequency I mean sound in the audible range (mainly for debugging), so I wouldn't expect any issues detecting it.

[khankuan]

I think the intention is to make it inaudibl to humans .and also less susceptible to interference.

[jonongjs]

Don't have the chance to test this out, but have you tried playing around with the bufferSize, size and step variables? I think the defaults were tweaked to work for higher frequencies.

Also, one thing to note is that we initialized our FFT object in audiosignlistener.js with a hardcoded sample rate of 44100Hz, when this should have been obtained from the audio context instead. So results might be wrong if you have a device that records at other rates.

Finally, regarding mobile browsers: this old project relies on ScriptProcessorNode, which has been marked as deprecated. I'm not sure if mobile Chrome and Firefox still support it. It might be better to change the whole ScriptProcessorNode code to use AnalyserNode instead.