Teensy 4.0 44.1k or 44.117k for sample rate

[Keith_M]

I'm using Iowa hills Hilbert filter designer ..in the designer its asking for sampling frequency ..dies the teensy 4.0 run at 44.1 or 44.117 kHz..I feel stupid asking this ..but I was unable to find out ....

 

[vjmuzik]

It is 44.1k, you can find it here: https://github.com/PaulStoffregen/cores/blob/master/teensy4/AudioStream.h

 #define AUDIO_SAMPLE_RATE_EXACT 44100.0f

 

[PaulStoffregen]

Yup. Teensy 4.x has a dedicated PLL with high resolution config, so it can create exactly 44.1 kHz.

The older Teensy 3.x board ran at 44.117647 kHz (or actually 48 MHz / 1088) because they lack a PLL for audio, so they're limited to creating the audio clock by integer division of the various system clocks.

 

[Keith_M]

Thank you very much ..I was getting confused across models ..what does the teesy 4 default to naturally if you don't define it ? ?.and question #2 ..does changing the above parameter allow you to step up the sampling rate to say 48k or 96k ?

 

[PaulStoffregen]

Default is 44.1 kHz.

If you change that define, most of the library will adapt. But some parts, especially USB and WAV file playing, have other dependency on 44100 Hz which that define doesn't change.

 

[Keith_M]

Thanks for the info ...I appreciate the response.?now to go and fix my filters ..lol