3129152020 n i'm standing alone the bela on sector
not sure what this means.
If you are using a Bela cape, the sampling rate is 44.1kHz. If you are using a CTAG cape, the sampling rate is 48kHz. On the host computer, the sampling rate can be either of those, or even another one.
Reading a file with
[readsf~] that was recorded at a different sampling rate than the one you are running at will indeed cause pitch change.