Is it possible to send the values obtained from rfft to an app file? Sorry if it's a silly question, but I can't seem to find the answer anywhere.

You will have to be more specific or you wont get any replies.
Are you creating an app with libpd? Or some derivative framework? Which one?

Sorry, yes, I'm using libpd. I'm trying to create a wide-band spectrogram app for Android.

Apparently, it cannot be done, since you can neither force the sampling frequency to be low enough nor the blocksize to be high enough to get a narrow-band spectrogram.

@MDobleZ said:

I'm trying to create a wide-band spectrogram app for Android.

@MDobleZ said:

Apparently, it cannot be done, since you can neither force the sampling frequency to be low enough nor the blocksize to be high enough to get a narrow-band spectrogram.

Wide? Narrow?

There are numerous ways of representing a spectrum graphically with or without [rfft] . Most have been covered within PD vanilla (libpd compatible) over the years.

If [rfft] doesnt cut it because you want detailed info on formants between 300 to 1500 Hz, you can use [sigmund~] to single out frequencies/peaks on a bandlimited signal

Thanks for your reply, bocanegra. Eventually, I found out Android allowed me to use a samplerate of 8000Hz and that was low enough to allow me to create a wideband spectrogram (125Hz per band). Thanks to everyone for your replies.