if you mean turn them into lists of floats from a signal, theres unpack~, drip,
and similar. you probably want an intermediary table anyways, to eg use a
logarithmic index for the tabread of the frequency bin.. therefore you can
proably bypass the need for drip~/unpack with a tabwrite~/tabread.

also you coan likely do it all in signal domain, for speed reasons..

there is no perfect window size. for the perfect looking spectrogram you
proabbly want several window sizes at once, one for the low freqs, and one for
the higher ones, and combine them into a single image.

but someting like 512 or 1024 samples will proably work to start with, unless
you need nice bass resolution

can you treat a 1 x 1024 'grid' as a PDP pix? if so maybe thats even faster than
signal ops. especially if theres GPU acceleration..