i used pic877 lcd buttons for menus and two cd 4059 as 32bit jam waveform gen
and a waveform restore passive circuit {res cap} pwm ports drive the clock
two 4059s in cascade output of firs tis the clock of the next
32 bits data using 2x 2 8 bit addressable selectors as an 8 bit port expander 4 bit selectable
good luck
here is a cool link for dds like this #
https://www.hit.bme.hu/~papay/sci/DDS/products.htm
Added after 14 minutes:
i see
its audio ranges you need
then use just the inbuilt functions for pwm
most pics have pwm output
its easy to use and most compilers have examples of how to impliment it
use a piezo sounder on just a free i/o
to make a software pwm its just a mater to switch on and off the i/o
at the right time
so a routine to turn on and off the ports pin is needed
thats all
my advice if your a real nubie is splash out and buy or build into one of the free or comerical kits that are avalible for learning
most compiler makers offer such development kits
also check out the magazines for competitions and free stuff
dont forget most companies inc microchip
will supply free samples to any business address
so buy a compiler and its development kit and study just it