I've spent a lot of time studying and learning personal computers, and related technology. There is a vast array of software available, and much of it free.
   One of the most fascinating works is a suite called Csound. Csound was founded by professors Vercoe and Boulanger at M.I.T, Mass.
   The software can do almost anything imaginable with sound. There are many contributors to Csound, which is also an open-source project. Mathematical models of real instruments have been constructed. Models of synthesizers such as the Moog and Korg have been done.
   My favorite is an emulation of a Hammond B3 by Josep Comajuncosas.
   I developed a cojuple of applications for my own use.
   I have some old 78-rpm records that are old and scratch from age and use. I no longer have a record player, or turntable, that has a 78-rpm setting. I decided that I could convert 78's recorded at a different speed to 33 or 45 speed. That's where Csound comes in.
   Csound has functions that will speed up a sound without altering the pitch. You would not get that 'Alvin and the Chipmunks' sound you would expect.
   After making the conversion, I was able to apply advanced filtering algorithms to clean up the sounds.
   Another use involved the B3 emulation I mentioned earlier. Another one of the contributors is Gabriel Maldonado. He wrote a Csound version that could run Csound in real time. I combined that with the emulation and a digital loopback connector and computer keyboard MIDI instrument program to 'play' the B3 emulation using my laptop's keyboard. The software could be set up to use a real MIDI keyboard instead.
 Csound is a great tool for exploring sound and music, when thought of as sound. A knowledge of the physics and mathematics of music goes a long way in Csound.