Manually write an audio file
I want to write an audio file (the particular format does not matter to me) by hand i.e. for each frame I would write manually which frequencies are present at which intensity. How do I do this? Is there some specialized software for this?
Solution 1:
You have the sox command with limited synthesizing ability.
Ex sox -n a.wav synth 6 sine 440 generate a 6s 440Hz file.
Once all your fragment files are created, use sox a1.wav a2.wav … result.wav to assemble.
See also https://sound.stackexchange.com/