hello, i need to produce sounds in Linux directly from a program, not using files (the program i want needs to generate sound based on various input ... so it can simulate say a hum) ..... i been looking around, but i cant find any info on what these sine / other waves do .... i understand the samples, sample rate, and stuff. but i cant find info on how to convert the numbers from a function into sound

do i take the numbers and change it endness to match the sound card? .... and what do things like "low pass" / "high pass" mean?

also i want to Analise the sound (split it up, similar to equalizers) .... is there any good tutorials on sound generation that i haven't found (i been searching real long, and the best i can find is "what sound waves are" , "examples of sound functions" (various number generating functions) and "how sound is represented in a computer" ... but nothing on the steps involved in generating or manipulating tones

anyone know where to find some good info i can use? (i plan to use SDL for audio i think)

You don't necessarily need to use SDL.

Writing data to /dev/dsp will play sound. Reading data from /dev/dsp will give you data from the capturing device (line-in / microphone, etc).

If you want to change sample-rate, sample-size, etc. a simple ioctl() call can do that, but you'll have to look up the syntax online. You WILL need the proper permissions to use /dev/dsp, so set that up beforehand.

In addition to what zhangmaike said, low pass and high pass refer to filters. low pass filters allow low-frequency tones to pass through the filter, and high pass ones let high-frequency tones through.

i see, thanks