Our stock music library is working on a found sounds album (using sounds recorded from an environment, like a kitchen etc.). I recorded a few sounds from the kitchen, but I'm wondering what the best way to process the sounds to fit them into a typical percussion set up? For example, I have a low frequency hit sound. If I want to make it a bass sound, would I compress it and apply a low pass filter? What would the process be for creating a snare?
It depends on what you want to achieve, as in how much of the environment you want to keep.
A kick sound needs a couple of things; Bass, and some high end to make it cut musically. I'd probably start (depending on the sample) with an eq to get it closer to what I want musically, and then compress to shape the sample. Then I'd use a multiband compressor to fatten out the bottom end and fill out the top so it cuts through the mix nicely.
As for a snare, you want something that stands out in the mix with a lot of that "sizzle and snap" that you get with a snare, to lead the track along. Basically engineer the samples to work with the music you want to write. You can use a compressor to shape the sample; for example if the tail of the "snare" is too long, either apply a compressor with a reasonable attack, maybe 40ms and a low threshold and high ratio, or apply a window or envelope to the sound, removing the bits you don't want. Once you've done that you can then multiband compress the sample to make it "drive" more -- but that really does depend on what music you want to make.
Just think -- what do I want to achieve, what music do I want to produce (would you do metal with a jazz kit?), how "kitcheny" do I want the kit to sound (you can get rid of all the kitchen if you work at it, but that would be pointless), what's it working with etc.