is there a way to make foobar auto skip or auto remove from playlist songs shorter than XX seconds ? like to avoid playing sound effects in SID files.

is there a way to prevent random to play some songs "too often" ? like, even if it's random, don't play the same songs twice in a row.

you could playlist/sort/sort by ... and write in %_length%, then manually remove the 1st N samples from the playlist....,

as for the 2nd question, afaik no.

Yep. Playlist -> Sort -> Randomize, and play with Playback -> Random disabled.

I have a feeling that this is not exactly what you were looking for, but at least it does what you're asking for..

Foobar works with true random, I think you are looking at it as shuffle. When in single mode with title formatting, a randomized playlist isnt so bad, but when you spend a lot of time tagging things just right so your formatted playlist looks great in album mode, randomizing the playlist just makes it look ugly.

But thats a small price to pay I suppose...