Ever heard of a critter called a “convolution reverb”? If you’re a musician who does stuff using computers, you may have. Otherwise, you may be hearing about it for the first time here. A short and rather technical description can be found on Wikipedia.
Most folks know what a “reverb” is when it comes to music and audio work: it’s a box you plug into your equipment that simulates what the sound would be if you were playing inside of a larger space. It’s used to give “depth” and “ambience” to musical tracks.
If you’ve ever gone into an empty house, garage, or building, you’ve probably noticed that when you talk or clap your hands that you hear some echos that trail off after a second or two. That’s called a “reverberation tail”. It’s caused by the sounds bouncing back and forth off the surfaces in the enclosed space — walls, floor, and ceiling.
The harder and more flat the surfaces are, the sharper and longer the reverberation continues.
I play Native American flutes, and adding reverb to flute music makes it sound a lot “richer” and more hypnotic. Unfortunately, the acoustical properties of most typical bedrooms (where I record myself) isn’t ideal for producing the kind of reverb tails you’d want for this sort of music. To get what you want, you need to record a very “dry” signal, then add reverb into the mix later on using the computer.