Impulse response reverbs are one of the handiest tools in the digital-audio junk drawer. If you’re new to the concept, prepare to be amazed. (And if you’re familiar with the technology, jump to the end of this post to score some cool free reverb sounds.)
Impulse response reverbs, also known as IR or convolution reverbs, fake the sounds of genuine acoustic spaces. Say you want to be make your tracks sound as if they were recorded in a 12th-century dungeon: Just visit your nearest medieval castle and set up a small PA system in the dungeon. Next, play a test signal (usually a sine-wave sweep or a starter-pistol shot) and make a recording of it echoing in the space. Back at your studio, your IR software compares the new recording to the original test tone, and creates a reverb preset that you can apply to any audio source. Just slap it on a guitar track, say, and voilà — you’re rocking out in the dungeon, minus rats, mildew, and torture implements.
But wait, there’s more! You can use the same technology to mimic hardware effects and speakers. Just run the test signal through an amp or effect, and you’ll have a digital clone of the physical device. Here’s a brief video demonstrating the idea:
