Recording Impulse Responses from Guitar Speakers

The sound of an electric guitar through a guitar amplifier is very heavily influenced by the frequency response and tonal color of the guitar speaker cabinet. If you make an impulse response from a guitar speaker cabinet, and then run a direct guitar amp signal through that impulse response in Space Designer (set to 100% wet), the direct signal will sound as if it was played through the speaker cabinet.

You will still need a microphone and audio interface to create an impulse response from a guitar speaker cabinet, but you won’t need an additional monitor speaker for the sine sweep—you will play the broadband sine wave into the guitar amp/speaker itself. If your guitar amplifier has an effects return, you can use it to create the impulse response. If your guitar amp does not have an effects return, you can either use a “re-amp” box (that will raise the impedance of your audio interface’s line out to the level required by your guitar amplifier at its input), or you can use a line level amplifier in place of your guitar amplifier (to amplify the sine sweep through the guitar cabinet).

You can experiment with microphone placement just as you would when miking a physical space, although the most common microphone placement is “close miking”—placing your microphone as near as one inch from the speaker itself. The illustration below shows how you might want to set up your guitar speaker cabinet when creating your impulse response.

Figure. Illustration of guitar amp microphone placement.