Impulse Response (IR)

Definition

An impulse response (IR) is a recording of how a space responds to a sudden burst of sound (an impulse). It captures all the reflections, timing, and frequency characteristics of that space.

How IRs Work

1. A transient sound (click, starter pistol, sine sweep) is played in the space
2. The room's response is recorded
3. This recording is loaded into a convolution reverb
4. The reverb applies the space's characteristics to any input

Advantages

• Incredibly realistic recreation of real spaces
• Can capture any space - famous studios, concert halls, unusual locations
• Preserves exact character of the original space

Limitations

• Less flexible than algorithmic reverbs
• Can't easily change decay time or size
• Higher CPU usage
• Static - the space doesn't "respond" like algorithmic reverb

Related Terms

• Convolution
• Algorithm
• Reverb