Impulse responses, or IRs, and the technology that makes them possible, allow us to digitally capture a sonic fingerprint. When IRs first emerged, they were used in the popular Altiverb convolution reverb plugin to recreate any acoustic environment imaginable. Impulse response technology has quickly evolved to include just about anything you can pass sound through, and is frequently used to emulate miked speaker cabinets for guitar production.
Without getting too far into the technical side of things, impulse responses are recorded in a specific way so that the input signal is very short, and the system’s output signal is the IR. It’s possible to capture a device’s, or whole chain of device’s, sonic characteristics when recording IRs.
There are many benefits of using impulse responses live or in the studio, which we’ll discuss further.
1. Real-World Acoustic Spaces at Your Fingertips
IRs provide access to a virtually unlimited palette of sonic flavors. When it comes to reverbs, real-world acoustic environments have been meticulously captured for digital recreation. If all your vocal needs is a Sydney Opera House reverb, IRs and the folks who capture them make it possible.
You can even go so far as to make your own, too. Have a bathroom that sounds fantastic? Capture an IR and use its natural reverb in future productions.
2. Access to Expensive Signal Chains
When it comes to using speaker cabinet IRs, these can give guitarists access to gear that is extremely expensive or otherwise unattainable. The average bedroom producer may not have access to a Royer R-122 and a sought-after speaker cabinet to track his/her guitar parts, but an IR of this exact situation exists somewhere!
3. Give Your Back a Break – No More Hauling 4x12s Around
Lugging around a 4×12 speaker cabinet is a huge hassle–period. IRs make it possible to forgo the traditional live setup and run straight to FOH with an impulse response handling the speaker emulation.
Your tube amp will still need a load box of some sort since there’s no physical cabinet handling it, but you can give your back a rest when you opt for IRs live.
4. Better Tones for Live Performance
Piggybacking on #3, using impulse responses live can enhance your rig’s overall sound. Because you’re no longer miking a cabinet, you’re immune to bleed from other instruments that might interfere and muck up your tone.
Eliminating variables like mic placement, too, means that a guitarists’ sound can be more consistent night to night.
5. Quiet Tracking and Practice
Let’s face it–few people are in a position where they can routinely push a 100-watt tube amp the way it’s meant to be driven. Those of us recording at home probably even have our amps set up in the same room as our DAW–zero isolation.
Setting up your amp with a load box and IRs means you can track and practice virtually silently while still dime’ing your head the way the guitar gods intended.
6. Unmatched Versatility
At this point, you’ve probably sussed out that you aren’t limited to a single acoustic space for reverbs, or one speaker cabinet for guitars, with IRs.