Using impulse response/convolution reverbs to help smooth out your sound.
Most of us would probably agree that the sound of a tasty reverb on a great guitar part is a thing of beauty. And you’d think that with all the latest generation of guitar plug-ins, this wouldn’t be that hard to achieve. Unfortunately, most of them are sorely lacking in this one all-important area. One way to get around this problem—aside from owning classic amps—is to use any of the widely available impulse response/convolution reverbs to help smooth out your sound.
As a quick reference, a convolution reverb is a process where a pulse or sine wave sweep is played back into a space or actual piece of gear such as an amp or reverb unit. Using a process called deconvolution, the sine sweep is then removed leaving a clean sample called an impulse response.
When needed, I tend to rely on a number of different plug-ins to get these great reverb sounds for guitar. Audio Ease Altiverb, Digidesign TL Space, Waves IR-1 and McDSP’s Revolver are used daily in my Pro Tools system, although there are several other excellent brands available as well. Specifics vary, but most will work across the popular platforms such as RTAS, TDM, VST and AU.
So, what is it about these IRs that make them better (typically) than a traditional reverb? While the quality of the actual sample is, of course, important, it’s the fact that you’re actually hearing the real thing. When you put your instrument “into” the reverb from an old Fender amp, the sound just comes alive. The depth and character of real reverb is an almost tactile issue, and each person will have their own opinions on their favorites.
One of my first go-to settings is Altiverb’s Fender Super Reverb. The samples done for Audio Ease by Joe Gore are simply selectable as Bright or Normal. The Reverb Time (RT) is fixed at 6.70 seconds, but you can shorten it if needed using the RT dial. Gore also has samples of a Magnatone 480, a Baldwin Amp and a Real Tube Reverb, all of which are also quite nice. Altiverb also lets you sample your own amps, which I and Vincent Miraglia of Analog Design group recently did when we recorded the tasty reverb of my 1964 Gibson Falcon amp; an amp I also turn to quite a bit when needed.
And don’t think about just using the sound of actual guitar amp reverbs. You can call up such goodies as EMT 140 and 250 plates, Echoplates, spring reverbs and echo chambers. By using a buss to send just a little bit to one of these IRs you can get dull-sounding electric guitar parts to stand out. For a really “wet” signal, enable the “Pre” button on your reverb send/fader. This will send the audio directly into the reverb, bypassing the fader level. You may have to pull your fader down to compensate for the dry/wet balance, but you’ll get a full wash of ’verb that way. Experiment with that setting for a lush sound.
Impulse response settings are not just for electric guitars or amp simulators. Amazing sounds can be had for acoustic guitars as well. Think about recording that beautiful acoustic you have in your bedroom, or in a small, tight space. Yes, it probably sounds good up close, but what if you wanted something more? This is the perfect situation to use an impulse response.
One of my favorites for acoustic instruments is The Stone Room at Masterfonics Studio in Nashville, Tenn. Available in the Waves IR-1, it adds an incredible sense of depth and brightness. Also, there are many other great sampled recording studios, scoring stages, churches, opera halls, arenas and even stairwells available. Not every studio/room works for the sounds you’re seeking, so its best to get a setting, and then on the plug-in itself run through different IRs. Sometimes the room is too big, too dark or too bright. That’s when it’s time to break out some more plug-ins.
The essence of dialing in one of these sounds is to get that perfect fit in a mix situation. To lift a track up or even set it back behind the rhythm section, you may want to try EQ-ing the reverb. Instead of just settling for the sound of that plate/amp/room, try placing an EQ after the reverb. While yes, some IRs have settings allowing you to EQ the actual output, they are usually limited in scope. I tend to use a good, flexible high-quality EQ such as the Sonnox Oxford EQ, Universal Audio Cambridge, URS A10 or the EMI TG1214. These allow me to really dig into which frequencies need to be boosted or cut. Of course, you can patch in a hardware reverb as well—whatever works best for you.
Placed directly after the reverb plug-in, you can then roll off the unwanted/unneeded low frequencies (usually below 120–150Hz) in the ‘verb itself to clean up the bottom of your mix. Then, by sweeping the EQ you can also boost and/or cut any frequencies to accentuate, like string noise on an acoustic or scratches on your electric part. Impulse response reverbs are simply great for adding character to a mix. For guitarists, it’s a surefire way to get that flat-sounding DI track or amp simulator to really shine. Poke around the Internet for yourself and see which version might work best for your studio setup. Your guitar will certainly thank you for it.
Rich is a producer, engineer and mixer who has worked with artists ranging from Al DiMeola to David Bowie . A life-long guitarist, he’s also the auther of Pro Tools Surround Sound Mixing and composes for such networks as Discovery Channel, Nickelodeon and National Geographic.