Attack of the Stacks: Fun with Virtual Amps

Why live in the real world, when the virtual one often lets you do a whole lot more?

By Craig Anderton

I like amp sims for a lot of reasons, but one of the main ones is it’s possible to create setups that would be really difficult to create in the physical world (or at least require having a chiropractor on retainer—along with a hefty bank account). As just one example it’s easy to stack multiple cabinets, feed them with different amps and effects, and create various kinds of stereo imaging.

One way to create a stack takes advantage of the fact that recording through amp sims records a dry track—the effects are added on playback. So you can duplicate this dry track, and add another amp sim setup in parallel. While this is easy to do, it means don’t hear the stacked sound until you’ve actually laid down a track. It’s often better to hear the stacked sound as you play, as that can influence your part as well as how the part (and sound) fits in with the track as a whole.

PARALLEL DISCOVERY

One option is to split your guitar into two tracks, set up amp sims, monitor through them, and record into both tracks simultaneously. You don’t have to use a Y-cord—simply set each track’s source to the input where the guitar signal enters your interface.

An even simpler option is to use an amp sim that allows for parallel amp paths. With IK Multimedia’s AmpliTube series, there are 8 signal routing options; Routing 2 creates two separate, parallel chains. The Line 6 POD Farm has a Dual button that creates two different signal chains, and Overloud’s TH2 also has two separate signal chains (Fig. 1).

Fig. 1: Overloud’s TH2 amp sim allows for two signal chains, but also includes a frequency crossover for sending different frequency ranges to the two chains.

Peavey’s ReValver and Native Instruments’ Guitar Rig both offer “splitter” modules for their “virtual racks” (Fig. 2). These let you split the input signal into two paths, where you can insert whatever amps, speakers, etc. you want. Then, the splits go into an output mixer for mixing and panning. (However, note that Guitar Rig lets you put splits within splits, while ReValver Mk III is limited to one split module per rack.)

Fig. 2: Peavey’s ReValver sends the signal through a splitter, which feeds two chains with “BluesMaker” heads but different cabinet and miking effects. The module at the bottom controls the mix, pan, and phase of the splits.

Waves G|T|R has stereo amps, which provide the same basic function as stacked amps. However, if you want a parallel path where you can add effects and such, then you’ll need to use two tracks, and two instances of G|T|R.

STACK APPLICATIONS

Stacking gives you all kind of sonic options; here are a few of them.

• What’s better than two stacks? Three stacks, of course! Place a chorused acoustic-type sound in the center with power chord sounds left and right, and you’ll end up with a huge sound. Add drums and bass...done.
• The frequency crossover modules in Guitar Rig and TH2 are very useful, because they let you do "bi-amping." The lows can go to one stack for heavy distortion, while the highs go to a second stack with less distortion to avoid harshness.
• Bass works well with stacks, as one stack can handle effects while the other reproduces the full range of the bass.
• And speaking of bass—if you mix a stereo rhythm guitar part so the channels are panned oppositely, then this opens up a space in the middle for the bass (the traditional stereo placement for bass is center).
• A rhythm guitar part going through two separate stacks which are panned oppositely is almost like having two guitars, but with the focus of a single guitar part. You can made the stereo width even more dramatic by delaying one of the stack signals by 10-25ms.
• Insert tempo-synched effects set to different rhythmic values in the two chains.This can give a really interesting feeling of motion, as well as enhance the spread of stereo effects.
• If there’s another instrument in the guitar’s general frequency range (like keyboard), and the guitar is set up in stereo, pan one guitar channel to center and the other right or left to “tilt” the guitar toward one side of the stereo field. Pan the other instrument oppositely in the stereo field. Now both instruments fill the stereo field, but don’t interfere with each other.

Get the picture? You can have a lot of fun with stacked amps, and you won't even have to lug around those big wooden boxes and stack them on top of each other.

Craig Anderton is Editor Emeritus of Harmony Central. He has played on, mixed, or produced over 20 major label releases (as well as mastered over a hundred tracks for various musicians), and written over a thousand articles for magazines like Guitar Player, Keyboard, Sound on Sound (UK), and Sound + Recording (Germany). He has also lectured on technology and the arts in 38 states, 10 countries, and three languages.