Radial’s BigShot ABY can be used to route one guitar signal to two amps simultaneously (or either one individually) and, importantly, includes a ground‑lift function.
I’ll soon record a sludge‑metal band and I need some advice. They want to record with them all playing in the same room at the same time, but there’s only one guitar. How would you deal with that in relation to the final mix’s stereo image? I wanted to pan the same guitar L/R, but of course I don’t want to make it mono again. Any good techniques?
Anon. via email
SOS Contributor Mike Senior replies: Well, there are a few options I’d suggest. The first is to just pan the guitar centrally, then rely on its room ambience to give it some width. However, given the well‑established metal trope of wide‑panning double‑tracked rhythm guitars, I wouldn’t expect that to deliver the kind of left‑right breadth the band will be looking for. Likewise, you could create some stereo width from the close‑miked guitar sound using panned multi‑miking, but again I’m not sure that’d create the degree of guitar spread you’d normally expect in metal.
While it might seem easier to leave the re-amping until after tracking, do bear in mind that a more impressive guitar sound on the tracking session will impact on how the band feels.
A more promising option should be to mic up two guitar amps with somewhat contrasting/complementary tones, and then hard‑pan those in the mix to generate a more obvious stereo spread, and there are a few ways you could implement this. My favourite option would actually be to set up both amps in the room either side of the drum kit, and feed them from the same guitar via a dedicated splitter box. Alternatively, you could just take a DI from the guitar on the way to a single amp, and then simultaneously re-amp that in a separate room while tracking — or indeed re-amp it after the main tracking session. Now, while it might seem easier to leave the re-amping until after tracking, do bear in mind that a more impressive guitar sound on the tracking session will impact on how the band feels, so the extra hassle of implementing the re-amping ‘live’ may be worth it in terms of improving the general vibe on the sessions, and potentially getting better performances as a result. And remember, even in that case, if you take a DI you can always rehash the live‑tracked re-amped sound later anyway, so there’s no need for live re-amping to tie your hands too much at mixdown.
Whether you create stereo spread by multi‑miking or by re-amping, though, you will need to beware of phase‑cancellation between the hard‑panned mics/layers in mono. Certainly, you should make a point of checking your guitar texture in mono while tracking, so that you avoid any nasty mono‑compatibility problems. If you find the sound collapses in mono, try flipping polarity switches on some of the guitar mics in the first instance, or changing the miking distances slightly if polarity inversions aren’t helping much.
Despite all of the above suggestions, though, it’s still possible that, by comparison with a lot of commercial metal releases, you might not be able to get a sufficiently impressive stereo spread in this way. If that’s the case, my last‑ditch solution would be simply to overdub a double‑track of the guitar part after the fact, and hard‑pan that against the live‑recorded guitar. You’ll likely need to add a bit of artificial room ambience of some kind to get the overdub to sit comfortably with the live track, but otherwise there shouldn’t be any real difficulties in doing that, as long as the player can adequately recreate their part. Honestly, if any metal band with a single guitarist asked me to do a record with them all playing together, this is actually the approach I would plan for as a backstop, simply because I could pretty much guarantee to get an appropriate guitar image that way. But, at the same time, I’d still try to get the best out of multi-miking / re-amping — if I actually managed to get sufficient width that way, I could then bask in the glory of saving the guitarist from all that manual double‑tracking! Always best to keep expectations in check and then over‑deliver!
Matt Houghton, SOS Reviews Editor, adds:While I’ve nothing to add to the approaches outlined in Mike’s reply, which lays out your strategic options very clearly, I thought it might be worth addressing the question of how, on a practical level, you might go about feeding two amps simultaneously from a single guitar. You can use a DI and re‑amp together, as he suggests, but if you don’t already have those, there are other options, as well as some approaches to avoid. It’s important that there’s an earth lift to break any ground loops that might cause problems, and that’s one reason you can’t really ‘bodge’ this using some sort of Y‑cable, and why a stereo effects pedal’s left and right outputs might not do the job either.
To do it ‘properly’, you’ll want a buffered splitter pedal or a transformer‑based ABY pedal; an ABY pedal’s footswitches allow you to feed the guitar signal to one amp, the other, or both at the same time, making it a useful utility gadget to have in your kit bag. Various manufacturers make them, and a good example is Radial’s BigShot ABY (shown in the photo). For stereo or more experimental setups (such as if you want to feed amps, DI boxes and modellers in parallel) the same company offer a device called the Shotgun that can feed four amps simultaneously from one or two input signals, and invert the polarity on any of them.