Sonically speaking, acoustic guitars have a bit of a split personality – a Dr. Jekyll and Mr. Hyde. There’s the way it sounds, and then there’s the way it sounds plugged in.
The rich, full bodied tone emanating from a quality guitar often bears no resemblance to the thin, choked sound that flows out of its electronic connection. It’s impractical to mic an acoustic guitar with a drummer ten feet away, so we plug it in! With mixed results. And sometimes, working with an acoustic guitar ends up being more of a salvage operation than a musical experience!
We’ll talk more about how to get the best possible sound from a finnicky flat-top in future posts. Today, let’s look at how an acoustic guitar should sound by picking out some things to listen for.
“Body” is the “warmth” in the lower midrange. It’s the lower frequencies that make a guitar sound “big” or “full-bodied”. On a sound console, look for it as low as 200 Hz or as high as 600 Hz.
“Attack” should be familiar by now. Most directly, it’s the sound of the pick or fingers striking the strings. It hangs out with the “in your face”-ness of the snare drum and electric guitar in the potentially annoying 2-3 kHz range. The “attack” is also responsible for the “scratching” sound when the guitar is strummed which is a critical percussive element of an acoustic rock mix.
“Shimmer” is something we talked about in our last post about electric guitar. Acoustic guitars have a similar high-midrange harmonic-rich “chime”. It starts around 4 kHz and goes up from there. “Shimmer” is usually what makes an acoustic sound “rich” or “pretty” or “textured”.
“Air” – while electric guitars don’t do much above 5 kHz, acoustic guitars are a full-range instrument with harmonics that can extend to the top of our hearing range. Found at 12 kHz and above, “air” can be a challenge to reproduce in live environments, especially when the source is equipped with less-than-desirable electronics. It’s usually present on good studio recordings, but may be more reflected room sound than the actual instrument.
This is a good time to point out that an acoustic guitar is not mixed the same way in a full band as it is by itself! This is true of every instrument, but the acoustic guitar may be the most obvious example. “Sweet Euphoria” by Chris Cornell shows off a full-range acoustic guitar with lots of body. It sounds great on this recording because it’s just guitar and a vocal – it has no competition! Compare that to “Over My Head” by The Fray. In this typical full band mix the acoustic guitar is reduced to little more than a scratch. The acoustic is most present in the second verse where it’s still predominantly a scratch but you can hear some nice higher harmonics too.
Here’s a good principle for live sound: “You can’t mix with only one ingredient”. It’s a no-brainer in the kitchen; at the sound booth it means you can’t properly EQ an instrument outside its context. Isolating an instrument can be a helpful part of a process and it’s useful for troubleshooting, but it won’t take you all the way there. You can start your soundcheck by listening to individual instruments (if you’re into that kind of thing) but don’t dial in too much EQ just yet. That full-sounding acoustic guitar may sound fantastic by itself on the soundtrack to “Party Of Five” but it might not fit when the rest of band joins in.
I often hear beginner sound techs trying to feature the acoustic guitar all the time. Maybe it’s because it’s what the worship leader is holding, maybe it’s just their favourite instrument. Regardless, it usually doesn’t pan out. A boosted acoustic can compete with other instruments including the lead vocal. Modern worship music – even the acoustic guitar-toting artists like Chris Tomlin, David Crowder and Charlie Hall – is usually mixed in the same vein as that song by The Fray. While the acoustic can really shine in quieter sections, once the whole band kicks in it tends to play more of a supporting role.
Well, that was my rant for the day. Enjoy some good music this week and pay attention to where acoustic guitars are placed in a mix – it may surprise you!