Capture & Optimize: Working With Guitars On The Live Stage

Electric Guitars

Taking Action

A handy trick I often use with open-back cabinets is to put an additional mic in the back. Once I flip the polarity of this signal and combine it with the front mic, I find the second mic adds a lot of body. This then enables me to achieve a range of sounds, from subtle rhythm to choppy lead, simply by moving the two faders throughout the song or set.

Also be aware that whenever using directional mics close to the source, you will encounter the proximity effect (whereby the bottom end is artificially enhanced). This can make guitars sound boomy and cause them to mask the frequencies of other instruments, such as the bass guitar, making the whole mix sound muddy. The best way to combat this is with a high-pass filter (HPF), as shown in Figure 1.

Figure 1.

While this is a great first step in minimizing proximity effect, I find that the slope of most HPFs (typically 24 dB per octave) can be a bit too steep to fully negate it. Therefore, a slope of 12 dB per octave (at a slightly higher frequency) is more likely to get the job done.

Unfortunately not all live consoles offer the option to change the HPF slope, but the same effect can be achieved using an EQ filter with a low Q. Figure 2 shows the same HPF, to which I’ve added a -6 dB filter at 120 Hz with a Q of 0.5.

Figure 2.

Once the amp is miked up and proximity effect dealt with, I then listen to the ambient sound of the amp while slowly bringing up the fader on the mic. If I hear the sound change as the two signals combine then I EQ accordingly and repeat.

Eventually I get to the point where bringing up the fader just increases the volume, which means that I’m now reasonably accurately reproducing the sound of the amplifier. I use this as the starting point from which I can process the sound further, if necessary, to make the guitar sit properly in the mix.

It could be argued that in this modern age of advanced digital processing we can ditch the guitar amps all together in favor of amp modeling and speaker simulation software. Various stand-alone units are available as well as computer software capable of real-time processing. One obvious advantage of this approach is that you can model a wide range of amp and cabinet combinations while effortlessly being able to switch between them, not to mention the fact that you no longer need to haul around that massive 4 x 12 cabinet.

Most live consoles also now include onboard amp and speaker modelling plugins that can be quite handy when a guitarist turns up without an amp or the basic sound would benefit from being re-amped. Having fewer amps on stage will invariably have a positive impact on the front of house mix, especially if used in conjunction with in-ear monitoring, thus ensuring a more consistent sound for both the audience and the musicians.