In response to my awkwardly-titled previous article, To mic or not to mic the backline? That is an interesting question raising fascinating further possibilities, engineer Howie Kaufman has some interesting comments…
There is another issue and for me, as a mixing engineer, it is a huge one. The problem comes from the fact that most every guitar cab is increasingly directional as frequency goes up.
The result of this is two-fold. Firstly, whoever the cabinet is pointed toward in the audience is getting blasted with the full range of sound, while the people standing off axis of the cabinet are getting a version of the sound that is effectively low-pass filtered, and more so as you move off-axis.
Not only are the off-axis patrons hearing a different tonality, but it is lower in level as well, so the balance with the rest of the band depends on where you are standing.
The second problem is that the guitar player himself is often in a different position in relation to the cabinet compared to the other band members and the audience. As a result the guitar player is making tonal decisions, with his pedals and/or guitar pickup switches and tone controls, that are not based on what most of the rest of the audience or band members are hearing.
I guess there is often a third factor – most working guitar players are nearly deaf after having stood in front of their amps for so many years. That means that they are even less able to judge either their volume or tonality properly. Taking all this into account makes me feel like the cabs should be miked so that the FOH mixer can at least adjust the balance and make some effort to shape the tonality so that what comes out of the main PA speakers is musically useful and covers the entire audience. At least that is my hope!
And thanks to another comment, from Vince Caminiti, here's a link that blows the topic a whole lot wider open…