Managing the Backline

   By Lisa F   Categories: Audio EquipmentGeneralLive Audio Show

In most small venues, a very significant part of the sound heard by the audience comes from the back-line—the amps and the drum kit on stage. The PA may only be needed to amplify the vocals and perhaps give the occasional leg-up for a guitar solo to achieve a well-balanced sound in the room, so keeping the back-line level under control and ensuring it produces the right sound is hugely important.

As a guitar player, I appreciate the sense of power that comes from playing through a large amp and speaker stack, but the reality is that your front-of-house mix engineer (or mixing musician, if controlling the mix from on-stage) will have a much better chance of producing a decent balance for the audience if the back-line levels are kept under control. No matter what the guitar player thinks (especially if he or she is wearing one of those Gibson T Shirts that says ‘Vocals—wasted time between guitar solos’!), the band has to balance to the available vocal level, and not the other way around! I’ve seen and heard too many live-sound disasters where the guitar player has decided how loud they want to be without giving any consideration to anyone else. The overall out-front level of the PA and back-line combined also needs to set with a view to the level of sound that the audience will feel comfortable with (or that the venue is licensed for!).

Of course, if the venue is fitted with a volume limiter, as too many now are, you simply have no choice but to stay beneath its threshold level, or you’ll constantly be having your power turned off. If you are forced to play at a venue plugged into one of those awful things, try to ensure that any piece of gear that includes a computer or DSP section is plugged into a different circuit that isn’t affected by the trip. When discussing this with the venue manager, make it very clear that this point isn’t open to discussion, as, even where data corruption isn’t a risk, there is still the problem that some digital devices (mixers, mainspowered computers, electronic drum kits, some modelling amplifiers and active speakers with internal DSP) can take half a minute or more to reboot, and if the whole show is going through a digital mixer, that could be a disaster. Try talking up the risk of both equipment damage and data corruption when pressing your argument.

Automatic volume limiters temporarily switch off the power when the volume in the venue exceeds a given threshold for a period of time.

For most line-ups, the audience will hear a better-balanced sound with at least some proportion of the on-stage instruments sound also coming from the main PA rather than just from the stage amps, so the practical question is about how to keep stage levels reasonable without compromising the performance. This is an especially difficult issue for those electric guitar players who rely on driving valve (tube) amps at a certain level to get their sound. And, of course, drummers!

Electric Guitars

From my own experience of playing guitar in bands, there are two main issues here, aside from that of being able to crank your amp hard enough to get the right sound: one is being able to hear the amplifier tone as the audience hears it, so you know what you sound like; and the other is being able to hear your instrument over the sound of the drum kit and other musicians. Stage monitors can help, but in small venues you may often only have vocal monitoring, so they certainly can’t be relied upon.

Guitarists who rely on valve (tube) amplifiers tend to need to drive their amplifiers fairly hard to get classic rock tones, but a valve head and a 4 × 12 cab can be ridiculously loud, and even a cranked 20-watt valve combo can still be pretty antisocial! One option, if you really want to stay with a high-powered amp is to use a power-soak to reduce the level reaching the speakers. A properly designed power-soak poses no danger to the amplifier, and if you attenuate a 100-watt amp down to the equivalent volume of around a 15-watt amp you’ll keep your essential tone, but the sound level will be a lot more manageable out front. Although, believe me, even that level can still be very loud in a small venue! This also brings with it, of course, a greatly reduced risk of hearing damage—a benefit that certainly shouldn’t be underestimated.

An alternative, if you’re still wedded to the idea of that big 4 × 12 cab, is to invest in a significantly lower-powered head, or perhaps one with a switchable-power output stage. The reality is that 15- to 20-watts of valve power (or 30- to 40-watts of solid-state power) will always be more than loud enough for a typical small venue, even without feeding it through the PA.

Small valve amps can sound wonderful when cranked up, as many classic recordings can confirm, and they will always produce a more convincing classic rock tone than using a 100-watt head with the master volume turned down. That’s because the ‘real’ rock guitar sounds all rely on a degree of power-stage distortion, as well as preamp distortion, and master-volume controls reduce the level hitting the power stage, thereby preventing it from compressing and overdriving.

Speaker attenuators, like this THD Hotplate, reduce the level going to the loudspeaker, thus allowing valve guitar amps to be driven hard to achieve distortion and compression without producing excessive on-stage noise.

Of course, if you are happy with the sound of preamp or pedal distortion, you can ignore everything I’ve said so far and just turn your master volume or pedal output down!

So, a compact, low-powered combo is undoubtedly the most practical solution for gigging in small venues. It won’t take up too much room on stage, it will fit into the back of your car, you won’t feel it is trying to dislocate your shoulder when you carry it into the venue, and your PA engineer will have a fighting chance of balancing the band’s complete sound. A good quality 1 × 12 or 2 × 10 combo will usually do the trick, and many pro players still use these even for festival-sized gigs, as they can get all the level they need via the PA and stage monitors. What matters is that you can get the sound that your want out of it and that you can hear yourself.

A small valve combo allows most guitar players to achieve a comfortable sound on stage without taking all control away from the front-of-house mixer.

Excerpt from The SOS Guide to Live Sound: Optimising Your Band’s Live-Performance Audio by Paul White © 2014 Taylor & Francis Group. All Rights Reserved.


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