One of the differences that separates amateur/semi-pro bands from the professionals is the quality of the sound balance that they present to their audience. Whereas the professional band will almost invariably have all their sound — vocals and instruments — controlled from a master remote desk, the modest club band generally relies on setting up a sound with the club empty and then tweaking that sound during the performance based on what they can hear and based on a lot of practical experience on what they want their sound to be. The main problem is that the stage is the wrong place from which to make such judgements.

The effect of this is that as each member of the band makes these adjustments any overall sound balance that was originally set goes to pot and almost without exception the volume level rises ("Turn it down lads, the neighbour's cat has just turned inside out!").

Even if the balance is about right the club band's problems don't stop there. How many performances have been totally wrecked by the club's sound level mains cut-off, either the old orange light style or the newer traffic light system? Either you get cut off in your prime or you spend the night with a permanent neck ache and the frustration of swooping the volume level up and down as you play in order to keep the mains flowing through your equipment.

The answer to the problems is obvious, and for most small bands totally out of their financial reach. A master PA system with a remote desk and operator, miking of the instruments from the backline amplification, outboard processing of the signal via graphic equalisers, echo, reverb, companding etc and all the other things we know can be done if money flows like water. How many bands have seen the pros working live or read through the 'PA Column' not a million pages from here and said "Well, if we had that sort of gear..."

As the main problem for most bands is lack of the gear rather than lack of a friend whose musical judgement you can trust, I would like to suggest an alternative system which, whilst by no means perfect, seeks to redress some of the imbalance between the semi-pro and the pro sound. It is by no means cheap, but you get a lot of control for your money — if you're not prepared to spend around £60 to dramatically improve your sound then don't waste your time reading any further.

To control or not to control

The main problem in designing a control system such as this is judging what to put in and what to leave out. Almost certainly I'll miss something out that your band needs or put in a lot more than you could get away with. It's up to each band to modify the design to suit their particular needs, although it's worth building in more control than you think you'll need to make room for future developments.

The idea is to control key backline amplifier controls from a remote position (ideally about half way down the hall) throughout the performance. My suggestions for what to control are:

1. Each individual microphone volume
2. The master vocals PA volume
3. Bass guitar volume
4. Lead guitar volume
5. Rhythm guitar volume
6. Keyboards volume

In addition the desk should have complete control over any vocal outboard processing through the amplifier's send/return loop and the desk operator should have a talkback facility (throughout the monitor system) to the stage. You will notice that I have not included any tone controls in my list as I've got to stop somewhere, but the facility of talkback should go some way towards offsetting this. All the controls I've listed tend to be low impedance so fairly long cable runs become possible.

System breakdown

The whole issue boils down to three sections:

1. A stagebox which is linked to the various backline amplifiers
2. A length of multicore cable with connector plugs
3. A control unit

In addition each amplifier to be controlled must be modified to link into the system. Appreciating that sometimes the system will not be required (rehearsals etc) these modifications will allow the amps to run normally when the system is not used.

Modifying an amplifier

With all amplifiers the technique is the same so I'll deal with the PA amplifier as this is the most complex. I am assuming that the sort of amp most people will be using is of the mixer/amp style beloved of HH, Carlsbro, Ohm etc.

Making sure that the amp is unplugged from the mains, remove the casing and reveal the electronics. If the amp has been used in the past few days then it is sensible to touch a 100 ohm resistor across the large power supply capacitors to bleed them of any residual charge. For each control that you wish to modify you will need a plastic, switched stereo jack socket and sufficient stereo cable to run from the volume control pot to a suitable position on the back panel and then back again. The pot has three tags on it as shown in Figure One and will also have its value stamped or printed on the case. Take a careful note of the pot value for later reference. At a suitable place on the back panel drill a hole and fit the stereo jack socket. Bear in mind that you will need a stereo socket for each control so space may be tight.

Make a note of which leads are connected to pot tags A, B and C and then desolder the leads (often more than one lead will be soldered to a particular tag, always keep them together just as you find them). Cut your length of stereo coax in half and solder the screen of one piece to the lead that was removed from tag C of the pot. Solder the black lead of the coax to the lead from tag B and the red lead to the lead from tag A. Insulate all three joints with tape. Complete the wiring of the other length of coax and the socket as shown in Figure Two. Test the amplifier to make sure that it works normally. If, at this stage, you want to convince yourself that the idea is going to work, wire a length of stereo coax to a stereo jack plug (as you are going to use this later use a length sufficient to run from the back of the amp to a central point at the back of the stage set up you usually use) connecting red to the jack tip, black to the ring and screen to the barrel. Get an identical specification pot to the one you have been working on, being careful to note whether it is logarithmic (lg or log printed on pot) or linear (ln or lin). Wire the other end of the coax to this using the same colour convention established in Figure Two. Plug the jack into your recently fitted socket and switch on the amp. You should now be able to control the volume using the remote pot. If it does not work then one of two things could be wrong:-

1. You have not correctly wired the jackplug/pot cable
2. The wiring to the jack socket is wrong. The coax from the original wiring should be connected to the metal 'fingers' that contact the plug when it is inserted in the socket.

So far, so good. If you can borrow a multimeter check the connections from the C tags of the pots of the PA amp. If you find that they are all connected together (almost certainly they are, probably to ground) then any other volume conversions you do on the amp can use mono sockets (use stereo coax screen connected at tag C with the original C wiring still connected to the pot and the screen cropped short and unconnected at the socket end — the black lead then connects to the mono barrel connection). This will save you a few pence but is of debatable value. It is probably easier to use stereo sockets, but do the test anyway as it will save a bit of fiddling about, if it's positive, when it comes to wiring the multicore.

Right. You've got a month to sort that out — making up the jack plug leads to run to the central stage position would also be useful but leave the ends unconnected for the moment, they will wire into the stage box (see next month's gripping installment).