Introduction to PA for Performers

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for Performers

By "performers" here we primarily mean vocalists and musicians who perform as part of a band, though it is possible that other kinds of users of PA systems will find the information on this site useful. We hope that the information on this site will help to remove some of the mystery surrounding this subject, and help you to get the most out of the system(s) you use.

System Arrangements

From a PA perspective, there are two distinct arrangements of systems used − though the real difference lies not in the nature of the system itself, but in by whom it is operated. The two arrangements are:

When the person operating the system is also a performer in the band. In this arrangement, typically adopted by bands of up to 4 members when performing in small venues, the mixer (or mixer-amplifer) is located on-stage and the responsible person will set up the system prior to the rehearsal, probably making small adjustments during the rehearsal and possibly during the performance. This is something of an "economy" arrangement, as although it has the advantage of avoiding the costs associated with another person, it suffers from the problem that even if a reasonable mix can be achieved initially, the responsible person cannot properly manage the sound throughout the performance to take account of dynamic factors such as a growing or increasingly noisy audience. (Even the initial entry of the audience can significantly affect room acoustics from those which existed when the system was set up.) This is not necessarily a matter of skill, it's simply that a person who is located behind the front-of-house speakers and is primarily focussed on delivering a good performance is at a significant disadvantage in comparison with someone in a good listening position who is concentrating only on the sound. Nevertheless, how much this really matters depends to a great deal on the acoustic expectations of the audience.

When the person operating the system is not a performer in the band. In this arrangement, typically adopted by larger bands and in large venues, the mixer is located at a suitable listening point (preferably central to the audience) and is set up and operated throughout the performance by one or more people dedicated to this task. Whilst this arrangement has the potential to provide a technically superior sound (which means, at the end of the day, more pleasing to the audience), it has its own problems in that it inevitably creates something of a divide between the performers and the sound engineer(s). To minimise this kind of problem it is essential that the performers have full confidence in the engineers, and see them as their essential allies. This will often mean that the performers will need to explain to the engineers what kind of sound they are hoping for, both on-stage and front-of-house; this will usually be an interactive trial-and-error process, requiring patience and respect by both parties. In some cases the performers may need to accept that their ideal sound is not achievable, given the limitations of the available PA equipment and of the venue.

Microphone Technique

Using a sound system is something of an art form in itself, and excellence can only be achieved through experience. Nevertheless, it is hoped that the following brief notes will provide some useful hints for performers, without getting too technical. You might also find it helpful to read the Introduction for Mixing Engineers, to give you some idea of what they are up against!

You can help to avoid feedback by the correct use of microphones. Do not point them at the monitors, and avoid wandering in front of the front-of-house speakers if at all possible. Maintain a reasonably constant distance from the microphone (except when deliberately varying the distance for effect), as advised by the sound engineer(s). Do not wrap your fingers around the basket of the microphone, as this is likely to decrease the microphone's in-built immunity to feedback.

If feedback does occur, the natural reaction is to increase your distance from the microphone. But whether this is the right thing to do depends upon how close you were to it at the time. If you were more than about 4 inches (10 cm) away, by moving further away you are actually increasing the chance of feedback, because the engineer must provide even more amplification to achieve the desired sound level for the audience, and this would make the feedback worse. So decrease the distance, so that the amplification required can be reduced. If however you were very close (less than 1.5 inches (4 cm)), moving slightly further away may be helpful because, with some types of microphone, being very close can decrease the microphone's in-built immunity to feedback.

The following illustrations show some possible positions for a vocal microphone, with associated comments, listed according to the angle of the mic. They assume the type of mic most commonly used for live performances (as opposed to studio recording), i.e. an end-firing type with a cardioid or super-cardioid pick-up pattern.

	1. A rarely-used position, generally employed only for situations such as a stand-mounted mic used by a drummer. (In such a situation, the mouth-to-mic distance must be kept fairly small, to avoid excessive pick-up of the drum kit.)
	2. A hand-held position sometimes briefly used during a performance, for visual effect. Good pick-up, with a considerable amount of bass boost (due to the proximity effect).
	3. A position commonly used by some rock and pop artists. As this position gives a very large amount of bass boost, it requires a type of microphone that is intended for such close-up use (such as the Shure SM58). Even quite small changes in the distance to the mic will have a marked effect on the amount of bass boost, and also on the amount of pick-up (unless heavy compression is in use). Not suitable for applications where facial expression is important, or when close-zoom camera work is in use, as the performer's mouth is completely obscured (except for profile camera angles).
	4. Similar to 3, but with less bass boost and less sensitivity to changes in distance. Slightly better visibility of the performer's mouth, giving an improvement for semi-profile and profile viewing angles.
	5. Even less bass boost and less sensitivity to changes in distance. However, reduced pick-up of the performer (especially with cardioid mics) versus other sound sources may be a problem when stage sound levels are high, or when the performer is in close proximity to loud instruments. (This is more of a problem when the performer has a quiet voice.) Better visibility of the performer's mouth for profile and semi-profile camera angles.
	6. Often a good mic position, but the performer's mouth is still largely obscured for frontal views.
	7. Often an ideal mic position when a certain amount of bass boost is desirable. Much improved mouth visibility from all angles.
	8. An ideal mic position for strong voices, when bass boost is not required and stage sound levels are not too high. Quiet voices may be difficult to amplify sufficiently, without feedback and/or pick-up of other sounds. The low sensitivity to changes in distance make this position very suitable for stand-mounted mics. Excellent mouth visibility from most angles.
	9. & 10. Useful positions when some bass boost is not a problem and good immunity to other stage sounds is required. They also provide reasonably good visibility of the mouth (especially 10.).

	11. An incorrect technique, giving rather poor pick-up of the vocals (particularly with super-cardioid and hyper-cardioid mics). The sound engineer may be able to compensate to some degree.
	12. The performer seems to think that this is a side-addressed microphone. As it isn't, the pick-up of the vocals will be extremely poor. The sound engineer will not be able to compensate for this; attempts to do so are likely to result in feedback and/or excessive pick-up of other sound sources and room reverberation.

For a slightly more technical discussion on the effect of microphone technique on the pick-up behaviour of microphones, see Use of Microphones on the Microphones page.

If you are using a hand-held radio microphone with an aerial that sticks out of the bottom end of the mic, take care not to hold the microphone around that part, as this can cause problems with the pick-up of the radio signal by the receiver.

If you are using a hand-held microphone that has been marked with one or more identifying coloured bands of tape, it would be of assistance to the sound engineer if you hold the microphone in a manner that keeps at least one of these bands clearly visible.

Musicians

Guitarists: To avoid loud crackles and bangs that are very unpleasant to your audience (and potentially damaging to the PA equipment), then unless your guitar cable has a self-shorting jack plug, or you have first used a pedal (or other means) to turn down or cut off your guitar signal, never unplug your guitar cable at the guitar end without being sure that the engineer has muted your channel at the mixing desk. If you are relying on the engineer to do this, then they will have to know when you are about to unplug; this could, for example, be communicated either by pre-arrangement (e.g. after a specific song), or through use of agreed hand-signals.

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This page last updated 26-Jul-2011.