What the PA System Cannot Do

It is important to remember that a PA system is always used for a purpose in a location, and although its design should always certainly address where and why it is needed, some environmental conditions cannot be solved by audio equipment.

Among other things, the PA system cannot:

Disperse sound evenly round corners

Where there isn’t a sight-line from audience to loudspeaker (behind pillars, alcoves, partitions, balconies), or where the audience is dispersed over a wider angle than the speaker system is designed to cover, some unevenness (or worse) is inevitable.

Covering the whole target area may mean you need extra loudspeakers, as well as additional processing so that time-alignment between separate speakers or speaker clusters is as close as possible.

Compensate for room reflections or resonance

Rooms can have an adverse effect on sound quality, and the more sound the PA system makes the worse it will get.

There is only so far you can go with loudspeaker placement and EQ, and a room with a 10-second reverb-time is going to present problems with intelligibility and frequency balance whatever you do with the sound system.

If you have to produce an event in a difficult space then you will obviously achieve some improvement using the best system and layout for the job, but you may achieve more by treating the space (with acoustic tiles, curtains, carpets, and anything else that reduces or disperses reflection) than by upgrading the PA system.

Make a mumbling talker or incoherent singer intelligible

Poor enunciation and bad microphone technique can be fixed: take elocution lessons, and learn how to use a microphone.

Where you will be dealing with inexperienced users (guest speakers at a meeting or conference, or the bride’s father), giving some brief pointers beforehand can be more effective than any system changes.

Make a cheap piezo pickup sound natural

A good EQ-section can do quite a lot with the most prominent colouration, but don’t expect miracles.

Similarly, using your own microphone can be a good idea, but the better the PA system, the more you will notice the difference between your £20 bargain and the other singer’s Neumann.

Both will sound their best if you have the best PA possible, but there is a lot of distance between them.

Clean up distortion in source instruments or backline amplifiers

If it was distorted before it reached the multicore it will still be distorted when it gets to the mixer, and at every subsequent stage.

Silence a noisy effects pedal or stop your guitar from buzzing near the dimmers

Single-coil pickups can pick up almost anything (including dimmers, induction loops, and the local taxi service).

There isn’t a ‘subtraction’ button on the desk, and although notch-filters and high-pass switches can reduce the effect of instrument-borne 50Hz mains hum, they can’t remove it.

Make a balanced sound out of a ragged unrehearsed noise

Although the mixer offers some control, it can’t completely compensate for poorly-managed dynamics, and certainly can’t stop the harmonica player from soloing over the lyrics.

A watchful sound-engineer can limit the damage, but can’t make the overdriven lead solo happen at the right time. In general, the better the system, the more clearly the audience will hear what the band is doing, so practice and rehearsal are at least as important as equipment or technicians.

Overcome poor planning or inadequate budgets

Covering big and/or difficult spaces optimally isn’t easy or cheap (and combining adequate levels with high intelligibility for every seat in every row may not be realistically or economically possible).