There seems to be a lot of misinformation in this thread.or lack of information regarding gain and level problems. The DJ isn't solely to blame!

To start with, any nightclub sound reinforcement system has multiple points where the gain structure could be mismatched/incorrect through the audio signal chain from music source point to speaker.

There are numerous considerations

Music source recording - I have seen many clipped tracks. no matter what you do with gain, square wave signal in, square wave signal out. No device or amount of gain can correct this.

Insufficient Operator - The DJ can account for a lot of problems with a nightclub sound system, but definately not all. You have the music source as a potential issue (already mentioned), incorrect usage of input gain sensitivty (the main problem with DJ users) and incorrect usage of the master fader.

After the DJ mixer then you have multiple problems in terms of gain which can be derived from poor design, poor installation or poor configuration/commissioning of the installed sound system.

At each point of manipulation whether it be in a analogue dynamics processing device (such as an EQ, compressor/limiter, crossover etc) or an Audio DSP/Speaker Management Processor there are multiple points where there can be gain mismatch. There are many problem areas here beyond the DJ purely because of the multitude of adjustment. For the blind, stupid and unware involved in audio system installation, Rane have an idiots device to simplify the gain structure process called RANE GAIN (see their website).

Beyond the audio processing and DJ, the final place where you will have gain/headroom issues are with the speaker and amplifier combination. I have seen many underpowered audio systems and it's usually the lack of potential in the provided amplifiers. There's one rule with amplification, you can never have too much (when utlised correctly) but having too little is what will break a system or I should say, cook your speakers crispy.

As a general rule, amplification should be specified at double the continuous rated power of a speaker (look at a 20-20K spec for both the speaker and amplification and reasonable THD figures). There is a lot of dodgey equipment manufacturers that put up a lot of smoke and mirrors and overrate their amplification products (Hello Crown Audio?).

Example for matching speakers and amplifiers:

A JBL AM5215/95 8 ohm cabinet has long term full bandwidth IEC power handling capacity of 350w. In this case I would look at matching it with an amplifier that can deliver a minimum of 700W RMS (20-20KHz) into 8 ohms per channel. This is the ideal approach.

Think of it driving a Bugatti Veyron (capable of 400kph) but you have to maintain 110kph being the freeway speed limit. An easily achievable objective. Now try doing that with a Fiat 500 with four passengers. What's gonna give? It's no different with sound reinforcement.

On a side subject relative to this discussion, I was recently looking for a remote SPL monitoring tool for a sound system I'm installing in the world's 4th largest mosque when I stumbled upon these DJ mixers which could be of use where imbecile DJ's are concened: http://www.dateq.nl/EN/products/disco_mixers/vibe.html

Last edited by TurntableTech: 17-Jun-10 at 04:54am

Reason: Typos. I'm not a wordsmith, I'm an audiologist and sound reinforcement consultant.