Residual Noise
Horn loaded loudspeakers and drivers have high sensitivities which means that they produce a relatively high output for a given electrical input. This includes the residual electronic noise of an audio system.
By setting gain structure properly and using high quality professional electronics, this noise should be at or near inaudibility.
Among the noisier electronic devices are 16 bit digital devices such as some signal delays. They have signal to noise ratios that are only 90 dB.
However, if the gain structure is set correctly this means that, for example, if the system can produce 120 dB SPL at maximum output, the residual noise should be about 30 dB SPL.
This would be acceptable for a quiet recording studio. If residual noise is a problem, gain structure is usually the culprit – it is never the loudspeakers.
Level Balancing
Once the system gain structure is set, the level balances can be adjusted. This may mean the levels between HF and LF sections of a biamplified loudspeaker, a full-range loudspeaker to subwoofer level, levels between multiple loudspeakers, or between main and delayed loudspeaker array.
The idea is to make the system sound the best it can without using any equalization. This may be done using acoustic test equipment such as an RTA (real-time analyzer), TEF analyzer or similar. You must always determine the final level balance by listening to a variety of known program material.
Level balancing can also be done entirely by ear if acoustic test equipment is not available. In any case, the preferred method of adjusting levels for balancing is to use the amplifier input level controls.
Important:
In order to maintain the system’s dynamic range that was maximized by setting the proper gain structure, do not turn up the input level controls of any of the amplifiers. For example, if you decide that a subwoofer is not loud enough, do not turn up the input level control of its amplifier. Instead, turn down the input level of the full-range loudspeaker’s amplifier.
Equalization
Once level balances are set, you can then equalize the loudspeaker(s), if necessary. Community loudspeakers are optimized for highly accurate and well balanced reproduction “out-of-the-box.” Generally, equalization should only be needed to eliminate difficult feedback frequencies or to adapt the system to a difficult acoustic environment.
You should not need more than a few dB of boost or cut equalization for any particular range of frequencies. The best equalization techniques involve cutting rather than boosting frequencies.
Final Results
Once the above procedures are followed, your loudspeaker should reproduce audio cleanly, clearly and with all frequencies in good balance.
Noise should not be audible and you should be able to drive the amplifier(s) in the system to maximum output on normal program material with no significant distortion or other undesirable sound. If limiters are used, the onset of limiting should occur just before any amplifier clipping.
Sometimes it's wise to remember the old adage "less is more"
