How many sound systems have been built and are in use? Many millions, for sure, and they’re found in all types of venues and for all kinds of programs.
So one would think we’d know exactly how to do it by now. But there seems to be plenty of examples to prove that we don’t.
Why should this be? What is it we don’t yet understand? Do we even know enough to know what we don’t know?
Perhaps we should start by trying to define the characteristics of a good system. Not just “it sounds good” but - exactly - what makes the difference between “good” sound and not so good.
Then we might be able to quantify how good each characteristic needs to be and how to judge whether it’s good enough or not.
After nearly 40 years spent designing and testing sound systems, I’ve finally come up with a list of the factors that I feel make up what we could call quality in a system, and why. For purposes of my discussion here, I’m going to confine my list and discussion to systems for speech reinforcement only, and will look at factors for music systems at a later date.
Reliability. The most important quality factor has to be reliability. No matter how good the performance of a system may be, if it fails to work, it is useless.
Reliability is largely an engineering matter, involving component selection, configuration design, and assembly and installation correctness, for example, but any system can be abused to the point of failure.
Significantly, failure may not be abrupt and catastrophic, but instead may take the form of performance decline due to damage.
One particular, and common, example of damage-induced deterioration can be found commonly-used transducer for higher audio frequencies, the horn and compression driver combination.
Drivers have a severe amplitude limit; if over driven, the driver diaphragm will impact the phasing plug, an essential part of the structure. If the diaphragm material is metallic, it can fracture and fail.
Surviving a Collision
Some diaphragms, however, are made of a resin-impregnated fabric, which is much less brittle and, therefore, more able to survive a collision with the phasing plug.
Repeated collisions, however, still cause progressive deformation (or warping) of the diaphragm, resulting in eventual failure and therefore, progressive decline of the driver’s performance characteristics.