LMA: Efficiency is NOT the only thing that matters in engines or drivers.
Phusis: And yet it's rarely prioritized or recognized as even ONE of the core parameters in speaker engineering.
Lone Mountain: Who on earth told you that? That's not true. Transducer engineers HAVE to consider ALL parameters to achieve a result that fits the target. More bass? Smaller size? Lower distortion? High reliabliity? Needs to be cheap? Needs to be high performance? Part of a mulitway application so bandwidth to 20K isn't an issue? A zillion decisions to make by the product manager/engineer in driver design with a specific goal in mind. So it goes like this: "I need a LF driver in a three way that has the lowest distortion possible, rolls off at around 42 Hz, system levels are to be 100dB sustained without failure for 24hrs. Price has to be under $500 retail". That's a helluva puzzle to solve. Most speaker manufacturers call up a their wholesale driver supplier and see how close they can get to something off the shelf that achieves that. Someone like Peerless in India, or JBL in India. Some try and build their own, like ATC.
Transducers (drivers) are one of the most significant physics puzzles of audio, involving materials science, hydraulics, electrical science, acoustics, mechanics- its a true rubiks cube. It is not some afterthought.
LMA: From product management experience at JBL and with ATC, a driver can be optimized for bandwidth OR efficiency. If you want more low end from a driver, it WILL be less efficient. IF you are willing to forgo some low end, you can go for efficiency.
Phusis: To some extend at least you can have your cake and eat it too: add size, but that's usually the one thing audiophilia wants to avoid, so, in that case it's either/or.
Lone Mountain: A transducer engineer, a good one, cannot set an issue aside cause he's guessing what his customer's customer cares about. They are engineering to hit some goal, always narrowly defined; there is no " oh lets go through a 5 year process to build this new driver and spend 10s of thousands on tooling and lets just see what we get when we are done". They know what the target is, they are working with materials and designs of things like formers and coils and spiders LONG before the first new driver is built. There is no guessing in engineering-most principles are well understood. There might be some experimentation, but that requires a very well funded engineering department and some very deep insight. Ray Cooke is such a person (KEF), as is Billy Woodman (ATC), Floyd Toole (JBL), Doug Button (JBL), etc etc.
Efficiency has it biggest influence because it determines what else you can or can't do in your design. Picking efficiency out of the very long list of design criteria as THE pointer to performance is like saying that one spec (THD) defines how great a piece of electronics sounds, one spec (MPG) tells you how good the car is, one spec (brightness) tells you how good a TV is. All of us involved in the making of audio gear know this idea is not true- unless we are unaware or just ignore all the other differences. There are some highly efficient speakers that just sound awful, no? Tube PreAmps sound amazing to many yet the THD spec indicates it would be horrible. Vinyl vs digital files- need I go on?
You are trying to reduce a very complex issue into some simple yes/no question and that is not possible with transducers or audio in general.
Brad
