High-falutin gobbledygook (yet again)
Well, after all this obfuscation with words like 'slow', 'fast', 'rhythm and pace' we have the bones of a real, logical, comprehensible engineering observation. Yet again, what is nothing more than a basic physical concept which a child could understand given suitable real-world non-audio examples, has been spun-up into high-falutin gobbledygook and then into audio folklore. Why does the industry have to treat the consumer as a dimwit? Anyone who attended high school should be capable of comprehending what's really under the smokescreen of guru-ism.
Reported a few posts back ...
So there you have it in a nutshell.
What does 'fast' mean?
Speed in a loudspeaker is related directly to damping factor applied not only to the cone but the cabinet itself (and maybe even the crossover). Usually lighter and smaller cones seem to react to changes in rhythm faster or more accurately due to lower mass (and lower damping but that's another issue). A heavier damped cone will respond more slowly to changes in signal than a lesser damped one. Most guitar amps stick to lightweight paper cones for this reason. So why bother with damping? Well if you don't bother then you run the risk of all kinds of distortion and frequency anomalies appearing.
Cabinet resonances can also make a speaker sound slow, not only slow as such, but ill-timed as well. Ill-timed can sound blurred, and blurred can sound slow. This effect becomes critical at low frequencies because they are comparatively slow in the first place.
How many car speakers have you heard that had poor 'timing'? Not many I bet, and the same goes for ghetto blasters and such. Furthermore I can't recall any headphones sounding slow in the same way as the comparatively ponderous loudspeaker can. In these cases the cone material is light .... Cabinet resonances also explain why boxless speakers will always sound more responsive to the signal, but once again this comes at a cost. Cabinet resonances become more obvious in relation to the amount of bass the speaker is asked to reproduce. The Harbeth thin-wall cabinet is still the best way of dealing with this ...
Forget non-specific ambiguous copywriters words like 'fast' and 'slow', 'rhythm and pace'. Substitute the engineering words high damping, low damping, optimal damping, over damping, under damping, inadequate damping and we can move the discussion forward in a way that we can all extract real understanding and application to our own listening experience.
Alan A. Shaw
Harbeth Audio UK