MJK wrote:So a straight untapered pipe is a Labyrinth or TL. But if it contracts uniformly by a total of 1% along the length it is now a tapered labyrinth. If that pipe expands uniformly by a total of 1% along the length it is no longer a Labyrinth or TL but is now a horn. Why is it not an expanding TL or Labyrinth?
The acoustic behavior of all three pipes (measured and/or simulated) will be for all practical purposes identical. Your jargon makes no sense, it is not based on technical performance differences. Do you really believe there are significant enough differences in the three pipes I propose to assign them different names/labels which in effect indicates different performance? I don't, these definitions demonstrates ignorance of the physics.
Sigh. No Martin, I do not believe there would be any significant difference whatsoever. As you know perfectly well. There will be a tiny amount, obviously, that equally obviously would in almost every case be impossible to measure outside the most sterile laboratory conditions. As I have stated several times, these are simply convenient terms or handles, and the practical results necessarily vary by degree. They are not meant to be crystalline definitions of a very narrowly applied / specific instances. I and others are happy with them, and will not be bullied into changing just because you don't happen to care for it. I can live with that: you will have to also.
You call a resonant straight pipe with mass-loading an MLTL. Fair enough, so do the rest of us, although Mass Loaded Quarter-Wave Resonator / MLQWR would be a more accurate description, if (
if) we are to apply hyper-narrow definitions, since the implication inherent to the TL term is impedance matching or flat impedance (unless we also insert 'mismatched' caveats), and if we were to demand adherence to such ridiculously narrow conditions then only speakers that could be said to adhere to it would be those where the enclosure is designed for the sole purpose of providing the flattest possible impedance load, with zero other considerations at all. Very few / nobody applies it so rigidly in practice, or believe it should be so. I certainly don't, nor, clearly, do you. In the same way, GM, myself and others use the term 'horn' with similar looseness to refer to expanding pipes. We are perfectly aware that a portion (or even the majority & in some cases all) of the usable BW is produced by resonant action, how much depending on how compromised the expansion is relative to the optimal.
Re the 1/2 wave mention, this is generally a reference to horns needing to be at least 1/2 wave long for maximum efficiency over the target BW. If expansion is minor, this is more or less irrelevant for practical purposes, obviously, but becomes progressively more significant as expansion increases. As noted, it depends on how rigidly one wishes to apply xyz terms. Some of us prefer to view the behaviour of enclosures as shades of grey (hopefully not 50) rather than fixed lines, as a progressive shift occurring as you move in one direction or another. YMMV as always.
