There was a good discussion started in another thread,
http://www.whatsbestforum.com/showt...nglish-version&p=338075&viewfull=1#post338075, on audibility and requirement of proper phase response in loudspeakers. Good suggestion was made by Michael to create a separate thread on that and I thought this would be a good place for it.
So let's have the necessary theory and listening tests results posted here and have a good discussion on this usually murky topic. There are definitely two schools of thought here as evidenced by loudspeakers with stepped drivers and those without it for example.
Yes, I think it is an extremely murky topic. There have possibly been listening tests in the past, but comparing what with what I am not sure.
Here's my take on some of the murkiness:
One of the main areas of confusion is that of phase versus pure delay. These are not the same thing. The stepped drivers you mention are giving time alignment between drivers, compensating for actual physical
delays. but this does not mean that the speaker has an overall neutral
phase response. The individual drivers have their own characteristic phase response, and in passive speakers are being driven via crossover filters which are also phase-shifting networks (not delay networks). The idea is to get the drivers to cross over with the same phase shift or, I think (having never tried to do this myself), cross over such that the resulting acoustic sum has the correct amplitude even if the individual drivers are not behaving ideally. The overall phase shift that occurs is usually not considered an issue. The resulting system is extremely complex, and what comes out in the time domain looks nothing like what went in. The 'get out of jail free card' is that someone at some time has decreed that humans are not able to hear phase shifts.
There is also a common argument that "The room completely swamps any phase shifts in the speaker", but this is based on a flawed assumption: that delays are the same as phase shifts. In the room, the ear is hearing the direct sound, plus
delayed (not phase-shifted) sound. Transients are not affected by delays in the same way as they are by phase shifts, and the ear seems to be able to hear past the delays to the direct sound pretty effortlessly.
None of this can be proved with mathematics (which often impress and of course always 'prove' something, but not necessarily the right thing).
All I know is that with the advent of DSP it is possible to take a punt, bypass the entire question of how audible this stuff is in theory, and actually try it. If we are half-expecting reviews of DSP active systems (e.g. Kii Three) to conclude that these systems are clinical, harsh, flat, grey, unmusical etc. then it is a pleasant surprise to find that they don't. In the words of Michael Fremer:
...what I heard from this system absolutely astonished me. There was nothing 'digital' about the presentation. Nothing. The top end was about as perfectly rendered as I've heard from all of these tracks as was the detail resolution. Response was top to bottom full-bodied... it was fast, ultra-clean and spectacularly transparent.
Instrumental textures and timbres were as accurate and realistically portrayed as I've ever heard them. The amount of true detail revealed in very familiar records was unprecedented...
...I went back to be sure and I'm sure. I played the rip of Richard Thompson's "The Angels Took My Racehorse Away" from Henry The Human Fly his first solo LP (UK Island) recorded by John Wood at Sound Techniques and I've never before heard the drum sound so realistic and life-like and I mean never. But that was just the start of what I heard from the many tracks I played. The rip of a lacquer of "Night in Tunisia" from the Blue Note album of the same title was downright astonishing. "Can't You Hear My Knocking" just about made me faint. I'll stop now.
http://www.analogplanet.com/content...system-you-will-ever-hear#OKojxhmWyEFzfi28.97