I'm never going to hear a megaspeaker in a good room am I?

I will never hear a great system in a great environment. Never.
Nor do I want to, really!
Because I will Never, Ever HAVE that great system in my little apartment environment.  There will be Excuses.  Compromises.  Deal with. Limited Dollars.  Thus Never Ever be satisfied with what I have.  Ignorance IS bliss. 

Hello,
Paul of PSAudio set up the room for the $50,000 Infinity speakers. Plus he is developing some of their own stuff. They have a pair of bookshelf speakers that play down to 30hz. I am not sure if they are doing listening sessions right now, but they do have what your asking. 

Erik posted:

" I don’t mean to nit pick but you listed this as beneficial:

1. Increased time delay between the first-arrival sound and the onset of the lateral reflections, and a generally increased decay time.

"Did you mean the last part? I thought generally in home rooms we want to decrease the decay time? Maybe I’m not understanding what ideal is here."

Excellent question!

Reflections done right are your friends!! And "done right’ STARTS with the reflections having the same spectral balance as the direct sound, or nearly so... a little bit of rolloff in the highs is normal. But not too much - note that Peter Snell included a rear-firing tweeter in the Type A to fill some of the top-octave energy which would otherwise have been missing from the reverberant field.

So everything I’m going to say in this reply is said with the ASSUMPTION that the off-axis energy’s spectral balance is essentially correct (which in practice tends to be the exception rather than the rule). This is not going to be an all-encompassing answer because this is a big subject.

By way of background, in home audio, I consider the transition between detrimental "early" and beneficial "late" reflections to be about 10 milliseconds. This figure is not arbitrary. Researcher David Griesinger finds the ear to be especially sensitive to aberrations between 700 Hz and 7 kHz, and according to Earl Geddes the mechanism by which the cochlea perceives sounds within this region implies that "you need a 10 millisecond reflection-free window if you want no coloration or imaging effects.”  

(Early reflections are not entirely detrimental - they DO increase the soundstage width, or "Apparent Source Width" [ASW], to use Floyd Toole's term.) 

ALL reflections convey spaciousness, but the earliest ones do so at the expense of clarity and imaging precision. Early reflections may also cause coloration, with arrival angle playing a role (the closer to the same direction as the direct sound, the worse). This would seem to imply that the floor and ceiling bounces are especially detrimental, but in practice they are not (imo the reasons why may be fairly complex).

Late reflections convey spaciousness without the detrimental effects which early reflections can have, so we want to preserve them as long as they are not too loud or last for too long, which is seldom the case in a normally-furnished home listening room. The wider the speakers’ radiation pattern, the greater the chance that we will indeed have too much in-room reverberant energy - but imo it’s probably more likely that too much reverberant energy is having its detrimental effects due to excess EARLY reflections rather than excess LATE reflections.

Spectrally-correct late-arriving reflections also help to convey rich timbre. This is one of the things the MBL Radialstrahlers do exceptionally well, especially when positioned far enough from the walls to avoid significant horizontal-plane reflections within the first 10 milliseconds. Spectrally-correct reflections also help convey liveliness.

So early reflections are a two-edged sword, but later reflections (done right) are virtually always beneficial. Therefore in my opinion we want to minimize the early reflections but encourage the late ones. And if we use a room treatment approach which is aggressively aimed at reducing the decay time, imo we are killing off some of our beneficial late reflections... that is, "beneficial" assuming they were "done right" (spectrally correct) in the first place.

Duke

Therefore in my opinion we want to minimize the early reflections but encourage the late ones.

@audiokinesis

Well, hmmmmm, I think in the context of what you posted above this makes relative sense, but don't most listening rooms have too long of an RT 60 to begin with, not to mention, it is usually pretty uneven.

So, you mean relative to early, coherent reflections, you'd rather have the energy come at the listener in the reverberant field time, but you are not suggesting the RT60 periods be made longer.

Is that correct?

Best,

Erik

For those who are curious, RT60 is the measure of reverberation time.  It answers "when does the signal decay 60 dB." and can be measured at different frequencies.

So an RT60 of 20 mSeconds at 1 kHz means that a 1 kHz signal will take 20 milliseconds to decay 60 dB.

Best,

Erik