Hi,
Stereo Mic said:
you will notice my comment contained the phrase IME , not IMO, therefore I am qualified to point out that not time aligning the signal below 100hz will have a noticeable impact on the perceived sound quality.
I have a good deal of experience on that too, including very large PA Systems with delay towers etc. I am not arguing against "time alignment" per se, I am merely pointing out something about the nature of multiple dispersed bass radiators to Simon and a good way of illustration is to go the extremes.
Would I fit a seperate subwoofer into every corner (time-delay or not), nope.
Stereo Mic said:
You also failed to address the issues of the second harmonic and vertical axial mode. Any reasons for that?
There are very good for me actually covering the, as indeed I did. Note that I pointed out that the "equal pressure (AT THE SAME TIME) at opposite walls/corners" will eliminate ALL odd order room eigentones (that is 1st, 3rd, 5th etc, usually after the 5th we tend to be near or above the modal range for normal rooms) and the EVEN room modes should be addressed by shifting the listening position with respect to boundaries and the pressure nulls so that for all relevant modes the listener is a the unity pressure point.
I did address the vertical mode in the suggestion to add the subs in the ceiling corners of the room, that is to kill the vertical odd modes.
BTW, as I am unaware of anyone ever having introduced and implemented such a system (for perfectly sensible reasons as I pointed out) no conclusions can yet be drawn if it would be preferable to have an LF system such as described, without time alignment and without room mode influences, or if a time aligned LF system with full room mode impact would preferable, or if the answer lies somewhere inbetween, according to taste.
My main point was to illustrate that adding more seperate subwoofers to a system must not inherently, as Simon suspected in his post, lead to a worse room mode problem.
Stereo Mic said:
Your directional loudspeakers are not directional at the frequencies we are discussing.
Ou contraire mon ami, MY OWN directional loudspeakers are most definitly directional at the frequencies we are discussing, as are th MEG RL901K's I have been occasionally championing as "pretty good loudspeakers".
Your posts suggest that you neither take the time to actually read my posts carefully (or you would noticed the indirect references to even order room modes and vertical modes), nor do you make sure you actually follow the reference I give, to understand WHAT I am discussing.
This limits my part in the discussion to simply refuting your wrong statements and does not actually add anything to anything.
Ciao T
PS, just to spite people like you, a commercial product in the initial design phase right now is a fairly compact, reasonably high output subwoofer which will be unidirectional down to around 35Hz and will become progressively more omnidirectional below, in order to provide the last LF octave my current main speakers (also in essence commercial and as I pointed out directional with a DI of 4.8db or more across the ENTIRE frequency range they cover) do not, due to a concious design limitation.