Duke,
Does the ceiling that the LCS speakers bounce off of need to be parallel with the floor? In other words, would these still work with a left to right upward sloping ceiling?
Are the timing delays simply a function of relative placement or is it done with some electronic delay?
Cheers,
James
Duke and I tested the full system in a local auditorium with 16' ceiling. Turning the LCS on/off all three persons present including my wife with better hearing them me, agreed LCS performance advantage seemed similar in 8' and 16' ceiling. I wrongly suspected performance loss with such tall ceiling, resulting from less LCS magnitude of effect resulting from the primary reflective boundary (the ceiling) being farther from the listener. IIRC, Duke explained the increased ceiling distance does not minimize LCS magnitude, it simply increases delay and spreads reflection over a larger surface area. If I understand correctly then, the net sum total of the Main Speaker (on-axis) and LCS effect is much less dependent on the ceiling than we might suspect.
We'll see what Dr. Duke says about this.
Delay derives from only LCS architecture, siting, and the boundaries. There is absolutely no electronic delay.
After repeating it in my head enough times (it IS hard to teach old dogs new tricks), I can clearly list LCS goals, which parameters were all defined by some of the world's most brilliant loudspeaker designers Dr. Floyd Toole and Dr. Earl Geddes. Ideal reverberant field qualities/parameters:
- Full range
- High in magnitude relative to on-axis signal
- Maximum random, decorrelated signal relative to on-axis signal
- Delayed 10ms-20ms relative to on-axis signal (11.3' to 22.6'...this spec is "fuzzy" rather than concrete)
The sum total effect of LCS achieves the above goals to greater degree than any other known production loudspeaker. The sum total extent to which any other speaker addresses #3 is zero. Even if some other method more efficiently addressed #3, it would require greater complexity and increase cost for unknown potential benefit.
This also relates to the ceiling being uneven L to R: I suspect it's very possible this could increase random/decorrelated effect, which could further improve performance. The greater is reverberant field decorrelated from on-axis signal, the better is performance. It's possible that the less symmetrical is the ceiling L/R the better is performance. Ideal reverberant field improves more than just image and spatial qualities. The better is the listener's pitch acuity, the more they will notice improved pitch center of notes. Listeners can and will notice greater interest in music with greater complexity.
Also, ideal reverberant field improves musical detail without resorting to any "tricks" such as exotic cone materials, costly cabinet materials, etc, etc. I have nothing against such practice, but after living with LCS and turning it on/off as many times as I have, I'm convinced the way it improves musical detail without any highlighting or etching is highly addictive, always pleasing, and never tiring on the ears.
There is reason to believe LCS can improve the performance of any speaker regardless its radiation pattern, even a planar dipole. Beyond what appears to be the premier reverberant field performance, LCS offers the following improvements for persons considering adding it to a pre-existing main speaker. One of the following advantages is definite, the other likely.
Deeper bass cutoff for Main Speakers that cutoff above the "low 30s." The floor is ideal for placement of the LCS speaker firing upward, especially behind the Main Speaker, which "shadows" the LCS' off-axis radiation to listeners throughout the room. Beyond that, the floor and nearby vertical boundaries are "free lunch" for increasing deep bass output. With floor and vertical boundary reinforcement we project bass cutoff in the "low 30s." This is especially nice for stand mount Main Speakers. Many audiophiles enjoy stand mounts over floor standers because they hate bass mode effects which are more prevalent with larger floor standing speakers, which segues nicely into the next item...
Free Bass Mode Damping in 3-D space and throughout the room, not electronic EQ which worsens performance at points other than the mic test location. The sum total of two Main Speakers and two LCS = four bass sources in the room, each occupying a different geographic space, exactly ideal per another PhD. named Pierre Sprey of Mapleshade, and others who promote Distributed Bass Array.
Users get to invert the polarity of either (not both) of the LCS full range speakers. Wow, you think, that will just totally destroy everything associated with spatial effects. And you'd be totally wrong. In fact, consistent with everything else advertised, in the mid/treble and spatial wise, you can not tell whether one channel is inverted or not. How's that for strange?
Why? Relative to on-axis signal most of LCS energy is delayed 10ms or longer. Inverting it's polarity is inaudible in the mid/treble range and has no effect on spatial quality because 180-degrees is such a tiny fraction of one percent of its delay time vs. on-axis signal.
But in the bass range it is audible, and only in a good way. It damps bass mode effects. Depending on the modes, on some program it's just audible, on others it's quite huge. Inverting one side normally works better than the other. Try both channels. You'll like the effect so much on the first channel you might be lazy and not try the other channel, which could work better. (Senator, I can not deny nor agree I am guilty of the charge.)
So beyond making your image and spatial dreams come true, you get a sub woofer and a good portion of the advantage of a Distributed Sub Array.
Lawn mower and breakfast in bed features coming.
