Question for artto

[chambers1517]

I was told in the home theater section this was a question for you. I have a theater room with 2 khorns and 3 lascalas. The room is about 14 wide and 21 deep. I have the khorns on the front wall which is 14 wide and a lascala in the wall behind an acoustically transparent screen. I have it raised so the tweeter level is even with the khorns. I have the rears on wooden boxes in the rear corners toed in. I have the boxes stained to match and they raise the rears to the same tweeter height. My dilema is that I don't have any room in the front for subs. My screen is about 18 inches from the floor and 18 inches from each khorn. I was wondering how it would work to use 2 denali in the rear corners. They have the same footprint as the lascalas so I could sit the lascalas on top of them. This would eliminate my boxes and alow the subs corner placement. What do you think?

[artto]

Well, first off, IMHO, a pair of Khorns, plus a LaScala, really have no place along a 14 wall. The toe-in angle, relative to the speaker spacing & listening positions is too great for the kind of polar coverage the Khorns were designed for. And to add two more LaScalas in the rear channels, and then you want to add subs, in a 14x21 room no less. Jesus! What are you trying to do? Commit suicide?

Next. The front speaker array should be lined up in the same plane. I have discussed this a number of times with Klipsch engineers over the years, as well as repeatedly read the Klipsch Audio Papers until I understood why. Consider this. When a recording company like Telarc (or the old Mercury Living Presence) makes true stereo recordings, they sometimes use a third center microphone. This mic is in the same plane as the flanking mics. Likewise, its the actual drivers of the speaker system that need to be in the same frontal plane.

I think Khorns are the wrong speaker for your situation. I also think its very difficult to match subs to them unless of course you want a very exaggerated unnatural sound. With Khorns the low-end performance is often determined by the size of the room, room proportions, and room acoustics. And your suggested placement for the subs is exactly where there are already the most standing wave problems, where there is excessive bass build-up, which in turn also causes the opposite effect (cancellation) in the listening area.

Hope this didn't sound to offensive my friend. WELCOME TO THE FORUM!

[formica]

Artto, your points are well taken but remember that this is a HT setup, where the rear channels only receive an occasional signal.... and the LFE channel extends below the audible range (just to know the T-Rexs are coming )

Based on what has been discussed in the original thread in the "subwoofer forum" I think the question was more in terms whether there was any scientific difference between front corner vs- rear corner placement of a subwoofer (below 20Hz to 60Hz)? My understanding is there shouldn't be much of a difference in a symmetrical room given the wavelength in question... but you may have had more experience with this.

The actual "ideal" placement of one or two subs (any of the 4 corners, front/rear centre, or L/R side centre) is obviously a more complex subject... depending somewhat on personal preferences**. An article (I believe by Floyd Toole) concluded that dual subwoofer placement mid-way on the side walls produced the flattest response in their test room... while the typical corner placement produced the loudest (but peakier ) response. But I think this is more involved than what was being asked...

Later...

Rob

** note: Personal preferences: although not my preference, some do prefer SPL over frequency response

[artto]

Youre right Rob. I admit Im not a big HT enthusiast. Too much disconnect between the 3-D sound & the flat 2-D visuals for me. And, the sound is often exaggerated (IMO) to, as you said let you know the T-Rexs are coming.

At any rate, raising the LaScalas off the floor that much will roll-off their low frequency response faster as they de-couple from the wall/floor room boundary. And corner placement will reinforce the bass output. The downside is, this (corner placement) often also means bass cancellation in other areas of the room, usually in the middle of the room where we usually do our listening/viewing. This is especially true as the room gets smaller.

The way I see it, there are four choices. You can move the speakers around until you achieve the best response for a particular listening position (similar result to what electronic EQ would do. What works good for one location will make things worse elsewhere), electronically EQ it with the same resulting compromises plus the added noise & distortion, use acoustic treatment especially in the vertical corners (for low bass this would have to be quite substantial, something like floor to ceiling Auralex MegaLENRD basstraps, but even these will not provide substantial control down into the sub bass region), or change the room size and/or proportions.

To me, it just seems that many people are trying to do too much, with the space they have available. It doesnt do components like Khorns any justice. But, like Ive said in the past, To each his own.