Cornwall III

[kktvbob]

It would be nice to see a Vert. Cornwall III for a center channel. I wouldn't want go to a Heresy center after running a vert Cornwall. A home theater with 3, 5, or 7 Cornwall III,s would be great but I may not look to up grade with out a good speaker for the center. Plus I need to hear this thing to see if it is worth up grading from the Cornwall,s I now own. What do you guys think.

[travisc]

is the Cornwall III shielded?

[kktvbob]

My self I don't need sheilding with a lcd tv. I think you only need it with crt tv's.

[oldtimer]

My self I don't need sheilding with a lcd tv. I think you only need it with crt tv's.

I could be wrong, but I was under the impression that shielding is necessary unless you have DLP. Or, of course, front projection to a movie screen.

[kktvbob]

Not with LCD I don't know about Plasma though. I have my Sony LCD sitting on my vert Cornwall for 2 years now with no problems. It also puts it at the correct hight.

[DrWho]

Shielding is only necessary for Tube TV's only (where the magnetic field from the speakers redirects the electrons that are flying out of the tube and striking the face of the screen). LCD and Plasma don't have flying electrons so there's nothing to worry about. []

Btw, why not just go with a normal cornwall III for the center? (putting the TV on top of it). Having your TV 40" off the ground is by no means too high - especially if you have a second row of seating. And the benefits of a perfectly timbre matched center channel with everything at the same height is immensly important too.

[SteelerFan]

Btw, why not just go with a normal cornwall III for the center? (putting the TV on top of it). Having your TV 40" off the ground is by no means too high - especially if you have a second row of seating. And the benefits of a perfectly timbre matched center channel with everything at the same height is immensly important too.

I agree, that's the configuration I'm dreaming of.[]

[kenratboy]

I still think with the inherant 'brightness' of the Klipsch, you could

pull off a big (>120"), perforated front projector screen and just

place the front three BEHIND the screen. There is something

elegant about literally having the sound coming from the screen - not

above, below, to the side, but FROM the screen.

Maybe throw a bed sheet over a LaScala or something and see if there is

really a sound difference - I cannot imagine a hi-end perforated screen

would degrade the sound to any noticable extent.

Someday, I hope to find out for real...

[DrWho]

There are two issues with perf screens: absorbtion and comb-filtering (reflections)

I read an article study thing that showed that in the cinema (aka not at home) the effect of a perf screen was merely a HF roll-off. I don't remember exactly what frequency this occurs at - something like starting at 10kHz with a rate of 6dB/octave. However, the situation is compounded by the fact that the perf-screen also reflects some of the sound as well...which then bounces off the speaker again and mixes with the direct signal causing comb-filtering in the higher frequencies. The lowest frequency at which this occurs can be raised simply by moving the speaker closer to the screen (thereby reducing the number of reflections and also increasing the direct to reflected sound ratio).

Anyways, the end conclusion is that the absorbtion can be accounted for with EQ, but the comb-filtering cannot (in fact, implementing EQ will increase the comb-filtering problem).

But theory aside, how audible is it? Side by side I have no doubt a difference could be heard, but without a reference point I think most people wouldn't notice it. I would actually anticipate the natural reverb of the room to greatly mask the effect (and keep in mind that it's not perfect comb-filtering because the reflections won't have the same amplitude).

[kktvbob]

I think most people don't use front projectors but use rear projector. As for setting the tv 40" up I think thats to high for sitting 10 to 15 feet away. The center line of the screen should be no more than 15 deg. from eye level. Putting the set on a vert Cornwall puts it at the wright hight. As for putting the speaker behind the screen goes. I don't think I would do that just because I don't run grills ether.

[TheSoundBroker]

There are two issues with perf screens: absorbtion and comb-filtering (reflections)

I read an article study thing that showed that in the cinema (aka not at home) the effect of a perf screen was merely a HF roll-off. I don't remember exactly what frequency this occurs at - something like starting at 10kHz with a rate of 6dB/octave. However, the situation is compounded by the fact that the perf-screen also reflects some of the sound as well...which then bounces off the speaker again and mixes with the direct signal causing comb-filtering in the higher frequencies. The lowest frequency at which this occurs can be raised simply by moving the speaker closer to the screen (thereby reducing the number of reflections and also increasing the direct to reflected sound ratio).

Anyways, the end conclusion is that the absorbtion can be accounted for with EQ, but the comb-filtering cannot (in fact, implementing EQ will increase the comb-filtering problem).

But theory aside, how audible is it? Side by side I have no doubt a difference could be heard, but without a reference point I think most people wouldn't notice it. I would actually anticipate the natural reverb of the room to greatly mask the effect (and keep in mind that it's not perfect comb-filtering because the reflections won't have the same amplitude).

Actually, the absorbtion isn't linear. It varies with frequency and it takes quite a bit of effort to get the speakers back to linear. I haven't worked with pro screens, but I found the effects of most perf screens in the home go a lot deeper than 10K. In the theater this is never a problem...but in the home it is a real issue if you place the center only behind the screen with the mains outboard. You actually defeat the tonal match and have to work somewhat to get it back. It is easily audible if you do a comparison with a motorized perf screen and a defeatable EQ. You'll hear it as a blurring of detail and particularly a blurring of vocal clarity. It tends to set the center channel apart from the mains if the center is solo. Also, you can't move the speakers too close to most sound screens

because the pressure coming off the woofer will cause the screen to

flap. Afterall, you do have essentially a solid surface that has tiny holes in it. But even with all that taken into account, having the speakers behind the

screen pays so many other dividends and benefits that it is still absolutely THE preferred way to go, even with having to go thru the other added steps necessary to help minimize the drawbacks.

I sell a screen for home theater that will NOT cause all the sound degradation and gives you all the benefits of centralized speaker location without the problems and without any potential image problems...Screen Research. Unlike other sound screens, it is made from a very specialized woven material. Not ony does it not cause any comb filtering, but you can put the speakers nearly touching the screen which just about eliminates any small amount of reflection that may exist. If you have all three speakers behind, you do need to make sure to have a surround processor that allows for adjustable center channel delay or your center channel will be too close. You do have to allow enough distance between the speaker and screen for woofer excursion or you'll get some interesting effects! Even better, frequency roll off is nearly non existant and the attenuation that is there is absolutely linear. NO re-equalization necessary and no tonal differentiation. The the only other sound screen I know of that has the same sound transmission characteristics is the Stewart Microperf, but they do so by using smaller perforations. Stewart makes great screens, but I understand the Microperf has the potential for moire issues with fixed pixel projectors, particularly as pixel count goes up and pixel size goes down. The SR screens will NOT cause Moire patterns since it is a woven material (and thus randomized instead of a regular pattern), so it is perfectly suited for digital projection. This is why it is the only sonic screen to carry THX AND ISF ratings on it.

I sell them, have installed several with THX Ultra 2 systems, and they really are that good. Besides which, the distributor is right here in Bellingham...darned handy!

[DrWho]

Actually, the absorbtion isn't linear. It varies with frequency and it takes quite a bit of effort to get the speakers back to linear.

Well that's what I meant when I said it's a roll-off (more absorbtion at higher frequencies and less at lower frequencies).

I was also told that moire issues go down with increases in projector resolution (ie, smaller pixels and more of them). But I don't see how that is the case so I'm not going to die defending that claim [] The most important thing is to make sure you are a proper distance from the screen - basically far enough back that you no longer can see any hint of the holes.

And if you're still adamently apposed to perf screens, then there is always the option of putting the speakers behind the black areas of the screen...which can be made of a more grill cloth like substance. Mains go on each side of the screen and the center channel can go either along the bottom or top depending on the room in question. But because the rear rows of a theatre need to have a clean line of site to the bottom of the screen, they should have no problem having an unobstructed center channel mounted at the bottom (but there is always the option of mounting above the screen).

[crexrun]

I have done a little reading on screens, and I always thought that the best HT would definitely have the center behind the screen as well. IMO, the easy solution to the problem of HF reduction from the screed material, and to not having the front L/R speakers behind the screen, is to simply have the outboard speakers have a removeable grille made out of the same material. Place the center as close as possible to the screen, and with grilles on the L/R it should sound close enought to work. The KP-301s I just got are plenty bright already, I would consider running the fabric on them fulltime if it didn't degrade performance noticeably. You could perhaps even get the fabric colored from the factory, and if not, you could find another acoustically transparent cloth, black or whatever, to cover the screen material if needbe. Just my opinion, and what I might try if I had this situation. Crexrun

[boa12]

sorry if mentioned, but have you guys checked out the clearpix screen?

http://www.hometheaterhifi.com/volume_11_2/clearpix-projection-screen-6-2004.html

when I was scoping FP, I checked it out pretty thoroughly. this is the one, but expensive as hell.

when are the Corn III coming? sorry, did a google & came here. LOL

I'm convinced I need a Corn center mounted upside-down above this new Sony.

screw trying to find another C-7 that doesn't match the Corns as well as another Corn or heresy (x2?) anyway.