False wall and audio sound

[Sir Terrence the Terrible]

Give it up loser, this post is cooked, your advice sucked, and this issue is over. You don't put a preforated screen out in space without acoustical control behind the screen, and taking into consideration the moire effect, and image losses. Just any old preforated screen just don't cut it.

[Resident Loser]

You don't put a preforated screen out in space without acoustical control behind the screen

Anyone want to try to make sense out of THAT one?

Given the fact that light and sound, which are both waves, can exhibit similar behavioral patterns, two superimposed patterns can can create a third, unwanted element at the point of intersection. With light, these can be seen as light or dark areas forming larger unwanted patterns and resolution abnormalities; in sound, intermodulation distortions and the like. Any interlacing of two repetitive patterns(or waves) can cause the phenomenon. Even in ostensibly single, stand alone units, e.g. poorly designed CRTs, can exhibit the problem if the pixel/raster ratio are not properly considered and adjusted for. Careful choice of both projector AND screen vis a' vis the propensity to moire' can be minimized by avoidance of similar spatial repetition ratio between the resolution of the projector and of the perforation density of the screen material...some screen maufacturers avoid the issue entirely by using a woven material, whose natural warp and woof allow for an excellent degree of reflectivity, while providing acoustical transparency and avoiding the pitfalls of machine-made perforations.

jimHJJ(...just thought I'd clear up any misunderstanding...)

[Sir Terrence the Terrible]

Anyone want to try to make sense out of THAT one?

Given the fact that light and sound, which are both waves, can exhibit similar behavioral patterns, two superimposed patterns can can create a third, unwanted element at the point of intersection. With light, these can be seen as light or dark areas forming larger unwanted patterns and resolution abnormalities; in sound, intermodulation distortions and the like. Any interlacing of two repetitive patterns(or waves) can cause the phenomenon. Even in ostensibly single, stand alone units, e.g. poorly designed CRTs, can exhibit the problem if the pixel/raster ratio are not properly considered and adjusted for. Careful choice of both projector AND screen vis a' vis the propensity to moire' can be minimized by avoidance of similar spatial repetition ratio between the resolution of the projector and of the perforation density of the screen material...some screen maufacturers avoid the issue entirely by using a woven material, whose natural warp and woof allow for an excellent degree of reflectivity, while providing acoustical transparency and avoiding the pitfalls of machine-made perforations.

jimHJJ(...just thought I'd clear up any misunderstanding...)

Nice quote from a website. I am sure this didn't just pop outta yer head. You haven't even addressed the sound issues, but I am sure you'll quote another website for that. Genius, pure genius.

[Resident Loser]

...any first-year art student is acquainted with moire' patterns, ain't nothin' new or particularly specific to HT...actually nowadays has more to do with digital reproduction of half-tones...in fact anyone who has looked through fenceposts, played with window screens or has worn polarized glasses is familiar with the concept...the mechanics and geometry are what they are...the words are mine, as anyone who reads my postings with regularity can plainly see...that is, anyone with intelligence.

As I've previously stated, I've forgotten more, about more things, than the likes of you will ever know...

jimHJJ(...you are beyond your ken...and it's gonna' be sooo cool...)

[jneutron]

Nice quote from a website. I am sure this didn't just pop outta yer head. You haven't even addressed the sound issues, but I am sure you'll quote another website for that. Genius, pure genius.

From what I have seen, when RL is qoting a website, he typically states that fact, or posts a link to the supporting verbage.

To say "I am sure this didn't just pop...." means you do not know for a fact one way or the other if this is direct or quote.

Why is it you are acting in this fashion? While I admit I have not been here much, I do not understand why it is a moderator is allowed to attack a poster in the manner you have shown over this entire thread.

Is there some history here that I am unaware of? Is this like that Star Trek episode with Loci??

This was actually one of the primary reasons I walked away from here..it is sad to see it has not changed.

Cheers, John

[HAVIC]

I actually stopped reading as a lot of this talk has been above my head. I do know if this a route I go I will most likely need to hire a pro. I may decide to not use the false wall and see how everything looks and if it bothers me I'll make the decision based on by a few pro audio shops in my area and analyzing what they told me with you guys.


However I did notice several people did not understand exactly what I was looking to do well here it is...

In the picture the outerbox is the original room (nothing is to actual size), this is from a top view.

In the picture the following stands for the letters.

A = my tower speakers
B= The False wall ( from floor to ceiling)
C= The Front Projector
D= The Screen mounted on the false wall

[gonefishin]

I actually stopped reading as a lot of this talk has been above my head. I do know if this a route I go I will most likely need to hire a pro. I may decide to not use the false wall and see how everything looks and if it bothers me I'll make the decision based on by a few pro audio shops in my area and analyzing what they told me with you guys.


However I did notice several people did not understand exactly what I was looking to do well here it is...

In the picture the outerbox is the original room (nothing is to actual size), this is from a top view.

In the picture the following stands for the letters.

A = my tower speakers
B= The False wall ( from floor to ceiling)
C= The Front Projector
D= The Screen mounted on the false wall

You've already got the tower speakers (and the rest of the audio system, I presume)...I'd look into getting the scrim cloth type wall to put your speakers and audio equipment behind. Like GMichael had advised.

With the right room lighting...you can choose to either keep the "theater wall" black as can be (which will be a nice plus for the projector screen! Spend the extra money on a quality screen here). But...with the right lighting...you could choose to keep everything hidden...or you can choose to shine a light on the audio rack...or speakers. You know...the way Disney (and other amusement parks) "show you" where the speakers are mounted. They usually go thru this presentation before the featured show begins.

This shouldn't mess with any imaging problems (or placement problems) with your existing tower speakers. Plus...you won't have to (nor do you need to) build a false wall in your home.

good luck

dan

[GMichael]

You've already got the tower speakers (and the rest of the audio system, I presume)...I'd look into getting the scrim cloth type wall to put your speakers and audio equipment behind. Like GMichael had advised.

With the right room lighting...you can choose to either keep the "theater wall" black as can be (which will be a nice plus for the projector screen! Spend the extra money on a quality screen here). But...with the right lighting...you could choose to keep everything hidden...or you can choose to shine a light on the audio rack...or speakers. You know...the way Disney (and other amusement parks) "show you" where the speakers are mounted. They usually go thru this presentation before the featured show begins.

This shouldn't mess with any imaging problems (or placement problems) with your existing tower speakers. Plus...you won't have to (nor do you need to) build a false wall in your home.

good luck

dan

I like your ideas. You got my gears turning now.

[jneutron]

You've already got the tower speakers (and the rest of the audio system, I presume)...I'd look into getting the scrim cloth type wall to put your speakers and audio equipment behind. Like GMichael had advised.

With the right room lighting...you can choose to either keep the "theater wall" black as can be (which will be a nice plus for the projector screen! Spend the extra money on a quality screen here). But...with the right lighting...you could choose to keep everything hidden...or you can choose to shine a light on the audio rack...or speakers. You know...the way Disney (and other amusement parks) "show you" where the speakers are mounted. They usually go thru this presentation before the featured show begins.

This shouldn't mess with any imaging problems (or placement problems) with your existing tower speakers. Plus...you won't have to (nor do you need to) build a false wall in your home.

good luck

dan

Crap...where did my post go?? Why was it deleted?

Sigh...here I go again..


If ya take some spotlights, and a plc, you could give IMAX a run..but ya'd still need to get some horns and 12 kilowatts of power.

As to the false wall..don't make it solid. To do so can invoke a group delay in the bass. I explain.

Back in '79, I ran a system in a bar/resteraunt (sp?), during the disco heyday. The layout of the club was, it had a open area in the front where tables were removed,a half height wall with two walk through openings. I'd setup my system (4 K horns with 300watts times 4) on the dance side of the wall, mixer and tables on the other.

When I first started to mix, I found that there was a big delay between the program in the left headphone, and the bass beat I heard in the other ear. It ran about 100 milliseconds, big enough to cause double beat mixes..the bane of all DJ's.

In investigating this, I found that as I walked through the doorway, or stuck my head through the opening in the wall, the delay went away..it was caused by the propagation of the sound through the remaining wall opening, which suprisingly enough, was over 60% clear. Strange..

If you place subs on the other side of a hard half wall, you will find group delay of the bass. If you put the sub on your side, there will be group delay to the empty side, then again as it comes back..mud city.

Havic: Why cut the room size down so much?

Cheers, John