Slaughter House Cinemas (Project Thread)

[bpape]

No need to isolate them They won't do much.

As for the HVAC, not gonna happen - sorry. HVAC HAS to be done prior to drywall, takes heavy boxes around flex duct, has multiple 90 degree bends in it, etc. A straight shot like that isn't going to be fixed. Wish there was a better answer - just being realistic.

Bryan

[salvasol]

carls64 wrote:

Looks good! however my screen is MUCH lower to the ground, so I would have to change that part. Anyone know of an good place to find reasonably price for fabric would be?

I got speaker cloth at Joanns ... $9.99 yd (54" width)

You can also get GOM (Guiford of main) online or better, get it from Bryan
Here is a links of the store where I got my accoustic carpet (http://www.acousticalsolutions.com/p...s/guilford.asp)

About the stage ... What about this pictures???


Here is the link to that thread if you want to read more http://www.hometheatershack.com/foru...on-thread.html

[bpape]

Excellent pics of how to build it. VERY nice and open - minimal framing to get in the way, etc.

Bryan

[smile711]

Hello.

Nice theater seats, BTW. Re the sub(s), I have only one DEDICATED (separate enclosure) Sub for my HT. My main L/R Towers have 12" subs which have plenty of power each, and then an 18" Velodyne in the Front Right, out from the corner. I had to do a fair amt. of experimentation, which you have eluded too. What will happen is you'll find DD 7.1 (assuming that's the minimum configuration) gives nice SURROUND sound for movies, etc., and some HD satellite programming (rare, unfortunately), and of course with Blu-Ray discs. Thunderous explosions, the cracking sounds of small arms fire in combat films, etc. So your Low Freq stuff for films will probably be great. That said, I mentioned several messages ago that I'm primarily a music person. Boy, oh boy, some of the classical music sounded awful when my HT's Dolby Digital 7.1 was set up. The low freq sounds (cellos, tympani, organ, etc.) had a dramatically "exaggerated" low end. My sound engineering buddy gave my system a look see, and he corrected it with a careful fine tuning using the "calibration" mic, etc. in my A/V receiver. I had NOT done a very good job doing it on my own---once HE did it (took about 1 hr.), the midrange, esp. center channel dialog just POPPED, and the excessive bass in classical music was gone. Films STILL sounded great, so overall, I was astounded at what 60 minutes of intelligent calibration and speaker positioning accomplished—i.e, done by a pro who had lots of experience doing high-end HT in our area. The cost to me was quite affordable, so no complaints there.

Of course, for Musical content, I always select the Music settings on my A/V receiver, and for Films, I select "video" for all of the various "surround effects." One thing I learned nearly 20 years ago is that you can RUIN a good musical recording with poor settings on your surround preamp (going back to the DD 2.1 days), so I've learned to be attentive to that.

With so many nice folks on this forum (along with your OWN experience and wisdom), you will end up with a great HT, no doubt!

Take care.

[carls64]

bpape wrote:

Excellent pics of how to build it. VERY nice and open - minimal framing to get in the way, etc.

Bryan

Yes! That is the approach I am going to take for sure, Tom has inspierd me in a number of areas for sure, my AV rack was the basis for mine. I am going to start drawing up some ideas, and I will post them.

I am not sure about the angle he has them I would think I could do straight ones (parallel with the screen) as mine will need to be at least 22" to accommodate the subs, maybe 24" just in case I upgrade my sub . I currently have my front L&R pointing slightly inward at 45 deg based on the THX requirements so I don;t know how that will work inside the structure, I would not want the sound to be pointing at one of the boards.

[bpape]

That's one of the reasons for the angled faces - to accommodate some toe-in without issues.

Also, remember that just because your sub is wider doesn't mean the sides need to be wider. If you play your cards right, there will be no bottom cross member to impair sub location. The small front members won't even be seen by the large waves put out by a sub.

Bryan

[carls64]

bpape wrote:

No need to isolate them They won't do much.

As for the HVAC, not gonna happen - sorry. HVAC HAS to be done prior to drywall, takes heavy boxes around flex duct, has multiple 90 degree bends in it, etc. A straight shot like that isn't going to be fixed. Wish there was a better answer - just being realistic.

Bryan

So placing some sort of baffle inside the duct like a divider that would separate the upper outlet (Kitchen) from the lower outlet (HT) would not help? I used Dynamat sound deading material around the outside of the duct to help with vibration of the duct.

[bpape]

The baffle will help and mid to high frequencies. The Dynamat will prevent the tin ducting from vibrating and amplifying mid to high frequencies. The bass will still go right through it like it's not even there.

Bryan

[carls64]

My grandson and I sat last night and watched the first full length movie on the HT and I have to say WOW! It was a wonderful experience. The sound and picture were excellent!

I used the auto calibration tool built into the Yamaha 663 and with the exception of it running me around in circles saying that speakers were out of phase (Never could get them all to be ok) we sat and watched a movie anyhow. Fantastic 4: Rise of the silver surfer! And even though it was on DVD, you could not tell it by me, the picture was great! I installed the projector last night, and just used the lens shift to position the picture, turn the picture upside down (or would that be right side up if the projector was upside down) and off we went!

[carls64]

bpape wrote:

That's one of the reasons for the angled faces - to accommodate some toe-in without issues.

Also, remember that just because your sub is wider doesn't mean the sides need to be wider. If you play your cards right, there will be no bottom cross member to impair sub location. The small front members won't even be seen by the large waves put out by a sub.

Bryan

I have 22 1/4" from the wall to the screen edge, and the current sub is about 18" maybe a little less. So if I went with the outside edge of the frame to be 24" I should have enough room. I would also need to leave enough room to put in the rock wool?

[carls64]

bpape wrote:

The baffle will help and mid to high frequencies. The Dynamat will prevent the tin ducting from vibrating and amplifying mid to high frequencies. The bass will still go right through it like it's not even there.

Bryan

That will help, because I don;t seem to have much trouble with the low freq its just the mids and highs I seem to be hearing, I had it turned up pretty loud last night or at least loud in the HT, and my wife said she never notices anything unusual and she was in bed sleeping! The HT is right above our bedroom, part of it and the other 3/4 is below the kitchen.

[carls64]

smile711 wrote:

Hello.
Nice theater seats, BTW. Re the sub(s), I have only one DEDICATED (separate enclosure) Sub for my HT. My main L/R Towers have 12" subs which have plenty of power each, and then an 18" Velodyne in the Front Right, out from the corner. I had to do a fair amt. of experimentation, which you have eluded too. What will happen is you'll find DD 7.1 .....

Is there a forum thread anywhere of your HT, and photos?

[bpape]

Sounds like a plan. Give yourself as open a frame as possible and leave the option to move the subs around if at all possible. Corners really isn't a good place for them.

Bryan

[carls64]

bpape wrote:

Sounds like a plan. Give yourself as open a frame as possible and leave the option to move the subs around if at all possible. Corners really isn't a good place for them.

Bryan

What is a good place for them, it seems that most of what I have seen they are in the corners. I do not have many options as the RCA are toward the corners ;-)

[bpape]

Longer cables will fix that problem...

Many people put subs in the corners because they've been told to by manufacturers that count on tons of boundary gain to make their subs sound like bigger subs (but it really doesn't work - just gives more boom and maximally excites all of the room modes - unless you can use 4 of them - 1 in each corner) The idea is to place the subs where they'll provide the flattest response. Start out with it/them between the mains and center channel if they both have to be in the front.

Corner mounting gives the most sheer output - but also usually very very far from the flattest response.

Bryan

[carls64]

bpape wrote:

Start out with it/them between the mains and center channel if they both have to be in the front.

Where would the optimum location be for them?

[bpape]

Optimum for 2 subs? 1 dead center on the front wall, 1 dead center on the rear wall.

Bryan

[salvasol]

carls64 wrote:

Where would the optimum location be for them?

You need to do the "crawling method"

Place the sub in your "sweet spot" and crawl around the room ... when you find the highest SPL is where you have to place the sub ...

As Bryan said, most of us use the subs in the corner because that's where is suggested ... but some manual tells you that "you need to find the perfect spot", for that you need to try different positions

I have two subs, one in the front right and the other inside the riser almost in the left corner (about a 1.5' from left wall) ... is not the best placement but that's all I can do right now, I try to compensate with EQ from my AVR (or at least is what I think I'm doing )

[thewire]

It is best to have the subwoofers in at least one of the room modes.

[bpape]

If you're going to do the crawl method, look for the SMOOTHEST response across the range where the sub will be performing - not just the loudest.

Bryan

[carls64]

Thank for all the suggestion on the sub placement, I will give that a try and see where I end up, start off in the center, but I am not sure I have enough room to put the DCM sub in the front and I am limited to height, and I don;t want to block my IR repeater (Exact center in my case may not have been the best place). I will have to look at my Polk sub and see if I can't put it in front and the DCM in the rear.

[carls64]

I tracked my theater seats and they are already in Atlanta, GA coming from Tampa,FL on their way to Bethalto, IL! They should be here Tuesday!

On the riser I have been doing some figuring and I may be able to get away with a 4'x8' riser that would give me floor level walkway all the way around it, is there any reason to have a riser any bigger than the seating are and room to walk to ge to the seats? That would save me on materials. I probably would have to anchor it to the floor (concrete) so if I have 4 people in the back row and they decide to lean back a little the whole thing does flip over with them in it That would be bad.

I originally planned to have the riser go all the way back to the back wall, because I have the opening for the AV equipment offset about 10-12" high to accommodate a rier, the way it is now the PS3 is at eye level, but I have about enough room in the AV "hole" for a couple more shelves.

[carls64]

bpape wrote:

If you're going to do the crawl method, look for the SMOOTHEST response across the range where the sub will be performing - not just the loudest.

Bryan

What do you use to measure? My ears?

[carls64]

I got to thinking maybe I do not need a "stage" so to speak, just enclose the bottom portion of the wall and sides making a shadow box, the lower shadow box would serve as the stage?

Tom, did a stage and filled the sides where he was going to place the subs, with sand, but my floor is concrete, would I necessarily need a stage to place the subs on? Just build a frame arround the area and cover with cloth, and fill with inhalation.

[thewire]

There is no such thing as a HT must have a stage. The purpose is to give the feeling of being at the theater, to add to the experience. It is often not practical because of space limitations or may even cause more harm than good by limiting a subwoofer placement, speaker placements etc. People redo a stage quite often. A stage is usually typical in large venues which will be a plywood structure with insulation inside of it. They are not as limited by space. I saw one at a theater once and it was the same thing only they used multiple layers. A stage filled with sand is going to give the subwoofer a large stable mass to sit on and you are correct this is mostly to add strength to the structure. If you have concrete you will have little to worry about the structure being non secure. You will want to pay extra close attention that things are not causing sound to be transmitted from one area to the next by using a method called "decoupling" where one surface such as your shadow box, does not come into direct contact with the next (wall). Also there are things called RC clips for attaching in such a method. If you place the subwoofers on the concrete floor (I used outdoor carpet) this will allow the lower LF frequencies to travel quite well to your seating area, no stage required. I walked around my room and bumped places with a hammer or broomstick to see if anything would vibrate, then rattle. I used alot of caulk and glue for added strength and I left my walls fairly flexable to absorb energy. It really depends on what resources are available. Sand is not going to make or break a good HT. I have never read where someone had redone a stage because they didn't use sand.