Home Theater Design and Construction

**chhelo** · **01-07-07, 06:18 PM**

Ethan,

The riser bass trap design is attached. I was planning to install them in 2 spaces on the riser. Each bay would be 14" wide by 84" long and approximately 10" deep.

One would be set up for low bass frequencies with 1/2" plywood and the other for mid bass with 1/4" plywood. Even considered splitting each 50/50 so the traps would be balanced in the riser.

Overall, the major question is will this work or is it a total waste of time to install traps in the riser. The other bays will be filled 50 to 75% with batt insulation and ported to introduce tactile response into the riser similar to the design I found posted and recommended by Auralex.

I may be far better of stuffing the whole thing with insulation and forgeting all the extra work and just install Buttkickers.

More pictures posted on the riser construction.

Chuck

**Ethan Winer** · **01-08-07, 12:28 PM**

Chuck,

> The riser bass trap design is attached. I was planning to install them in 2 spaces on the riser. Each bay would be 14" wide by 84" long and approximately 10" deep. One would be set up for low bass frequencies with 1/2" plywood and the other for mid bass with 1/4" plywood. Even considered splitting each 50/50 so the traps would be balanced in the riser. <

The problem is that type of bass trap needs to be able to vibrate freely to work well. So as soon as you put seats etc on top it will not be a bass trap anymore. It might still help a little, but that's about it.

--Ethan

**chhelo** · **01-08-07, 02:05 PM**

Ethan,

In my design the plywood panel that serves as the top of the absorber is a couple of inches from the top floor of the riser. It will be free to vibrate up and down. The one though I had was that the narrowness (14") of the chamber would cause the plywood sheet to be too stiff. As in the panel absorber designs I have seen it would be airtight and have the insulation speced in between the top panel and the bottom panel (wall) side of the absorber.

In short I was trying to design a panel absorber into the riser.

However, if the broadband bass wave will be affected by the riser deck, carpet pad and carpet to such a point that it may not have enough energy remaining to vibrate the plywood. Additionally, as those woud be such long wavelengths it may be to narrow of an absorber to make a difference therefore, I would be better off building separate devices for the corners and celing separate from the riser.

If this is the case I just need to build separate absorbers for the corners and ceiling.

The other thing I have going for the room is each side wall is just sheetrock on studs with 3.5 inches of fiberglass batts on the attic side of the wall. From what I have read the bass waves will just radiate through the walls and never return. Over 20 foot of depth on each side in the attic. Too bad for the neighbors.

Chuck

**Ethan Winer** · **01-09-07, 09:48 AM**

Chuck,

> In my design the plywood panel that serves as the top of the absorber is a couple of inches from the top floor of the riser. <

Yes, but the solid layer of OSB above it won't let any bass waves through. Unless I'm reading your plans wrong.

> if the broadband bass wave will be affected by the riser deck, carpet pad and carpet to such a point that it may not have enough energy remaining to vibrate the plywood. Additionally, as those woud be such long wavelengths it may be to narrow of an absorber to make a difference therefore, I would be better off building separate devices for the corners and celing separate from the riser. <

Exactly.

> The other thing I have going for the room is each side wall is just sheetrock on studs with 3.5 inches of fiberglass batts on the attic side of the wall. From what I have read the bass waves will just radiate through the walls and never return. Over 20 foot of depth on each side in the attic. <

Maybe the really low stuff will pass through, but sheet rock reflects well enough to cause problems down to 40 Hz if not lower.

--Ethan

**chhelo** · **01-09-07, 11:48 AM**

Ethan,

Thanks for the guidance. I'll scrap the plans for that grandious idea and stuff the riser with insulation and installed the floor. Time to get it completed and carpeted so I can have the seats delivered.

Chuck

**chhelo** · **01-11-07, 08:55 PM**

Preliminary design for the left and right walls. Lower portion covered with OC703 covered panels and decorative panels up top with drapes in between. Sconces in front of each curtain.

Hard part will be selecting the materials.

Riser will be completed this weekend and will post pictures.

Chuck

**chhelo** · **01-12-07, 08:39 PM**

Completed the construction of the Riser. Guess we will see if the subs will make it active. Just in case its wired for Buttkickers if I need them.

Next item is building the screen wall.

Chuck

**Sonnie** · **01-12-07, 09:03 PM**

Nice work Chuck...

Is this going to be a DIY screen?

**chhelo** · **01-13-07, 11:42 PM**

Sonnie,

Thinking about it. I want a curved screen for 2.35:1 but have not figured out how much curve to build in. I know it has to do with which PJ and lens setup you use and I am still trying to figure out which PJ to buy.

I would like the Runco RS1100 with Cinewide and Autoscope but there is no way to afford that kind of hardware.

Mitsubishi 5000, JVC RS-1, or Sharp DLP are some of the contenders. Leaning to DLP if I can afford it however.

Chuck

**chhelo** · **01-15-07, 08:46 AM**

I found some black fabric over the weekend and attempted to render the actual fabrics to see how they look on the computer.

Using Smartdraw software and it's not the easiest to get to work. Hard to import the photos and getting the trim fabricto render good.

Attachement with black fabric attached.

Chuck

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