# New home theatre room acoustics



## gopi_16 (Mar 9, 2013)

Hi, i m setting up a new home theatre room. 16X12 ft room suze. Can some one guide me in step by step activities to set up good acoustics. What makes a good acoustic.?


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## bpape (Sep 14, 2006)

We would need a lot more information.

Size and aspect ratio of screen?

Number of seats and people?

Type of speakers?

Room height?

Plans/pictures/etc?


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## Talley (Dec 8, 2010)

Many will say to load up absorption panels and bass traps and although those are needed they really can suck the life out of the room. Yes.. you do need some absorption but diffusion is my personal preference as a "main" treatment.

Absorption in the corners works well and small absorption panels to capture the primary reflection points on the side walls works well. 2D diffusers in the ceiling are awesome and QRD type along the rear sidewalls behind your head and the back wall are great also. You can also do some fractal diffusers too.

So... what makes good acoustics?... speaker location, listening position location, controlled RT (reverb time) and eliminate/reduce flutter/echo. You only want enough absorption to help flatten the low end frequency response so it all boils down to speaker(sub) location and treatment. 

Remember. echo/flutter can be reduced by diffusion and absorption but diffusion reduces echo/flutter without reducing the RT60 (decay) time thus keeping a room more "lively".

Here is a great video with ending before/after... 




Also this one...


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## bpape (Sep 14, 2006)

Agreed. No more absorption than is required to bring the decay time curve into the desired range for a specific room volume and usage. Diffusion can be very useful in some places and given enough space for the diffusion to properly develop. In smaller rooms, that many times is the limiting factor for diffusion. You either end up being too close to it or you end up using diffusers that are thinner so you can sit closer to them so they miss more of the 'guts' of the music.

Recommended distance is based on the wavelength of the lowest frequency at which a diffuser will function.


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## Talley (Dec 8, 2010)

bpape said:


> Agreed. No more absorption than is required to bring the decay time curve into the desired range for a specific room volume and usage. Diffusion can be very useful in some places and given enough space for the diffusion to properly develop. In smaller rooms, that many times is the limiting factor for diffusion. You either end up being too close to it or you end up using diffusers that are thinner so you can sit closer to them so they miss more of the 'guts' of the music.
> 
> Recommended distance is based on the wavelength of the lowest frequency at which a diffuser will function.


Correct.... Good point.

Somewhere I read a general rule that for diffusion you want to be 1 foot away for every inch in depth the diffuser is made. So if you made a 7" thick diffuser then you would want to be 7 feet away as a "general rule".

Personally I'm doing an acoustically transparent screen so I can have a wall of fractal style diffusers behind the screen and 2D style diffusers at the primary reflection points in the ceiling with cloud absorption above my head and will be building some 18" x 7' x 2" thick absorption strips to use at all ceiling/corner joints and will sit approx 3' away from each corner with an 12" x 7' x 2" thick absorption strips at an angle to fill the corner.... of course this could be replaced by bass traps if needed. The side primary reflection points I haven't made up my mind yet... I"ll have to play around with all sorts of types to see how it works out.

any other location along the non primary directing walls I plan on either fractal or 2D style diffusers. 

The nice thing about the absorption strips I'm making they will be out of foil faced steel building wall/ceiling insulation so one side will be foil faced the other side will be insulation only. This way I can flip them around and have them reflective but capture side reflection and/or have the insulation face out so it absorbs more.


THE ABSOLUTE main thing about acoustics is throw something up.... listen.... change it up and choose which works best in your particular room / listening tastes. Some prefer liveliness and some prefer a quieter room. It's all up to YOU.


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