# Basement Treatment Help (L-shaped room)



## metube (Nov 12, 2021)

Hi!

I finally have the opportunity to setup a semi-dedicated space for Music and Movies. For now I will have a 2-channel setup, but I was given an older Pioneer 7.1 that I may get working as a 3.1 (or replace it with a better 5.1 system).

There are some obvious imbalances in the room, but I was planning on making some changes:

Reconsider speaker placement (currently 3.5 feet from the front wall, 3 from the sides)
Add absorption behind speakers
Consider additional bass traps in front wall (where I am not sure)
Beyond that, I'm definitely wondering if adding diffusion over the sidewall with the couch is just adding issues without measurements. The couches are short (~2.5 foot high), so there is a good amount of bare wall. 

Open to any ideas to improving acoustics. I would like to keep both couches, but am open to other configurations.


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## Da Wiz (May 8, 2019)

You want your 2 ears to receive the same sorts of sound in the same amounts of time. There are 2 ways to do that with the layout in the drawing... 1 would be to dampen sound like crazy to the left of the couch and on that "kick-in" just behind the left side of the couch. Next you have to deaden the reflections far from your right ear down the play area. That means damping the area where there's door labeled 56", and the corners near the stairs so you don't have long-delay reflections coming back towards your couch. The SECOND way you can do this is to add a wall between the theater area and play area that extends the wall behind the bookcase, all the way to the wall behind the soft. Match the "step" in the existing foundation wall in your new wall so the shape of the back of the room behind the couch is the same on both sides. Now each ear will receive reflected sound and direct sound in the same amounts for both ears. The ideal you are going for is for the left and right sides of the room to be identically shaped so the sounds that reflect back to your ears have identical surfaces and dimensions on the left and right. I would say #1 is probably more practical, but will not be as effective as the #2 option. So much depends on just how good you want the sound to be. Also, if that's a 65-inch TV for your display... technically you should be sitting closer than 10 feet from the TV... it should be more like 7 to 7.5 feet from your eyes to the screen. And the best viewing will be with the center of the TV aligning with the height of your eyes seated on the main couch. In this room, if you will have side-surround speakers, those should be dipoles to keep the sound from being too loud or too localized. The dipole speakers spread the sound out a bit. If there will be rear surround speakers, those can be direct radiating if there's 6 feet of space (or more) between the rear surround speakers and the ears of the main listener on the couch. If there's less than 6 feet of space to the rear surrounds, you may like dipole speakers for the rear surrounds better also. After this, you can consider putting some absorbing room treatments at the first reflection spots for each speaker... that will be FOUR different places, 2 on each side wall. Put a mirror flat on the wall at eye-height and with someone sitting in the main seat, have them look at the mirror and when you move the mirror along the wall, at some point you'll be able to see one of the 2 main front speakers... mark that location on the wall with painters tape or something else non-destructive. Then keep moving the mirror along the wall until the listener on the couch sees the OTHER speaker... mark that with painters tape, Repeat that process on the other wall. Install absorbent materials covering those reflection points. Make each one about 8 to 12 inches wide and as tall as you can (the height will help stop echos from traveling along the wall surface. Make these absorbers "open" on the sides and absorbent on all 4 sides plus the surface facing into the room. These can be ugly or covered with fashionable grill cloth for appearance's sake.


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