room acoustics


I'm tearing out the panelled walls in my listening room and have the opportunity to design some acoustic treatment into the room as I refinish it. My reason for posting is to seek advice from those who have travelled this path before. The only plan I have so far is to make the amplifier/speaker wall absorptive (via several inches of insulation). I'm most concerned about the effects of the sliding-glass door and the off-center fireplace. A description of the room follows. The room is 12 by 19 feet. (speakers are on the short wall.) The leftmost 3/4 of the opposite wall is a brick fireplace. (the other quarter is the entrance to the kitchen ... no door) The left wall also contains a sliding glass door. The right wall is uninterrupted until you reach the rear of the room, where there is another passageway ... 90-degrees to the aforementioned Speakers are full-range, and the listening position will be out in the middle of the room. Any help is appreciated. David
davidw80c7
To use software to calculate treatments requires extremely detailed measurements and a perfectly symetric, closed room. Otherwise, a detailed investigation with advanced software is needed. Just experiment to tastes. To know how to treat your room depends on what music you listen to. If its Jazz or Classical, dead rooms will sound awful. The best "generic" advice is treat all the corners with bass soakers (you'd be surprised what foam products like Aurelex will do here), treat the primary reflection points with a broadband absorber that will reduce reflections, but not soak em up all together. It is important to use a material that absorbs equally through the spectrum so you dont change the reflecting material's balance. After this, diffusive treatments ( Bookshelfs with random items in them) will give you a life like ambience, while minimizing time/phase problems and seating location nulls. As for subs, I have never seen one mounted on a platform as to equal the height of the main woofers! Just play something with a rolling bass line with the sub at your seating position, and walk around the room till you find the quietest bass response, and put the sub there. This is opposite to some advice which tells you to put it in the loudest response is, but this will give you a boomy response. Good luck, and remeber to experiment to taste, don't follow some rigidly applied rule, and don't deaden the whole place! Dead front or dead rear rooms, to me, kill the ambience.
I just bought some software from RPG (www.rpginc.com) called Room Optimizer. It is supposed to calculate speaker & sub placement as well as room treatments. Not the best looking software, but it might help you setup your room & place your software.
Hi people Interesting tip by Blair Zasitko, and nice trick of HifiHarv! I plan to buy RPG Profoam Level one for $50/6 pieces + shipping ...is it a good price? My crampy small room (11X19, with the system on the short wall)is so accoustically incorrect! I'll try Blair's tip since that's the one I can afford right now. Any suggestion on how to place an Infinity BU-120 (12" 150W) sub? Should be on the front speakers' horizontal axis or not? Thanks in advance!
Get in touch with a company called ASC, accooustiic sciences corp. (www.tubetrap.com). Chris will give you driectiioon. Peace. Judd
I'm surprised how little interest there is here on room tuning. I can't tell you how to cure your room problems, but, one thing I have learned after fooling around with HiFi since 1970 is this:It is very easy to over damp a room. The sound will loose a certain life like sparkle that is not a brightness per say, but, the natural sound of real instruments. Untill I discovered the Room Tunes products I was always struggling with the compromises of traditional methods like hanging rugs, or, acoustic foam, etc. The corner tuning pillows make a huge difference without soaking up all the natural timbre. It is easy to over do it with the standing "delux" room tune panels. I only use two in my room. Anyone using Room Tunes please try this simple tweak: Cut a piece of heavy duty Reynolds Wrap one inch smaller than the pillows and slightly crumple it up to give it a slightly uneven texture. Dont squeeze it into a ball, just crumple slightly. Now affix it to the pillows with one piece of double stick tape in each corner. Just for fun, lets refer to this as the Harvey mod. I have "wasted" most of my adult life working on this stuff and all I ask is a little recognition. Try this and let me know what happens, you will be surprised. I have a host of other tweaks to offer. Try this first. Also, don't use anything but Heavy Duty foil.
Think that acoustic treatment will help? Try this (it's free!). Get a friend first. Get a mirror (bigger = better). Now sit in your listening spot. Have your friend move the mirror around on a side wall until you see the tweeter of one of the speakers. Then move it until you see the tweeter of the other speaker. Mark the spots, and repeat with the other side walls. Now get some pillows, cushions, or other sound absorbing things, and place them, using tape, or what-have-you, to cover the spots. Use at least 16" square pieces. Now sit and listen. You should hear wider soundstage, more accurate imaging, and better spatial sense. Now try the same trick with the wall behind you. Listen again. Even better? If so, do the wall in front of you. Better still? Do the cieling. Still better? Try the floor (if uncarpeted). Experiment. When you go too far, it will start to sound dead. Once you have found the setup that you like, find some pro-made acoustical treatments, like sonex, to replace the pillows. You can buy them at audioadvisor.com, needledoctor.com, etc. Blair Zasitko
Hi, a) live end/dead end The 'dead' end goes behind you, not the speakers. b) you should have a problem in the low 30's (HZ) which would need a helmholz resonator. you should also have one in the treble region which would require something absorbtive on long walls 1/2 way between speaker/listening chair good luck, late ps, you will need a good book, try Acoustic Techniques for Home and Studio by Everest
I am not trying to downplay the good effects of proper room treatment but I think that a lot of audiophiles do this to try to correct a poor digital front end. If you are not using a D/A converter I would try that before spending extra cash on rebuilding walls. You can buy an adcom gda-600 used for under $350 and start off with a 75ohm video cable as the digital innerconnect. If your cd player does not have a digital output you can also get that used for cheap. If your cd player is throwing away digital information you can NEVER get it back. Also, many cd players blend the lower bass to mono and that in itself will muddy up a room's sound.