# Help treat LR while DW out of town



## hgoed (Mar 22, 2010)

I've got the house to myself for 2 years, so I thought I'd turn the living room into a theater room (sort of) while the wife is gone. I'd like to use this thread to seek help with room treatment as the project evolves. I'll post a room schematic when I get to my home computer, but I like to post while I'm on the clock

I don't have any equipment yet and currently just listen to headphones, so I'm not exactly sure at this point what I need to treat. I have a few questions at the start which I'll try to ask one post at a time--

First--I plan on getting a 55-60" LED TV rather than a projector--is there a best way to situate the TV to minimize front wall/TV reflections? I was thinking of placing it on a stand about a foot out from the front wall and adding some treatment behind it, but I don't know if there is a way to minimize the reflections from the L, R, C channels off of the TV itself. Any thoughts or better ideas?


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## DanTheMan (Oct 12, 2009)

The best way I've found to reduce the TV reflection is to move it up, above the speakers. I certainly don't hear a TV glare now. To do this though you should really have speakers whose vertical pattern is a little due north. Some studio monitors are designed like this to minimize console reflections.

My basic treatment plan looks like this:
http://dtmblabber.blogspot.com/2010/12/room-treatment-advice-quick-and-dirty.html

Dan


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## hgoed (Mar 22, 2010)

Thanks. At this point, I can set the speakers up any way that works best. The seating position will be about 8 ft. away, so I can't raise the TV too high. 

In theory, if the mains don't end up having great of vertical off axis sound (I'm not sure if I'm using the right terminology) would placing the mains and center lower but with a slight angle to to make the direct line at ear level compensate for that? 

Otherwise, and sorry if this is obvious, how do I tell how a speakers' vertical pattern is? I'm guessing that the off-axis response graph should look as close to the direct as possible, or am I missing something?


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## hgoed (Mar 22, 2010)

Another question--although I don't really plan on using front wide speakers at this point, the Audyssey DSX site seems to show placing those speakers right where the first reflection should be. How do people set that up given that, as I understand it, that's one of the most important places to put absorbtion? Do they put the speaker surrounded by absorbtion, try to just drown out the reflected sound with a stronger signal from the matrixed sound, or something else?


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## DanTheMan (Oct 12, 2009)

Your terminology is perfectly comprehensible. The downside is a slightly lowered image height. With these big TVs you just have to pick your poison. You could try the other way around or forget the center channel. I prefer this way with a center channel. IMO it's the most important speaker.

Knowing what your speaker's vertical polar response requires measuring. No manufacturer is publishing this unfortunately even though it's importance is rather obvious. People will argue that, b/c there little study done on it. None the less, we have plenty of studies on FR and big dibs are audible. If you are listening to a dip(I"m not talking about me:nerd, you'll soon know it. What speakers do you have?

I'm not sure on the last post.

Dan


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## hgoed (Mar 22, 2010)

I'm starting from scratch [Actually I have some speakers from Roy Allison that I've lugged around with me for 20 years, which still sound nice, but they're pretty beaten up and no longer suitable for my living room] I could buy or build...I've got some designs in mind that I'd like to build, but I wanted to envision the room first so that the box dimensions didn't interfere with anything else I wanted near/on the wall. Anyway, I thought measurement was further down the line. Maybe I should start with some basic speakers and an amp, measure, and move things around as the project evolves......... 

That second question was just a curiosity. Assuming I get the room acoustics right, I shouldn't need a shed-load of speakers to produce pleasing and enveloping sound.


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## hgoed (Mar 22, 2010)

Here's the room I'm working with. I don't know if the schematic will come through...but I'll keep trying. I've got no furniture in the room at this time, but the idea is to have a pair of seats just behind the center of the vault. Other stuff will likely be piled in there eventually


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## DanTheMan (Oct 12, 2009)

Your idea looks like a good one. More absorption though will get you less envelopment--unless were talking just behind the speakers. You'll need diffusion for better envelopment after you get tons of absorption. It really does take a lot to make it dead however.

Dan


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## hgoed (Mar 22, 2010)

Yeah, it never occurred to me that, even though the character of sound would change based on what speakers/amp/source I choose, the reflections and room modes should be virtually the same for a given speaker position.

I'm off to learn how to measure sound...

Thanks for your help so far Mr. The Man.


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## DanTheMan (Oct 12, 2009)

Your welcome. Sorry I couldn't be of more use. Measuring sound is so simple with REW. John made this Dan proof. What exactly are you looking to do and what equipment do you have--computer, audio interface, mic?

Dan


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## hgoed (Mar 22, 2010)

Warning: tangential rambling below!

Well--the grand plan is to set up the living room for HT (but in reality it'll most likely be used for watching DVD versions of TV shows). The room is pre-wired for 7.1, but I'm probably going to start with 5.2 and expand as I see fit. No kids yet and family is 2.5k miles away, so the setup can be semi-permanent, with the option to re-arrange things for the occasional social gathering. 

My current set-up is somewhat irrelevant as I currently use my office for everything and my living room is empty. My wife is working in another state for the next 2 years, so I have the run of the house, and I need a project to keep my self sane. 

My electronic purchase decisions are heavily influenced by the fact that this house was designed to run on solar power--so some people's multiple-kilowatt amplifiers are not so appetizing to me (I don't think people calculate power costs into their purchase decisions, but it can add up to a few hundred per year). I had pretty much resigned to getting one of the Pioneer Ice-based amplifiers, or making my own Class D amp. Subs may be a problem, but I'm hoping Behringer's new iNuke amps will be efficient enough to drive a couple of subs without having to add an extra solar panel.

Ideally I'd run everything off of a computer, but I don't think there is good enough software DRC within a price I'm willing to pay. That's why I'm working on the room acoustics first. Anyway, I'm pretty sure I'll end up using a laptop for the video and digital audio source, outputting HDMI to a receiver, then to the monitor and speakers. That way, I could just unhook the laptop and move it to my office, to my basement, or to anywhere else I felt like having a setup.

Mic wise, I don't know...I'm still trying to figure this all out. I kind of thought that was last, and that I would use whatever came with my amp or maybe an ECM8000 with some kind of mic amp...but I really don't know that much yet. I'm thinking I'll just run by Best Buy, buy some cheap HT in a box, set it up and measure so I can make some proper decisions before laying down some real money.


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## Crossblade (Jul 21, 2010)

For initial measurements why don't you borrow speakers from a friend. I am not sure it is a great idea measuring some cheap HT-in-a-box system and basing your treatment on that. For example, if its tiny-cheap-subwoofer has a peak at 100Hz, it doesn't mean it is your room's fault! 

In addition, I believe that there are some simple things that you don't really need to hear and measure to treat - broadband absorption at early reflections and as much and as efficient (thick) bass trapping you can afford. 

Wish you luck!


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## hgoed (Mar 22, 2010)

Yeah--I should make a friend:nerd: I pretty much just moved away from everyone and work enough that is kind of a difficult thing for me. 

I actually was considering the subs as a separate thing. I'm almost sure that I'll need room treatment as well as EQ for them. I thought I could get closer to perfect with the mains though. The HTIB idea seemed rather stupid to me this morning (for some reason I had a different state of mind). Baffle steps, driver position and variations would make measurement misleading. Maybe I'll just do the light bulb and mirror thing to identify all of the modes, but that seems like it could get kind of complex as I add more speakers.

I'm giving myself 2 more weeks of pontification, but then I need to get off this computer and start setting something up. Luckily I have a high tolerance for failure, 'cause that's about the only way I learn.


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