Thread: HOME THEATRE
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Old 13-03-2011, 12:07 AM   #16
THX1138
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The THX speakers will of course be tuned to the room size when the engineer installs them (I kid you not!!)
Jay, thats actually an incorrect approach to speaker EQ believe it or not, and not all stores have certified THX's installers, or non THX certified installers. Anyway, you don't want to tune the speakers to the room. What you want to do is prevent any acoustics from interfering with the tuning process. Thats why alot of speakers don't sound as good as they should, even after being tuned. I have worked with the THX enigeers for the commercial cinema many times, and they all do the same thing. They all do far field EQ. Thats actually in the back 2/3rds of the theater. When you do that you get the acoustics involved with the tuning process and it gives you a false reading on the sound analyzers. The result is a really high boost on the high frequencies, and if you have ever been to a theater where the sound is ear-piercing, and shrill, then you know the projection tech is using a far field EQ approach. If the sound is muddy, dull and shrill, then projection tech is using just one acoustic mic at far-field distance. Multi-mic readings give you better results but still wont sound flat if a far field approach is used. Theater techs ( and the THX ones alike ) are trained to accept that that is what cinema sound is supposed to sound like.

Same thing applies to home theater. If you set the mic at the listening position, you get the room acoustics involved in the sound readings. The best way around the problem is get the mic up close to the speaker ( near field ), that way the acoustics are for the most part removed from the readings, and you get a really flat response. I did that at a theater I used to work at and got alot of really good feedback from movie watchers. The company projection tech; however, was furious and said I didn't know what I was doing and changed the tuning back. Customers were kinda pissed after that happened. And the manager never sided with me on the issue, even though I was approved to do such work on the system.

I have used the same near-field technique for home theater and it still works. You still want to acoustically treat the room by all means, because it prevents/ and or lessens severe room reverb, slap-ecos and bass traps.

The bad thing about home cinema is the built in Audyssey EQ that alot of receivers and preamps now have. It takes alot of control away from the user because it does it all itself. And it instructs you to set the mic far field, at the listening position. And it uses a totally different kind of a test tone that what is normally used.

i am not an expert. maybe what murabi wants is a suggestion what you would buy with his budget

Well, I sill don't know what he really wants. He seems to be going back and fourth between a Home theater PC and standard home theater components. Until he settles on what he wants to go with, I really cant help him much.
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