# Getting Started



## f0zz (Dec 1, 2011)

I've had a dedicated theater for about 3 years now. Everyone enjoys the room and I don't have any real complaints about it, but I know it could sound better. My question is, where do you guys recommend starting the acoustic improvements process? I have REW and a MiniDSP for my subwoofers. 

What measurements should I start with?
Where do I measure from?
Do you take averages from all the main seats (my room has 9 seats, 4 front,5 rear)?
Would photos of the room help?

This is a project I'm giving myself for the winter. I'd like to get some audible improvements before spring.


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## bpape (Sep 14, 2006)

I assume the front row is primary and the other row is more 'overflow' for friends, kids, sports, etc. Either concentrate on the front row or the center seats in both rows pending how you use them.

REW will let you see what's going on.

Be willing to move the seats within the restrictions of the riser.

Work with sub location to smooth response the best you can.

Once you do that, then treat the room to address early reflections and excessive decay times. Anything you cannot address with treatment or movement, you can EQ - just understand that EQ cannot effectively address multiple seats. You will only be able to EQ the problems that are common to the seats you are concentrating on.


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## f0zz (Dec 1, 2011)

Front seat are really the only ones I'm concerned with.
They cannot be moved as they are bolted to the floor.

My subwoofers are (4 of them) are built into the wall. I could move them, but I would need to change my screen to an AT version.

I'm limited in some aspects to what I can do.


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## bpape (Sep 14, 2006)

Well, you've really kind of handcuffed yourself by not being able to move seats or subs. At this point, best you'll be able to do is address decay time, early reflections (and those 2 things can still make a very nice difference), and maybe some response issues pending what/where they are and then have to deal with the rest purely with EQ. Again EQ can only deal with peaks (for the most part) and things that are common problems to all seats. No real way EQ can deal with say a peak at 100 for the 2 middle seats and a null at 100 for the 2 outer seats in the same row.


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## f0zz (Dec 1, 2011)

I'm going to find a way to move the subwoofers. I'm not sure if I'll build a separate enclosure for each of the 4 subs or in pairs or?


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## bpape (Sep 14, 2006)

4 individuals gives the most flexibility. How much you can gain from it all depends on how flexible you can be with positioning. According to the Harman research, either the 4 corners or the center of the 4 walls gives the most benefit for the majority of seats.


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## f0zz (Dec 1, 2011)

4 corners is possible, but doesn't that also mean no bass traps in the corners?

I can do the middle of the front and rear wall, but the side walls won't be practicle.


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## bpape (Sep 14, 2006)

If you do the 4 corners, you'd just do the absorbers above the subs up to the ceiling.


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## rab-byte (Feb 1, 2011)

Bpape,
Correct me if I'm wrong but he can tune the subs with level and phase to move the image to the proper location for his primary listening position. By splitting the mono LFE into his 4 sub-amps (internal to the sub or external in the equipment stack) and make adjustments there. 

He would still need to address standing waves in the room but making those adjustments would do a lot for him.

Right? I'm still learning the ins and outs of room acoustics.


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## bpape (Sep 14, 2006)

Not going to impact the image much if at all but yes, they will need to be adjusted appropriately for best response. Using the 4 corners helps some with the primary length and width modes. Still other things to address such as decay time, early reflections, non-modal peaks and nulls, etc.


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## rab-byte (Feb 1, 2011)

Could deadening the riser help?
I've been in theaters where the riser just seemed to amplify the rear sub horribly.


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## bpape (Sep 14, 2006)

You can use it as a bass absorber. Regardless the top should be 2x 5/8 or 3/4 MDF and the cavities should be insulated.


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## rab-byte (Feb 1, 2011)

That make so much since.


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## f0zz (Dec 1, 2011)

I've gone over the room and what I can do to modify the subwoofer locations. I am able to move the subwoofers to just about anywhere on the front wall (behind the AT Screen im about to purchase) and the lower half of the rear wall. The rear wall cannot have corner mounted subwoofers as there are access doors that cannot be relocated. All the subwoofers would need to be inwall (all 4).

are there calculators that can give a rough idea of what a room response would be like or is trial and error the best method?


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