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Discussion Starter · #1 ·
Hi all,
I'm expecting delivery of a few subs to test out over the next 30/45 days.

I want to make sure I'm testing with a good setup and placement of the subs.

I keep coming across REW and the UMIK-1. I use a HTPC in my setup, so I am thinking of trying out REW.

I just have a few questions before spending the $100 on the MIC.

1. Is this needed if my AVR has MCACC Advanced?
2. Is there a benefit to using REW over the AVR room correction?

I guess I'm not sure which way I should go...
 

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REW is not room correction, it is used to measure the frequency response in your room (among many other things): http://www.roomeqwizard.com/

This will show you the frequencies you may want to raise/lower to achieve a flat response, but has no means by which to adjust those frequencies. That would be up to either manual adjustments in your amp/AVR, or add-on equipment such as the miniDSP.
 

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Search on:
ground plane acoustic measurement

And read this link (and the other three in the series):
http://www.audioholics.com/loudspeaker-design/subwoofer-measurements/page-2

You're lucky in that there is a tried and true method for measuring subwoofers anechoically without an anechoic chamber. Were you to measure several subs in this manner, the results would be of interest here, but also of great value in helping you decide what stays. The Audioholics article series should be particularly interesting.

You're unlucky in that the performance of a subwoofer is frequently of little importance compared with its location in the room, and the room's response to it. That leads to things like MCACC which try to "fix" the issues.

REW isn't designed to "fix" anything. It's general purpose acoustic measurement freeware that can allow the user to learn a lot about their system, and if they understand what it's telling them, "fix" some aspects of room audio response before running MCACC. There's a lot to room measurement and optimization, but making measurements is the start, and doing so while selecting subwoofers is a good place to start.

Have fun,
Frank
 

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Discussion Starter · #4 ·
I think that is where I'm confused. If I take measurements and for example see that between 40hz and 60hz there is some what of a drop in dB, then how do I resolve that? I don't mean specifically, but theoretically what would need to be done to get that frequency response line on the graph to be as flat as possible?
 

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REW is not a room correction system per se, but it can automatically download EQ settings to many popular software controllable equalizers like the Berhinger units. Barring that, you can simply print out the data and manually set your equalizers up.

But as stated above, this is not a Dirac like system. You could in theory do the same thing the Dirac does if you have enough handles on your processing gear. But that would be a slow manual and difficult endeavor at best.

You may also want to look at www.minidsp.com. They have a few true room correction devices that are quite reasonable like the new Dirac box for $1000 as well as a lower cost DIY system for those who want to tweak.
 

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I think that is where I'm confused. If I take measurements and for example see that between 40hz and 60hz there is some what of a drop in dB, then how do I resolve that? I don't mean specifically, but theoretically what would need to be done to get that frequency response line on the graph to be as flat as possible?
A lot can be accomplished with sub/speaker placement, number of subs, position of MLP (Main Listening Position), room treatments, sub distance tweak, etc.

Outboard EQ (i.e. MiniDSP) should be the very last thing you do, if it's needed at all.
 

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Another way to look at is like this. You would want to give you room correction feature the best chance to succeed.

Getting familiar with REW and optimizing subwoofer placement is a good starting point. Other methods such as listening etc.. are possible just not as scientific.

Later on looking at whole room response, reflection etc.... is good stuff but more advanced. All the details and teaching are online.

Do research on the type of USB Mic as well.

Good luck.
 

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I think I understand now.

Basically people are using the REW setup for measuring. Then moving speakers/subs around, remeasuring, etc...
Yup, you got it now. :)

Why is the EQ a last resort?
Because EQ can introduce distortion, especially when boosting. If you can get a flat response with placement and room treatment the system will sound better than by just resorting to EQ. However, there's nothing wrong with a little EQ after you've put as much work into the system that you can...some rooms just don't like to cooperate. ;)

Would this help with the subs? I have no experience with EQ at all.
http://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4
Yes, the MiniDSP is the "go-to" sub EQ around AVSForum.

I was thinking of the UMIK-1 MIC.
Good choice!
 

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Discussion Starter · #10 ·
Thanks Alan. I was expecting my subs to show up tomorrow/Monday, but apparently the PB1000 is back ordered until 4/17.

The XS15se I ordered should arrive sometime next week, so I guess I have time to order the MIC now and setup REW :)

I guess it doesn't hurt to get the hang of it with my existing sub first.
 

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Yup, there is definitely a learning curve with REW....the more time you spend with it, the better. ;)
 
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