# REW to place main speakers



## t6902wf (Nov 14, 2008)

Can I use REW to help place my main speakers? Would I need to upgrade from the Radio Shack Meter to Behringer ECM8000 Measurement Microphone?

How is the Behringer mic hooked up?

I have experimented with the speakers and not heard a huge difference in sound but it can be hard to pick up changes. I use my dedicated HT for 95% movies.

For what it is worth here is a photo of the front speakers you get an idea of the placement. I have moved the subs closer to the center channel due to REW readings. The Subs are HSU ULS-15's the LCR are Paradigm LCR 450's.












Any help is appreciated.

Bill


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## Wayne A. Pflughaupt (Apr 13, 2006)

Wow, good looking room!



t6902wf said:


> Can I use REW to help place my main speakers?


 What do you mean by "place" the speakers?

Regards,
Wayne


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## brucek (Apr 11, 2006)

> Can I use REW to help place my main speakers?


Yes.



> Would I need to upgrade from the Radio Shack Meter to Behringer ECM8000 Measurement Microphone?


The RS meter is only accurate to about 3KHz. For full range the ECM8000 (plus preamp) or Galaxy CM-140 is a good choice (and well worth the investment).



> How is the Behringer mic hooked up?


See the REW Cabling and Connections Basics thread...



> The Subs are HSU ULS-15's the LCR are Paradigm LCR 450's.


Really nice looking theater.....

brucek


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## t6902wf (Nov 14, 2008)

Thanks for the compliments on the room, I do woodworking for a living so it was all in a days work for me.

What I mean by place is locate and point. I have read much more about deep bass but I assume you want to limit big peaks and valleys in the higher frequencies also?


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## tonyvdb (Sep 5, 2007)

t6902wf said:


> Thanks for the compliments on the room, I do woodworking for a living so it was all in a days work for me.
> 
> What I mean by place is locate and point. I have read much more about deep bass but I assume you want to limit big peaks and valleys in the higher frequencies also?


I wouldn't worry about the so called "deep bass" as your mains should not be going below 60Hz anyhow let the subs do the work. Have you tried moving your subs to the outside corners? I think that just by looks your mains are fine just where they are.

I also agree, very nice work on the room


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## t6902wf (Nov 14, 2008)

tonyvdb said:


> I wouldn't worry about the so called "deep bass" as your mains should not be going below 60Hz anyhow let the subs do the work. Have you tried moving your subs to the outside corners? I think that just by looks your mains are fine just where they are.
> 
> I also agree, very nice work on the room


I have measured and moved the subs and they measure and sound fine.

I am wondering if I can improve the sound by adjusting the placement of the front speakers.


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## Wayne A. Pflughaupt (Apr 13, 2006)

t6902wf said:


> I am wondering if I can improve the sound by adjusting the placement of the front speakers.


Well, judging from the picture, you don't appear to have much "wriggle room" in the placement department.

Still, it never hurts to experiment. As brucek mentioned, the RS meter is only accurate up to about 3 kHz. Fortunately, the rule of thumb is that the room's effect on a speaker's response is primarily below 1 kHz, so the RS Meter should do fine for what you want.

Regards,
Wayne


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## tonyvdb (Sep 5, 2007)

t6902wf said:


> I am wondering if I can improve the sound by adjusting the placement of the front speakers.


Given the close proximity to your seating position I would not think much more can be done. I think maybe moving them in to wards the screen maybe a foot would help with the imaging for the person sitting in the center of the front couch. Can you push the front seats back a bit?


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## t6902wf (Nov 14, 2008)

tonyvdb said:


> Given the close proximity to your seating position I would not think much more can be done. I think maybe moving them in to wards the screen maybe a foot would help with the imaging for the person sitting in the center of the front couch. Can you push the front seats back a bit?


I had the basement finished when we built the house. The HT was just dry walled no moldings or paint. With all that was going on with my business and building the house I did not have the time to do the kind of research needed before building a HT. I made the room to short, bummer. The room is TIGHT.
There is no room to move the chairs. The reality is that very seldom does someone sit in the front. If they do its a kid or we have company. Truthfully the near field position of the speakers dos not sound bad.


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## tonyvdb (Sep 5, 2007)

You stated in your first post that you like how they sound "_I have experimented with the speakers and not heard a huge difference in sound but it can be hard to pick up changes_" I would not worry about it and just enjoy it. I only wish my room looked as nice as yours. 
You may want to raise the front left and right speakers maybe another foot so that they fire more over the front row if that is where you sit most of the time. Your center looks good.


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## t6902wf (Nov 14, 2008)

tonyvdb said:


> You stated in your first post that you like how they sound "_I have experimented with the speakers and not heard a huge difference in sound but it can be hard to pick up changes_" I would not worry about it and just enjoy it. I only wish my room looked as nice as yours.
> You may want to raise the front left and right speakers maybe another foot so that they fire more over the front row if that is where you sit most of the time. Your center looks good.


I may try that, thanks.

Being that I figured out REW, I need to measure something??
I do want to pull the subs out from the wall a bit and see if the sound changes.


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## tonyvdb (Sep 5, 2007)

I know I mentioned it earlier but placing the subs in one corner maybe stacked could really help with your lows.


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## t6902wf (Nov 14, 2008)

Here are the measurments of the subs as shown they sound boomy in the corners.
I don't think I need any more bass loading
Subs Audyssey on dynamic volume on









Waterfall of the same plot


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## tonyvdb (Sep 5, 2007)

That graph does not seem right but as I'm no expert in using REW maybe some one else can chime in on that. What are the dimensions of the room? Looking at what you posted there is a bump at 80Hz That would acount for the "boomyness" you hear what is the crossover set at on your receiver?


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## Wayne A. Pflughaupt (Apr 13, 2006)

Re-calibrate the graph for a vertical scale of 45-105 dB, and a horizontal scale of 15-200 Hz. The "Graph Limits" button at the top right of screen is where you do that.

I'd suggest re-doing your waterfall at 300 ms for starters, with the scale set to LIN ("Frequency Axis", also at top right of the screen). I find that setting is much easier to analyze compared to the standard LOG setting.

Regards,
Wayne


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## tonyvdb (Sep 5, 2007)

After talking with member brucek I realize some flaws in my judgement on your placement of the subs in that your subs are very capable and placement where you have them should be more then fine.:hide:


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## t6902wf (Nov 14, 2008)

Tony no big deal, it is an odd response. I am concerned with it.

Wayne and Bruce do you see a need for EQ? I was thinking about the the SVS EQ1. Both of my subs measure very close to one another. It appears EQ may be a waste of money. It may be able to help that waterfall. It appears I have decay issues?

Here is the waterfall Linear, I don't know why it stops at 110









Here is the log waterfall










Here is the subs with Audyssey on, Dynamic volume off.










Dynamic volume raises the line, here is dynamic volume on.










I would like to overlay these graphs on top of one another, how do I do that?

Thanks 

Bill


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## brucek (Apr 11, 2006)

> Bruce do you see a need for EQ?


Nope, not at all.



> Here is the waterfall Linear, I don't know why it stops at 110


Bug in the program. That's why you use LOG and not LIN......



> It may be able to help that waterfall. It appears I have decay issues?


Not in my book you don't....



> would like to overlay these graphs on top of one another, how do I do that?


Use the Measured tab and select the graphs in the checkboxes...

brucek


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## t6902wf (Nov 14, 2008)

Measured tab, thanks. I had found that early on and then forgot where it was. 

I'll bet you don't find a lot of people that admit they are a little disappointed that there is nothing to tweak!

Hmm?

Here are the left and right channels to 3000, the room is heavily dampened. All the tan panels in the photo are 1" fiberglass.
1/3 smoothing









No smoothing










Any comments or observations?

Thanks again,

Bill


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## Wayne A. Pflughaupt (Apr 13, 2006)

t6902wf said:


> Wayne and Bruce do you see a need for EQ?


Only if you feel you need to precisely dial in a house curve.



> Here is the waterfall Linear, I don't know why it stops at 110


Sorry, wasn’t aware of the bug. Change the upper graph limit to 100 Hz. Seems to work for me.

Regards,
Wayne


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## t6902wf (Nov 14, 2008)

That odd at 100 its fine for me also.

Are those L and R channels normal?


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## brucek (Apr 11, 2006)

> Are those L and R channels normal?


Tell us what we're looking at? 

Is it left main with both subs, then right main with both subs?

brucek


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## Wayne A. Pflughaupt (Apr 13, 2006)

t6902wf said:


> Any comments or observations?


This is where you would experiment with different positions and compare readings. You’re looking for the smoothest response above the crossover frequency. Use only one speaker, not both, to avoid possible comb filtering from the mic not being positioned at a perfect equidistance between them. Since your room is symmetrical, any reading/position with one speaker will automatically be valid for the other.

Regards,
Wayne


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## brucek (Apr 11, 2006)

> Use only one speaker, not both


Wayne, I've always done one channel with sub, then the other channel with sub, then finally with both in concert to see if there are some cancellations at the lower octaves (50-300). 

I always felt the REW mono signal was perfect for this. Certainly a stereo signal (music) that only comes from one side or the other won't cancel, but when you have a singer (for example) coming from both speakers, you could get cancellation at the listening position. You wouldn't pick this up by just testing each side by itself. Comments?

brucek


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## t6902wf (Nov 14, 2008)

That is individual graphs for the left and right speakers.
Set to small, crossed at 80. Fed a 20 to 3000 signal.
No subs involved.

I did move the left and right speakers around a bit. I have the measurements saved on another computer. I did not have time to analyze the graphs but there was nothing radically different between them.


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## brucek (Apr 11, 2006)

> That is individual graphs for the left and right speakers.
> Set to small, crossed at 80. Fed a 20 to 3000 signal.
> No subs involved.


To say I'm skeptical would be an understatement. 
I find it hard to believe that you are graphing a speaker set to small with an 80Hz crossover.

Below is the same axis and scaling you are using with a target line that shows what the response should be for a speaker set to small with an 80Hz crossover. Compare it to your two speakers? Would you say you either had a sub involved or your speakers were set to large (actually I don't feel the 450's would go that low).










What are your thoughts?

brucek


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## t6902wf (Nov 14, 2008)

I think I am not sure. I am pretty sure that is less the subs?

I will not be able to redo the measurements for a while so it will have to wait.
The system sounds pretty good in any event.

At home I have a measurement without Audyssey I'd like to post it is pretty interesting.

Thanks Guys.


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## Wayne A. Pflughaupt (Apr 13, 2006)

brucek said:


> Wayne, I've always done one channel with sub, then the other channel with sub, then finally with both in concert to see if there are some cancellations at the lower octaves (50-300).
> 
> I always felt the REW mono signal was perfect for this. Certainly a stereo signal (music) that only comes from one side or the other won't cancel, but when you have a singer (for example) coming from both speakers, you could get cancellation at the listening position. You wouldn't pick this up by just testing each side by itself. Comments?
> 
> brucek


There’s absolutely nothing wrong with that approach. 

Like Dr. Who noted here, how you take the readings depends on what you’re trying to accomplish. If you want to check a speaker’s response, say for the purposes of equalizing, or to accomplish improved response via positioning, then you don’t want the other running, because of the possibility of comb filtering polluting the measurement. 

Also, in a situation like mine, where one speaker is near a corner and the other near an open staircase, you can expect them to have different response below ~500 Hz, so you definitely don’t want to measure with both running.

Naturally, once you’ve completed EQing or whatever, you’ll want to check response with both speakers. At that point you’re then looking for something different – possible cancellations, as you noted, or any other deviation that might show up. You just have to be mindful at that point, comb filtering is not what you’re concerned with, so ignore it if looks worse.

So like I said, there’s really nothing wrong with your approach. I do it, too.  And Bill should do the same. :T

Regards,
Wayne


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