# My first attempt with REW



## Bucket (Aug 12, 2009)

I think I did everything right, but please take a look and let me know what you think.

First, the room is roughly 12'x22', in the basement, with underlay and carpet on concrete. It has never sounded very good, especially the subwoofer. There are a lot of corners in the room - three outer walls with pony walls and a beam and a duct crossing the room. The echo is pretty bad.

I made two DIY pillar bass traps for the back of the room, and will be doing some more at the front when I get time.

For measuring I have a Radio Shack meter to a laptop and UCA202 to a Denon receiver to a SVS PC12-Plus.

Placement is limited to near-field, behind the couch. I moved it around until I found the most even response.

First is without the pillars in place:








And with the pillars:








Any suggestions on the 24hz-ish hump? Should I just bring it down with the single band EQ on the sub?

I'm hoping once I get some more treatments in the room it may look a little better.

Thanks in advance for any advice.


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## Jason_Nolan (Jul 4, 2008)

If you can use the EQ on your sub to bring that 24hz peak down, it doesn't look bad at all. Not surprising since you have the sub nearfield, but nothing wrong with that.


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## glaufman (Nov 25, 2007)

How many seats do you have and where in the room are they?
Just for argument's sake, take a scan with the mic 8'4" from the front wall, and another with the mic 13'7" from the front wall...
Are either of these positions better, and if so, are they palatable for seating?


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## Bucket (Aug 12, 2009)

Seating is two love seats side by side, wall to wall, with one other chair. The love seats are about 2' from the back wall right now. With the 100" screen out from the front wall I don't have a lot of room to move the seats toward the front. I'll try some measurements farther into the room tonight though to see what I get.


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

> Any suggestions on the 24hz-ish hump? Should I just bring it down with the single band EQ on the sub?


A 20+ dB cut is pretty severe. Filters that deep end up cutting a very wide path, so the sub’s EQ needs to be an accurate parametric filter with an bandwidth control.

Regards,
Wayne


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## Bucket (Aug 12, 2009)

I fooled around with the EQ a bit and couldn't get a good result with the deepest cut. I did manage to bring it down a little though. At the deepest cut I was getting large dips under 20hz.

Before EQ:








After EQ:








I still need to run Audyssey - would it level it out any more? I could pick up a DSP1124 to do a better job.

I'll probably leave it with the results after Audyssey for a while. I want to finish the room treatments, and with friends from out of town staying with me for the next couple of weekends I probably won't get much done.


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## laser188139 (Sep 19, 2009)

You did not mention how you have the SVS PC-12 Plus configured. It appears to have 3 choices of port configurations yielding different tuned frequencies. Do you have yours set for the 20Hz tuned frequency? It could be that your sub's tuned frequency is lining up with a room mode to exaggerate the response, and by changing the tuning you could end up with something a little less peaky. 

Bill


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

Yeah, try the port options Bill mentioned. Audyssey can’t hurt either, but I expect you’ll end up needing a BFD to fully tame that peak.

Regards,
Wayne


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## Bucket (Aug 12, 2009)

Thanks, I hadn't even considered the ports. I'm on the 20hz tune, but I'll try it out and see what happens. I'm sure I'll end up with a BFD at some point but right now I'm having fun just trying different things. I can't believe I took this long to try REW.


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## GregBe (Apr 20, 2006)

You may want to try the sealed mode. Getting that sub rolling off early might bring down that peak somewhat.


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## Bucket (Aug 12, 2009)

Yeah, I'll try sealed too, but I'm worried about having enough power. I've got a houseful of company this weekend so I'm not going to get much done, but I'm hoping to get my room treatments done early next week and then try some testing.

There's a sale this weekend at one of the music stores in town so I might go see if they have a BFD too.


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## cyberbri (Apr 27, 2006)

The room treatments will help with the boominess and some cancellation in the higher frequencies, and make it sound better of course, but you're not going to tame a 24Hz peak with bass traps. You'll see this better if you do 15-500Hz and run the sweep through the mains and sub combined.

Running REW with through the sub and mains combined is also important to see how the bass interacts in the range where they are overlapping, so you can better set phase, plus sub distance in the receiver (see graph in my sig for the drastic difference changing the sub distance can make). 

I agree that you should try sealed or a lower tuning frequency. With it near-field, directly behind the couch, you shouldn't have issues with running out of power. I have a similar sized room with a HSU VTF3 Mk2, with it directly behind my couch as well. The sub doesn't bottom out and it gives me plenty of bass calibrated about 2-3dB hot ("even" on the RS meter) and eq'd flat (see my signature). And I usually listen at -10 to -5 for action movies. Moving it from a front corner to behind the couch gave me the extra bass and slam I was missing and saved me from wanting to upgrade my sub.


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## Bucket (Aug 12, 2009)

Thanks cyberbri, good points. Once my company clears out after the weekend I definitely want to try the lower tunings. I just get started with REW and now it seems like I don't get any time to try things out. Next week I should have some time again.


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## Bucket (Aug 12, 2009)

Okay, here is a measurement with one port plugged (16hz mode). Red is no EQ, Green is with EQ, Blue is 20hz all ports open with EQ.

Is this still too much of a hump, and how noticable will the 24hz dip be? I can smooth it out some more with the sub's eq. I haven't tried sealed mode yet.


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## Bucket (Aug 12, 2009)

I played around with the eq some more. The black line looks better except for the spiky dip just below 40hz. What do you think?


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

The black line is (obviously) the best so far. It'll probably take relocation to fix that 60+ Hz problem.

Regards,
Wayne


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## cyberbri (Apr 27, 2006)

How are you picking what filters to apply? REW does a good job of predicting filters up front, and then you input those filters, re-measure, and tweak the filters and add new ones to get the response to look like what you want. It helps to have the "target" line shown so you can aim for something.

Others seem to eq the sub by playing it on its own, but I personally run the sweeps through the receiver so they play through the mains and sub, and I eq the sub that way. That lets me see how the whole system will sound when it plays together.


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

Bri, as far as I can tell the only equalization he has available is a single filter from his subwoofer.

Regards,
Wayne


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## cyberbri (Apr 27, 2006)

Ahh, bringing down that 24Hz peak...


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## Bucket (Aug 12, 2009)

Yeah, Wayne's right. I was just seeing what I could do with that peak. I'm very limited on placement options but I'm going to try moving it around to see what improvements I can get to that 60hz dip when I get a chance.


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## cyberbri (Apr 27, 2006)

You may need to move your seating location as well in order to see a change to that 60Hz dip. Say 1 foot forward or something.


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## Bucket (Aug 12, 2009)

cyberbri said:


> You may need to move your seating location as well in order to see a change to that 60Hz dip. Say 1 foot forward or something.


Here's a question I don't think I've come across yet:

Can I just move the SPL meter forward when measuring, or does the furniture need to move too for an accurate measurement?


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## glaufman (Nov 25, 2007)

At these frequencies I think just moving the mic would give you a pretty good idea of what to expect.


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## cyberbri (Apr 27, 2006)

glaufman said:


> At these frequencies I think just moving the mic would give you a pretty good idea of what to expect.


Exactly.


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## Bucket (Aug 12, 2009)

Thanks guys for all the help.


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## Bucket (Aug 12, 2009)

So I finally got time to try some different furniture placement. Red is the old placement, green the new.









It didn't do much for the 35-50hz drop but the 60ish hz dip is gone. How noticable will that drop at 35-50 be compared to the frequencies above and below? The system is used mostly for movies and games, with some tv and a little music.


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

IMO the 60 Hz and 35-50 Hz depressions are broad and deep enough to have an audible effect. I think you should look into parametric equalization. 

Regards,
Wayne


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