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-   -   Equalizing the average listening position [WARNING high graph count ahead] (https://www.hometheatershack.com/forums/rew-forum/9526-equalizing-average-listening-position-warning-high-graph-count-ahead.html)

GollyJer 02-20-08 03:32 PM

Equalizing the average listening position [WARNING high graph count ahead]
 

OK, I wanted to post what I did this weekend in hopes of getting some feedback on the process. It also makes for a good resource to come back to when I do this again. :innocent:
My room is used mostly for movie and tv viewing and the goal was to optimize the listening environment for the "average" listening position.

Some things I know but can't help.
1) A corner isn't always the best place for dynamic subwoofer performance.
2) Seating close to a wall is not optimal.
3) Large openings to other rooms is not optimal.

Seating, sub, and speaker placement are pretty much dictated by the room. I'm dealing with it the best I can. Here's what it looks like.
http://farm3.static.flickr.com/2160/...057be1e678.jpg
Each colored dot on the couch represents a point of measurement. As you read through this post the color of a line in a graph corresponds with it's position on the couch.

So here's the steps I used:
1) Measure from each listening position.
2) Use the average tab in REW to calculate the Average (red) curve.
3) Use "Set Target" on the Average curve.
4) Move the mic around the room to find a position that produces a curve close to the Average curve. I call this the Testing Postion (black).
5) Use REW to suggest EQ settings but adjust by hand with BFD.

And now for the charts! FYI, I'm using a Hard-Knee House Curve.

The chart on the left is the baseline measurement and the right is the corresponding "after adjustments" measurement.

Blue Position
http://farm3.static.flickr.com/2150/...0498c5c333.jpghttp://farm3.static.flickr.com/2151/...2d28e28399.jpg

Green Position
http://farm3.static.flickr.com/2293/...e9d10bb443.jpghttp://farm3.static.flickr.com/2367/...e5fa8e21f0.jpg

Purple Position
http://farm3.static.flickr.com/2331/...e4c89e54f1.jpghttp://farm3.static.flickr.com/2410/...3439d13e6f.jpg

Grey Position
http://farm3.static.flickr.com/2311/...ccb124537a.jpghttp://farm3.static.flickr.com/2165/...64bb7496fc.jpg

Orange Position
http://farm3.static.flickr.com/2284/...679b44b68a.jpghttp://farm3.static.flickr.com/2003/...4c5152ef36.jpg

All In One (for fun)
http://farm3.static.flickr.com/2152/...48b16acd29.jpghttp://farm3.static.flickr.com/2148/...8e65739b30.jpg

Here's what the average looked like before adjustments.
http://farm3.static.flickr.com/2130/...a6c19a59b1.jpg

After finding the average, I moved the mic around the room to find a Testing Position where the graph looked close to the average. Here's the Testing Position curve overlaid with the Average curve. It's from the black/red dot on the couch:
http://farm3.static.flickr.com/2269/...8a14b2fc1f.jpg

From here, I started to compute and input EQ settings. The first I settled on was a 6.5db gain at 20 Hz with a bandwidth of 3. During speaker matching, my SVS sub only needed to be at 1/4 gain to match the SPL reading of the mains. I could have also adjusted this on the sub itself with it's one PEQ setting, but chose to do it with the BDF. After running REW again after the 20Hz increase, I started tackling the peak at ~63Hz. An adjustment of -18db with a bandwidth setting of .25 helped it out. Then I adjusted the hump at ~94Hz (my x-over is set at 100Hz) and it took a -15db at .2 bandwidth.

For some reason I don't have the after adjustment Testing Position chart, but I do have the after adjustment Average chart:
http://farm3.static.flickr.com/2005/...c1462a2178.jpg

It's not exactly perfect, riding below the target in the 50 to 80Hz range. I'm sure this is due to the excessive adjustments at 60 and 90. Also, when looking back at the After Adjustment individual charts, green, purple, and gray got better, but blue and orange got significantly worse. It took a lot more gain than REW suggested to get the Testing Position peaks to normalize. At this point I'm thinking I should simply take them out.

Ultimately, I need to go back to the drawing board on the filter settings, but I think the process is decent. With some trial and error I should be able to dial this thing in a little better.

What do you guys think? Is this process sound? Should I leave out the outlier testing positions (blue and orange)? Could the "center of a rectangular room" have something to do with the weird blue charts?

Thanks for your feedback.

-Jeremy

tonyvdb 02-20-08 04:42 PM

Re: Equalizing the average listening position [WARNING high graph count ahead]
 

Yes, Thats a tough setup to work with. May I ask, how do you have your rear speakers placed? Are they pointed just the way you have them drawn on the diagram?
If so I would turn them in towards the center of the room (approximately the coffee table area) this will give you far better coverage of the seating on the side wall.

mswlogo 02-20-08 05:01 PM

Re: Equalizing the average listening position [WARNING high graph count ahead]
 

Nice job presenting, that's for sure.

My room is setup very similar except the dinning area is off to the right of sweetspot listener position rather than behind. I think your setup would do better than mine. I do exactly as commented in the previous reply and angle the rears towards center of the room if you have not already.

I disagree with your comment #3. Your sweet spot being away from walls is a good thing. In fact #2 and #3 conflict. Large openings to other rooms is not such a bad thing.

I'm surprised your sub doesn't give you more problems than your graphs show.

Why didn't you just build filters off the average curve directly than try to find a test point closest to it?

I would sweep to 500hz and see how your main speakers are blending in.

brucek 02-20-08 06:27 PM

Re: Equalizing the average listening position [WARNING high graph count ahead]
 

Quote:

Why didn't you just build filters off the average curve directly than try to find a test point closest to it?
Agreed.The average of multiple measurements will not have the same attributes as a spot you find that happens to match it. The spot you find may have a dip that wouldn't respond to gain if you threw a jet engine at it or any other number of problems that simply don't agree with an average.

Take your multiple measures, create an average and let REW work on that new average plot to show you the filters (along with your manual tweaking) to get to a reasonable response on the computer. Enter the filters and redo your multiple measures and see how you feel about it. Then tweak a bit.

You may find that you have to be a bit selfish about the sweet rectangle in the middle and let people you don't like sit in the side seats. If you don't you may find everyone is dissatisfied.

Also watch entering too much gain. Also note that filters with a BW less than 5 are getting a bit narrow and won't be that effective over a large area.

brucek

imbeaujp 02-20-08 06:34 PM

Re: Equalizing the average listening position [WARNING high graph count ahead]
 

Hello,

Why don't you place your sub in the opposite front corner ?

The distance from the listening position(s) will be more equal ?

Wayne A. Pflughaupt 02-21-08 04:59 PM

Re: Equalizing the average listening position [WARNING high graph count ahead]
 


Jeremy,

Judging from the bandwidth settings you mentioned, and seeing their effects on the graphs, I take it you’re using the FBQ, not the BFD?

Quote:

The first I settled on was a 6.5db gain at 20 Hz with a bandwidth of 3.
From the looks of your graph, it looks like you’re using this filter to raise the level of everything below 40 Hz – i.e. nearly half of the sub’s entire range. Not the best way to use an equalizer. It would be better to instead realign your Target Curve down to ~75-78 dB.

I suggest averaging the blue, green and purple positions. I wouldn’t worry about the orange and gray. Those are crummy viewing positions anyway, let them hear crummy bass, too. :laugh:

You could then set up a second program on the equalizer and EQ only for the sweet spot, and use that one when you’re viewing or listening to music alone. :)

I agree with Jean-Pierre’s recommendation to try different placements. Sometimes moving the sub a few feet from the corner down one wall or the other can smooth things out, and still be close enough to it to realize the improved extension and SPL corners give.

Regards,
Wayne

Sonnie 02-21-08 05:20 PM

Re: Equalizing the average listening position [WARNING high graph count ahead]
 

Quote:

brucek wrote: (Post 82532)
You may find that you have to be a bit selfish about the sweet rectangle in the middle and let people you don't like sit in the side seats. If you don't you may find everyone is dissatisfied.

Quote:

Wayne A. Pflughaupt wrote: (Post 82758)

I suggest averaging the blue, green and purple positions. I wouldn’t worry about the orange and gray. Those are crummy viewing positions anyway, let them hear crummy bass, too. :laugh:

You could then set up a second program on the equalizer and EQ only for the sweet spot, and use that one when you’re viewing or listening to music alone. :)

I'd be selfish most of the time. How often does anyone else sit in that room with you? I suspect most people would never be able to tell a bit a difference. I have pretty much always equalized my main listening position and anyone that has ever sit in any other seats still always say it is great.

The idea to average a couple to three positions might be an option if you have a second preset where you can store it for when that audiophile buddy comes to visit he will get a good response, otherwise, I would shoot for the primary position only.

GollyJer 02-21-08 07:48 PM

Re: Equalizing the average listening position [WARNING high graph count ahead]
 

First of all, thanks for all the comments guys. The interaction on this forum is top notch.

Quote:

mswlogo wrote: (Post 82514)
Nice job presenting, that's for sure.

I disagree with your comment #3. Your sweet spot being away from walls is a good thing. In fact #2 and #3 conflict. Large openings to other rooms is not such a bad thing.

Why didn't you just build filters off the average curve directly than try to find a test point closest to it?

I would sweep to 500hz and see how your main speakers are blending in.

Thanks.
Comment #3 is speaking towards the gray and orange position (next to the wall).
At this point I think building filters for the average curve then remeasuring all positions to recalculate the average is probably the best process.
Blending the mains is my next major area of understanding to tackle. They always seem to take way off (on the graph, not necessarily acoustically) when testing.

Quote:

tonyvdb wrote: (Post 82510)
Are they pointed just the way you have them drawn on the diagram?
If so I would turn them in towards the center of the room (approximately the coffee table area) this will give you far better coverage of the seating on the side wall.

They were pointed in a little but I've now pointed them in a little more. I generally have 4 people on the couch while watching.

Quote:

brucek wrote: (Post 82532)
Take your multiple measures, create an average and let REW work on that new average plot to show you the filters (along with your manual tweaking) to get to a reasonable response on the computer. Enter the filters and redo your multiple measures and see how you feel about it. Then tweak a bit.

Agreed. This is how I will approach this from now on.

Quote:

imbeaujp wrote: (Post 82534)
Hello, why don't you place your sub in the opposite front corner ?

The diagram isn't perfectly to scale regarding door placement and swing direction. The doors over there actually swing in and are closer to the left wall than shown. There's no way the sub would fit.

Quote:

Wayne A. Pflughaupt wrote: (Post 82758)

Jeremy,

Judging from the bandwidth settings you mentioned, and seeing their effects on the graphs, I take it you’re using the FBQ, not the BFD?

Correct. I updated my signature (now that I can) with specs so it will be easier to identify such things.


Quote:

Wayne A. Pflughaupt wrote: (Post 82758)
From the looks of your graph, it looks like you’re using this filter to raise the level of everything below 40 Hz – i.e. nearly half of the sub’s entire range. Not the best way to use an equalizer. It would be better to instead realign your Target Curve down to ~75-78 dB.

I suggest averaging the blue, green and purple positions. I wouldn’t worry about the orange and gray. Those are crummy viewing positions anyway, let them hear crummy bass, too. :laugh:

All good advice. This is exactly the way I'll approach curve adjustment in the next go round.

Quote:

Sonnie wrote: (Post 82762)
I'd be selfish most of the time. How often does anyone else sit in that room with you? I suspect most people would never be able to tell a bit a difference. I have pretty much always equalized my main listening position and anyone that has ever sit in any other seats still always say it is great.

The idea to average a couple to three positions might be an option if you have a second preset where you can store it for when that audiophile buddy comes to visit he will get a good response, otherwise, I would shoot for the primary position only.

Most of the time two, but very often at least four people are sitting in the room. You're right in assuming that they probably can't tell the difference though. Being selfish seems to be a common theme around here. :heehee: I'm almost always sitting in between purple and green which happen to have the best curves at the moment. :bigsmile: I think it's a great idea to have two presets. One where I optimize for the average of Blue, Green, and Purple, and one where I optimize my alone time listening position.

Thanks again for all the advice guys.
-Jeremy

brucek 02-21-08 08:01 PM

Re: Equalizing the average listening position [WARNING high graph count ahead]
 

Quote:

I think it's a great idea to have two presets.
I thought the FBQ only had one memory slot - where BFD has ten?

brucek

Wayne A. Pflughaupt 02-21-08 08:09 PM

Re: Equalizing the average listening position [WARNING high graph count ahead]
 


:duh: Oops, didn’t know that…

Regards,
Wayne

GollyJer 02-21-08 09:14 PM

Re: Equalizing the average listening position [WARNING high graph count ahead]
 

Yeah, the FBQ doesn't have presets. I'm hoping to get something like this set up with my HTPC for the next go round. I'm assuming it'll have unlimited presets.


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