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Listening position graph help
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russkny
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#1
30th December 2013
Old 30th December 2013
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Listening position graph help

Hey everyone,

I recently did some quick preliminary measurements of my room to determine the best listening position in an untreated space, and was wondering if anyone would be able to tell me which graph represents the most ideal theoretical listening position based on these measurements.

The tests were done with a Dayton Audio UMM-6 mic, pointed directly at the speakers at various distances from the speakers (no sub, speakers' range is 48Hz to 21kHz). The speakers remained stationary throughout the measurements, located as close to the front wall as possible, with the tweeters angled towards the listening position.

I just wanted to let you know that I'm not trying to achieve perfection, I'm simply trying to determine the best listening location with these tests – something that would be more accurate or scientific than just randomly selecting my listening position based on where I "think" it should be, or even at the suggested 38% distance.

Attached are some of the more "distinctive" graphs I picked (and their corresponding waterfall graphs), as well as the full REW .mdat file.

REW mdat

Thank you for your assistance in advance!
Attached Thumbnails
Listening position graph help-59.jpg   Listening position graph help-59-w.jpg   Listening position graph help-67-38-.jpg   Listening position graph help-67-w.jpg   Listening position graph help-85.jpg  

Listening position graph help-85-w.jpg   Listening position graph help-103.jpg   Listening position graph help-103-w.jpg  
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30th December 2013
Old 30th December 2013
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I looked at it quickly, but it seems the second test is the best to start with. Keep in mind that you really should be testing one speaker at a time and after you treat the room you may find that moving a bit will help.
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31st December 2013
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what are the dimensions on the room?
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31st December 2013
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Hi Glenn,

Thank you for taking a look at those graphs. I'll do some more tests with one speaker at a time. In the meantime, just so I know what I'm looking for, would you be able to tell me why the second graph ( 67(38%).jpg ) is better than the third ( 85.jpg )? I personally thought that the third graph would be better, since while it has larger peaks, it seems to have less dips, and also doesn't have a peak around 47Hz like the other graphs.

Thanks!
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31st December 2013
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Quote:
Originally Posted by The Vulture View Post
what are the dimensions on the room?
Hi, the room is almost square, 13.4ft x 12.25ft. The speakers are situated along the shorter wall.
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31st December 2013
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I was looking strictly at the low end as that is the hardest to fix in a small room. As I said in my last email though you may find that moving after treatment helps.
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31st December 2013
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Difference

Quite small changes in the response, perhaps because the speakers are so close to the front wall. Interesting. In the REW .mdat, the first measurements looks best to my eye.
Zoom to see LF fully, e.g. 30-300.
Try moving the speakers out from the wall in increments. They may well be at the best (least bad) location right now, but we need to know for sure. If a better Speaker location appears, then test for optimum listening position again.

DD
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2nd January 2014
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Hi all,

Hope everyone had a great New Year's!

I redid the tests, this time moving the speakers along with the mic to retain the equilateral triangle, and also testing L, R and then L+R speakers.

I took quite a few measurements, too many to fit into one .mdat file, in fact, so I had to separate the data between two files - one with individual L and R graphs and one with L+R.

This time around, I think the listening position closer to the middle of the room produced the best graphs (79-83), but I could be wrong, since I'm still not sure what to look for exactly in a FR graph. The biggest changes between graphs, however, were noticed around 46Hz, 76Hz, 84Hz, 96-106Hz, 147-167Hz, 203Hz and 222-242Hz.

Download REW data

Thanks for all your help and happy 2014!
Attached Thumbnails
Listening position graph help-lp-61-l-38-.jpg   Listening position graph help-lp-71-l.jpg   Listening position graph help-lp-79-l.jpg   Listening position graph help-lp-81-l.jpg   Listening position graph help-lp-comp.jpg  

Listening position graph help-lp-comp-offset.jpg  
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3rd January 2014
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Looking at the graphs again, I think 79 and 81 represent the least worst listening positions. Would you agree?
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4th January 2014
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Sorry to bump the thread, but I would really appreciate it if someone would be willing to take a look at these graphs (and perhaps the .mdat files) and give me some feedback, please.

Listening position graph help

Looking forward to your replies!

-Russ
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4th January 2014
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Like I said I would treat the room then remeasure and move again. You may just find that 61 gives the best overall response in the end.
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4th January 2014
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Quote:
Originally Posted by russkny View Post
Looking at the graphs again, I think 79 and 81 represent the least worst listening positions. Would you agree?
Its extremely unlikely your going to solve things through repositioning alone. This is why people treat their rooms.

Agree with Glenn.
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5th January 2014
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Priority

Quote:
Quote:
I redid the tests, this time moving the speakers along with the mic to retain the equilateral triangle
I would give LF performance a much higher priority than keeping a triangle going.

DD
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5th January 2014
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Quote:
Originally Posted by DanDan View Post
I would give LF performance a much higher priority than keeping a triangle going.

DD
To a point, I agree.
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5th January 2014
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Thanks for your input, everyone!

I will definitely treat the room and then retest and reposition if necessary, however, as a starting point, could you please let me know which graph represents the optimal listening position currently, in an untreated room? I am simply trying to understand the FR graphs so I know what to look for in terms of problem areas. I realize that the graphs will most likely change once the room is treated, but for future reference, would you be able to tell me why, for instance, graph 61 is "better" than graph 79? Or is it not?

For example, is it less troublesome to have a larger peak in the 84Hz region, but have much smaller peaks between 147-167Hz (graph 61), OR would you "prefer" to have a much smaller peak in the 84Hz area, but have larger peaks around 149Hz and 165Hz? Hypothetically speaking, if the room was treated, and changing listening positions yielded these graphs, which one would represent a more ideal location? I don't know if I am making myself clear enough, but basically what I'm trying to determine is which of these graphs shows the least worst listening location (and why), regardless of whether the room is treated or not, simply based on the graph data.

Thanks for your patience and assistance once again!
Attached Thumbnails
Listening position graph help-61vs79.jpg   Listening position graph help-79vs83.jpg  
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5th January 2014
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Before

The first position 61 still looks the best to my eye. Use zooming to see LF vividly. Use Waterfalls.
Using an equilateral triangle fixes the Width dimension and the Listening position.
This means that many positions remain unexplored.
You cannot simply fix one dimension and then move on to the next. They are interactive.

DD
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6th January 2014
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Quote:
I realize that the graphs will most likely change once the room is treated, but for future reference, would you be able to tell me why, for instance, graph 61 is "better" than graph 79? Or is it not?
Basically I think hammering down the 80ish hz spike will be easy to do, and you still have plenty of "beef" (low end) below that. All the other placements seem to "lack" in low end response.
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14th January 2014
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DanDan and Glenn, thank you so much for your feedback.

Glenn, just to make sure I understand correctly, it shouldn't be too difficult to eliminate or diminish that 84Hz spike, however, all other graphs show lack of lower frequencies (below 84Hz) which could present a problem and may not be fixed with room treatment. Is that the gist of it?

If I understood this correctly, would you say that graph 65 or 67 is "better" than graph 61 since the low frequency curve (between ~45 and 60Hz) is closer to 0db?

(I offset the graphs to bring down 1KHz point to 0dB with smoothing set to 1/1, as suggested in this post).

Thank you!
Attached Thumbnails
Listening position graph help-61vs65vs67.jpg  
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