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Discussion Starter · #1 ·
Dear All...

Finally I found some time to assess the room behavior.
Please sorry if you find too many measurements, but I wanted to cover the several variations

Study 2 "extreme positions" for the loudspeakers...A and C, and something in between..
"A" the furthest it can be away from the back wall (BW), it's 150cm (around 59.055 inches).
"C" the closest I can think of (being dipoles), at 99cm from BW (39.173 inches).
Probably I will find the optimum position in the end, between the two, hopefully...

For the room there is 3 possible listening positions
"1" At the sofa, closest to the speakers (around 4 meters from BW)...
"2" at the table, "chair 1"...(higher in ear position, and around 5 meters from BW)
"3" at the table, "char 2" when I usually work when at home.

Having the convenience of Lyngdorf Room Perfect (RP), I uses both at "A" and "B" speakers.
Besides the overall room measurements, it calculated filters optimized for focus positions (listening positions), so I could commute RP ON and OFF, for A,1,2,3 and C, 1 and 2...

I will post the mdat file and also some graphs...
Using the "index" table bellow you can know the exact conditions of each measurement...

Please feel free to comment the mdat measurements and also I will share some findings and graphs for us to discuss.

In the end I hope I can take away some possible measures (maybe some bass trap) that will improve the sound quality and enjoyment from the system...

This is my almost my first try with REW, so any comments to improve graph taking are much welcome...

Thanks!
 

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Discussion Starter · #2 ·
I am having troubling uploading mdat file so, for now, only the summary table and some graphs...

Measurements here with no toe in and no equalization...
 

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Discussion Starter · #3 ·
Hello All...

It seems a lot of "swing" between the room nodes of 45 and 70 Hz and the deep dip in 80Hz...

Could someone suggest what kind of acoustical measures I should start to be looking at?

Thanks!
 

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Discussion Starter · #5 ·
The 80 Hz notch is probably a timing/phase issue between sub and mains. Play with the distance settings in your AVR and see if that can be cleaned up.

Any chance you could post a room diagram?
Hi! I have a pure stereo setup...no AVR, but a Lyngdorf (kind of TACT) and two QUAD ESL's....
I will try to put a room diagram...for now some more data.

My room is a rectangle of:
Lengh = 25ft (7,62m)
Width = 16ft (4,88m)
Height = 8ft 4in (2,55m)
On the left a bookcase makes some absorption, and on the right there is more reflection (glass window).

REW simulates the room nodes and they are according to what the charts say...modes of 45hz and 70hz are there...and make an impact.
How to tame them?
My guess would be work with some absorption centered around 45 to 70, but...
Since ESL's are dipoles, M. Linkwitz says we should not put absorption behind them...instead diffusion can be used...
My question is: he Mr Linkwitz is right, I should avoid place absorption on the corners behind Loudspeakers, but maybe I can place them in the opposite wall...

Thanks a lot for your comments.
 

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Discussion Starter · #7 ·
Acoustic room treatment questions are best asked ( & answered ) within this sites Home-Audio_Acoustics forum .

There, an expert from GIK Acoustics ( or anyone else who frequents that forum ) should be able to help you out .

:sn:
Thanks Earl, I will go there..
But everything started for me using REW and I am still learning my way around this great piece of Software!
Also still wanting to try to optimize more my speakers placement...
 

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Discussion Starter · #9 ·
What are you hoping to improve in your speaker placement? Some of us are big on getting a deep soundstage with sharp, solid imaging.
Better linearity in the bass region...See the huge peaks at room modes 45Hz and 70Hz, to fall abruptly around 80hz..

I feel I can get better bass (better tuned, even more precise..).
Soundstage is already great...especially in the more forward (into the room) position...
Imaging is great, if it's there in the recording...not too sharp, more a continuum left to right, when done right, yes I do have it...

But bass can be better (even of QUAD's are not bass heavy) especially with classic rock and orchestral music.

I might get a sub in the future to help the ESL's..
 

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Hi! I have a pure stereo setup...no AVR, but a Lyngdorf (kind of TACT) and two QUAD ESL's....
I will try to put a room diagram...for now some more data.

My room is a rectangle of:
Lengh = 25ft (7,62m)
Width = 16ft (4,88m)
Height = 8ft 4in (2,55m)
On the left a bookcase makes some absorption, and on the right there is more reflection (glass window).

REW simulates the room nodes and they are according to what the charts say...modes of 45hz and 70hz are there...and make an impact.
How to tame them?
My guess would be work with some absorption centered around 45 to 70, but...
Since ESL's are dipoles, M. Linkwitz says we should not put absorption behind them...instead diffusion can be used...
My question is: he Mr Linkwitz is right, I should avoid place absorption on the corners behind Loudspeakers, but maybe I can place them in the opposite wall...

Thanks a lot for your comments.
Are those measurements with/without a sub? As for room treatment you will need a whole lot to treat those low frequency's, also depends if those peaks are caused by a sub if using one???
 

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Discussion Starter · #12 ·
Are these graphs after the Lyngdorf set filters?
As seen in the graphs above, "no room correction" (no fllters).
But I have also the measures and graphs with RP ON. I will share them also, so you can see the effect of the filters.
While the filters can improve linearity (and indeed, it's easily heard the improvement), the fundamental issue of the room is not completly solved by the room correction sofware. So my ideia is to apply some acoustical treatment on the room first, so that the RP will have to work much less (and correct much less, also).

Unfortunately I was not able to post mdat file here... Is over 70MB, so probably something to do with size?

Thanks.
 

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Discussion Starter · #15 ·
Re: Comparing With and Without Room Correction (RP) at A1

Guys...
Here is the very positive effect of Room Perfect (RP).

Interestingly the software had not a drastic effect on the peaks and valley on the range 45 to 90, but improved...
But it's more on the upper bass and midrange where the benefict is clear (more focus, better bass articulation)...

At "A" position (150cm from back wall) the software indicated around 20% of room correction.
At "C", which is closer to the wall (100cm), the software only corrected around 13%.
This is contrary to my intuition that a freer flow position would be easier...and clear demonstrates that results are a lot related to the mathematics on the room...
 

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Discussion Starter · #16 ·
Re: Now effect of moving listening Position (green) and RP (orange)

Folks...

Now I am posting a graph that displays moving to a chair behind the sofa (1 meter, approximately) and at a higher point...


The purple line is the previous situation (A1).
In Green is just the effect of moving to A2.
In that point there is a shift and now the higher room node is around 69 Hz! Followed by a even deeper drop at 130 Hz...From Room Simulation in REW it appears that in this position axial modes from Lenght and Height are very closed and some tangential ones too...

Then I calculated the filters from RP for this A2 position. You can see the effect in the Orange Line...
It seems that the issue of 130Hz was clearly solved...There was some attenuation around the big 70Hz peak...the rest of the mid band was much worked on...

This A2 with Room Perfect was one of the best compromises (huge sound stage) but has two practicability issues as the chair is much less comfortable and the speakers are too much inside the room living space..
 

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Discussion Starter · #18 ·
Re: Comparing With and Without Room Correction (RP) at A1

So does it sound better?
´

If corrected by RP, yes, sounded very engaging...
If not, sounded strange at times, depending on the program...

I all cases thought, a deep stage was always behind the speakers...

But like I said, the room gets less practical with the speakers so forward...so I am trying something different...with them at about 109cm from back wall..
 
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