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Is this a good room correction strategy?

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khrisr

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I played around with the setup a bit more yesterday and here are some findings -

1. Turns out having symmetrical placement of furniture is quite important. I corrected a significant non-uniformity in the upper frequencies by moving a couch by 6". This non-uniformity only shows up when measuring with both L+R speakers so I guess its due to phase interactions.

::: FIG 1 ::: L+R Response with symmetry improvements

couch_reflections.jpg


2. I tried to improve the 50-100hz dip by moving the speaker around the entire available space but it does not budge. This leads me to believe now that adding a single subwoofer will not solve the problem. Maybe 2 or 4 might do it but thats beyond my budget at the moment so I'm going to suck it up and live with the dip for now.

3. Having a slight downward slope in bass response makes a huge difference for bass heavy tracks. The following was an experiment I did measuring the first 30 seconds of "Get Lucky" - Daft Punk. Moving the balance of energy from mid-bass to lower end made it so much better (granted this one is a bit over corrected but it was quite a revelation).

::: FIG 2 ::: Mid bass correction
corrected_daft_punk_get_lucky.jpg


4. So this is where I'm at after all the tweaks. I suspect the dip between 7-15 khz can be improved by adjusting position of rugs which are a bit non-symmetrical currently.

::: Fig 3 ::: Response after correction (L / R / L+R)

corrected_SWP_L2533BC_R25BN.jpg



::: Fig 4 ::: Spectrogram after correction (this was a lot worse before I fixed the layout asymmetry)
corrected_spectrogram.jpg


::: Fig 5 ::: Waterfall after correction (I installed a DIY diffuser to improve RT60 in the mid bass from 0.7s down to about 0.5ms)

corrected_waterfall.jpg


::: Fig 6 ::: Predicted response + target (L)

filters_SWP_L2533BC_R25BN_left.jpg


::: Fig 7 ::: Predicted response + target (R)

filters_SWP_L2533BC_R25BN_right.jpg
 

Chromatischism

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2. I tried to improve the 50-100hz dip by moving the speaker around the entire available space but it does not budge. This leads me to believe now that adding a single subwoofer will not solve the problem. Maybe 2 or 4 might do it but thats beyond my budget at the moment so I'm going to suck it up and live with the dip for now.
When that is the case, the seat needs to move to see a difference.
3. Having a slight downward slope in bass response makes a huge difference for bass heavy tracks. The following was an experiment I did measuring the first 30 seconds of "Get Lucky" - Daft Punk. Moving the balance of energy from mid-bass to lower end made it so much better (granted this one is a bit over corrected but it was quite a revelation).
Slope is good. Even better if you can extend that to 20 Hz. I think a subwoofer would help a lot.

Here you can see my crossover from my speakers to my subs, with a rise down to the 20-30 Hz region greatly enhancing everything from music to movies. Black line is the combined response. When looking at bass, you can restrict the graph to something like 10-300 or 15-200. I've standardized on 10-300.

Rythmik FV15HP2 + Buchardt S400 + Audyssey XO.png
 

Bear123

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When that is the case, the seat needs to move to see a difference.

Slope is good. Even better if you can extend that to 20 Hz. I think a subwoofer would help a lot.

Here you can see my crossover from my speakers to my subs, with a rise down to the 20-30 Hz region greatly enhancing everything from music to movies. Black line is the combined response. When looking at bass, you can restrict the graph to something like 10-300 or 15-200. I've standardized on 10-300.

View attachment 144934
This is a great example of why subs and eq(even using just a Denon AVR) are all but required for high fidelity, and why "pure 2.0" is most often not. 120 dB of SINAD from a 2.0 DAC and a pair of speakers is not the path to high fidelity.
 
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khrisr

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When that is the case, the seat needs to move to see a difference.

Yes it does improve if I move further out but I only have about 2 ft of additional space. The axial component of the null can be moved out to 120hz so that helps in case I bring in a sub but the longitudinal part does not change appreciably within the space I have.

Here you can see my crossover from my speakers to my subs, with a rise down to the 20-30 Hz region greatly enhancing everything from music to movies. Black line is the combined response.

View attachment 144934

Your response looks perfect! The clean roll off below 100 hz really helps I suppose. Mine has a substantial dip so I probably wouldn't get it so clean.
 

Chromatischism

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Yes it does improve if I move further out but I only have about 2 ft of additional space. The axial component of the null can be moved out to 120hz so that helps in case I bring in a sub but the longitudinal part does not change appreciably within the space I have.
If you can get your worst modes down below 100 Hz that is ideal since you can then use subwoofers to fill that in.
 
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