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Post your room modes correction PEQ settings

Absolute

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Crossover is quite high: 120Hz so it's coming from the single sub and the L&R speakers contribute very little, if anything, there in the nodal region.
Ok, thanks for clarifying. Outsiders like me usually forget how the system is configured between posts. Very often there's a dip around 70 hz due to floor-ceiling cancellation, so that could be it.
You find that out by measuring at different heights.

It's easy to walk into the trap of trying to boost such a cancellation, but it never ends well. Aside from boosting the cancellation with the same amount you boost speaker output, you end up with crazy peaks at the same frequency somewhere else close to the listening position, which will indeed be audible at other points in space.

Personally I feel a 70 hz cancellation is particularly bad because there's a lot of energy and drive in the music around there, so I would try to see if there's a way to avoid the issue. If I'm not mistaken human chest cavity also has the resonance frequency around that area, so important if you like the punch in the chest :)
 

Daverz

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I've been experimenting with the MMM technique and the rePhase plugin in REW. Just showing the left response here:

left_target.jpg


I chose a tilt of 0.8/octave based on someone's recommendation and then just eyeballed the target level to match the response above 1kHz. I used a max frequency of 600 Hz and allowed 18 dB of gain. The max headroom required is 10.9 dB, which is fine with 4V DAC output and 1 or 2 V amp sensitivity. I export the filters as impulse responses and then convert them to work with brutefir.

left_predicted.jpg



Equaliser: rePhase
Jul 7 14:24:07
Filter 1: ON PK Fc 23.60 Hz Gain -11.40 dB Q 9.630
Filter 2: ON PK Fc 29.65 Hz Gain 18.00 dB Q 4.510
Filter 3: ON PK Fc 34.00 Hz Gain -24.50 dB Q 12.310
Filter 4: ON PK Fc 40.65 Hz Gain 18.00 dB Q 4.250
Filter 5: ON PK Fc 53.30 Hz Gain -19.20 dB Q 6.870
Filter 6: ON PK Fc 67.90 Hz Gain 18.00 dB Q 21.010
Filter 7: ON PK Fc 77.00 Hz Gain -7.10 dB Q 7.520
Filter 8: ON PK Fc 91.30 Hz Gain -8.60 dB Q 8.200
Filter 9: ON PK Fc 126.5 Hz Gain 8.30 dB Q 12.090
Filter 10: ON PK Fc 147.0 Hz Gain 11.90 dB Q 14.870
Filter 11: ON PK Fc 173.5 Hz Gain -5.30 dB Q 1.860
Filter 12: ON PK Fc 212.0 Hz Gain 8.90 dB Q 11.170
Filter 13: ON PK Fc 293.0 Hz Gain 9.20 dB Q 11.780
Filter 14: ON PK Fc 408.0 Hz Gain 9.80 dB Q 13.060
Filter 15: ON PK Fc 508.0 Hz Gain 11.70 dB Q 14.710
Filter 16: ON PK Fc 516.0 Hz Gain -7.00 dB Q 3.380
Filter 17: ON None
 

ernestcarl

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Very often there's a dip around 70 hz due to floor-ceiling cancellation, so that could be it. You find that out by measuring at different heights.

Personally I feel a 70 hz cancellation is particularly bad because there's a lot of energy and drive in the music around there, so I would try to see if there's a way to avoid the issue. If I'm not mistaken human chest cavity also has the resonance frequency around that area, so important if you like the punch in the chest :)

Occasionally and in shorter doses... I'm not typically one who likes the physical sensation of bass frequencies permeating throughout one's body for too long. At some point in a 2-hour-long blockbuster movie, I eventually find myself lowering the volume below my reference. My tolerance has been reduced a bit as I got older...

I haven't used the standing option for my desk in a while -- I know, I know... I'm a lazy bastard and prefer to sit on my ass -- but bass is more linear when the increased height option is applied for this sit-stand desk setup.

However, being much closer my relatively short ceiling (7ft.), it affects the non-bass FR more due to ceiling reflections. Specular reflections changes quality of the timbre by a small amount too -- nothing major though.

Okay, the ff. measurements may be more amenable when it comes to bass critical listening to others here:

1595401276685.gif


1595401333157.gif


1595401471891.jpeg

Decay looks a bit more ragged in places due to some complex biquad PEQs for this 'stereo only' setup; yet again, nothing causing any obvious impairment soundwise.

1595401394632.jpeg

Fronts are delayed by 10ms which helps align the peak energy seen in the wavelet.

1595401436648.jpeg

Better now, I think. Very Satisfactory, bass-wise speaking...

Seriously, I need to just put my UMIK-1 inside it's box now! Lest I find myself deep within the dark pits of audiophilia nervosa again. LOL
 

ernestcarl

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I've been experimenting with the MMM technique and the rePhase plugin in REW. Just showing the left response here:

View attachment 74608

I chose a tilt of 0.8/octave based on someone's recommendation and then just eyeballed the target level to match the response above 1kHz. I used a max frequency of 600 Hz and allowed 18 dB of gain. The max headroom required is 10.9 dB, which is fine with 4V DAC output and 1 or 2 V amp sensitivity. I export the filters as impulse responses and then convert them to work with brutefir.

View attachment 74609


Equaliser: rePhase
Jul 7 14:24:07
Filter 1: ON PK Fc 23.60 Hz Gain -11.40 dB Q 9.630
Filter 2: ON PK Fc 29.65 Hz Gain 18.00 dB Q 4.510
Filter 3: ON PK Fc 34.00 Hz Gain -24.50 dB Q 12.310
Filter 4: ON PK Fc 40.65 Hz Gain 18.00 dB Q 4.250
Filter 5: ON PK Fc 53.30 Hz Gain -19.20 dB Q 6.870
Filter 6: ON PK Fc 67.90 Hz Gain 18.00 dB Q 21.010
Filter 7: ON PK Fc 77.00 Hz Gain -7.10 dB Q 7.520
Filter 8: ON PK Fc 91.30 Hz Gain -8.60 dB Q 8.200
Filter 9: ON PK Fc 126.5 Hz Gain 8.30 dB Q 12.090
Filter 10: ON PK Fc 147.0 Hz Gain 11.90 dB Q 14.870
Filter 11: ON PK Fc 173.5 Hz Gain -5.30 dB Q 1.860
Filter 12: ON PK Fc 212.0 Hz Gain 8.90 dB Q 11.170
Filter 13: ON PK Fc 293.0 Hz Gain 9.20 dB Q 11.780
Filter 14: ON PK Fc 408.0 Hz Gain 9.80 dB Q 13.060
Filter 15: ON PK Fc 508.0 Hz Gain 11.70 dB Q 14.710
Filter 16: ON PK Fc 516.0 Hz Gain -7.00 dB Q 3.380
Filter 17: ON None

+10.9dB around which area?
 

Absolute

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That looks really good! What do you mean by standing at LP? You standing up and measuring at the ear height?
 

ernestcarl

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The headroom required numbers are

10.9 dB at 67.9 Hz
10.2 dB at 87.5 Hz

Just wondering how the response 'sounds' around that area after EQ. Did you run any tones/sweep/noise around that bass area and listen? a +10dB boost is pretty intense.

*just checked and the vandersteen quatro appears to be a large floorstander. The amount of boost may not be a problem for them, but as @Absolute has mentioned previously, "boosting the cancellation with the same amount you boost speaker output, you end up with crazy peaks at the same frequency somewhere else close to the listening position, which will indeed be audible at other points in space." If this were applied to a large living room space and that has more than one listening position, other areas in the room certainly will be affected.
 
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Daverz

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Just wondering how the response 'sounds' around that area after EQ. Did you run any tones/sweep/noise around that bass area and listen? a +10dB boost is pretty intense.

I haven't yet, but I've done similar boosts without apparent audible problems.

Also, I haven't compared with a lower "Individual Max Boost" (which won't fill in the dip at 70 Hz). To be honest, I'm still in the playing around phase, and it seemed cool to fill in that dip.
 

ernestcarl

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I haven't yet, but I've done similar boosts without apparent audible problems.

Also, I haven't compared with a lower "Individual Max Boost" (which won't fill in the dip at 70 Hz). To be honest, I'm still in the playing around phase, and it seemed cool to fill in that dip.

I suggested synthetic sounds since listening with generated tones/band limited noise is far easier and quicker than going through a long bass tracks playlist to determine if changes made were really acceptable. It also allows you to actively move around while listening how the overall sound changes before and after your corrections.

As I mentioned on an earlier post as well, filling a null in the bass in my desk sitting position so that it levelled completely (measurement-wise) didn't sound good after all. Partially filling it (less aggressive boost) gave better better results 'sound-wise' -- this also makes my EQ changes affect adjacent areas (besides the MLP) less.
 

dasdoing

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@ernestcarl there is noise at the bottom of your waterfall. or you have to sweep louder, or lower the waterfall (I think 40dB of a span is enough). also to see how far your pretty heavie bass ringing below 40Hz goes make t bigger
 

ernestcarl

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@ernestcarl there is noise at the bottom of your waterfall. or you have to sweep louder, or lower the waterfall (I think 40dB of a span is enough). also to see how far your pretty heavie bass ringing below 40Hz goes make t bigger

40dB right?

Here you go:

1595412790135.jpeg
 

ernestcarl

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you need more t (Time Range). you wanna see your problem range ring out.
see an exampe. both are same meassurement

View attachment 74624View attachment 74625

Sorry, was it for the first waterfall I posted (sitting) or the new one (standing)? Can't understand why the SPL in your graphs are so high...

All the settings should be the same as with yours above except for the SPL scaling.

*OK. The second one... I see. Wait a sec.
 

dasdoing

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Sorry, was it for the first waterfall I posted (sitting) or the new one (standing)?

doesn't matter

Can't understand why the SPL in your graphs are so high...

As I said in another topic (you responded that) my calibration didn't work. have not tried too much as I am not realy interested in absolute values

All the settings should be the same as with yours above except for the SPL scaling.

well, my room is treated


I gues this should be a lot clearer now:

View attachment 74628


now we can see where your below 40Hz ringing is just about to start fading out. you probably need t=1000 to see the whole thing, but on the other hand this allready shows that you have 2 heavie modes effecting everything below 40ish. however, as you probably know, no eq can adress this
 

ernestcarl

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No actual bass traps here other than the couch at the back of the room -- if you can call that a bass trap.

Yes, that long tail end of the sub bass (seen clearly in the spectograms) is more room-related than anything else. Not sure how much bass trapping would be required (space is at a premium here) or if it's even financially feasable to treat -- probably would require an architectural change in the room.

1595415031455.gif


My correction fixed some of that, but aslo added energy elsewhere.
 

ernestcarl

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Huh. Even better, and as you said, it looks much clearer now with the t set to 1000 ms in the waterfall graphs:

...

Okay, I think I'm now so sick of this GIF effect! LOL

edit: switched to none seizure inducing image:

1595465297703.png
 
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dasdoing

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No actual bass traps here other than the couch at the back of the room -- if you can call that a bass trap.

Yes, that long tail end of the sub bass (seen clearly in the spectograms) is more room-related than anything else. Not sure how much bass trapping would be required (space is at a premium here) or if it's even financially feasable to treat -- probably would require an architectural change in the room.

View attachment 74629

My correction fixed some of that, but aslo added energy elsewhere.

filling the gaps adds to the ringing. while attenuating the modes will take a little from it

Huh. Even better, and as you said, it looks much clearer now with the t set to 1000 ms in the waterfall graphs:

View attachment 74632

Okay, I think I'm now so sick of this GIF effect! LOL

this the 1-0-0 room mode. it is produced by standing waves between front and backwall.
see modes calculation* for my room; the first two modes are still visable in my plot https://amcoustics.com/tools/amroc?l=408&w=293&h=243&re=EBU listening room
you probably would need a very thick abosorbtion layer at the whole backwall (or frontwall?) to adress this; because it is so deep (below 40Hz).
I remember in pictures you have a small room behind a door at the backwall? bass couldd be building up there too (the whole room turns into a (bad) subwoofer).
A fun exercise you can do is play a sine tone in your problem frequencies https://www.szynalski.com/tone-generator/
then take your SPL meter and check the energy in the corners, at the walls, and in the small room. where the energie is the highest, absorbtion will be the most effective

*this is theoraticly; windows, doors and other stuff is not in the calculation
 
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Absolute

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EQ will reduce ringing in both level and time. Fortunately studies have shown that ringing in the low frequencies is inaudible, only frequency response is audible. No peak = no ringing to our ears.
Above 90-100 hz it's audible though, so treatment will still improve the sense of bass speed/punch/impact.

This is highly controversial among acousticians (if that's a word), but controlled studies have shown this to be true. So why is it still controversial and debated? It might very well be because we're not measuring in enough places in and around the seating position to EQ sensibly, especially when it comes to filling in dips. Filling in a 5 dB dip where the same frequency has a flat response above and below the microphone position will for all intents and purposes suddenly become a 5 dB peak to our sensitive full-body low frequency "hearing".

If you don't have enough small-banded pressure absorbents to take out a single peak without affecting other ranges it's very hard to disprove the conclusion in the studies because any other treatment for bass frequencies will also fix the audible range above 100 hz.
With science on my side I'm happy to recommend broad-banded treatment from 100 hz and up to save the insane amount of space needed to absorb frequencies below 80 hz :)

If you put on headphones and play 30 hz through them, there's no punch involved. Only rumbling. Dealing with ringing that low makes no sense, it's rumbling either way. Just make sure the rumbling is at the correct SPL.
 

dasdoing

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EQ will reduce ringing in both level and time.

Not where you boost. have you seen his graphs?

Fortunately studies have shown that ringing in the low frequencies is inaudible

Unfortunaly this may be true for a sine wave with no end, but as soon as you stop it it will play on for the period of the ringing. and this is very anoying. ever heard of one note bass? it's because the ringing note will mask the next one which allready plays while the ringing one is still audible. ringing is especialy anoying for percussive instruments with a wide frequency range. imagine a kick drum with a high energy range from 50HZ - 100Hz. now imagine a big ringing frequency at 80Hz. the kick will sound normal in the begging, but the 80Hz note will stay for much longer. another anoying effect is when one instrument exites overtones at the ringing frequency. sudenly the overtones play for longer then the base. if all this is inaudible for you, it's because you never heard a bass treated room. once you hear the difference any ringing at any place "screams" into your ear.
 
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