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Bass arriving out of phase at the listening position

F1308

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Did you try moving the speakers or the listening position? No, because unfortunately I can't really do that. As you can see on the pictures it's a small room and the current layout is the only one that's practical.
Regardless, I see no issues in moving things a bit and see if the sound changes for better.

:):):):)
 
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edechamps

edechamps

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More experiments with moving the speakers or microphone: (this is vector sum relative to rms sum)

moves.png


As you can see, even if I move stuff around (which is not a viable solution in practice, anyway), it's all pretty much crap.

Placing the speakers on the floor doesn't really solve anything either, which makes me pessimistic about the idea of using subs placed on the floor close to the mains to work around the problem.

I guess one option I haven't considered is to replace the bass traps with tuned bass traps specifically designed to fight these problematic frequencies. But I'm reluctant to go through the hassle given I have no idea if it would actually work…
 
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Peluvius

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You mentioned that your measurements were taken with the windows closed. Have you tried opening the windows or otherwise trying to vary the volume of the space if that is possible? Have you tried running GLM on this (8330As?)? I would be interested to see how this would look in a Grade report.
 

Draki

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This happens more often then you think, a new version (V2) of the Acourate FIR DRC software was implemented just to deal with it.
Could you please link to this V2 version?
This comes up in Audiovero for the AccourateDRC (i.e. the 'old'version...)
 

RayDunzl

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I might do some more experiments with microphone/speaker locations.

Try this experiment:


As mentioned earlier, I don't "hear" the measured hole in the bass with music, and here is an example where the microphone doesn't hear it either.

Top, in-room, then left and right CD source.

CD: Carla Bley - Life Goes on - Piano, electric bass, saxophone

Where's the hole?

index.php


In other cases, where the bass part of the stereo track is mono and not severely panned, the hole does show in the measurements.
 

thewas

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Absolute

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I have the exact same issue in my asymmetrical room. A huge hole around 60 hz when both playing together.
Interestingly enough neither Audiolense or Dirac corrects it because they both optimize one speaker individually.

All-pass filter works, but so does reducing the volume in one channel in the dip area.
 

restorer-john

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At the distances you are talking in that miniature room, any microscopic movement of your head or mic will produce crazy response changes.

Nirvana is not achievable in that space.
 

F1308

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At the distances you are talking in that miniature room, any microscopic movement of your head or mic will produce crazy response changes.

Nirvana is not achievable in that space.
That was my very own reasoning when suggested moving things " a bit ".
 

thewas

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I have the exact same issue in my asymmetrical room. A huge hole around 60 hz when both playing together.
Interestingly enough neither Audiolense or Dirac corrects it because they both optimize one speaker individually.

All-pass filter works, but so does reducing the volume in one channel in the dip area.
Which Dirac version do you use as the newer 3.x are supposed to have better bass handling?
 

restorer-john

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That was my very own reasoning when suggested moving things " a bit ".

Yes, a bit. Perhaps, a whole lot. Like into another house with a room bigger than my closet.

Just accept the room is a "mom's basement" type of deal and he should wait until funds allow something better, where you aren't strapped in a chair a few feet away from 4 speakers, whinging about bass arrival times. Made me laugh actually. Who knew?
 
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edechamps

edechamps

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As mentioned earlier, I don't "hear" the measured hole in the bass with music, and here is an example where the microphone doesn't hear it either.
In other cases, where the bass part of the stereo track is mono and not severely panned, the hole does show in the measurements.

Interesting. Intuitively I would expect most stereo recordings to have mono bass in the 80-120 Hz region (with an implicit assumption that it's played back in phase) but I'd love to be proven wrong!
 

F1308

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Interesting. Intuitively I would expect most stereo recordings to have mono bass in the 80-120 Hz region (with an implicit assumption that it's played back in phase) but I'd love to be proven wrong!
I wonder why should be so .
I compose music and placing waves on left and right channels is not a standardized thing for me but it will depend greatly on the depth I pretend and very much on many other things such as providing movement and stage width...
80-120 Hz means E2-B2 if [email protected] and this is home for trombones, tubas, timpani (larger sizes), harps, pianos, harpsichords, pipe organs...cellos, harmonium...double basses...

Last month I finished a song and thunder was placed on left and right channels with the appropriate panning that clearly depicted the thunderstorm arrival, huge extension of it as thunder went overhead and around and finally passing over while slowly dissapearing on the "east"...
 
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edechamps

edechamps

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You mentioned that your measurements were taken with the windows closed. Have you tried opening the windows or otherwise trying to vary the volume of the space if that is possible?

Just tried it with both the window and door open. The results were significantly worse. (Note that the window can only be opened by a small amount due to its design.)

Have you tried running GLM on this (8330As?)? I would be interested to see how this would look in a Grade report.

These are 8030As, not 8330As. They don't come with GLM.
 

Sokel

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Have you experimented with height?

If it's a floor-ceiling bounce colliding that will alter the measurements by a lot.They do seem a little higher than they should be,maybe it's the pic.

Are the stands adjustable?If not try a book under each speaker,just for test.
 
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edechamps

edechamps

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Have you experimented with height?

In this post I show the results of putting the speakers directly on the floor. It doesn't help much.

They do seem a little higher than they should be,maybe it's the pic.

The acoustic centers of the Genelecs are exactly at ear height when I'm seated.
 

pierre

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Hi Etienne, i would add flanking subs like https://www.rythmikaudio.com/FM8_specs.html or 2 genelec 8050. They are small esp. not thick and they cover the range you want. As you know, you will need more channels on your interface and some filters. If it is for music/video only then FIR filters are efficient and the latency is not bothering.
For GVC, … latency is annoying. I had good results with them in a squarish room before.
 

Sokel

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In this post I show the results of putting the speakers directly on the floor. It doesn't help much.



The acoustic centers of the Genelecs are exactly at ear height when I'm seated.
In this case I would even suspect the big panel surface,can be resonating pretty badly sometimes,just to take out of the equation I would test it.
Have you tried covering it with something thick to test? (only careful that can take the weight!)
 
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edechamps

edechamps

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In this case I would even suspect the big panel surface,can be resonating pretty badly sometimes,just to take out of the equation I would test it.

You mean the bass traps? I already did a number of measurements with some/all of them taken out of the room as I explained in my first post. Still out of phase, and unsurprisingly the individual frequency responses are worse.
 

Sokel

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You mean the bass traps? I already did a number of measurements with some/all of them taken out of the room as I explained in my first post. Still out of phase, and unsurprisingly the individual frequency responses are worse.
I mean the TV.
 
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