Stereo Bass using subwoofers

[pjug]

OK. Just done with stereo subs ABX.

Subs are Paradigm Seismic 110 (10 inch sealed subs with 800 Watts RMS capability). Both subs eq using multiple microphone position to handle room modes. Subs about 12 ft away from my seat. Subs on front wall ~10 ft apart.
Room is living room, about 5000+ cubic ft. Ceiling height is ~18 ft. Front wall width is ~23 ft. Room opens on the back right to the rest of the first floor. Room opens on top middle to upstairs.

Chain: laptop -> Gustard x16 -> Sabaj A10h -> subs

9,10,11,12 were easy. 13 and 14 not as easy, but still all got 10/10.

Yes, it is directional and I can hear tones coming from left vs right. Again, thank you very much for creating the test files! I appreciate all your efforts!

View attachment 156809

View attachment 156810

View attachment 156812

Thanks for doing this. Even though the test is flawed (I don't know how much EQ does to remedy the room asymmetry issue ), it is interesting that you are getting the impression of a strong L and R shift. I wonder if someone here has stereo sub setup where the room gives a good symmetrical response in the sub bass, and can try this.

 

[Pdxwayne]

Thanks for doing this. Even though the test is flawed (I don't know how much EQ does to remedy the room asymmetry issue ), it is interesting that you are getting the impression of a strong L and R shift. I wonder if someone here has stereo sub setup where the room gives a good symmetrical response in the sub bass, and can try this.

Even in rectangular enclosed room, research already shown artificial bass tones can be distinguished between dual mono vs stereo subs.

My 3 perfect ABX results using real music clips (low passed at 80hz) with strong artificial 30hz tones are not surprising. Even if you low pass at 40hz, I would say I can still sense the directions.

About that research, see my post at

Stereo Bass using subwoofers

Thank you all for supplying the papers I was looking for. I believe welti's test design is considerably lacking and designed to fail. I will be analyzing his samples (to the best of my ability since I do not see that he listed at what time from each track his test samples are from) Edit...

www.audiosciencereview.com

 

[pjug]

Even in rectangular enclosed room, research already shown artificial bass tones can be distinguished between dual mono vs stereo subs.

My 3 perfect ABX results using real music clips (low passed at 80hz) with strong artificial 30hz tones are not surprising. Even if you low pass at 40hz, I would say I can still sense the directions.

About that research, see my post at

Stereo Bass using subwoofers

Thank you all for supplying the papers I was looking for. I believe welti's test design is considerably lacking and designed to fail. I will be analyzing his samples (to the best of my ability since I do not see that he listed at what time from each track his test samples are from) Edit...

www.audiosciencereview.com

Just want to say I didn't mean to doubt you, it is just a little unfortunate about the flaws in doing this ABX. It seems both sides have papers to back up their positions and I am not up on that and to be honest this is just a curiosity for me, as I don't see running subs in stereo as a practical solution for me.

Still, I might mess around with the ABX myself, just to see. I can speed up the track to 45 hz or so to let me try this with some main speakers in a couple different rooms.

 

[Pdxwayne]

Just want to say I didn't mean to doubt you, it is just a little unfortunate about the flaws in doing this ABX. It seems both sides have papers to back up their positions and I am not up on that and to be honest this is just a curiosity for me, as I don't see running subs in stereo as a practical solution for me.

Still, I might mess around with the ABX myself, just to see. I can speed up the track to 45 hz or so to let me try this with some main speakers in a couple different rooms.

If people use many of the papers to say "most" people can't really tell the differences in low sub bass directivity in most music, yes, I would agree.

But, using those papers as the absolute authority to say "no one" can sense directivity in bass below 80hz, well, it is in itself not scientific. Telling others that they don't know what they are hearing because researches already "proved" that no one can sense directivity below 80hz, again, not logical. Note that I am not talking about you.

Anyway, you said "speed up the track to 45 hz". I don't quite get this? What does "speed up" mean in this context?

 

[pjug]

Anyway, you said "speed up the track to 45 hz". I don't quite get this? What does "speed up" mean in this context?

Sorry I should have said 1.45X speed or whatever it will be so that the spectrum peaks at 45Hz instead of 31Hz. So just play it faster in Audacity if it is not ABX, or make new files where the track is sped up for ABX.

 

[Pdxwayne]

Sorry I should have said 1.45X speed or whatever it will be so that the spectrum peaks at 45Hz instead of 31Hz. So just play it faster in Audacity if it is not ABX, or make new files where the track is sped up for ABX.

Do let us know about your listening tests results. I will predict you will do fine with 20db and 9db files, but might have a bit problem with 3db files.
: )

 

[Soundmixer]

Even in rectangular enclosed room, research already shown artificial bass tones can be distinguished between dual mono vs stereo subs.

At which frequencies, sine waves or pink noise, the position of the sub(or subs), the filter slope of the low pass filters, and the acoustical traps that neutralize the room from those subs?

Where is the data to support this comment?

 

[Pdxwayne]

At which frequencies, sine waves or pink noise, the position of the sub(or subs), the filter slope of the low pass filters, and the acoustical traps that neutralize the room from those subs?

Where is the data to support this comment?

I thought you are the expert and knew about all the papers written by Welti? Why ask me?

If you genuinely want to learn, get the zip file from

Microsoft OneDrive

onedrive.live.com

Open file 12979. Read the whole article. Understand it. Especially check out figure 3 and figure 7. Make sure you understand what both figures convey.

That is all I will say to you.

 

[Soundmixer]

But, using those papers as the absolute authority to say "no one" can sense directivity in bass below 80hz, well, it is in itself not scientific. Telling others that they don't know what they are hearing because researches already "proved" that no one can sense directivity below 80hz, again, not logical. Note that I am not talking about you

This sounds like a justification to prove a point that no research so far has proven. This comment can be easily folded back on you. The idea you CAN sense directivity in bass below 80hz is not science, and therefore not logical. Without any proof you can sense directivity below 80hz, it is illogical to say you can.

 

[Pdxwayne]

This sounds like a justification to prove a point that no research so far has proven. This comment can be easily folded back on you. The idea you CAN sense directivity in bass below 80hz is not science, and therefore not logical. Without any proof you can sense directivity below 80hz, it is illogical to say you can.

Hmm???? ABX results were provided two days ago. See

Stereo Bass using subwoofers

Hmm, this particular one is about difference in 32 to 34 Hz. If I turn off ARC, then right subs will have significant dB peak due to room mode, and left sub will have significant null due to room mode. The difference, based on the measurements, should be in the +10db range. This +10db imbalance...

www.audiosciencereview.com

There is a reason that you are being ignored by many. Learn to admit you are not the expert sometimes. Be humble sometimes.

You are back to "not worth my time" list. Bye bye.

 

[Soundmixer]

I thought you are the expert and knew about all the papers written by Welti? Why ask me?

If you genuinely want to learn, get the zip file from

Microsoft OneDrive

onedrive.live.com

Open file 12979. Read the whole article. Understand it. Especially check out figure 3 and figure 7. Make sure you understand what both figures convey.

That is all I will say to you.

Thank you for the papers, but I have already read them and they do not prove your point at all. I don't think you understand them as much as you want to prove your point, which you haven't. Spatial information loss does not mean stereo information, just out-of-phase information. Since there are no direction cues below 60hz AND most bass is mono, that is a small penalty to pay for the few recordings that have out-of-phase signals at low frequencies. The plus by using bass management is a smoother response over multiple seats and multiple rows of seats. There is no benefit at all in chasing the elusive idea that stereo bass is better than mono bass, especially when you falsely use papers that do not support your point, as support for your point.

Open file 12979. Read the whole article. Understand it. Especially check out figure 3 and figure 7. Make sure you understand what both figures convey.

I was there when Welti presented this paper before the convention. His conclusions is as follows.

"It is a fundamental truth of statistics that not finding a statistically significant result does not prove that there is none. It is always possible that the test simply did not find it. The listening tests described were designed to be as sensitive as possible with respect to finding a significant result. Given the conservative nature of these tests, the fact that significant audible differences were in most cases not found for music stimuli suggests that such differences are small."

That last sentence disproves all of your comments on this subject. What he said live at the convention was those "audible differences" came in the form of "bassiousness", but the effect even then was elusive even with material with significant out-of-phase information.

If you genuinely want to learn, get the zip file from

It seems you haven't learned from the material you posted, especially if you read the conclusion from the paper you emphasize. It is patently clear you don't want to learn, as you are pushing a narrative that you cannot and have not proved.

 

[Soundmixer]

Hmm???? ABX results were provided two days ago. See

Your methodology for this ABX has not been reviewed by a disinterested third party, which makes it invalid. We have a long history of people designing a test, and then validating their own work without it being reviewed. I say boo to you on this!

 

[Soundmixer]

There is a reason that you are being ignored by many. Learn to admit you are not the expert sometimes. Be humble sometimes.

The reason I am being ignored by "many" (which in reality is just a few) is because those "many" have a vested interest in proving a point that they really cannot and have not proved. They are not interested in reading about things that are counter to their myth-based beliefs.

 

[Sancus]

Your methodology for this ABX has not been reviewed by a disinterested third party, which makes it invalid. We have a long history of people designing a test, and then validating their own work without it being reviewed. I say boo to you on this!

Look I think this whole stereo subs thing is silly too, and that it's weird to fixate on adding 1 channel of low-bass specifically when multi-channel is a basic requirement to get decent spatial information out of music, but this IS the "Stereo Bass using subwoofers" thread!

If people want to do their personal ABXes to prove they can hear some level of directionality, it's not very productive to come into this thread and berate them for it. I'm pretty sure everyone here is already aware that these aren't real blind tests or studies, and that there could be 100 different problems with the tests. That's fine, we're all here to learn and have fun.

If you find yourself arguing with almost everybody still posting in a thread it may be wiser to just take a step back and go elsewhere!

 

[Soundmixer]

If you find yourself arguing with almost everybody still posting in a thread it may be wiser to just take a step back and go elsewhere!

Or you could stay and keep participating in the discussion. If the whole point of any posting is for sheeple and the agreeable to participate, this forum and others like it would be boring as hell.

 

[FrantzM]

Look I think this whole stereo subs thing is silly too, and that it's weird to fixate on adding 1 channel of low-bass specifically when multi-channel is a basic requirement to get decent spatial information out of music, but this IS the "Stereo Bass using subwoofers" thread!

If people want to do their personal ABXes to prove they can hear some level of directionality, it's not very productive to come into this thread and berate them for it. I'm pretty sure everyone here is already aware that these aren't real blind tests or studies, and that there could be 100 different problems with the tests. That's fine, we're all here to learn and have fun.

If you find yourself arguing with almost everybody still posting in a thread it may be wiser to just take a step back and go elsewhere!

I am with ou on your fist paragraph...

From there we diverge.. entirely. A lot has been said about the so-called "stereo" bass in his thread. The argumentation is, to be charitable, lacking. We are left with vociferous claims of been able to hear what most people on the planet can't. That requires discussion, serious discussion. it goes counter to the body of serious and peer-reviewed studies and , frankly , to the daily experience of regular audiophiles. Under 60 Hz, we don't, can't hear directionality... In this thread flimsy and customized ,allow me that term, interpretations of scarce papers have been put forth. Not answering to them in a serious way is giving up to what I believe is ASR: Audio Science Forum.
This is what a discussion forum is about. Discussing, Not just agreeing because some people are having a lovefest on their (unverified) observations...

Peace

P.S. I will soon open a thread on my (and so many other people) ability to hear differences between audiophile Ethernet cables...

 

[DonH56]

I did experiments in-room (treated), anechoic, and out in a field (poor man's anechoic chamber when I couldn't use the university's) and the results aligned with basically every other study back then (early 1980's). Localization and stereo bass around 80 Hz and below was a non-entity; directional information was being provided by the subs at higher frequencies. A steeper crossover (low-pass filter) eliminated essentially all directivity -- we went up to 8th order IIRC in steps from 1 to 8 (1, 2, 3, 4, 8 -- I think, long time ago). There was a gradient from say 60 Hz to 100 Hz or so over which different listeners could identify the sub's location with a fairly strong peak (most listeners) at 80 Hz. Out of doors was easiest to localize and in-room the hardest since the room's response dominated the bass. I tend to think sub localization is mainly due to the 12 dB/octave (second-order) roll-off of many (most? most of mine, anyway) AVRs so, even though the crossover is set at 80 Hz, there is still significant energy at 100 and all the way to 160+ Hz. That is the only reasonable argument for stereo subs to my mind; the fact that crossovers are not brick walls and thus the subs have enough higher-frequency energy to provide some directionality.

Assuming the source has it, of course...

 

[Pdxwayne]

@FrantzM and @DonH56, I would really love to hear your interpretation of the paper mentioned in https://www.audiosciencereview.com/...tereo-bass-using-subwoofers.11034/post-930973

What is your view of the paper? Is it a proper paper?

What is your view of the conclusion for table 7?

 

[Pdxwayne]

I did experiments in-room (treated), anechoic, and out in a field (poor man's anechoic chamber when I couldn't use the university's) and the results aligned with basically every other study back then (early 1980's). Localization and stereo bass around 80 Hz and below was a non-entity; directional information was being provided by the subs at higher frequencies. A steeper crossover (low-pass filter) eliminated essentially all directivity -- we went up to 8th order IIRC in steps from 1 to 8 (1, 2, 3, 4, 8 -- I think, long time ago). There was a gradient from say 60 Hz to 100 Hz or so over which different listeners could identify the sub's location with a fairly strong peak (most listeners) at 80 Hz. Out of doors was easiest to localize and in-room the hardest since the room's response dominated the bass. I tend to think sub localization is mainly due to the 12 dB/octave (second-order) roll-off of many (most? most of mine, anyway) AVRs so, even though the crossover is set at 80 Hz, there is still significant energy at 100 and all the way to 160+ Hz. That is the only reasonable argument for stereo subs to my mind; the fact that crossovers are not brick walls and thus the subs have enough higher-frequency energy to provide some directionality.

Assuming the source has it, of course...

May I know in any of your prior tests, did it involves artificial low sub bass in the 30hz?

See the description of the files: https://www.audiosciencereview.com/...tereo-bass-using-subwoofers.11034/post-928692

The files are all filter at 48db sloop at 80hz. The main tones are artificial bass in 32 to 34hz. The files are difference of intensity between left and right of 20db, 10db, and 3db.

It was tested in big room (5000+ cubic ft) that opens to the rest of the house with subs eq to deal with room modes. So it is not a typical closed room and not your typical non eq subs. More details here:

Stereo Bass using subwoofers

Hmm, this particular one is about difference in 32 to 34 Hz. If I turn off ARC, then right subs will have significant dB peak due to room mode, and left sub will have significant null due to room mode. The difference, based on the measurements, should be in the +10db range. This +10db imbalance...

www.audiosciencereview.com

I am pretty sure that none of your tests involved such 30hz artificial sub bass tones with such big db difference between left and right channels. I really hope you can perform tests with such files with a stereo subs yourself, and then come back to let us know about your own observations.

Test files available here:

Traust - Google Drive

drive.google.com

Start with files 9 and 10. If you cannot sense a different, no point going further.

 

[Pdxwayne]

I am with ou on your fist paragraph...

From there we diverge.. entirely. A lot has been said about the so-called "stereo" bass in his thread. The argumentation is, to be charitable, lacking. We are left with vociferous claims of been able to hear what most people on the planet can't. That requires discussion, serious discussion. it goes counter to the body of serious and peer-reviewed studies and , frankly , to the daily experience of regular audiophiles. Under 60 Hz, we don't, can't hear directionality... In this thread flimsy and customized ,allow me that term, interpretations of scarce papers have been put forth. Not answering to them in a serious way is giving up to what I believe is ASR: Audio Science Forum.
This is what a discussion forum is about. Discussing, Not just agreeing because some people are having a lovefest on their (unverified) observations...

Peace

P.S. I will soon open a thread on my (and so many other people) ability to hear differences between audiophile Ethernet cables...

Other than me, there are at least 3 other people in this thread who can hear directivity with stereo subs. So, after you read Welti's paper and my ABX results, why not have the curiosity to say to yourself, maybe a certain artificial bass tones, in a certain left and right balance difference, can show directivity in a certain room?

Like you said, this is a science forum. Why not get as many people as possible to independently verify my findings? Are you able to help and try the same tests as mentioned in post above?