Locating bass <80Hz?

[OHtaru]

For purposes of the OP's question, i.e. "Can sound <80Hz be localized in a small room?" does it really matter if we can locate bass at < 80Hz in anechoic conditions or not? Several of the articles sighted point out that the room and the position in the room all play a part in the ability to localize LF sound. To me the most likely answer is that under anechoic conditions, it is much more difficult to locate bass, than in a small room. Then the next question is that for integrating a sub in a small room do we need to take these "small room localization effects" into account?

It’s the actual sound that matters, not the abstract rules, based on waaaay too simple models.

Perhaps we can't effectively localize low frequencies at all. It's all just an illusion. At least after I moved the subwoofer to the center line of the room, the bass image is centered and blends well with the satellite speakers, basically achieving the goal that "the bass seems to come from the satellite speakers." But when the subwoofer is placed in the corner of the room, it's completely different—the low frequencies are completely disconnected from the satellite speakers.

 

[Mnyb]

I still ask very practical questions in the spirit of the op ( for the record i use xover frequency lower than 80 hz ).

No practical subwoofer solution set at xover 80 produces only <80 frequencies. Even if you had a magic filter the sub itself would produce distortions or even br tube sounds . Or even very good closed box subs would make walls floors and close by furniture vibrate and thus making overtones.

So the question is really under what circumstances can you locate an actual subwoofer and how to mitigate practically.

It’s an fun academic topic wheater it’s possible to localise <80 hz at all . But it does not help much with the practical implementation .
Is it even possible to test with any actual sound source ? Can you discern between being able to locate the source of the sound from being able to locate <80 hz ?

This tread inspired me to maybe try my subs in stereo not mono and also do my rew measurements again one channel at the time ?

I’m been given the impression that multiple subwoofers placed in different locations in your room should even out the response when playing in mono I have only two subs , maybe I don’t get this effect before I deploy a complete swarm of subs ?


Also in practice I find my two KC92 subs very ”quiet” I have not heard anything bad from them, I have bass but almost no discernible side effects

 

[Sokel]

If we can not locate bass in anechoic conditions, it simply means we can not locate bass.

If we feel like we still can locate bass in a small room, it means there has to be some other effect that makes us feel like we are locating the sound source.

So in order to figure out if we can locate bass in a small room, we need to figure out if what feels like we are able to locate the bass is not the source itself, but a mode that plays with our ears. The only way to figure out this is to rule out modes, and that means we need to test this in an anechoic chamber.

Part of the below experiment was conducted outside, at the top of a hill, so no anechoic but no room either.

https://assets.swoogo.com/uploads/4646601-673c03ab61c93.pdf

Maybe it was not about localization per se but it did show the difference so I take localization as a secondary effect. Or placement if you will.

 

[Heinrich]

Part of the below experiment was conducted outside, at the top of a hill, so no anechoic but no room either.

https://assets.swoogo.com/uploads/4646601-673c03ab61c93.pdf

Maybe it was not about localization per se but it did show the difference so I take localization as a secondary effect. Or placement if you will.

And again the Lund / Griesinger stuff. May I say:

NOT PEER REVIEWED

Did you ever consider to do some real work in replicating the experimentation, rather than theorizing about things you are not exactly trained on? I mean, there was a third or forth stiff reminder of Fourier Analysis after somebody got the terms 'wave', 'frequency' utterly wrong, full stop. Reiterated, the psycho-acoustics gets misused like 'quantum' in cable discussions.

May I say: less critical listening, enjoy, more critical reading

 

[Sokel]

And again the Lund / Griesinger stuff. May I say:

NOT PEER REVIEWED

Did you ever consider to do some real work in replicating the experimentation,

My gear is a little big to move up the hill, I have to admit that.
But my music, at my room is unlistenable with bass summed to mono.

(note, I have tried any combination and placement there is, my room is dedicated and I can do whatever I want in it)

Same with other setups crossed high, proportions get to big enormous, mouths like caves and so.
So, in some sense, yes, I have.

Edit: at the "Bass and Subwoofers" thread there are measurements of my music down low.
If that's how they are recorded that's how they must be played back, I'm adamant about it, that what hi-fi means.

 

[TheZebraKilledDarwin]

At least after I moved the subwoofer to the center line of the room, the bass image is centered and blends well with the satellite speakers, basically achieving the goal that "the bass seems to come from the satellite speakers." But when the subwoofer is placed in the corner of the room, it's completely different—the low frequencies are completely disconnected from the satellite speakers.

The practical result in the real world. That's all that counts for the listener.

While experts always want to make poeple believe their theories were the know-all, because that secures their reputation and income, the truth is theories only help as very rough guidance. For example a measurement with a mic says nothing about very important factors of sound quality: imaging, depth, perceived dynamics.

 

[Heinrich]

The practical result in the real world. That's all that counts for the listener.

While experts always want to make poeple believe their theories were the know-all, because that secures their reputation and income, the truth is theories only help as very rough guidance. For example ...

Well said, I didn't dare to be as direct, but yes. The extensive, controversial theorizing burries practical contributions that many micght be after first. And not the least, despite all the buzzwords used, content remains quite shallow, not even taking basics like Fourier Analysis--I mean acknowledging 'frequency as a human abstraction with tight mathematical rules--into account.

 

[Sokel]

Well said, I didn't dare to be as direct, but yes. The extensive, controversial theorizing burries practical contributions that many micght be after first. And not the least, despite all the buzzwords used, content remains quite shallow, not even taking basics like Fourier Analysis--I mean acknowledging 'frequency as a human abstraction with tight mathematical rules--into account.

Have I missed your practical contribution and experience to it?
Can you point me to your post about it?

 

[Heinrich]

Have I missed your practical contribution and experience to it?
Can you point me to your post about it?

Post #95. And there were other, from others that got swamped by inconclusive second hand back and forth on controversial speaker-audio-psycho-acoustics. Not one of the latter considered real self-made experimentation, not even a suggestion on what to do. Questions were just ignored, e/g that on what the electrical physical signal coming out of the cochlea would look like before evaluation by the neural network that the human brain is.

It's not that I don't understand the discussions due to lacking background. To the contrary.

 

[Sokel]

Post #95. And there were other, from others that got swamped by inconclusive second hand back and forth on controversial speaker-audio-psycho-acoustics. Not one of the latter considered real self-made experimentation, not even a suggestion on what to do. Questions were just ignored, e/g that on what the electrical physical signal coming out of the cochlea would look like before evaluation by the neural network that the human brain is.

It's not that I don't understand the discussions due to lacking background. To the contrary.

Ok, more or less what I have described as well and the way I play.
That does not mean I dismiss anything else though.

At some other room maybe the effect (AE) is not present or it's even more pronounced than mine.
Or bass is not easily localized or even easier than mine.
Endless possibilities, as rooms/setups.

And we maybe don't know it all, but the controlled experiments we do have (like Lund's, yes) point to the right direction. More is needed of course so we can built a rock-solid model to follow.
But clues are there.

 

[DanielT]

Or even very good closed box subs would make walls floors and close by furniture vibrate and thus making overtones.

Subwoofers can make things shake and rattle. It happens from time to time. The large windows in our summer house can rattle when the subwoofer is pushed hard. Clearly audible if the speakers are turned off and only the subwoofers are played. No problem locating where the rattling sound is coming from because, well, it's the window. Which paradoxically makes it harder to localize bass coming from the subwoofer. However, I would rather prefer that than the rattling windows.
(I have somewhat fixed that problem now)

Sometimes not only audible rattling due to the subwoofer but also visible:

It looked a bit fake with that window blowout, but still.

 

[OHtaru]

This tread inspired me to maybe try my subs in stereo not mono and also do my rew measurements again one channel at the time ?

Commercial music is almost always monoized bass before its release, so this might be a waste of effort.

 

[Heinrich]

... controlled experiments we do have (like Lund's, yes) point to the right direction. More is needed ...

For one the presentation and so the experiment wasn't peer reviewed. If there is more into it, I would expect Lund to issue a real paper, get it peer reviewed. Second do the things still needed. He has a ton of resources at hand, right? He's invited to validate the case. But, instead, they (whoever) sell subbass-speakers referring to his claims as they say 'for future use'. In prospect of a feature to come sooner or later, don't miss out!

Commercial music is almost always monoized bass before its release, so this might be a waste of effort.

Hm, I think the o/p's request was targeting something else. If a subwoofer single, necessary w/ mono input could be localized as the single speaker it is. Plus, if that would be the case regardless of position. And plus plus (my fantasy), if that would be the case anyway, what to do about it.

For the record, my two (stereo) subwoofers are localizable to be positioned at that wall, but I would first look for cues originating in distortion originating in air leaks or overdrive with complex signals.

 

[levimax]

Commercial music is almost always monoized bass before its release, so this might be a waste of effort.

Are you sure about that? Here is a thread on the topic https://www.audiosciencereview.com/...music-has-stereo-bass-with-easyeffects.61716/

 

[levimax]

And plus plus (my fantasy), if that would be the case anyway, what to do about it.

No matter the observation or theory I think these is enough information to answer your question:

1. Use a large and acoustically well treated and designed listening room.
2. All speakers in system are full range and positioned strategically in the room.
3. Light DSP to fine tune to taste.

Expensive and not practical in many cases but pretty much guaranteed to work. Once you start "compromising" then the questions start coming on what is the best compromise.

 

[TheZebraKilledDarwin]

Are you sure about that? Here is a thread on the topic https://www.audiosciencereview.com/...music-has-stereo-bass-with-easyeffects.61716/

I'd warn against imagining you can hear "stereo bass" as it suggests the ability to perceive low-end frequencies in stereo, similar to how we localize higher-frequency sounds.

It works differently, but it - of course - impacts the sound. By making the side channel audible, as suggested in this comment, you can hear how much low-end content is anti-phase or not monoized.


Think about it: even in genres where bass and kick are mono-optimized for loudness and to avoid stealing headroom from each other:

In intros and interludes, where wide sounds (pads, sequencer sounds, low strings) often play a prominent role, the bass region is not monoized. Three reasons come to mind:


1. Wide sounds great. Full-range wide sounds even better.


2. Perceived width depends on movement and phase changes between speakers. It sounds better, more organic, less static, and less sterile.

These simplistic model theories pushed on consumers often lead to a binary view of right and wrong, like: "Bass can't be localized, so monoized bass is good enough for high-quality playback." Sounds logical, if you follow that theory, right?


Consider this: if something sounds too digital during production or mixing, analog-modeled gear is used to make it sound acceptably good.
But can you consciously hear the x-amount of distortion added to a vocal? No. But you still hear it by perceiving the indirect effects of increased warmth, smoother upper mids, silkier treble, softer consonants, ...


The same applies to width or imaging. We might not consciously "hear" anti-phase in the low end of certain instruments, but we sense the effects of it.
Therefore a moving, non-static low end, even if humans can't localize these frequencies, has been part of sound design for decades.
And when it comes to multichannel surround, as I discussed in another thread, this is also true for all the surround channels.


I’d even argue the opposite:

Because full-range width on some instruments sounds so good, producers and engineers always keep an eye on a correlation meter. It’s a constant balance between the appealing sound of width and preserving mono compatibility.


3. Improved contrast. If everything sounds wide, nothing sounds wide:

The perceived contrast with main instruments, like the kick or lead vocal, increases when mono instruments appear—and vice versa.

It’s all about movement and contrast to create interest.
Since vinyl is no longer a dominant medium for release, if a track is to be released on vinyl, it is simply remastered specifically to handle the anti-phase in the low end.

 

[levimax]

I'd warn against imagining you can hear "stereo bass" as it suggests the ability to perceive low-end frequencies in stereo, similar to how we localize higher-frequency sounds.

It works differently, but it - of course - impacts the sound. By making the side channel audible, as suggested in this comment, you can hear how much low-end content is anti-phase or not monoized.


Think about it: even in genres where bass and kick are mono-optimized for loudness and to avoid stealing headroom from each other:

In intros and interludes, where wide sounds (pads, sequencer sounds, low strings) often play a prominent role, the bass region is not monoized. Three reasons come to mind:


1. Wide sounds great. Full-range wide sounds even better.


2. Perceived width depends on movement and phase changes between speakers. It sounds better, more organic, less static, and less sterile.

These simplistic model theories pushed on consumers often lead to a binary view of right and wrong, like: "Bass can't be localized, so monoized bass is good enough for high-quality playback." Sounds logical, if you follow that theory, right?


Consider this: if something sounds too digital during production or mixing, analog-modeled gear is used to make it sound acceptably good.
But can you consciously hear the x-amount of distortion added to a vocal? No. But you still hear it by perceiving the indirect effects of increased warmth, smoother upper mids, silkier treble, softer consonants, ...


The same applies to width or imaging. We might not consciously "hear" anti-phase in the low end of certain instruments, but we sense the effects of it.
Therefore a moving, non-static low end, even if humans can't localize these frequencies, has been part of sound design for decades.
And when it comes to multichannel surround, as I discussed in another thread, this is also true for all the surround channels.


I’d even argue the opposite:

Because full-range width on some instruments sounds so good, producers and engineers always keep an eye on a correlation meter. It’s a constant balance between the appealing sound of width and preserving mono compatibility.


3. Improved contrast. If everything sounds wide, nothing sounds wide:

The perceived contrast with main instruments, like the kick or lead vocal, increases when mono instruments appear—and vice versa.

It’s all about movement and contrast to create interest.
Since vinyl is no longer a dominant medium for release, if a track is to be released on vinyl, it is simply remastered specifically to handle the anti-phase in the low end.

I think one of the biggest issues not discussed is that the process of "summing to mono" can be problematic when done "at playback time". In studio, most competent engineers can sum to mono below a frequency in a way that "sounds right" for the total mix. When "summed to mono" is done at playback time it is a different story as every system has a different crossover point and "summed to mono" at 40 Hz is going to sound different than "summed to mono" at 200 Hz. In addition the "summed to mono" signal on the subs is "different" than the signal on the mains and is going to be "blended" at the crossover with unpredictable results depending on the crossover point and the amount of uncorrelated bass.

 

[Suono]

The same applies to width or imaging. We might not consciously "hear" anti-phase in the low end of certain instruments, but we sense the effects of it

What should we hear? If we hear the effects, we hear it!
What you wrote in this post is what differentiates a high-fidelity stereo system from a system that reproduces music.

 

[TheZebraKilledDarwin]

 

[pablolie]

I waited and waited to see him talk about which g*d*mn frequency he refers to as "bass". Finally, around the 10 minute mark, he slides things to 120Hz. Of course that's in the directional range already. Disappointingly, the low bass is smack in the middle in the example, not proving much. The other examples seem exaggerated on purpose, the tracks sound quite different and I don't believe it is simply the bass presentation. But that's just how it sounds to me. Then at 13min or so he sets 3 ranges and centers anything under 80Hz. Hmm.

In a nutshell, this entire video had 0% to do with locating bass under 80Hz. It was about manipulating stuff anywhere between 80 to .. forgot... was it 300Hz..? ... and sliding stuff and asking what sounds better... and everything sounded like FX garbage anyhow.