[knownothing2]

Is that (literally) right?

Is it banned because it always end up with the recent kind of discussions we’ve seen so far in this thread—mostly not soundstage-related?

Are you referring to the examinations of human character, intelligence, and other potential personal attributes, or discussions of gear and gear performance that weren’t immediately connected to perception of soundstage, or both?

kn

 

[castleofargh]

My theory on soundstage is that if a headphone delivers left and right channels accurately, the “soundstage” perception varies greatly from song to song, with most them having a relatively “small soundstage” and closer to center.

The headphones that have a very large perceived soundstage, I feel, have some sort of artificial modulation/forced channel oscillation to make it feel as if sound is coming from different places around you. Also, making quiet sounds quieter and adding a bit of reverb can also contribute to this effect.

Again, this has just always been my internal theory.

I basically agree with you.
You can't really force much about spatial localization and general imaging with just headphones. A headphone swap can have a big impact, but it's hard to control and impossible to make it right, as different people need different FR for example, and also because it's very far from enough for realistic impression of space and soundstage.

What changes is(non-exhaustive list on the top of my head):
- The amount of distortions(not just THD). Not something spatially meaningful for us(EDIT: not meaningful to predict the resulting perceived space, not that it has no ability to impact it), but as it end ups being like having extra sounds that have no reason to be here, it most likely does affect our global perception of sound.
- The amount of isolation from "outside" sounds. Depends on how our brain will interpret that, chances are that it will consider something like maybe having our head in a box that isolates us from outside, or maybe it just keeps us conscious that the sounds only come from the headphone. Either way, it's unlikely to help feel a big space even if the music signal is fine.
- The frequency response. Always important, more so at some frequencies than others when it comes to sound localization. With huge variations from headphone to headphone.
- Channel matching. It's very common to have a few dB of difference between left and right cup at some frequencies, meaning those differences are applied to the interpretation of all FR cues used for sound localization. Ironically, people have a very hard time noticing it. It's one of those things that makes me smile when people talk about stuff at -100dB, but they have never been conscious of 1 or 2dB here and there on the left cup changing every sound at every sound levels at those frequencies. Anyway, not noticing what the problem is does not mean they don't feel consequences when interpreting the signal for spatial cues.

And in a smaller way, or ways that end up mainly into what was already listed:
- Comfort(how easily you can forget about wearing headphone).
- Angled drivers, leading mostly to a FR change, but one that might remove one HRTF component from being 'wronger'.
- Bigger drivers, leading mostly to a more stable FR when we put the headphone on our head again. And of course other consequences for distortions, resonance frequency and whatever other consequences for being bigger, that should end up impacting FR and distortion. Maybe a bigger, more uniform wave front makes it easier for the skin on the ear to feel some vibrations? IDK.
- How much they physically shake? Same thing as above. I have no idea when that's good or not, or how much it might affect our perception of space. If they do shake, I imagine there are consequences for distortions too.
- Amount of crosstalk in the cable. If it isn't huge, people won't notice. I would tend to worry more about the amplifier's level of crosstalk. Not necessarily unloaded, what we read as spec, but how much it becomes into a low impedance low sensi load. That's an amp thing, but it's really how the headphone is made that will decide how bad it could potentially get with a given amp. Anyway, I don't list it at the top because we tend to notice only rather massive amounts, which will come to be a thing only under particular circumstances, not determined just by the headphone.


And I think that might be it. Some people talk about internal reverb, given the size of the cup, those don't qualify as spatial cues for humans(the distance/delay given is way too small), and I haven't read anything(not saying it doesn't exist, just I personally haven't read such paper) suggesting it is perceived in any way or that it affects our interpretation of space at all. I suspect that the amount of isolation from sealed cups might be a bigger perceptual deal than how they echo with tiny delays, not much bigger than when sounds bounce from different parts of the outer ear. Just my guess, though.


My point I guess is that it is much easier to just consider a fairly clean headphone with a fairly smooth frequency response, and alter almost everything relevant to imaging with more control, range, and accuracy, using some DSPs, starting with EQ. The rest as you said is in the song we play and will change greatly from song to song.

 

[knownothing2]

- The amount of distortions(not just THD). Not something spatially meaningful for us, but as it end ups being like having extra sounds that have no reason to be here, it most likely does affect our global perception of sound.

If soundstage as it is engineered into a recording and our perception of it is a function of how accurately a musical recording is reproduced by the transducers, then wouldn’t it follow that any distortion imparted by some element(s) of reproduction would effect how we experience or perceive soundstage?

kn

 

[castleofargh]

If soundstage as it is engineered into a recording and our perception of it is a function of how accurately a musical recording is reproduced by the transducers, then wouldn’t it follow that any distortion imparted by some element(s) of reproduction would effect how we experience or perceive soundstage?

kn

Yes, that's how I imagine it. By altering the signal in an audible way, it's likely to change how we interpret some of it. But it's also not something simple or consistent enough to correlate say a THD value with a particular imaging. That's why I said "Not something spatially meaningful for us, but". It's not something clear like, ILD, ITD or reverb.
I understand, however, how that sentence alone can read as overly dismissive of a possible impact on perceived imaging. I could have said what I was thinking about more clearly, and you're right to point it out.
I do believe just about any audible change in sound (and even non audio stimulus) can change our interpretation of space because said interpretation is a pudding of data, and it's hard to fully predict what will be ignored and what will make it into the final space cake.

I guess that's where the distinction between causing change, and controlling or predicting the subjective impact, become more relevant.

I edited the post to hopefully clear the poorly worded sentence.

 

[bigshot]

It depends on what the distortion is affecting. Bass distortion isn’t likely to affect soundstage.

https://flexbooks.ck12.org/cbook/ck...on/inverse-converse-and-contrapositive-pcalc/

 

[XTF1]

It depends on what the distortion is affecting. Bass distortion isn’t likely to affect soundstage.

https://flexbooks.ck12.org/cbook/ck...on/inverse-converse-and-contrapositive-pcalc/

If bass distortion is really bad, can’t you start seeing high-order harmonics polluting freq. ranges that may play a role in soundstage?

An example would be the Senn. HD600/650 with their impedance hump at 100-150 Hz: with a weak amp, not only they may lack bass in that area, but amp. harmonic distortions start affecting higher freq.
The HD600/650 are not renown for their soundstage to start with, but this could contribute to the comments that they “open up” (as more “open” soundstage?) with “better” amp., mostly amp. having more voltage.

 

[bigshot]

Does bass distortion usually get high enough to compromise upper frequencies to the degree that it starts messing up depth cues? I would think if it’s that bad everything would be clearly messed up.

 

[XTF1]

What changes is(non-exhaustive list on the top of my head):

Group Delay? I have read that our ears are sensitive to steep phase variations over frequency (but not to slow variations or absolute phase), which is exactly what group delay is about.

Another input to characterize the sound stage abilities of HP & IEMs?

 

[bigshot]

What circumstances would need to be in place to reach audible levels of timing error with digital audio in a home system? I can’t think of any besides bad speaker placement in a bad room or some weird DSP being engaged by accident.

 

[The Jester]

Interesting question,
Is our natural distance perception to do with something similar to group delay as sound waves of different frequency travel through the air at different speeds ?

 

[KinGensai]

If bass distortion is really bad, can’t you start seeing high-order harmonics polluting freq. ranges that may play a role in soundstage?

An example would be the Senn. HD600/650 with their impedance hump at 100-150 Hz: with a weak amp, not only they may lack bass in that area, but amp. harmonic distortions start affecting higher freq.
The HD600/650 are not renown for their soundstage to start with, but this could contribute to the comments that they “open up” (as more “open” soundstage?) with “better” amp., mostly amp. having more voltage.

Those are pretty high order harmonics you are talking about. THD numbers start rising past 1% at 50Hz and below on typical HPs, so we're talking 6th order to 8th order harmonics to start getting to the pinna gain region where I notice the most effect to spatial cues from FR. By that point, the distortion is very attenuated compared to the lower order harmonics, so I can see hideously distorted low ends possibly having an effect, but I think you have far bigger problems immediately in the low end if that's the case.

 

[gregorio]

If soundstage as it is engineered into a recording and our perception of it is a function of how accurately a musical recording is reproduced by the transducers, then wouldn’t it follow that any distortion imparted by some element(s) of reproduction would effect how we experience or perceive soundstage?

The way you’ve worded that question makes it pretty much impossible to answer, because the variables are almost infinite. Firstly, what soundstage engineered into a recording? Every recording has different soundstage, many are dramatically different and even the exact same aural soundstage cues are will be heard/perceived differently depending on factors such as other aural soundstage cues occurring simultaneously, frequency content and auditory masking. Secondly, the perception/experience of soundstage can be affected by influences that have nothing to do with sound or hearing, visual cues and cognitive biases being two obvious examples. So already we have an almost unlimited number of variables that could affect the perception of soundstage, which even includes absolutely no difference in the sound whatsoever, just a difference in visual cues or some cognitive bias/es for example. If we exclude these cases, using DBT/ABX for example, we can restrict “any distortion” to only “audible distortion” (as castleofargh stated) but we’re still left with an awful lot of variables which results in the correct answer to your question being: Potentially yes but it all depends on your personal perception of soundstage (your HRTF in the case of HPs/IEMs, your room acoustics in the case of speakers, your listening skills, etc.), the exact nature of the audible distortion (it’s magnitude, duration and frequency), the specific recording you’re reproducing AND, how all these variables interact. For example, an audible distortion may have a frequency range that *would* affect your perception of soundstage but is confused enough by other soundstage/positional cues in the recording or masked enough by other freqs in the recording for it not to affect your perception of soundstage. Obviously this is a very vague answer, to potentially provide a more precise answer will require a more precise question.

If bass distortion is really bad, can’t you start seeing high-order harmonics polluting freq. ranges that may play a role in soundstage?

Potentially but it very much depends on the variables mentioned above, the content of the specific recording for example, etc.

Is our natural distance perception to do with something similar to group delay as sound waves of different frequency travel through the air at different speeds ?

No. Our distance perception is based on: Level, obviously more distance results in lower level (extremely roughly, according to the inverse square law). Frequency, more distance results in less mid/high frequency as high freqs are absorbed more by materials (inc. Air itself). And reflection parameters, more distance typically results in more reflections and/or longer delay times, more diffusion, less HF in the reflections, a higher level of reflections relative to the direct sound, any combination of these, plus other parameters.

G

 

[XTF1]

Our distance perception is based on…

Do small head movements also play a role in distance and position (soundstage) perception?
Hence, perhaps, the group delay topic for a headphones/IEM: introducing clues that our brain process as soundstage (???)

 

[VNandor]

Yikes, I'm sorry to hear about those deletions. That's not cool (imho).

But I don't see anything like that in the rules....?

https://www.head-fi.org/articles/posting-guidelines.14048/

(it does say, in the interest of forum civility, to express everything as your opinion, even when posting about science. Which I suppose is what I also have been trying to get to happen all this time too)

The 5. point of the Posting Etiquette is:
"If what you want to post includes words/phrases like "placebo," "expectation bias," "ABX," "blind testing," etc., please post it in the Sound Science forum."

The 6. point of moderation is:
"Discussion of blind testing is only allowed in the Sound Science forum."

In practice, not every post related to proper testing is removed from all the other subforums other than sound science, only the ones that gets reported by enough people. As a result, the discussion about controlled testing outside of this forum is civil (otherwise it would get removed or moved here) but isn't mentioned or given nearly as much as importance as in the sound science subforum.

Discussions about how sighted testing is superior to blind testing because it confirms what audiophiles already know virtually always stay up while any mentions of how dishonest it is to claim that someone hears differences between two devices but only if they see/know which one is playing during the test without any controls applied gets almost always removed under the pretense that bringing this fact up causes "pointless flamewars".

 

[gregorio]

Do small head movements also play a role in distance and position (soundstage) perception?

Yes, they can. In the real world our vertical acuity is far less accurate than our horizontal acuity, so typically we’ll move our head to gain a visual cue. There’s also the “cone of confusion” and we’ll typically do some small movement, like tilting or swivelling our head to resolve the ambiguity. With reproduced stereo sound, just moving our head a couple of inches can make a very significant difference to soundstage perception due to room acoustics but it requires fairly specific conditions for such a small movement to have such a significant impact.

Hence, perhaps, the group delay topic for a headphones/IEM: introducing clues that our brain process as soundstage (???)

I’m not sure how the “hence” figures here, what the connection is between the two questions, unless you’re talking about head tracking with HPs? Maybe you mean slight differences in how you wear/position the HPs or IEMs?

Group delay can be audible in some cases, due to crossovers in the transducers, but it again depends on: The recording (content being reproduced), to an extent on room acoustics AND has to be quite severe, as low as around 2ms is the threshold in certain freq bands.

G