Hard facts from a HUG member

Sorry, I don’t understand. Are you saying stereo is different from mono?
I fully agree with this.
I personally have not experienced depth and height in sound stage in stereo set ups in a obvious way. Again that maybe because I have not yet listened to a two channel system that can do this convincingly.
Since most performances and studio recordings have the musicians on the same floor (level) the height aspect doesn’t bother me. But being able to identify who is in front, at the back etc would be fantastic!
In cinema and multichannel home theatre systems I guess clearly identifiable sounds from all directions would be important (achieved by placement of speakers all around)

Let me try to explain, in stereo there are two channels but they each carry different frequencies,amplitudes and timing. It is these differences that cause the stereo effect. As I am sure you are aware stereo is an effect that takes place in the brain when the brain combines and interprets the two signals arriving at both ears. As an example if you have a guitar signal of equal amplitude in both channels but one channel has a slight delay then the sound will not be centered and instead will shift to the other speaker which has a signal that is not delayed. I am not talking about DSP but the signal itself as present on the CD/file etc. Our brains use level and timing to determine direction, this is why we have two ears where the level and timing at both ears of the presented same sound is processed by the brain to determine direction and distance. Our hearing is not perfect but it does a decent job of it. This is my understanding.
 
8. There is no spatial 3d information in the signal. It is stereo, a left to right difference in loudness and running time. It‘s all in the signal. Two times mono. Height, depth etc. is a conceit. That is what stereo was invented for. It‘s not your fault or weakness. For height a second pair of speakers is necessary. With different signals, recorded from different microphone (higher) positions.
IMO it is impossible to get the height with stereo and where recording has been done with just 2 microphones. Whatever semblance of height anyone gets is probably some hallucination. Accurate rendition of height will be possible only if the recording is done in two planes. One horizontal (the way it is done for stereo) and one vertical plane with top and bottom microphones. And of course playback done with 4 speakers - Left + right speakers and top ceiling + below the floor speakers? :eek:
In short what you need is a basic version of Atmos adapted for stereo
I was wondering about this too. But I really haven’t heard any 2 channel system that convincingly showed layered depth or height.

That is not to say it’s not possible. Just that I have not experienced this.
Are you able to experience this with headphones? Forget about height, but do you get the feeling of layered depth with headphones?
 
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IMO it is impossible to get the height with stereo and where recording has been done with just 2 microphones. Whatever semblance of height anyone gets is probably some hallucination. Accurate rendition of height will be possible only if the recording is done in two planes. One horizontal (the way it is done for stereo) and one vertical plane with top and bottom microphones. And of course playback done with 4 speakers - Left + right speakers and top ceiling + below the floor speakers? :eek:
In short what you need is a basic version of Atmos adapted for stereo
When we talk about height in the stereo image, it is not exactly height info/sound that you get using height channels in a multi channel setup. It is the height of the soundstage in front of you. With the right speakers, acoustics and placement, you can get height that is taller than the location of the tweeters. The sound will be airy and differences in height of various images in the soundstage is clear. Sitting in your listening chair, if you look at the tweeters, it will look as if it is not making any sound at all. The sounds will be in the soundstage around and above it. It is quite uncanny.
 
When we talk about height in the stereo image, it is not exactly height info/sound that you get using height channels in a multi channel setup. It is the height of the soundstage in front of you. With the right speakers, acoustics and placement, you can get height that is taller than the location of the tweeters. The sound will be airy and differences in height of various images in the soundstage is clear.
Somehow I never get this, even with headphones. Whatever semblance of height I get is because of 2-way, 3-way speakers where instruments sound to be coming from top and lower frequency and vocals coming from the height of the midrange drivers. When I listen with headphones, it becomes worse.
 
When we talk about height in the stereo image, it is not exactly height info/sound that you get using height channels in a multi channel setup. It is the height of the soundstage in front of you. With the right speakers, acoustics and placement, you can get height that is taller than the location of the tweeters. The sound will be airy and differences in height of various images in the soundstage is clear.
True. This is very much palpable even in my modest setup.
I also get a (faint ) perception of depth on some extremely well recorded music , say Time Out by Brubeck , or Chesky’s Audiophile Demonstration CD.
 
A good way to know if height works is to listen to a stereo recording of a helicopter landing. Will we able to hear the helicoptor up in the sky and when it lands, hear it in front of us. I wonder if there is such recording?

This is totally different than a car approaching or receding. That type of sound I can easily make out and is same as the depth of the soundstage.

My understanding is like this. Speakers cone can move only backward and forward. Sound travels because of air pressure changes and that change is happening only forward and backward (if we discount reflections from the floor and the ceiling). So how can we judge the height if there is no air pressure changes happening in the vertical plane?
 
So here they are:
“Hard facts:

16/44 Is sufficient.

There is no spatial 3d information in the signal. It is stereo, a left to right difference in loudness and running time. It‘s all in the signal. Two times mono. Height, depth etc. is a conceit. That is what stereo was invented for. It‘s not your fault or weakness. For height a second pair of speakers is necessary. With different signals, recorded from different microphone (higher) positions.
Yeh kuch hajam nahi huvi.
(Can't digest these)
 
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Are you able to experience this with headphones? Forget about height, but do you get the feeling of layered depth with headphones?
Yes, nicely with some recordings, and specially with open back HPs.
With closed back HPs the layering is apparent but within the confines of the head.
 
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Yeh kuch hajam nahi huvi.
(Can't digest these)
It’s definitely a provocative list with some “facts/opinions” that challenge our long held beliefs.
Uneasiness, discontent, indigestion, or waiting for a epiphany…all part of the journey and discovery?

Do explain why (if you wish to, of course) I am sure it will enrich the discussion.
 
Yes, nicely with some recordings, and specially with open back HPs.
With closed back HPs the layering is apparent but within the confines of the head.
Try repositioning the speakers. It took me lot of experimentation with positioning to get depth. It was only when I pulled the speaker quite a lot further into the room did I get depth. I think it is reflections. Also I have an odd L shaped room.

It’s definitely a provocative list with some “facts/opinions” that challenge our long held beliefs.
Totally agree, especially with the thing about height. When you don't have top to bottom information recorded (like the left to right recording), how is height possible? I'm looking for answers. My long held belief is that without height channels, this is impossible or illusion at best. See this discussion on reditt, where others too are saying that you require minimum of 4 speakers to get height. Height has lot to do with psychoacoustic. See the video after the reddit comments.



Shooting Down a Lost Drone and why Dogs Tilt their Heads - Smarter Every Day 173​

 
Chasing the chimera… You are right; my research and interest indicates the topics and areas I am fascinated about.
Hope we are all talking about the same thing :)
I do get a nice wide sound stage with clear separation. The decay of some notes is fabulous. There is nice heft and substance to the sound overall.
I just don’t get any perception of height
I also don’t get a clear sense of individual musicians positions front to back.
Hopefully I will figure it out.

I think you are absolutely right. In fact ever since the Croft arrived, I have been moving the speakers a lot. Sometimes three or four times a day trying to understand what each position does to the sound and my room acoustics.
I currently have them pulled out about 5’ away from the wall in front of me, 2.5 metres apart and @2.5 metres from my ears at the listening spot. (Even got a laser measure for this :))
In essence I am trying near field to eliminate room effects as far as possible.
Astonishing to notice the change that even a 2-3” move sideways creates.
The layered depth I am seeking is still elusive in my room.
If the room permits and family is understanding, you could try positioning your speakers one-fifth into the room from front wall (the wall behind the speakers) and side walls. Use measuring tape. Start listening with the speakers firing straight into the room. Gradually toe in the speakers towards the listening position. At one particular angle you'll find that the stereo phantom centre particularly good/locked with the tonal balance between the bass, mids and highs is well balanced. You should be able to get decent, if not good, layering with some sounds playing well behind the front plane of the speakers. The ability to present layers is also a function of how three chain resolves tiny nuances in the music. Details buried deeper in the mix will sound as if it's further back because it's less louder. The above exercise will also bring into focus the image. Specific instruments and voices will have their specific placements in the semi circular sound stage that envelopes the speakers.

An old pillow or cushion placed at the first reflection point on the sidewalls should sharpen the imaging further.

Happy fiddling:)
 
More about the height thingy that people see to hear in stereo recordings. This thing known as HRTF varies from person to person.

Head-related transfer function.​

HRTF is a response that characterizes how an ear receives a sound from a point in space. As sound strikes the listener, the size and shape of the head, ears, ear canal, density of the head, size and shape of nasal and oral cavities, all transform the sound and affect how it is perceived, boosting some frequencies and attenuating others. Generally speaking, the HRTF boosts frequencies from 2–5 kHz with a primary resonance of +17 dB at 2,700 Hz. But the response curve is more complex than a single bump, affects a broad frequency spectrum, and varies significantly from person to person.

Below is an interesting post on the height thing that some people hear and some don't
[1] As time as gone on I've got better equipment and found some good recordings that seem to have more 'hidden' clues with regards to positions.
[2] Would it be correct to say that people who 'perceive' height with IEMs are over interpreting?
1. That's a very common circular logic fallacy amongst audiophiles. As others have pointed out, due to individual headphone colouration, individual HRTF and individual perception, the human brain can sometimes mis-interpret the relationship between frequency, phase and levels of the sounds/instruments which are actually in a particular mix and create an illusion of height information. The circular logic comes into play because if a group of audiophiles decide that they like this unintentional height illusion then: Any equipment which seems to enhance this perception is better than equipment which doesn't, any mixes which seem to exhibit this phenomena are better than those which don't and therefore, anyone who doesn't perceive this illusion either has poor equipment, poor hearing or both. The reason this is all a fallacy is because there is no height information in stereo, the equipment isn't "good" because it's revealing "hidden clues" because there are no hidden clues to reveal, just a fluke of the interaction of the elements in a mix with the headphones, HRTF and perception of each individual. We could just as easily say/decide that as there is no height info in a stereo mix, any equipment which creates an illusion of height is poor/bad rather than good, anyone who perceives it has flawed perception or any mix which exhibits it has a fault/problem.

2. I don't think we can generalise in this way. Many people do experience the perception of "height" in some mixes with some headphones/IEMs, I certainly have. Some are probably experiencing it purely because of some cognitive bias; numerous testimonials and reviews by those who have experienced it (or believe they have) and the assumption that more expensive equipment must be better/more "revealing" are just two of many common biases which can lead to an "over interpreting" or even, the belief that "night and day" differences exist where in fact there are none.

You can follow this discussion here https://www.head-fi.org/threads/how-do-we-hear-height-in-a-recording-with-earphones.840736/
 
@Analogous : One track you can play to easily check depth perception- BB King’s The Thrill is Gone from Apple Music. King’s guitar should come from the phantom centre slightly shifted right , but from behind the speaker plane.
 
IMO it is impossible to get the height with stereo and where recording has been done with just 2 microphones. Whatever semblance of height anyone gets is probably some hallucination.
Almost any stereo recording carries height info. This is the reason why speakers are mounted at exactly the same height and spirit levels are used to check for front-back level and left-right level of the speakers. Many footers and stands have individually adjustable footers for this very purpose. Properly adjusting the heights and levelness of both speakers results in additional "lock" of the stereo image. This adjustment is cheap (buy a spirit level costing a couple of hundred rupees) and does not take much time and is easy to perform. No hallucination involved.
 
@jls001
Not sure if height info is implicitly encoded in stereo. It may be a mixing artifact, when the engineer plays around with levels.
As for the illusion of depth and height the speakers+room and the harmonic profile of pre/pwr/IA matters.
I call it illusion cause, change in position or change in one or more components makes a difference in presentation.
In my home, depth is very easily perceivable, height is a bit elusive. Maybe because I move the speakers to listening position every time.

@Analogous
To add to what @Bloom@83 suggested for test tracks, here are a few more

Hit The Road Jack (Ray Charles)
- the chorus girls will be slightly behind right speaker
- Ray's voice and piano will be between left speaker and center, but a bit more recessed as compared to the chorus
- this is also a good track to ensure L/R are not flipped during cable experiments

Aigiri Nandini (Rajalakshmee Sanjay)
- the lead vocals are dead center and just behind speaker plane
- mrudangam goes from right to center
- tambura is slightly behind the singer (a typical Carnatic music arrangement)

Sossity (Jethro Tull)
- try to listen to a Steven Wilson remaster if possible
- there are two instance when Ian Anderson plays the tambourine
- in the first it seems like its at singer's thigh to tummy height
- in the second it seems like its above the singer's head
- in fact I experienced this in another FM's rig with towers; have been searching for it in my rig (maybe I need to smoke up :D)

Cheers,
Raghu
 
Yes, @raghupb , the height info is not explicitly hard coded in the stereo mix (afterall we have only left and right channel), but one can hear better phantom centre when both speakers are height and level matched. Most of us tend to concentrate on distance of speakers from listener and toe-in angle. I'm suggesting from experiences in setting up speakers that we should additionally level and height match the speakers for a more refined sound.
 
@jls001
Not sure if height info is implicitly encoded in stereo. It may be a mixing artifact, when the engineer plays around with levels.
As for the illusion of depth and height the speakers+room and the harmonic profile of pre/pwr/IA matters.
I call it illusion cause, change in position or change in one or more components makes a difference in presentation.
In my home, depth is very easily perceivable, height is a bit elusive. Maybe because I move the speakers to listening position every time.
Yes. And just like you can't record stereo with just one microphone, you can't have height without 4 microphones as a minimum. Even if there is any height information encoded artificially in stereo recording, it cannot be rendered with 2 speakers. You require minimum of 4 speakers with the MLP suspended mid air between the top and the bottom speaker.

Whatever illusion of height one gets is because of reflections and the distance between the tweeter and the lower frequency drivers in a speaker box. The height illusion is illusion at best, not real and totally depends on the speaker construction. One of the pair of floorstander I have is the Cadence Arista speaker with siltech electrostatic panel and Thiel low frequency driver below the electrostatic panel. But the low frequency driver is tilted upwards (almost by 15 degrees). This causes some of the sound appear to be coming from the floor. Also with this speaker, while listening to Ken Mo, it appeared Ken Mo to be singing sitting on some raised stage high above the ground.

IMG_20220202_112150235.jpeg
 
It’s definitely a provocative list with some “facts/opinions” that challenge our long held beliefs.
Uneasiness, discontent, indigestion, or waiting for a epiphany…all part of the journey and discovery?

Do explain why (if you wish to, of course) I am sure it will enrich the discussion.
I'll replace the word "beliefs" with the word "experiences". Belief need not have basis but experience does.
16/44 Is sufficient
Call me old school; I doggedly held on to my CDP and my CD collection. Having done many experimentations with sources like CDP, Laptop etc. using connectivity options like RCA, Coaxial, Optical & USB, many times, in the presence of FMs like @linuxguru @srinisundar @murali_n @mohamednaseer @Rajiv & @Thad E Ginathom while at Chennai and came to a conclusion that CDP with RCA & Coaxial sounded the best, in the given setup. I along with FM @gvenu once visited Shiva of Acoustic Portrait fame and auditioned the same tracks on his reference set-up; from redbook CDs on his CDP & high resolution files from a laptop, both routed through his DAC to their flagship amps & speakers. The differences were not night and day though perceptible. Streaming was unheard of those days, at least I didn't.

Fast forward to August 2021, I was transferred to Mumbai and brought my DIY Bookshelfs and Bluesound Power Node that I acquired from @Yelamanchili manohar which was later replaced by Paradigm Powerlink & Nuprime STA9. Streaming and digital have come of age I must say. I listen to Tidal which I find leagues ahead than Spotify. The same tracks on my Marantz sound ordinary in comparison.
There is no spatial 3d information in the signal.
In my personal experience, I have listened to countless CDs/ Vinyls where, the soundstage is huge withth width going well beyond the speaker boundaries with well perceptible depth and many CDs with very small height and soundstage, mimicking a concert hall. That's why I'm skeptical of these statements.
 
Yes, @raghupb , the height info is not explicitly hard coded in the stereo mix (afterall we have only left and right channel), but one can hear better phantom centre when both speakers are height and level matched. Most of us tend to concentrate on distance of speakers from listener and toe-in angle. I'm suggesting from experiences in setting up speakers that we should additionally level and height match the speakers for a more refined sound.
<snip>

Whatever illusion of height one gets is because of reflections and the distance between the tweeter and the lower frequency drivers in a speaker box. The height illusion is illusion at best, not real and totally depends on the speaker construction. One of the pair of floorstander I have is the Cadence Arista speaker with siltech electrostatic panel and Thiel low frequency driver below the electrostatic panel. But the low frequency driver is tilted upwards (almost by 15 degrees). This causes some of the sound appear to be coming from the floor. Also with this speaker, while listening to Ken Mo, it appeared Ken Mo to be singing sitting on some raised stage high above the ground.

<snip>

In fact the first thing I noticed when KEF R300 came home was the centering.
In my home, I don't have too many options for placement.
Position 1: Front baffle is about 20" from wall, 6 feet apart; I use this at low volume for easy listening (either KEF or MA)
Position 2: Front baffle is about 40" from wall, 7/8 feet apart; this is when I have the house to myself ;) (only on KEF)

Luckily I have no real side wall reflections to worry about, due to open floor plan of living room.
One less thing to worry about.

Maybe multi-way towers can produce the illusion of height better due to interplay of mid/tweeters?

Cheers,
Raghu
 
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