Hi-Fi News article on Hearing

[Phil Leigh]

Good article in Feb Hi-Fi News by Barry Willis and Dr. Doug Mahar on human hearing.
Their observations and conclusions on the "stereo illusion" and height/depth (or rather the lack of it!) in most playback situations is very interesting...although annoyingly they sort of "chicken-out" in the final conclusion by saying (my words):
"There really isn't any soundstage info except for left-right laterality, but its vital to retain maximum detail so your brain can do its best shot at fooling you that there is".

Actually on reflection I suppose that is a reasonable argument.

[zanash]

An interesting aside ....

to generate a perception of depth and height ..get the chesky test disc

http://www.chesky.com/core/details.cfm?productcode=JD037&productcategoryid=1

track 11

this simulates both up and down and depth....via a chirping sound
this has cause consternation to at least three people who claimed that stereo does not do height!


the music on the disc is pretty good too.

[Phil Leigh]

An interesting aside ....

to generate a perception of depth and height ..get the chesky test disc

http://www.chesky.com/core/details.cfm?productcode=JD037&productcategoryid=1

track 11

this simulates both up and down and depth....via a chirping sound
this has cause consternation to at least three people who claimed that stereo does not do height!


the music on the disc is pretty good too.
OK thanks...I'll check it out. IS there any info on HOW they do this?

[sleepysurf]

I use that particular track extensively, whenever "tweaking" my speaker placement. It sounds like it's a handheld air "puffer" being recorded. They run it three times- left and right channel "up", left to right "arc" (and back), and left to right "lateral" (and back). I never heard it properly until I got my ML Summits, and optimized their positioning. Once you achieve that level of soundstage detail, there's no going back! IMHO, this single test track separates the "audiophiles" from the wannabes! The disc also has a number of other superb test tracks, including speaker phase.

[zanash]

It doesn't real say on liner notes ....just calls it LEDR Listening Environment Diagnostic Recording

I found this
http://www.stereophile.com/features/772/

using the up test I get a slight flat top but a smooth curve up and down o both sides using my ML Aerius i's

[Phil Leigh]

Thanks - interesting article. Seems the LEDR uses psycho-acoustic "trickery" (aka convolving reverb) to fool the brain.
This wouldn't work for anything much more complex than a single sound source being "moved" in this fashion. I'll pick up the Chesky disk and give it a spin...

[GuyDebord]

Do any of you know if there is a downloadable version available?

thanks

[Timothy Stockman]

The track "Rain" from the Suzanne Ciani disc "Hotel Luna" has some fairly interesting stereo effects with the synth-generated "raindrops". I think the key to hearing it the way it was intended is to have good phase linearity in your speakers. I don't think one would "chicken out" about the fact that there can be more than left-right to the stereo effect after hearing this track.

[Phil Leigh]

Please don't misunderstand me - I know how to simulate "depth" through phase/eq manipulation in the studio...but it is just a simulation or psycho-acoustic trick, it's not real. Seems the LEDR track also manages to do this with "height" which is clever.

It's when people talk about "realistic soundstage", "depth" and "height" in the same sentence that I get agitated. :o)

[sleepysurf]

...using the up test I get a slight flat top but a smooth curve up and down o both sides using my ML Aerius i's

Ha! I had Aerius i's, before moving up to the Summits! As for "LEDR" height, try adusting the speaker tilt. Here's an old post (from the ML Owners Club) showing what I did... http://www.martinloganowners.com/~tdacquis/forum/showpost.php?p=8175&postcount=4

Check out the other superb discussions on that ML forum!

The Chesky LEDR sounds man-made, as opposed to the Prosonus version discussed in S'phile. Either way, it's a great test.

[Phil Leigh]

The Prosonus uses a "spatial reverberator" to create the effect. In 1989 this took a mainframe - can now be done by pretty much any modern DSP chip. It's completely manmade!
What it is doing is to mimic the way our ears work to locate sounds in 3-d and then basically invert the process, causing our brain to believe the sound is moving - when in fact it isn't.

[sleepysurf]

Here's a link to that Chesky CD. Unfortunately, they don't have an mp3 or FLAC downloadable version, but the CD is still available.

http://www.chesky.com/core/details.cfm?productcode=JD037&category=1

One caveat though, folks ordering from Chesky direct have reported lots of problems with tardy order fulfillment. I suggest using a more reliable source.

[alekz]

I suggest using a more reliable source.
... eMule ;-)

[Timothy Stockman]

Please don't misunderstand me - I know how to simulate "depth" through phase/eq manipulation in the studio...but it is just a simulation or psycho-acoustic trick, it's not real.
If fact, stereo itself is an auditory illusion, whether it's recorded by microphones or created in a DSP chip. The reality of reproduction is that there are two discrete speakers. The "soundstage" is an illusion created in the brain, which is fooled into hearing "phantom" sounds from directions other than the speaker locations. This is akin to color television, which fools the brain by giving the impression one is seeing a whole spectrum of colors, when in fact the TV screen only has three discrete phosphors: red, green and blue.

BTW, Suzanne Ciani used a midi-controlled spatial DSP system made by Roland for her recording. It was done in 1991, so I'm sure it is primative by today's standard, but it is did produce quite convincing phantom sounds, not just between the speakers but above, below and well past the sides of the stereo speaker array.

[Phil Leigh]

Timothy - I've written about the stereo illusion in the past - and been flamed for it!
Where can one find the Ciani recordings?

[vdorta]

Soundstage height? It doesn't exist! I know everything sounds the same! I refuse to look through that demonic telescope!

[alekz]

Soundstage height? It doesn't exist! I know everything sounds the same! I refuse to look through that demonic telescope!

Ha-ha... Try that disc before making such statements. It DOES work.

BTW, you have two ears "placed" horizontally. In the real life, how do you know if the sound comes from above or from beneath?

[vdorta]

Ha-ha... Try that disc before making such statements. It DOES work.

LEDR? What LEDR?

I have owned and used the LEDR (Chesky Records Jazz Sampler and Audiophile Test CD, Vol 1) for several years.

[Phil Leigh]

Ha-ha... Try that disc before making such statements. It DOES work.

BTW, you have two ears "placed" horizontally. In the real life, how do you know if the sound comes from above or from beneath?

Because that is actually where the sound comes from in real life! - Cannot be achieved by speakers in a fixed position for fairly obvious reasons...

[alekz]

Because that is actually where the sound comes from in real life! - Cannot be achieved by speakers in a fixed position for fairly obvious reasons...

Have you heard the sample from the above mentioned disk?

[alekz]

LEDR? What LEDR?

I have owned and used the LEDR (Chesky Records Jazz Sampler and Audiophile Test CD, Vol 1) for several years.

Yes, LEDR. In my system it works precisely like explained in the notes. The source of the sound rises up (left speaker, then right), then makes an arch.

[Timothy Stockman]

Suzanne Ciani's disc "Hotel Luna" may be ordered from her web site: http://www.sevwave.com/isell3/results.php?action=showproducts&category=Limited%20Compact%20Disc

Also available at the usual sites like Amazon:
http://www.amazon.com/Hotel-Luna-Suzanne-Ciani/dp/B0000000KK/ref=m_art_pr_6

Track 3, "Rain" is the one where she uses the Roland spatial DSP system. Suzanne Ciani is affectionately known as "The Diva of the Diode" in recognition of her long history of electronic music, but Hotel Luna is an satisfying mix of synthesized and acoustic instruments. The title track mixes an acoustic guitar and string quartet with her synth. I've been a big fan of hers since her "first" album, "Seven Waves" and have many of her synth and piano albums in my collection.

[alekz]

Will they ever begin to sell FLAC's online....

[SoftwireEngineer]

Yes, LEDR. In my system it works precisely like explained in the notes. The source of the sound rises up (left speaker, then right), then makes an arch.


Yes, LEDR. In my system it works precisely like explained in the notes. The source of the sound rises up (left speaker, then right), then makes an arch.

Are you guys referring to the track that sounds like an African drum roll, that goes around you ? I think this works only when you have a wall behind the listening position.
I think depth/space is 'construed' based on the sum of direct and reflected sounds. It is a very common practice in studio recordings to add reverb and put individual instruments to the left or right (panning) or behind. This is the reason they prefer to start with close-miced recordings (dry) and then use plugins to create the reverb effect. This 'space' though artificial is 'real' and if you have a hi-fi system should be able to enjoy this effect.

[zanash]

LEDR? What LEDR?

I have owned and used the LEDR (Chesky Records Jazz Sampler and Audiophile Test CD, Vol 1) for several years.

then if your not experienceing the illusion I'd suggest that there is something a miss ....this can be any number of things ranging from hearing problems to equipment issue through room interactions, only you will know which.

I bought the disc when it was first released and have used it to set systems up, possibly a hundred plus of all levels of performance ...I have never not heard the effect

even the cheapest systems have been able to make a stab at reproducing the illusion. I'm sorry your unable to hear this effect ....but that does not mean it does not exist it just means you [for whatever reason] are unable to appreciate the full effects of this excellent disc.

[alekz]

Nicely put zanash. Oh, you gave me a good idea. I'll try that track on my kids' computer speakers!

[zanash]

Yes I've tried it on mine ....its relatively feeble but they are only 2' apart and very small.

[vdorta]

alekz and zanash, thanks for the efforts, but I was just trying to be funny. Of course LEDR works as advertised.

[alekz]

alekz and zanash, thanks for the efforts, but I was just trying to be funny. Of course LEDR works as advertised.
Phhhoooeeey... what a relief ... other threads in this forum made your tongue in the cheek less visible without a smile drawn on it with a permanent marker... ;-D

[Phil Leigh]

Suzanne Ciani's disc "Hotel Luna" may be ordered from her web site: http://www.sevwave.com/isell3/results.php?action=showproducts&category=Limited%20Compact%20Disc

Also available at the usual sites like Amazon:
http://www.amazon.com/Hotel-Luna-Suzanne-Ciani/dp/B0000000KK/ref=m_art_pr_6

Track 3, "Rain" is the one where she uses the Roland spatial DSP system. Suzanne Ciani is affectionately known as "The Diva of the Diode" in recognition of her long history of electronic music, but Hotel Luna is an satisfying mix of synthesized and acoustic instruments. The title track mixes an acoustic guitar and string quartet with her synth. I've been a big fan of hers since her "first" album, "Seven Waves" and have many of her synth and piano albums in my collection.


Thanks that is useful info - I will track down the disk.

[Phil Leigh]

Have you heard the sample from the above mentioned disk?

Not yet - the disk is on order. However, perhaps I should clarify my earlier post...OK here goes:

A speaker - like a microphone - is ultimately a very simple device in its purest form. It is a diaphragm that moves back and forth in a more or less linear fashion. There are only two key relevant variables - how quickly it moves back/forth (frequency) and how far it moves (amplitude). It has no concept of directionality - it cannot steer a sound left/right or up/down - it merely projects sound forward (usually) from its diaphragm in a broadly conical pattern.

(Note this doesn't not apply to special cases such as the Soundfield Mics or that clever Yamaha directional speaker array in a box)

If one were to place a 2-d array of microphones or SPL transducers in front of a pair of speakers playing the LEDR track, they will record what is actually happening...in other words, as the sound "appears" to us to transit in an arc, in fact it is merely panning left-right, since that is all you can actually do! The mics will not be fooled.

The mics will not record a movement in height, because there is none. Our brains are inferring the height element from the psycho-acoustic info embedded in the sound.



The reason I want this track is to test what happens if you compress it. Theory suggests that at a certain bitrate, the effect will collapse due to lack of information. Also this could be used as a suitable (albeit non-musical) test track for system end-to-end integrity since the better/more easily a system can reproduce this trick, the better its information preservation capabilities (stress: IN THEORY).


Just to restate my position - ignoring the trickery of things like LEDR, it is not possible to accurately reproduce "depth" or "height" (even if it were actually recordable in the first place!) from speakers that are very few in number and fixed in position relative to our ears.


What we are hearing is what we want or expect to hear/were genetically engineered to hear.

[alekz]

Not yet - the disk is on order.
Good! Let's wait a bit, then :-)

[Phil Leigh]

Good! Let's wait a bit, then :-)

I think you misunderstand me! ... I've spent 25+ years messing around in studios with this sort of stuff. I have no doubt I'll hear the "effect" :o)

[alekz]

I think you misunderstand me! ... I've spent 25+ years messing around in studios with this sort of stuff. I have no doubt I'll hear the "effect" :o)
Oh, sorry! I thought by saying:



Cannot be achieved by speakers in a fixed position for fairly obvious reasons...


you meant that it's not possible to hear that effect. My apologies! I should have read with more attention. This phrase explains it:



Our brains are inferring the height element from the psycho-acoustic info embedded in the sound."

[Phil Leigh]

Oh, sorry! I thought by saying:



you meant that it's not possible to hear that effect. My apologies! I should have read with more attention. This phrase explains it:

You got it! - I realised I wasn't clear, hence the lengthy post!