Any replications of the AES study showing that SACD sound can't be distinguished from CD?

[garyrc]

Are there any replications of the AES study showing that the quality and definition of SACD sound can't be distinguished from CD in a statistically significant manner?

How about studies that look at whether the presence of music through surround channels changes (improves?) the clarity and detail of sound coming through the front speakers? Strange things can happen (or be imagined). Didn't Carver maintain that the sound of a crackling fire in a fireplace changed (improved) the sound of digital playback?

Couldn't the task of "listening through" the ambience of surround information in order to better hear the main channels be expected to change attention, as well as cortical arousal?

I know AES used some good speakers, including one electrostatic. It seems to me they should have also used at least one horn loaded model (the Jub?) and one ribbon.

[mike stehr]

What on earth is cortical arousal? Is that like a eargasm? []

[garyrc]

What on earth is cortical arousal? Is that like a eargasm?

Eargasm is probably associated with higher cortical arousal, or even, perhaps, the relief thereof. []

The "cortical" in cortical arousal refers to arousal in the cerebral cortex. I probably should have just said "increased activation in the brain," because fluctuations of brain arousal in response to music can occur in many brain sites. These fluctuations are part and parcel of experiencing any of the arts. To oversimplify: up to point, increased arousal improves some kinds of perception of complex stimuli, as well as pleasure. After the arousal climbs to an optimum point, further increases interfere with perception of external complex stimuli, and become noxious. It's the famous inverted "U" curve, with either perceptual accuracy, aesthetic
pleasure, or any one of a number of other response variables on the
ordinate, and arousal on the abscissa. We seek out certain art experiences, in part, to manipulate our arousal. We may select a given piece of music, and set the volume control on our preamps to produce the desired arousal level and peaks for the mood we are in ... the end of Beethoven's 7th, nice and loud, is the antidepressant that works best for me. I warned you I was going to oversimplify.

The Canadian psychologist, D.E. Berlyne summarized his pioneering work in the book Aesthetics and Pychobiology, mostly dealing with visual stimuli and arousal. Berlyne looked at many variables contained in art (e.g., complexity, novelty, loudness, brightness, size, etc.) that would produce fluctuations in brain arousal. He looked at arousal boost, jag, and my favorite, boost-jag. Before Berlyne, Robert Dreher found that people who were indifferent to music (there are some), had much smaller physiological responses to music (primarily GSR) than music lovers (those who played instruments, sang, or simply listened to music often). Later investigators got similar results using a variety of measurement devices, including EEG, etc. One researcher (name temporarily gone) could statistically significantly reverse observers' prefererence of one painting over another by manipulating the presence or absence of white noise.

[Quiet_Hollow]

...and my favorite, boost-jag.

Same stuff the Flaming Lips smoke?

[Boxx]

What on earth is cortical arousal? Is that like a eargasm?

Cortical arousal is the activation of the recticular section of the brain (middle brain, cerebelum, etc) and increases heart rate, breathing rate, vigilance, muscle tone, etc.

It basically supercharges you like adrenaline.

[mike stehr]

Learn something every day...I confused cortical with hearing I suppose...

Thanks for the clarification, Garyrc and boxx.

[garyrc]

What on earth is cortical arousal? Is that like a eargasm?

Cortical arousal is the activation of the recticular section of the brain (middle brain, cerebelum, etc) and increases heart rate, breathing rate, vigilance, muscle tone, etc.

It basically supercharges you like adrenaline.

It's my understanding that the brain-stem reticular formation is probably the most important structure in the arousal system, in which the hypothalamus,
thalamus, and cerebral cortex all take part. The reticular formation
probably electrically controls the level of alertness of the cerebral cortex, i.e. "cortical arousal."

"Higher arousal" can vary from a bit higher to fever pitch arousal, the supercharging Boxx metioned.

Although the various manifestations of arousal tend to vary together (e.g., all increase or decrease in intensity at the same time and in the same direction), in experiencing art, the mean levels of all tend to go up except heart rate which can either go up or down (de Jong). During the art experience, particularly with a clearly temporal art like music, there are wild fluctuations.

For our discussion, surround sound is more complex than two or three channel, and can be louder. Increasing complexity and increasing loudness both raise arousal. Higher arousal can increase sensitivity to external stimuli and increase ability to detect detail (unless it's "over the top" of the inverted U curve mentioned above). So ... would 5 or 5.1 channel SACDs using surround channels increase perceived detail -- even in music coming from the front speakers -- and therefore seem to be of higher resolution than 2 channel CDs?

[Chris A]

Are there any replications of the AES study showing that the quality and definition of SACD sound can't be distinguished from CD in a statistically significant manner?

I know that I cannot hear the difference between the SACD tracks and the CD-layer tracks on the same disk to any level of significance, if any at all. (Maybe this is a general statement of the poor state of recording and producing of CDs and SACDs to be far, far less in practice than what they should be.)

What I can hear is that the disks that have SACD layers sometimes are done much better than the typical CD with loads of compression -- but I have seen loudness-war SACD disks (and own one or two of them).

Couldn't the task of "listening through" the ambience of surround information in order to better hear the main channels be expected to change attention, as well as cortical arousal?

This is fairly esoteric from the standpoint of how you would do the tests: what kinds of music to use, what kinds of room and speakers (anechoic two-channel or surround sound?) and how to design the tests to be statistically significant. These questions are squarely in the ralm of psychology/physiology. As a result, I'm not sure how to respond to your questions other than by personal experiences, which probably aren't very reliable for this area.

Chris