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AES Journal Forum: Comment by Scott Dorsey on "Natural Sounding Artificial Reverberation"

Title: Natural Sounding Artificial Reverberation
JAES Volume 10 Issue 3 pp. 219-223; July 1962
Comment by: Scott Dorsey

This was really the first paper ever written that solidly explained artificial reverb.  It's aimed mostly at reverberation for hall enhancement, but everything in it applies also to artificial reverberation for recording and audio processing as well.  It explains what is important and what is not and shows some typical flow charts of systems which later could be implemented digitally.  This paper describes what is needed, and then later papers describe how to implement that.  But this is really where it began, even though artificial echo and reverberation systems had existed before, because it makes the first attempt of setting a mark for a natural-sounding effect. 

Posted on June 27, 2023 at 3:43:23 PM EDT

AES Journal Forum: Comment by Scott Dorsey on "Considerations on Providing Audio Coverage in Television Production Studios"

Title: Considerations on Providing Audio Coverage in Television Production Studios
JAES Volume 26 Issue 11 pp. 863-866; November 1978
Comment by: Scott Dorsey

This paper is an introduction to the role of the audio engineer in television production in the 1970s.  Many different mixes are provided for different purposes, many of which today would be provided by intercom systems, and not very many sound people.  One operator mixing for the broadcast, one operator mixing for sound reinforcement, an A2 on stage and boom ops and that's it for sound staff.

And yes, the Magnificent Marble Machine that is given in the example stage layout is an actual television show and there are examples of it on youtube.  And there are no lavalier mikes anywhere.

This is well worth reading just to remember or to imagine a world in which television game shows would have an orchestra on set. 

Posted on May 22, 2023 at 6:00:37 PM EDT

AES Journal Forum: Comment by Milind N. Kunchur on "Cable Pathways Between Audio Components Can Affect Perceived Sound Quality"

Title: Cable Pathways Between Audio Components Can Affect Perceived Sound Quality
JAES Volume 69 Issue 6 pp. 398-409; June 2021
Comment by: Milind N. Kunchur

Hello all,
First, a closely related followup paper on time-domain and other
electrical characteristics of interconnect cables is now published can be downloaded from:—Kunchur.pdf
(Reference: IOSR Journal of Electronics and Communication Engineering, vol. 16, no. 6, pp. 40-53 [2021 December]. DOI: 10.9790/2834-1606014053)

Some points that emerge are:
* The new paper compared electrical-noise differences (which appeared to be the leading potential cause of sonic distinguishability in the previous JAES paper) between two unbalanced (single-ended) interconnects: M (which is the same as the previous cable B) and S (a single-ended version similar to previous cable A). A  large noise difference was found between M and S (both unbalanced), similar to the previous cables A and B. Thus the superior shielding of the more expensive cable brand appears to be the main reason for its better noise performance rather than balancing.

 * Uncommon time-domain effects such as reflection sequences and non-ideal capacitive behavior, along with noise, have more to do with the electrical performance of interconnects than commonly measured parameters such as resistance, reactance, and frequency response.

* The measurements and calculations show that it is impossible for an interconnect to act as a reactive frequency-equalization tone control (contrary to the comment "cables are ...  reactive in order to act as  a tone control"). Timbre (tonality) depends on much more than the power spectrum. This will be explained in more detail in another forthcoming article (I will post the reference once that paper is complete, probably by the end of 2022).

* There seems to be a misunderstanding about the big picture and significance of what was accomplished in this work, judging from comments such as " hardly news to anyone..." and "...the point of the paper...".

High-end audio represents a minefield of controversy and a tug-of-war between subjectivists and objectivists, partly because of different standards for what is considered to be "known" or "proven". Never mind cables and topology, there is a whole group of people out there who believe that only loudspeakers make a sonic difference. If the standard for scientific proof is an IRB approved blind test published in a peer-reviewed journal, they would be right! (If anyone has knowledge to the contrary, please provide the journal citation/s.) Listening tests are tricky and can easily produce both false negative and false positive results (see references [32–36] in the new paper). Many listeners who claimed that a certain difference was obvious, have failed when challenged to prove it through a blind test. All of this is discussed at length in the papers. So it was not already known (in the sense of being scientifically proven as discussed above) that such a small change in system configuration is audible.

The two papers — containing 26 pages, 18 figures, and 93 cited references — represent more than 4 years of work. A couple of friends comparing system configurations at home is not quite the same. Although that might be a practical way to tune and improve a personal system, the goal here was to bridge the divide between believers and skeptics by providing a more formal proof. The papers also go to great lengths to describe the equipment, room acoustics, and experimental protocols and analyses in enough detail to allow other interested researchers to replicate the experiments.

Someone viewed the work as an "...immense headache...painful...". Formal scientific research — and for that matter serious endeavors of other kinds — can indeed be difficult and grueling. But never painful, as it is done out of passion and dedication. Knowledge generation in research is, by its nature, a stochastic and fragmentary process. A neatly tied up final result cannot be ordered from a menu. Each work contributes pieces to the puzzle, which gradually coalesce to form a complete picture. For example, there were numerous publications on wide-bandgap semiconductors that culminated in the final research and development of LED lighting. If each of the prior works is viewed as a partially empty glass, we wouldn't have the current lighting revolution. The present JAES paper was vetted by 4 reviewers in addition to the editors.  It is clear in its statement of what was accomplished and what more needs to be done. Whenever  any reader extends this work and fills in some missing pieces, please do post that journal reference here. We all look forward to it. 



Posted on January 30, 2022 at 7:36:04 PM EST

AES Journal Forum: Comment by Scott Dorsey on "Providing Foldback with Out-of-Phase Loudspeakers"

Title: Providing Foldback with Out-of-Phase Loudspeakers
JAES Volume 19 Issue 4 pp. 306-309; April 1971
Comment by: Scott Dorsey

The author places two conventional sealed-box loudspeakers back-to-back and drives them with opposite polarity wiring to create a figure-8 pattern with a deep null in the plane on which they sit.  This allows two speakers to be placed directly behind a lectern so that PA monitor audio can be heard by listeners on stage without much leaking into the lectern microphone.

This technique is extremely effective and seldom used today.  Other later variants have come out of this such as putting two floor wedges on opposite polarities so that a lectern microphone can be very carefully placed at the null between them.

These techniques can give more than 20dB improvement in gain before feedback but are no longer taught today.  If you use them in convention jobs they can delight and amaze the house crew, just make sure that the microphone is fixed in place and cannot be moved out of the null.

Posted on August 16, 2021 at 3:38:29 PM EDT

AES Journal Forum: Comment by Eric Wenocur on "Cable Pathways Between Audio Components Can Affect Perceived Sound Quality"

Title: Cable Pathways Between Audio Components Can Affect Perceived Sound Quality
JAES Volume 69 Issue 6 pp. 398-409; June 2021
Comment by: Eric Wenocur

The relative merits of "high-end audio" products have been debated for decades because most of the claims made for outrageously overpriced cables and power cords are indefensible. At the same time, this paper's claim that interconnect differences are audible is hardly news to anyone who works with audio equipment!

So was the point of the paper to show that a cable costing $1000/m is, in fact, better than one costing $25/m? Or simply to find the smallest possible change in "sonic character" that a human can perceive? If the former, one must ask if the purported difference is even due to the cables, since many other factors in the testing setup could cause a subtle difference in perception. The fact of comparing balanced and unbalanced connections is only the most obvious. The circuits comprising those different interfaces would also be somewhat different. The electrical characteristics and condition of the connectors might factor in. Measured differences of hundredths of a millivolt (that's .00001V) could be attributable to all sorts of effects. Even the selection of source material could skew the listening results in both physiological and psychological ways.

If the latter, one could devise much simpler (and less contentious) ways of trying to assess what listeners can or cannot perceive. But even so, attempting to quantify extremely subtle differences in sonic character, which is entirely subjective, prone to human error, and can only be described with adjectives that are also subjective, seems highly fraught.

This paper shows a valiant effort to control every aspect of a test scenario, and must have been an immense headache to perform. I found it painful to contemplate. But in the end I don't see how meaningful results are possible. More importantly, the test cannot answer two critical questions: What is sonic character or "sound quality"? And is it worth spending a boatload of money on any part of a system that *might* result in a miniscule change (compared to what?) in that quality? Unfortunately the consumers taken in by certain types of "audiophile" products are naive to the point of self-deception. But the effects of marketing, ignorance and ego is a subject for a different paper.

Posted on July 7, 2021 at 3:36:57 PM EDT

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