Auditory Scene Analysis

[Bill Bainbridge]

Frank, I completely understand your point of view and respect it. I've had quite a few dear friends over the years who have (with their limited financial means) developed playback systems by careful component selection and electronic modification that were pleasant, sometimes astonishing to listen to. Would you consider your system to be more analytical or euphonic, if you'll permit my use of those over-used terms?

 

[fas42]

Analytical, if I was forced to choose - meaning, you're getting everything on the recording. I prefer to use the term "convincing", because the result of hearing all of the recording, with minimal addition on the playback side of audible artifacts, is a very convincing illusion. One of the qualities of this type of presentation is that the speakers become completely impossible to locate as a source of the sound - the brain has accepted the projected 'scene' of the recording as the reality of the auditory experience.

 

[Bill Bainbridge]

I guess by that you mean Analytical, tweaked by you until the "trigger point" you imply in other posts is reached at which point it becomes "convincing". This delicate balance possibly is between the two poles of- "harshness" that some feel with intensely articulate system tuning, and "serenity" that lead some Euphonic systems to be less than engaging.

That you find that "trigger point" to be so dramatic in its results, yet subtle in its arrival may indeed mean that your MMN thresholds have been sensitized, and brings to mind some implications regarding ASA research in general.
It kind of begs the question: How has MMN been modified for subjects who have suffered chronic disorders as a result of PTSD? I knew a Vietnam Vet back in the 80's that confessed to me that all music forms were uncomfortably "noisy" and "jarring" to him after coming home. "Shellshock" may have irreparable effects on the perception thresholds, as if (for him at least) highly organized sounds were then rapidly vacillating MMN to the point of perceived physical discomfort.

You asked me in another thread to try to provide sources for my conclusions regarding the inter-dependency of perceptual variables such as JND of loudness, vs. timbral factors. I'm not finding those references immediately (in my download library), which means they might have been based on an excellent book I read by John Pierce - "The Science of Musical Sound". In it he revealed to me an answer to a "roughness" perception (that I had discovered on my own when I was an electronics tech in the late 80's) that can occur when a steady-state signal is subjected to Amplitude Modulation. When the AM is too fast (a higher frequency of modulation) the sound is perceived as being "rougher" even when the modulation is of a perfectly sinusoidal shape.
In other words, the signal and modulator may be perfectly harmonic free (both sine waves) yet, the "earbrain" perceives the result as distorted. This may demonstrate the dynamic attributes of perception, and in particular the importance of envelopes, on perceived audio defects.

The following is a repeat post of mine from a couple of other threads-
Just a quick post to point out an online primer on psychoacoustics with relevant data regarding JND of loudness being approximately 1 dB, under conditions of mid-range frequency, mid-level SPL, and "normal" noise shape:
http://acousticslab.org/psychoacoustics/PMFiles/Module04.htm
Relevant to this thread- If JND for Loudness is measured at 1 dB for these "normal" conditions, wouldn't it be prudent to calibrate our systems (whenever possible) to 0.1 dB? After all, for critical conditions in other areas of engineering a 10:1 design factor ("safety factor") is not uncommon.

See the text approx. "Effects of Duration on Loudness" and onward. Time-based effects (envelope) may have an effect on perception of Loudness (and by implication) many other perception metrics: Pitch, overall Frequency Response/ Timbre, and possibly others. This shouldn't actually be too surprising, given that the initial stimuli to these responses have two primary variables: Energy and Time.

At risk of redundancy, I'll C.C. this post to the ASA thread as well, as it relates to perception in general.

 

[fas42]

Yes, I work towards the "trigger point" - a typical system will be harsh as improvements are made, because the remaining distortion anomalies will be more strongly presented, it will be easier to hear "what's wrong with the sound", still. Euphonic efforts are going about it in a poor fashion, IMO - the distortions are either masked, or so much detail is discarded that it's "throwing out the baby with the bathwater".

The trigger point first occurred when I was totally unprepared for it to happen - such behaviour from an audio system was completely new to me. That it wasn't just me was confirmed by my wife, who reacted to the difference in the sense of "I hate that particular recording you always put on!" changing to "Wow, I really like this music - who is it?" - and I said "Guess what? ... ". IOW, the presentation changes so dramatically, in the subjective sense, that it seems an entirely different experience in the listening. MMN sensitivity problems would come into it for some individuals, so that they never hear the subjective alteration - and I suspect it would be those for whom live, acoustic music is unpleasant for whatever reasons, as you say. My take would be that all those who have no trouble distinguishing recording playback from live music making would have a trigger point, which may vary from individual to individual.