Audiophile Fundamentalism

morricab

Well-Known Member
Apr 25, 2014
6,938
2,947
603
Switzerland
Although Geddes work on loudspeakers includes subjective listening tests and was published and refereed, his work on on amplifier distortion is just a proposal - he carefully and honestly writes "To be useful we must show this metric provides a better correlation to actual subjective evaluations than current metrics." (quote from his site) The tests carried in his paper on audibility of non linear distortions were carried with headphones. His work focused on finding a metrics that correlated with subjective sound considering that THD and IMD have no correlation to the perception of the distortion that they are intended to represent, but was just preliminary and IMHO can't support any firm practical conclusion on relative subjective evaluations .

Cheever work is a Master Thesis, nothing else, we addressed it before in WBF. Anyone reading if fully can see it was supposed to be a starting point, proving he has the competence and capacity to go on more in depth studies. It is outdated, and as we can expect most of the time from a master thesis, superficial in fundamental aspects - no one has time to carry significant work in such a reduced period.

IMHO not enough to support any fundamentalism, unless you carry some listening tests in scientific conditions to pursuit and validate their work - no one except you seems currently interested in their work.
I would not say it is fundamentalist...it is scientific and it builds and agrees with the important earlier work from the likes of D.E.L. Shorter and Norman Crowhurst as well as some white papers by Nelson Pass... Science is a methodology for understanding things we don’t...this is not fundamentalism...
 

morricab

Well-Known Member
Apr 25, 2014
6,938
2,947
603
Switzerland
Although Geddes work on loudspeakers includes subjective listening tests and was published and refereed, his work on on amplifier distortion is just a proposal - he carefully and honestly writes "To be useful we must show this metric provides a better correlation to actual subjective evaluations than current metrics." (quote from his site) The tests carried in his paper on audibility of non linear distortions were carried with headphones. His work focused on finding a metrics that correlated with subjective sound considering that THD and IMD have no correlation to the perception of the distortion that they are intended to represent, but was just preliminary and IMHO can't support any firm practical conclusion on relative subjective evaluations .

Cheever work is a Master Thesis, nothing else, we addressed it before in WBF. Anyone reading if fully can see it was supposed to be a starting point, proving he has the competence and capacity to go on more in depth studies. It is outdated, and as we can expect most of the time from a master thesis, superficial in fundamental aspects - no one has time to carry significant work in such a reduced period.

IMHO not enough to support any fundamentalism, unless you carry some listening tests in scientific conditions to pursuit and validate their work - no one except you seems currently interested in their work.
Have you done a master’s thesis? I have both written one (and a Ph.D thesis) and been the mentor of one (as well as mentored a Ph.D). The content can be mostly theoretical but it can be mostly experimental as well. Cheever’s thesis is more theoretical but out of date ? Please highlight the areas that have been superseded by newer knowledge that invalidates his arguments. There was some limited testing as well but I agree it’s not enough to be conclusive regarding his metric.

Geddes has a quite controlled set of experiments and it is regarding the perception of non-linear distortion...a valuable topic for sounds of electronics (Geddes has concluded in a couple papers that non-linear distortion in speakers is largely a non-issue). So what it is with headphones? That eliminates a lot of other variables. Some of the worst performers in his subjective tests were the best measuring because of the nature of the distortion. Keith Howard did something simpler but came up with interesting conclusions about distortion patterns.
 

microstrip

VIP/Donor
May 30, 2010
19,223
3,409
850
Portugal
Have you done a master’s thesis? I have both written one (and a Ph.D thesis) and been the mentor of one (as well as mentored a Ph.D). The content can be mostly theoretical but it can be mostly experimental as well. Cheever’s thesis is more theoretical but out of date ? Please highlight the areas that have been superseded by newer knowledge that invalidates his arguments. There was some limited testing as well but I agree it’s not enough to be conclusive regarding his metric.

Geddes has a quite controlled set of experiments and it is regarding the perception of non-linear distortion...a valuable topic for sounds of electronics (Geddes has concluded in a couple papers that non-linear distortion in speakers is largely a non-issue). So what it is with headphones? That eliminates a lot of other variables. Some of the worst performers in his subjective tests were the best measuring because of the nature of the distortion. Keith Howard did something simpler but came up with interesting conclusions about distortion patterns.

As long as your references on the subject are Cheever, Geddes and Howard, nothing to add to my previous comments - people can easily research these authors, they have a very reduced work on amplifier distortions.

All we could get from these works is that THD and IM are poor indicators of sound quality and we need a proper metric - nothing new. But no way good THD and IM figures are indicators are poor sound quality.
 

morricab

Well-Known Member
Apr 25, 2014
6,938
2,947
603
Switzerland
As long as your references on the subject are Cheever, Geddes and Howard, nothing to add to my previous comments - people can easily research these authors, they have a very reduced work on amplifier distortions.

All we could get from these works is that THD and IM are poor indicators of sound quality and we need a proper metric - nothing new. But no way good THD and IM figures are indicators are poor sound quality.
You clearly don’t get the point of wha they indicate.
 

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. This is THE place where audiophiles and audio companies discuss vintage, contemporary and new audio products, music servers, music streamers, computer audio, digital-to-analog converters, turntables, phono stages, cartridges, reel-to-reel tape machines, speakers, headphones and tube and solid-state amplification. Founded in 2010 What’s Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals, we enjoy learning about new things and meeting new people, and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing