Dr. AIX's POSTS — 24 December 2014


Continuation from yesterday…

He continues with a discussion about the midrange improvements that high-resolution audio was supposed to offer. He states, “it was not in any way dependent on extended dynamic range.” After more than 7 years, he’s telling us that the study was really designed to test the audibility of “musical material in the upper 40 dB of the signal space, when played at normal levels.” Why didn’t they put that in the abstract of their paper? Why didn’t they limit their research and subsequent paper to the audibility of midrange attributes in hi-res vs. standard res? They should have limited their research to things like true timbres, consistent spatial imaging, and reverb integrity rather than conclude that there is no audible difference between high-resolution and standard resolution audio.

I guess I’m one of the “scornful people” that is arguing that high-resolution audio presents differences because of the increase in dynamic range and the potential for ultrasonic frequencies. I think CDs do a great job with timbre, imaging, and reverberation…and the midrange sounds just fine.

He’s right that real high-resolution recordings are rare. “In other words, there are very few discs on which one would expect any audible difference at all; none where the difference is easy to hear; and none where it is audible at normal playback levels. You have accepted the science behind all this! Welcome to reality. It appears our paper has had more influence than we could have dared to hope.”

They should have included some of these rare, real high-resolution discs but were satisfied with the likes of “Goodbye Yellow Brick Road” as a real high-resolution album. They tested standard resolution audio discs that didn’t contain the attributes that they were looking to find. The research was flawed and should be ignored.

Mr. Moran is satisfied that humans are unaffected by sounds above 20 kHz. “Everyone who argues that these are important has taken the research and its conclusions about human perception that were well established forty years ago, and thrown them out the window.” I don’t believe a proper study has been done that unambiguously establishes this one way or the other (the new Stuart/Craven study looks promising). But given that 96 kHz/24-bit has engineering benefits, doesn’t cost anymore to implement, and provides a more accurate reproduction of the original music event, I’m going to err on the side of including ultrasonics. Why wouldn’t everyone?

The most interesting part of the Moran statement is the final paragraph. After having dismissed the importance of increased dynamic range in a previous paragraph, he points out that “there is one disc whose dynamic range exceeds the CD’s limit: The Hartke recording on Hilliard. When I discovered the properties of this disc, I turned the system way up and conducted a test using only the initial fade-in of the room sound. The difference was easily (and of course provably) audible. This is all in the paper, so, as has so often happened, those arguing that we didn’t use such a recording /have not read what we wrote.”

Does this mean that they should have used dynamic range as a metric for hi-res audio? Perhaps so.


I’m still looking to raise the $3700 needed to fund a booth at the 2015 International CES. I’ve received some very generous contributions but still need to raise additional funds (I’ve received about $3400 so far). Please consider contributing any amount. I write these posts everyday in the hopes that readers will benefit from my network, knowledge and experience. I hope you consider them worth a few dollars. You can get additional information at my post of December 2, 2014. Thanks.

Forward this post to a friend and help us spread the word about HD-Audio Forward this post to a friend and help us spread the word about HD-Audio


About Author


Mark Waldrep, aka Dr. AIX, has been producing and engineering music for over 40 years. He learned electronics as a teenager from his HAM radio father while learning to play the guitar. Mark received the first doctorate in music composition from UCLA in 1986 for a "binaural" electronic music composition. Other advanced degrees include an MS in computer science, an MFA/MA in music, BM in music and a BA in art. As an engineer and producer, Mark has worked on projects for the Rolling Stones, 311, Tool, KISS, Blink 182, Blues Traveler, Britney Spears, the San Francisco Symphony, The Dover Quartet, Willie Nelson, Paul Williams, The Allman Brothers, Bad Company and many more. Dr. Waldrep has been an innovator when it comes to multimedia and music. He created the first enhanced CDs in the 90s, the first DVD-Videos released in the U.S., the first web-connected DVD, the first DVD-Audio title, the first music Blu-ray disc and the first 3D Music Album. Additionally, he launched the first High Definition Music Download site in 2007 called iTrax.com. A frequency speaker at audio events, author of numerous articles, Dr. Waldrep is currently writing a book on the production and reproduction of high-end music called, "High-End Audio: A Practical Guide to Production and Playback". The book should be completed in the fall of 2013.

(24) Readers Comments

Leave a Reply to Admin Cancel reply

Your email address will not be published. Required fields are marked *

10 − eight =