Dr. AIX's POSTS — 17 December 2014


The study that I mentioned previously happened today. I packed up a bunch of donated equipment and headed to the other side of the San Diego Freeway to help set up and view a session or two of the study. The basic idea is to survey typical listeners of all ages, backgrounds, and musical interests about their knowledge of high-resolution audio. After a few basic questions about their own listening habits and musical preferences, they had the chance to audition portions of three tracks of mine in both MP3 (256 kbps) and the original 96 kHz/24-bit PCM formats.

The hardware was graciously provided by Sony and Teac and consisted of a UD-501 DAC connected via XLR balanced cables to an AX-501 integrated amplifier and then to a couple of $239 Sony SS-CS3 tower speakers. The system was billed as a setup that an average consumer could afford. Lest you doubt that this gear could actually reach the JAS definition of Hi-Res Audio, the super tweeters on the speakers spec to around 40-50 kHz.

The Teac gear is also capable equipment. The AX-501 says its frequency response is down 5 dB at 60 kHz and has a S/N ratio of 100 dB. The UD-501 DAC has all of the PCM and a couple of DSD rates including 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, 192 kHz, 352.8 kHz, 384 kHz and DSD at 2.8/5.6 MHz. It also supports word lengths of 16/24/32-bits. The signal to noise ratio is 115 dB and frequency range extends from 5 Hz – 80 kHz (-3dB). Teac should start using the Hi-Res Audio logo…this gear seems to meet the specs.

During a planning phone call it was decided that the researcher would play a track at reduced resolution or high-resolution…followed by the other file (switching the resolution, obviously). I don’t believe this is the best way to “hear” the differences between samples so I rigged up my Pro Tools rig with both stereo audio files playing simultaneously with the ability to seamlessly switch between them on the fly. Playing the files one at a time requires great sonic memory and doesn’t allow for instant comparison of the same section of the tunes. I was ready but for resource reasons…they choose to play my 96 kHz/24-bit PCM WAV files on a PC using the Teac software playback software through a standard USB cable (borrowed from a printer in the facility).

The organizers also strongly suggested that the participants be able to listen to the files through headphones, which presented other problems. The guy from Sony brought a Samson C-que 8 multiple headphone box. I plugged it in and took a listen through a set of Sony’s new Hi-Res MDR-10R headphones (they do carry the logo!). The phones specs read 5-40 kHz. I played the “Mosaic” by Laurence Juber, which won the CEA “Demmy Award” back in 2002 for the “Best High Resolution Audio” track. Both the gentleman from Teac and I agreed that the Samson box was incapable of delivering high-resolution audio or even marginal quality audio. In fact, the sound was horrendous.

Luckily, I cam prepared with a Rane headphones splitter…nothing of ultimate audiophile quality, but it was clean and available.

The AIX Records sound files were randomly identified as Selection_1_A or Selection_1_B. Both the MP3 version and the High-Resolution version were played back at 96 kHz/24-bits. I converted the MP3 using Sonic Studios’ Process converter back to 96/24 so that I could use them in the same PT session AND so that the display on the front of the DAC would read 96/24 PCM in both cases.

As a trial run, one of the staff people from the facility came in to the space and listened intently to the “Mosaic” track. His eyes widened as he listened…I could tell he was thoroughly entranced. As he left the room, he came over to me and said, “I can actually hear the fingers of the percussionist tapping on the congas. The details of the sound are amazing.”

I didn’t have the heart to tell him he had been listening to the MP3 file.


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 $2500 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.

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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.

(9) Readers Comments

  1. Recent results from a breakthrough study conducted by DTS using the first direct neural pleasure response sensors; the 19-25 year old ‘gamers’ could instantly switch from lo-def video to UHD, and from low-rate MP-3 to ultra-clean stereo. When the video switch occurred, the responses were so minimal as to be statistically useless. When they switched the audio, the responses went through the roof. This seems to contradict what too many cynics say. Don’t sell the human ear so short. It took organic food a while to catch on too.

    • What is “ultra clean stereo”? They didn’t specify the specifications or provenance of the material that they played. I know the folks at DTS and will try to get more information. SO perhaps the message is our brains know it’s lossless audio but our ears don’t.

  2. Mark wrote:
    As a trial run, one of the staff people from the facility came in to the space and listened intently to the “Mosaic” track. His eyes widened as he listened…I could tell he was thoroughly entranced. As he left the room, he came over to me and said, “I can actually hear the fingers of the percussionist tapping on the congas. The details of the sound are amazing.”

    Maybe he was telling you what he thought you wanted to hear.

    • He didn’t know anything about me or the realities of the test. He just loved what he heard…and it was a very good sounding MP3 file.

  3. Whether you can actually hear the difference today between ‘hi-res’ MP3 files and real hi-res audio is, in some ways, irrelevant.
    Regardless of your audio chain and its current ability to reproduce or not hi-res files, one should always download the hi-res version. Why? Because, if one enjoys music, eventually your audio chain risks going through an upgrade and, believe me, when that happens, and it will, you don’t want to be disappointed by your music collection. It has happened to me in the past with CDs. That’s when I painfully understood that not all CDs are created equal (production-wise or otherwise).

    Kudos to music stores that allow listening to music before buying (a local store in my area allows listening through headphones so one can compare different versions when different versions exist).

    Your download or purchase is your ‘negative’ and, as in photography, you want to store the highest quality. It is easy to downgrade to any ‘convenient’ portable format while, most importantly, preserving the original hi-res to enjoy on a quality audio chain (whether you own one now or later).

    Unfortunately, many budding audiophiles risk a major disappointment when one day they actually hear the poor quality of their ‘conveniently-sized’ downloads. Maybe the music industry planned this all along to ensure future sales…!

    • There is a point at which there is no reason to increase the sampling rate and word length…it doesn’t get you any greater fidelity. The continued increase in fidelity will be in the production chain not the delivery end of the music business.

      • Maybe then all this study can show is, that the most important part is, that the recording/mastering is done right!

      • Hypothesis; If downloads supplant physical media, and streaming supplants downloads, how will one then actually OWN a personal music collection? To all who have a sizeable LP,CD, or SACD collection, I have only one thing to say; keep it and add to it. Someday, we will hear the refrain ,” You don’t miss your water ’til the well runs dry.” Count on it.

  4. Hi Mark,

    I just finished listening to your test files. I played them from my PC over firewire to a Mytek Stereo 192 DSD directly feeding a pair of PreSonus Eris E8 powered monitors. With 1 being best and 3 worst Selection One was A=1, B=3, c=2. Selection 2 was A=3, B=1, and C=2. Selection 3 was A=3, B=1, and C=2. It was hard to tell the CD and MP3 files apart, my confidence level isn’t very hard there.

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