Dr. AIX's POSTS — 29 December 2014


I took this quote from the opening of the introduction page of HighResAudio.com, the German digital music download site that features most of the tracks offered through their license deals with the big three labels. You might think that we’d be way past this very basic question by now, but in reality we’re not. Because the answer to the question is not clear.

Just today, I received a brief email from a reader. He was having some difficulty downloading the files I prepared for the research project undertaken a couple of weeks ago. After we managed to get him the files, he responded:

“Thanks for teaching me about FTP downloading. I was clueless. Now that I have had the opportunity to listen to the files I would like to add a comment.

A number of your posts have claimed that it was an unfair test to compare MP3 – CD – HiRez when the original source material was from standard resolution sources. I believe it is also an unfair test to compare MP3 – CD – HiRez when the source material is sourced from well recorded true HiRez sources. I can only say that I have never heard MP3 sound so good.

What I did hear in the first set was that the low level cymbals tended to blended into the background in the file that I believed was an MP3 file.

It appears that the true HiRez digital resolution of the source might be more important than the delivered file resolution.

Perhaps the best that can be would be audio that is recorded, mixed and processed at 192khz and then down converted to 96khz for distribution.”

The point that Mike made was that the fidelity of the source material is a major factor in the quality of the delivery files no matter the format. He’s right and he’s not the first person to point that out. I remember a phone call years ago from a guy that was over the top about the sound quality of the AIX recordings he heard…and it turned out that he was listening to the Dolby Digital versions because he hadn’t yet acquired a DVD-Audio player. The quality of sound was there in spite of the lossy format.

The fact is High-Resolution Audio doesn’t always sound better than CD spec audio. It has the potential to be better but only if the source recording contains more stuff than a CD can deliver.

The answered offered up on the HighResAudio site cites three major factors to explain why HRA sound better than CDs. I’m going to focus on the first one and then return to the others in subsequent posts. They say:

“1.) The CD offers a resolution of 16 Bit and therefore 65,536 discrete steps to digitize an analogue music signal. That limitation causes distortions especially audible as noise within quiet parts of the music. That quantization noise is always present and comparable with the noise of a tape or LP but because of its digital nature more distracting.”

And here’s the solution to this very poor description of quantization errors.

“1.) Modern electronics is able to reach a dynamic range of around 120 dB by choosing higher bitrates of 24 Bit. The quantization noise is negligible because of the huge amount of quantization steps available.”

The number of discrete levels offered by 16-bits is 65,535 (I start counting from 0 so I get one less than they did). With a properly dithered input signal, the “distortions” they claim occur are really just very low level noise spread across the entire frequency spectrum. I usually don’t call “noise” distortion because it doesn’t affect the actual signals just the background against which we experience the music. And the noise of a 16-bit system is over 90 dB below the maximum level…much lower than the noise of an analog tape or LP (which hover around 50-60 dB below the signals. And in direct contradiction to their reasoning, the noise is virtually impossible to hear unlike the distractions presented by analog tape or vinyl LPs.

As to their solution, modern engineering can capture dynamics using 24-bit words and reduce the noise floor even further. I’m not sure what “quantization steps” are but I believe they’re referring to the increase in the number of amplitude levels available using 24-bits. The quantization noise is still there but the noise floor is much, much lower than that produced by a CD.

But it’s all for nothing if the sources that you’re capturing in 24-bit PCM audio were made from analog recordings. Their sources don’t need the extended number of bits in high-resolution audio because they only use about 10-12 bits.

More coming.


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 $3500 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.

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