Dr. AIX's POSTS — 06 January 2014

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Audiophiles and music lovers all around the world deserve to know what high-resolution or high-definition audio is. This has been an issue for me for a long time…and it still remains. Leaving aside the question of whether it matters or not, high-resolution audio should mean something. But everyone in the audio business wants a piece of the term. In the current case, the processing that the MAX-D people are promoting as an “audio process that restores lost compressed harmonics, and brings high definition (HD) sound to digital media” is as far from the truth as one could be unless you skew the definition of HD-Audio beyond recognition.

Here’s my definition of HD-Audio or high-resolution audio. It is an audio recording that meets or exceeds the capabilities of human hearing and more…that means it must have the potential of reaching around 120-130 dB of signal to noise ratio (24 bits in PCM terms) and capture all of the frequencies up to at least 20 kHz and even the next octave to 40 kHz. That means that analog tape, vinyl LPs and standard resolution digital (CDs, DSD 64 and all compressed formats) do not qualify.

I get a lot of push back from vinyl fans and even professional audio engineers that love their analog tape machines. It’s hard for them to get past the notion that something that sounds great can’t be high-resolution. There are lots of examples of classic recordings that will forever be standard definition but can still make your heart or head soar. I’m okay with all of that. Where I have a problem is when a company like MAX-D misleads everyone in their sphere about what they’re doing.

So today, I did a little experimenting. It seemed to me that their comparison between a music source that wasn’t MAX-D processed and one that was played a little loose with the audio facts. I recorded the audio portion of the first promotional video (you can find this at MAX-D Demo) and did a spectral analysis of the section that features the tune “Give Me Everything (Tonight) by Pitbull.

Take a look at the spectragram below (by now you should be getting pretty good at interpreting these things, right?):

give_me_everything_spectra

Figure 1 – A spectragram of the “Give Me Everything (Tonight)” showing the original in the demo, the processed file and the original from Youtube [Click to enlarge].

So here’s what we have:

1. The MAX-D processed version is between 3 and 10 dB louder than their “original”. This is especially apparent in the low end and above 4 kHz. They boosted the overall level AND both ends of the frequency range. And everyone knows that louder is better.

2. The high frequencies of both the original and the processed portions of the demo track are non-existent beyond 17 kHz. Their “so-called” HD-Audio output isn’t even as good as a standard definition Redbook CD.

3. I tried to purchase the tune on iTunes but it’s not available in this country for some reason. So I captured the output of the YouTube version. This is not an accurate plot of the energy in the released CD version (especially in the high end) but it does show that the people at MAX Sound attenuated the low frequencies of their “original” to make theirs sound better. No wonder everyone that hears the MAX-D “taste test” goes for the hyped version.

4. It’s a pretty good bet that they modified the original. In the YouTube version, I hear a lot more spaciousness and clarity…this is just an educated guess but it would make their version sound a lot better than the “demo original”.

I’ll let you judge for yourself if this “proprietary” process is anything special. It’s certainly has nothing to do with HD-Audio. If they simply claimed that it is a realtime music enhancement processor, I don’t think I’d have a problem with it. It processes the sound be making the processed file much louder…especially in the high and low ends…and they do some frequency specific phase shifting to expand the image.

But it’s not high definition audio.

What I can’t figure out is why professional audio engineers and even Mick Fleetwood have gone on record as “endorsing” the MAX-D process. It is a publicly traded company and their stock has been on a gradual descent from $.25 to around $.19 on last close.

Next stop Las Vegas…CES 2014, here I come.

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(2) Readers Comments

  1. Hi Mark,
    Very interesting posts…a few comments. First, I imagine there are many companies out there that realize the business of software “enhancers” is potentially VERY profitable but competitive, so they have to exaggerate their language and use “HD” whenever possible…too bad the consumer is more often disappointed or misled.

    Also on a different topic, after considering this topic of “HD or not” I’d have to agree with you that for a piece to be accurately labeled high definition or high resolution, the entire signal path from recording to final mastering should cover at least 96kHz/24bit. After following your posts and other article these last months, I will agree that anything that is originally recorded on analog shouldn’t be considered truly HD (though of course they still have the potential to sound amazing). I confess that I do enjoy vinyl. Though I’m still trying to figure out what the particular quality is that is appealing? Is it the fact that the sound path is (usually) removed from digital domain or is it more the physical medium itself, the vinyl that imparts a unique tonal character.

    Ok well digress a bit, the question I thought of after reading your article is assuming care was taken to make true HD digital recordings and if that source material was produced for a vinyl album, could the physical medium support 120dB of dynamic range and > 25 kHz? For instance, many of Morten Lindberg’s projects from 2L are offered on either Bluray or vinyl (Direct Metal master) derived from the same DXD recording. There are many high quality tonearms as well as cartridges that have needles with specs into the ultrasonic range, so my inclination is that with a quality recording and turntable/hardware, ultrasonics may be present. The real question then is the dynamic range once the digital recording is translated to analog on the vinyl medium?

  2. Mark,

    I stopped being a fan of standard analog tape and vinyl LPs back in the 70s, when I started waiting impatiently for consumer digital technologies to become available. The first generation of standard 44.1/16 media and equipment was an improvement over analog tape and LPs, at least for anyone without an almost unlimited budget, but it clearly was not yet HD-Audio. I agree with you that none of these formats can be HD-Audio, but I believe that your statement “That means that analog tape, vinyl LPs and standard resolution digital (CDs, DSD 64 and all compressed formats) do not qualify.” is a bit too strong.

    As you have shown, the current analog tape standards do not support HD-Audio, but that does not mean that a new analog tape standard that does support HD-Audio, 96/24 equivalent, could not be developed and implemented using modern technology. A new completely HD-Audio analog tape technology could be developed, but after significant development time and expense, all you would have is an analog technology that still isn’t any better than current digital technology and still doesn’t rescue those old less than HD-Audio analog tapes. I believe that Todd’s question about vinyl LPs has the same answer. Yes, an HD-Audio version of vinyl could be developed, but it wouldn’t offer any improvement over current digital technology, and it couldn’t rescue old vinyl LPs that never had the frequency and dynamic range required for HD-Audio encoded in the vinyl. Actually there already is an analog disc technology that could probably be adapted to support HD-Audio, but that technology, Laser Disk, has almost disappeared due to the superior digital technologies that replaced it.

    For standard digital formats, there have been efforts to make improvements while still living with 16 bits. I am interested in your opinion of two of these improvements.

    The first is HDCD. By changing the encoding method HDCD increases the dynamic range, but it introduces noise when played on a player without HDCD decoding. I believe HDCD is a possible marginal candidate for HD-Audio.

    The second improvement is Sony SBM. I acquired a Sony PCM-R500 DAT (with SBM) in 1997 and used it for years to record solo piano and chamber music. While SBM on the PCM-R500 is not HD-Audio, I had the opportunity to compare DAT recordings of the same source with and without SBM, and with the same amplitude the 16 bit SBM recording always sounded better. Looking at the waveforms on a computer, the SBM waveforms looked smoother, less jagged.

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