Dr. AIX's POSTS TECH TALK — 12 January 2014

By

If you want to get high-resolution audio out of a DVD or Blu-ray player, you would hook up the optical or coax digital output of the unit and connect it to an external DAC, right? Well, actually not. The output of those optical outputs would be limited to 48 kHz because of restrictions specified by the format specification…which are driven by the record labels. They don’t want us to have access to the “master quality” files.

But never fear. Where there’s a will there’s a way. It turns out that it is possible to peel the 96 kHz/24-bit REAL high-resolution data stream from the HDMI connection. I tried this a while back with a box from monoprice but unfortunately I couldn’t get it to work with my Oppo BDP-83. I contacted the monoprice support people and was assured that the unit would handle 96 kHz/24-bits but it wasn’t lighting up the 48 x 2 indicators on the front of my Benchmark DAC2.

After talking to a few informed friends, I learned that not every DVD or Blu-ray player works with these audio extraction boxes. By this time, I had returned the monoprice box and purchased a Kanex Pro HAECOAX Audio De-Embedder unit for about $66 from Amazon. It’s a really small square unit that has an external power supply, HDMI in and out, an indicator light and a switch that selects between the 5.1 surround and 2.0 stereo audio streams.

I tried this box on the HDMI output of the Oppo BDP-83 player that I have in my office and I got the same result. So I switched to trouble shooting mode. Perhaps it’s not the extraction box but the disc player that’s causing the problem. So I took the Kanex Pro box and Benchmark DAC2 into the studio and connected them to the output of another Oppo Blu-ray player…this time a BDP-95, the 3D capable second generation machines equipped with the Sabre DACs.

Finally, I got the 2X blue light on the front of the DAC2 to come on. The high-resolution 2.0 channel stereo mix from my Blu-ray discs can be converted using an external DAC using the HDMI output instead of the S/P DIF coax or TOS Link jacks. My plan is to transfer a few of my tracks to analog tape using my Nagra IV-S and send them around to the reel to reel community and see if they enjoy first generation recordings made from digital sources.

And that’s what I did at my booth at the CES show. I connected one of the HDMI outputs from the same Oppo BDP-95 to the KanexPro box HDMI input and the HDMI output to the HDMI input of the Sony flat screen video monitor that Sony supplied to all of the vendors in the HRA room.

I used an inexpensive regular 75 Ohm video cable to connect the output of the Kanex box to one of the S/P DIF inputs on the Benchmark DAC. You know the ones…they have yellow RCA connectors on the end and usually come bundled with DVD players. I was very surprised that my choice to use a cheap cable to get the digital bits from the KanexPro unit to my DAC was noticed by more than a few individuals. These folks insisted that I replace the $.50 cable with a “high quality” digital interconnect. They were absolutely certain that the fidelity of my system was suffering because of the cheap video cable.

What do you think? Will an expensive coax cable, USB or HDMI cable affect the sound output of an audio system?

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

Share

About Author

Dr. AIX

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.

(15) Readers Comments

  1. Despite many assurances in the 80’s of engineers that the current flows equally through $o.50 cables as well as $ 300 cables, it has been proven since then that that is not the truth.
    I am not one the guys that would put his cables on lifters to not tough the ground and such, or spend $2,000 for a 1m digital cable, but I truly believe a decent cable makes a very audible difference.
    Maybe not a good analogy, but BMW or Ferrari just don’t drive well with the U.S. 89 regular gas. Put in the 98 octane that is used in Europe and you get the best performance that one can expect.

    cheers

  2. Hi mark,

    I am intrigued that you are raising the topic of the influence of the choice of output on the sound of (your) precious recordings.

    And I am also pleased to notice that you are using a relatively modest Oppo BDP 83 Blue Ray player for performing comparison tests.

    Your intuition is correct, the HDMI cable is intrisically a better (read: high-speed) design audio transfer interface then USB or other older formats.

    So the ‘standard’ HDMI cable connection on your OPPO will endeed reveal a high quality signal transfer for both 5.1. and 2.0

    But I believe it will interest you that Mr. Paul Mcgowan (founder PSAudio) is one of the pioneers and active promoters of the I2S – I2S signal transport. For achieving the best solution for this, Paul used a protocol using HDMI cable..!

    Some amusing communication in which he defends this I2S protocol against the DCS ‘camp’ can be found here:

    http://www.psaudio.com/vanilla/discussion/comment/17570

    an extract form the page:

    archive_Paul McGowan October 2010
    Posts: 0archive_member
    We publish the specs for this and several DIY sites carry the schematics. It does not follow the HDMI standards. We use HDMI because ther guidelines for building the HDMI cables require very strict performance standards that work perfectly for I2S.

    It will be intersting to find out if your Oppo BDP 83 HDMI output can be connected to a I2S- HDMI input of your ( or other, maybe PSaudio ..) DAC

    I hope you appreciate my input. I am a 52 years old musiclover and ‘critical’ audiophile. With critical, I mean that I have seen to much bullsh..t being sold to snobs who have no clue what the true value is of an optimised audio and acousticallly balanced system.

    I am much aware that there is no ‘absolute sound’ achievable when listening to music which is recorded on 24 or 48 (or more) channels, mixed and mastered to 2-channel stereo while the engineer’s taste as well as the audio system in the recording room is of paramaount influence on the end-result.

    But the fun and passion to chase and achieve the optimum result inside my own living room at reasonable price levels, that is what makes my heart tick.. 😉

    And as with many things in life, many times ‘less is more’

    – Peter –

  3. Happy New Year! Many thanks for your fine recordings – they are a revelation. Also, I am one of those who read your daily posts religiously and I have learned a great deal and look forward to more.

    Your posting today seems to highlight the heart of the conundrum faced by those of us trying to assemble a flexible multichannel system for high resolution playback; i.e. one capable of playing AIX Records and other high quality Blu-Ray discs, playing downloaded high resolution files, etc. Consider the possible components: one of the fine Oppo players, some kind of high-end receiver or alternatively a preamp/processor coupled with separate amplifiers, and a video device. If you allow the Oppo to decode the digital stream (i.e. use the analog outputs), then how do you use the pre-pro? But if you use HDMI out of the Oppo, what is the Oppo doing other than extracting the digital off the disc, since you are now using the DACs on the pre-pro and the video processing is being done downstream as well?

    If you can point me to a link where I can get more knowledge and understanding, I’d appreciate it. Alternatively, perhaps this issue might be a continuing topic in future posts.

  4. I think as long as the bits arrive undamaged the what cable is used
    makes no difference. I have used normal audio cables for the coaxial
    digital out for years, cheap eBay and mono price HDMI cables and
    whatever I can scrounge up when I get a new piece of gear and end up
    short on cable. As long as it can pass the bits properly it wont care.
    If the audio or video starts breaking up or it refuse to do anything
    at all then the cables aren’t good enough.
    I have really cheap HDMI cables that refuse to handshake and work with
    one device but work happily with another so sometimes it’s the devices
    trying to talk to each other, and the cable, for whatever reason as
    switching to a different style cheap cable usually fixes it so I have
    silver ones, black ones, and black with RF chokes on both ends.
    Sometimes the gauge of wire inside might help and that’s about it
    though I do think the RF chokes SHOULD help a bit getting rid of stray
    analog RF garbage interfering with the 1 and 0’s.
    If all your doing is using a simple cable to get the digital audio
    again as long as everything lights up and you get sound you should be
    good to go.
    The industry makes obscene amounts of profit making cheap but nice
    looking cables for audio then labeling them for digital only and
    convincing gullible users that they have to use them to get quality
    sound. They also try to say you need a special cable to hook your sub
    up to a A/V receiver or processor too and same thing, any OK cable
    that fits will work.
    Terry

  5. Mark,

    Of course expensive, exotic cables are not better than properly manufactured inexpensive ones. This has been debunked so many times that it is not worth talking about anymore.

    By the way, I must thank you for the Kanex Pro tip. I have got it to work but in a different application than you mentioned. I hooked up my Oppo 980H’s HDMI output to the Kanex, set it to output DSD over PCM over HDMI and – wonder of wonders – it is transcoding DSD to 88.2 PCM over HDMI and outputting it over the Toslink out. I have been wanting to get at the raw digital content of my single layer only SACDs for years. I suppose it would be better to get the raw DSD files or be able to transcode them to PCM using a better(?) transcoder than what is in the Oppo. But I really don’t care about DSD anymore…I think it is compete bulls**t designed to benefit only Sony. The PCM transcode I am hearing from the Oppo sounds pretty damn good.

    I don’t now how I missed this. Once again, thanks a lot Mark!

    • One of the first SACDs I picked to transfer was a single layer from Sony, Wynton Marsalis’ Standard Time Vol. 1. This was recorded in Sept. 1986 on a Sony PCM 3324 24 track digital machine. This is a recorder only capable of 48k at 16 bits as far as I can tell unless it was later upgraded. So Sony reissues this in SACD format which far exceeds the resolution of the original digital format. Unless this machine was upgraded to 24 bit by 1986, it looks like a pure ripoff by Sony. Hence my comment above.

  6. Oh boy, now you poked the hornet’s nest! Good luck with that one.
    Personally I would be hard pressed to think the signal path of 0 and1’s can be affected by the choice of cable via coaxial and especially optical (unless the length is extreme). HDMI is a different animal and length definitely matters but its usually a case of it works or doesn’t work. On the other hand, I like to think there are properties of certain cables that help on the analog side. I can get on board with maintaining good connectivity, but there is a lot of snake oil. Most third party testing done over the years scientifically proves the differences between lamp cord and most high end cables are insignificant (as it pertains to speaker wire) and in some cases find that some of the higher end cables actually hinder performance. What kind of cable do engineers use in the recording studio, mic cables, patch cables? Are they $200 a ft.?

  7. Interesting post. Thinking about this from a data perspective and the fact that the cable run is only 3 ft, it’s a case of what is the data error rate, there’s no retransmit in this protocol, and is the square wave signal arriving in enough accuracy for the receiver to correctly interpret the binary state and the time. If the receiver is buffering and clocking hence handling any jitter then there’s going to be no difference between the cables.

    Just think, if a Cat 5 cable can run a digital signal at 1 Gbits/sec for a distance of up to 100 ft with perfect data rates and no errors, almost any wire should be able to pass the RF carrier onto which the digital audio bit stream is modulated over 3 feet. If the carrier can get through the change in carrier will get though too.

    There are good reasons for getting a good HDMI cable for video with the 17 Gbps band width. But that’s not the bandwidth required for Audio. So the only real way to tell if such a short cable would make any difference would be to run a signal though it to some form of signal analyzer. But it’s all down to how the chip that reads the input is dealing with the signal that determines the output that it can generate.

    I have spend time and effort on picking good analog cables because I have and can still hear a difference in the analog domain. But the choice becomes subjective and a matter of taste – do I like a “bright” cable or a more muted one. But I don’t spend a lot of time selecting cables that carry digital signals. Fiber Optic cables can carry the signals for miles to the point where the leading edge of the pulse get blurred to the point where it can’t be reliably determined. At that point the signal is lost.

    So again as long as all the bits get through correctly $5 for a 6ft S/PDif light pipe is going to “sound” just as good as a $100 cable.

    I’m really enjoying the news letters and the Blu-ray disks from AIX records. Now when people visit and want to see my home theater it’s no longer Master and Commander Far Side of the World – Shape in the Fog that goes into my Oppo BDP-105 it’s now AIX Records recording of Steve March Torme and the band. Leaves people blown away and makes me smile.

  8. Mark,

    I was not aware of the Kanex Pro Audio HAECOAX De-Embedder, and I ordered one almost before I finished reading your post. It will be interesting to see what devices and protocols work with it. Thank you.

    On using inexpensive cables, if the cable being used meets the requirements (specs) for that use, then it doesn’t matter how much the cable cost.

    Terry, as of HDMI 2.0 there have been 6 versions of the HDMI standard. Versions 1.3 and 2.0 both increased the maximum clock speed. Some of your mixed results with HDMI cables may be caused by using pre 1.3 HDMI cables with 1.3+ HDMI devices.

    • Thanks Mark U. I kinda figured that one as well as I started buying HDMI cables once I got newer DVD players and multiformat audio DVD players that actually worked with my Toshiba 2005 HDTV with 2 HDMI inputs so always tried to get the best cheap ones I could find but final standards weren’t even out when I started so yep, some are older slower tested ones, and some gear is just picky about playing nice with other gear so when I have issues I just swap things around till everythings happy again.
      Probably need to pickup some more newer ones as every time I get a batch I try to find the highest standard I know of, but some are just pretty generic but were dirt cheap for a bunch so were worth taking a chance on as long as most of my gear is happy with them.
      Don’t think any of my gear is up to 2.0 standard.

  9. As long as any of the listed cables supplies a solid electrical connection I do not believe expensive cable will make any difference in the sound of the system. I use the same yellow video cable as you to connect my computer to my Pioneer receiver to play all my HD and ripped to flac CD files. I the cable isn’t doing anything that can be measured to the digital stream, it won’t make an audible difference.

    I’m also very skeptical about the value of hyper expensive interconnects and speaker cables. 1K+ a meter cables, really, come on.
    This coming from 63 year old man who’s been an audiophile for 40 years. Over that time I spent hundreds of dollars on audio cables and all these years later I feel I was conned by the high end audio press and manufacturers.
    Let the flame begin. LOL
    Sal

  10. We have been talking about 5.1 channel output from Kanex, but has anyone tested stereo signal? I see the unit has stereo output (and apparently downmix capability) so it can definitely extract 2.0 from HDMI signal, but that’s analog. I want to keep signal in digital domain. Has anyone confirmed that a 2.0 source can be extracted from HDMI and passed through digital to an external DAC?

    • Yes , that’s how I connect my Oppo BDP-103 to my Oppo HA-1 when I want to use the Sabre DAC in the headphone amp. Be sure to push the little button to light the LED and it works great for hi-res sources. (For some reason, I get occasional brief dropouts when the button/LED is off.)

      There is now a newer 18gbps Kanex model HAECOAX3 that passes 4k/60 at 4:4:4 and has a more convenient slide switch. I plan to use this with my Oppo UDP-203.

  11. Sorry for the delay in getting this response posted…I just returned from a week on the slopes of Vail. I’ve been talking about 2.0 channel stereo output in the digital domain using the Kanex box…not 5.1. My goal is to transfer the 96/24 files from my BD discs to analog tape using my Nagra IVS for those interested.

  12. Cables exist simply to pass electrical voltages between signal processing blocks which, in an ideal (but impractical) world would be constructed close enough together no cables would be necessary. So, it stands to reason that the length is the real enemy- the longer the cable the more opportunity for resistance, inductance, capacitance, and shielding to affect a given frequency signal in detrimental ways. Any 3 ft commercially made coax cable would likely perform flawlessly at audio analog and digital frequencies.

    HDMI cables are more difficult as they are twisted pair with difficult connectors. For great information on HDMI cables check this BlueJeans link http://www.bluejeanscable.com/articles/hdmi-cable-information.htm

Leave a Reply

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