Ayre DX-5 bluray player - Page 17

Originally Posted by Charles Hansen

b) The test results you get depend almost as much on the test equipment as on the device under test (DUT). The original MAR system used a 16-bit data acquisition card in a desktop computer. This gave relatively poor performance and was later replaced by a 24-bit acquisition card. This newer card gives better results but is still trying to make very low-level measurements whilst inside the noisiest possible environment -- a computer!!

Originally Posted by GGA

The outgoing audio signal does not contain any video. It is output as balanced MMHR (Multichannel Meridian High Resolution, RJ45 connector/CAT5) or single ended as Smartlink (S/PDIF or when encrypted it is called MHR, RCA connector).

Originally Posted by GGA

One may choose to output video over HDMI or just the audio. Perhaps you mean the incoming signal is polluted and stays polluted because they don't separate the ground?

Originally Posted by GGA

The HD621 does accept 100-250V. Does that automatically mean it is a switching power supply?

Originally Posted by GGA

No one else can really use it because of the encryption and there are no other SSPs I know of with 6-channel digital inputs.

Originally Posted by GGA

Meridian retail price is $3000. The Theta upgrade price or release date has not been announced but the speculation is that it will be more and may require replacement of the DAC cards. A new Meridian 861 version 6 will set you back some $26,000 or more. Meridian processors nowadays seem to be designed to be used with their digital speakers. Their top DSP8000 speakers are $65,000 a pair, up from $40,000. They use zeroes differently than most of us.

Originally Posted by edorr

The Casablanca upgrade will be around 5,000 for HDMI. However, you need the right DAC cards in the processor which will set you back another $7,000. So the difference between using a stripped down Casablanca as a controller for a six shooter and upgrading to HDMI is easily $10,000. That easily buys me a Marantz UD9004.

If the Marantz turns out to sound as good over an all analog six shooter as an Oppo into Casablanca over HDMI this would be my preference (purely because of the economics). My personal expectation is that the analog six shooter route will sound better on multi channel SACD (because of DSD direct conversion in the source component), and the HDMI route will be better on Blu Ray / DVD.

I guess the very best would be to use the Ayre HDMI into the Casablanca but this would be a $20,000 proposition, and is not within my reach.

Originally Posted by HDMIinfinity

Charles, if you want just contact the guys at audioholics and they will walk you through the process of measuring jitter.

Originally Posted by dicey

Don't be a dick.

Originally Posted by HDMIinfinity

The specs are the same.

Originally Posted by HDMIinfinity

The Ayre C-5xe measured 289 picoseconds peak-peak both for 16-bit CD playback and 24-bit DVD playback, have you improved upon this since it also uses the same DAC as the DX-5?

Originally Posted by HDMIinfinity

Charles, if you want just contact the guys at audioholics and they will walk you through the process of measuring jitter.

Originally Posted by Charles Hansen

Well then clearly they must sound the same...

Why do you suppose that they make two different parts, then???

This is why I said that jitter numbers are meaningless. Listen to what I say and go read the article I linked. That will get you started.

The 289 psec number came from when JA was using a 16-bit card in his computer. All of the jitter he was measuring actually came from his test setup.

When Hi-Fi New measured the C-5xe with the 24-bit card, he reported 120 psec for 16-bit data (the limit of the test) and "< 10 psec" for the 24-bit data.

But all of those numbers are still meaningless. Miller never said how his machine figures out those numbers. It is a big secret. The way that real engineers measure the performance of a clock is with a phase-noise plot. This is a million times better than any single number could ever be. But it is still useless.

Why? Because even if you were an experienced engineer and had looked at thousands of phase-noise plots, you still couldn't tell how something was going to sound.

I'll say it over and over. The only way to know how something sounds is to listen to it.

Originally Posted by Charles Hansen

Are you joking?

Look, they run a nice website and do nice tests and have an Audio Precision 585 (it does multi-channel and HDMI, but does not have the resolution of the AP 2722).

I have nothing against them, but even they would agree that they are not the world's leading authority on time-based measurements...

Originally Posted by Charles Hansen

There is no standard way to measure jitter, so putting out number would be meaningless. You would end up comparing them to some other numbers that were obtained by a completely different method. You would think you were comparing "apples to apples" but you wouldn't be.

Originally Posted by Charles Hansen

YIKES!!! That's one of the problems with "upgradeable" designs -- the upgrades can be awfully expensive...

One point is that the Oppo (and the Ayre) will deliver DSD across the HDMI connection. So unless the Theta converts to PCM this shouldn't be an issue.

I still think that the Oppo across the HDMI into Theta's DACs will sound better than the Marantz DAC's into an analog volume control. But that's just an educated guess. The only way to know is to listen to both configurations.

Originally Posted by HDMIinfinity

Do you have a link to some measurements that would indicate interference from the computer?

Originally Posted by HDMIinfinity

One can accept a DSD signal and one can't, the whole LPCM/DSD thing has been discussed to death.

The classe SSP-800 measured well less then 100PS as well, since you were discussing the jitter importance in the DX-5 at what point did you find the jitter became audible?

Originally Posted by HDMIinfinity

And you know for sure that is all they changed? Just asking since sending information out of a computer does not contain high levels of jitter so I don't see how this could be affected.

Originally Posted by edorr

The Theta will only accept PCM from multi channel SACD sources, so the Oppo or Ayre will need to convert DSD to PCM (same is true for the Meridian HD621) to work with the Theta - hence my guess SACD may still sound better over the analog outputs into a stellar volume control. But you are right, it is all educated guesswork and I will wait and listen first before deciding which way to go.

Originally Posted by Charles Hansen

I'm done.

Originally Posted by dicey

Totally agree. But could you at least give us a rough idea of the overall percentage of jitter reduction that would be gained when using the A/O HDMI vs. the A/V HDMI? Perhaps using a percentage value?

And thanks for all of the info so far.

Originally Posted by Charles Hansen

No, we haven't measured it yet. But even if we did, I wouldn't tell you any numbers. What would they mean? If the audio-only output had half the jitter, would it sound twice as good?

Remember, the only place that jitter matters is at the DAC chip in the SSP. So a better source is always going to sound better, but the actual jitter number at the DAC chip is going to depend highly on the clock recovery circuit in the SSP.

In 1997, we started using the Miller Audio Research Jitter Analyzer, a National Instruments Labview program that makes use of a high-performance A/D and DSP card (originally AT-bus, then PCI-bus) housed in a PC. The National Instruments card is connected to the player's or processor's analog output while it decodes the Dunn J-Test signal. The Miller software then searches a high-resolution, FFT-derived spectrum of the device's noise floor for identifiable symmetrical sidebands in order to then calculate a jitter total. However, the NI cards that are the basis for the Miller Analyzer use 16-bit A/D converters. Although the Miller software uses extensive signal averaging to lower the contribution of these converters' self-noise, it limits the system's resolution to around 120 picoseconds of jitter, which is higher than the jitter of the very best digital audio products now available.

The source for the measurements was 16-bit data encoded either on CD or as a WAV or FLAC file stored on a computer hard drive. The 0dB reference in all the graphs is the level at which each player reproduced a full-scale tone at 1kHz. The center frequency of each graph is 11kHz, with a horizontal frequency range of 7.5-14.5kHz.

Originally Posted by Charles Hansen

The Ayre has many differences compared to the HD621 that reflect the differences in each company's design philosophy.

EDIT: The information in this next paragraph is completely wrong. I apologize for posting this, as I was confused.

The HD621 gives lip service to separating out the audio signal so that it "is free from video pollution". This is pure marketing BS. The HDMI audio signal must be sent along with a (minimum) 720p video signal or the link will not work. They probably send a gray or black screen, but whether that will improve the sound quality is questionable at best. To add insult to injury, it uses a switching power supply that will inject noise into the AC mains and also any equipment connected to the unit.

EDIT: The HD621 does separate the audio out as it is sent on either S/PDIF links or Meridian's proprietary MHR (Meridian High Resolution) link that uses CAT 5 cabling. S/PDIF is relatively easy to isolate by using a high-speed pulse transformer that only costs a few dollars. I do not know if these are used, either in the HD621 or at the inputs of the Meridian processors. I would assume that they are used at least in the processors as it is a fairly common feature used in many digital products. Again, I apologize for the error.

In contrast, the Ayre has opto-isolators so that the ground of the video section (player + display) is electrically separate from the ground of the audio system (player + SSP/preamp + amp). This isolation is crucial for obtaining both the best picture quality and the audio quality. The power supplies in the Ayre are purely linear, designed for the lowest possible noise, both for the circuitry and the AC mains.

The main thing that the Meridian unit does that is unusual is that it includes "upsampling" for the audio. I suppose that their current line of SSP's are not able to be upgraded to their new "apodising" digital audio filter (a similar filter is included in all current Ayre digital products in a user-selectable "Measure" position, although we have found a better-sounding filter that we incorporate in our "Listen" position) so this is a way to allow their current customers to upgrade to both HDMI capabilities and Meridian's new digital filters.

However if you read the fine print there are at least two flies in this ointment:

a) The maximum data rate is 96 kHz. Higher sample rate material will be downsampled!

b) The unit does not accept the "DSD" signal that is output from SACD's.

It is probably a good choice for someone who already owns a Meridian processor, but not for anyone else.

Originally Posted by edorr

Interesting. However, here is my question. If I fed the Meridan HD621 HDMI out of your player would it sound any better than plugging in a standard Oppo? From what I read into your post, it would not and the HD621 would actually degrade the Ayre signal send over HDMI.

In other words, you can either separate audio/video, buffer and reclock the signal in the source (Ayre) or the sink (Meridian), but doing it on both ends gets you nothing extra.

This is interesting because it suggest your player would get stellar performance with most high end processors (classe, anthem etc), but it would do not nothing extra for the Meridian.

If Theta comes out with their HDMI upgrade I have to assume they will also do their version of "separate audio / video, buffer and reclock", to get their very pricey system to perform up to standards. Again, this implementation may then be highly HDMI source component agnostic.

All speculation I realize - lets wait for some product to actually ship and let our ears decide!

Originally Posted by edorr

Interesting. However, here is my question. If I fed the Meridan HD621 HDMI out of your player would it sound any better than plugging in a standard Oppo? From what I read into your post, it would not and the HD621 would actually degrade the Ayre signal send over HDMI.

Originally Posted by Charles Hansen

Let's put it this way -- if we knew of a way to get less jitter out of our HDMI audio-only output, we would have done it. So either the Meridian guys know something we don't know or else adding the box would reduce the performance. Your ears are the most reliable judge...

But all of this becomes moot if any of the SSP manufacturers get off of their lazy butts and implement Audio Rate Control. This was announced in the HDMI 1.3a spec in November, 2006 and virtually eliminates jitter. Sony and Pioneer have proprietary versions of it in case you were planning to use a Japanese receiver in your state-of-the-art theater....

The Ayre DX-5 will implement ARC on the HDMI audio-only output, but it only works if there is a compliant sink (receiver) at the other end. We have a Pioneer receiver in-house and have decoded most of their proprietary commands. If there were enough demand, we could make the DX-5 compatible with Pioneer receivers...

I don't know why Arcam or Classe or Theta or you name it aren't implementing this yet. It will radically improve the sound quality of HDMI-sourced audio.

Originally Posted by Charles Hansen

I don't know why Arcam or Classe or Theta or you name it aren't implementing this yet. It will radically improve the sound quality of HDMI-sourced audio.

Originally Posted by Charles Hansen

Let's put it this way -- if we knew of a way to get less jitter out of our HDMI audio-only output, we would have done it. So either the Meridian guys know something we don't know or else adding the box would reduce the performance. Your ears are the most reliable judge...

But all of this becomes moot if any of the SSP manufacturers get off of their lazy butts and implement Audio Rate Control. This was announced in the HDMI 1.3a spec in November, 2006 and virtually eliminates jitter. Sony and Pioneer have proprietary versions of it in case you were planning to use a Japanese receiver in your state-of-the-art theater....

The Ayre DX-5 will implement ARC on the HDMI audio-only output, but it only works if there is a compliant sink (receiver) at the other end. We have a Pioneer receiver in-house and have decoded most of their proprietary commands. If there were enough demand, we could make the DX-5 compatible with Pioneer receivers...

I don't know why Arcam or Classe or Theta or you name it aren't implementing this yet. It will radically improve the sound quality of HDMI-sourced audio.

Originally Posted by edorr

I remember first reading up on ARC when I tried to understand why my Denon 2500 BTCI HDMI Digital Transport into my Onkyo 885 sounded like crap, and asked myself the same question.

I bought a Pioneer BDP 09, ran it though the analog MC bypass and never looked back. This is why I am not sure the Theta HDMI implementation will sound better than say a Marantz UD9004 through the six shooter. In any case, it will be interesting to hear from Theta if they will be implementing ARC on their new Compli Blu Ray player and forthcoming HDMI interface on the Casablanca.

by the way, would ARC be implementable through a firmware upgrade?

Originally Posted by dicey

I like the idea of a 2-box design with a great multichannel DAC/preamp in one box and the video switcher/scaler in the other with a data cable connecting them.

Wuddya think?!