Differences between CD / DVD player?

[scriven]

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On 7/12/2005 10:25:15 PM DrWho wrote:

...so these jitter graphs are showing changes which should be inaudible...

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Doc,

If that was an SPL graph I would agree with you.

I am not sure exactly what they are showing in that graph. The X-axis is labeled "JITTER FREQUENCY in Hz" and the Y-axis is "dB". I would expect the jitter values to be in pecoseconds. I have no idea how to relate a time value to dB. Since the jitter can change the frequencies of the reproduced signal it may well be audible. (I have never heard it but that doesnt make it inaudible!)

Here is the link to the original article. The excerpt is from page 6.

[jbsl]

Dr Who My reciever is a Denon 4800 and my dvd player is a Denon 2900 and a NAD C542 CD player. So both are very good but the 4800 is 4 years old so the newer recievers should do a better job. But since my reciever is old I'll run the analog out to my Luxman. I don't see any reason to upgrade my reciever since it can do 7.1. But the very dangereous upgrade bug is telling me I need the brand new Denon 4806. When I get off work I'll go play with the digital conections and compare to analog.

Xman

[Yesfan70]

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On 7/12/2005 7:01:19 PM scriven wrote:

Yesfan,

They are measuring an electrical signal using 0dB (the max) as a baseline signal level. That is why all the values are negative. It is not an SPL measurement so asking how "loud" it is doesn't make any sense.

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Appreciate the clarification Scriven.

If you go by the graph, what would be the "safe zone" where the change in signal wouldn't be audible?

[scriven]

I have no idea because I don't understand exactly what that graph is saying. (See my earlier post in this thread.) I think that I understand your question but I can't answer it because this graph is not a good example to work from.

[nicholtl]

I think the point is that not all digital transports are made equal. Which in turn means using a digital toslink or coax does not mean you'll get the same sound, regardless of the player being used.

I don't know either what a potential "safe zone" in jitter is, but again, I've heard differences in a variety of players used as transports (which, by the way, inherently means they are not using their own DAC's, so there's no need to keep clarifying that), and I think if I can, anyone with a decent pair of ears can.

[wheelman]

I've used at least a few dvd player to say the least as transports, and they all sounded different when playing back cd's using the same DACs' in my ht receiver. Some had more weight, or warmth others had more detail and some had an anemic bass quality to them. Should I say lack of quality? Power supply in the player itself I bet has a little to do with sound quality. Some good cd players weigh more than a low level Ht receiver.

[DrWho]

Well the only problem that can slip into a digital signal path are errors with timing...it sounds to me like a lot of you guys are using DACs that have no onboard buffer before the DA stage, thus allowing the time errors that seep in to screw up the timing with the DAC. I can see a lot of HT recievers doing this because they'd be cheaper to build this way. I would bet the differences are significantly less on a fancy schmanzy outboard DAC.