You're missing the point completely. It's not as simple as "the bitstream is transmitted intect or it is not". At the implementation level, this "bitstream" is actually a sequence of precisely-timed voltage transitions. This stream is decoded by the DAC to produce the analogue waveform. If the timing of those transitions is slightly out then the analogue waveform is distorted.
Only if you don't buffer. :) For any sane transmission protocol it is just as simple as bit-identical or not.
Ah, but the AESEBU/SPDIF Digital Audio Interface is *not* a sane transmission protocol.
> How well this data is
transformed into in anologue waveform and what distortions the analog signal might suffter on its way to the speakers is another chapter.
Almost. The general concensus is that a DAC supplied with a jittery input stream will not sound good.
Everything else can be fixed by reclocking and hinges on the quality of the reclocking.
Ah, but who said anything about re-clocking?
I did. IIRC in every post from the very start. You probably just read my, admittedly stupid, bitrate --> jitter conclusion and discarded the rest of my posts.
Check again. You may have been *thinking* reclocking, but you didn't mention it.
Not all DACs do re-clocking. Those that do it well are not cheap.
I remember having written something along the lines of "why don't all DACs do this, when RAM is so cheap?"
That relates to buffering, which is *not* what we're talking about; at least, it's not what *I'm* talking about.
http://www.av123.com/products_product.php?section=processors&product=1.1
$1000 for a DAC with a bit of RAM? I guess they can get away with it... makes me wonder how something like the M-Audio 66 stacks up, jitter-wise :)
Actually, The M-Audio SuperDAc is particularly susceptible to jitter. Check the archive of [EMAIL PROTECTED] for more details.
You seem to be saying that you agree that jitter exists as a problem
Sure
and are presenting several mechanisms to reduce it.
Spot on again. I think this whole thread was about reduction of jitter, seeing as it started with the suggestion of replacing the clock chip.
It was. But some folk seemed skeptical about whether or not jitter was a real problem.
Personally I find buying a DAC that properly buffers and reclocks preferable to a clock chip upgrade.
That's one solution, but not the only one. A clock chip upgrade (€29 + 12v PSU) might be more cost-effective.
I never said that jitter is *always* a problem, merely that in low-budget equipment it often is.
Consumer audio equipment is designed to a budget
K, maybe I'm really confused... I think we were talking about combining a Squeezebox (high priced consumer item) an external DAC (hardly a consumer item) and perhaps other upgrades (clock) to get something audiophile out of the Squeezebox.
Not really, we're discussing how to get the best out of the Squeezebox. My agenda also covers "bang-for-buck" ie. "champagne" quality at "vinegar" prices, to butcher a metaphor.
A consumer just lives with the analogue out. It's not _that_ bad really.
It isn't bad at all. Before I modded my preamp, neither myself or another contributor to this list could hear any difference between the SB analogue outs and either my Art DI/O or his Arcam Delta DAC or his Perpetual Technologies P3-A with P1-A correction engine.
On his higher-end system (Naim) there were clear differences. I can also hear a difference now I've modded my amp.
For the audiophile enthusiast, what's $1000 for a DAC. If it's done right it's the only thing you'll need to get great sound quality out of almost any kind of digital input.
Erm, audiophiles aren't always idiots with bottomless pits of money to throw at snake-oil solutions. Some of us want to get "the sound" with minimum possible outlay - I have four kids who come first!
R. -- http://robinbowes.com
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