Eric Woudenberg wrote:

> I don't understand why you say you disagree. Simon says that if all
> errors are corrected there is no difference. You say that there may be
> differences if there are more errors than can be corrected. The ACIRC
> error correction algorithm for MD is a fixed procedure, manufacturers
> don't have "better" or "worse" versions. The nature of the algorithm
> is that if the BLER (block error rate) is less than 220, the original
> data can be fully reconstructed.

Agreed.... what I was trying to say was that in circumstances where the
BLER is >220 the sound will deteriorate. I still maintain this is more
likely to occur on some of the cheaper brand disks. I have had experience
of this happening on some Memorex blanks which developed large error rates
after only a few weeks use.

> No one here is discussing the audible quality of discs with
> uncorrectable errors. We're discussing whether there can be audible
> differences in discs with BLER well within the "fully correctable"
> threshold.

Sorry, I assumed we were discussing the effect or error rates on sound
quality generally, I did not realise it was restricted to 0<BLER<220.

> I find it irritating that Sony tries to make a marketing case for
> "better" sounding discs when they know the only problem, if any, is to
> be found in players with noisy electronics.

I agree entirely.

[ In response to comment on MO]

> Please pardon me, but this sounds like pure conjecture. May I ask
> whether you know anything about the physics of MO recording?

I'm not qualified in that area, but I do have some understanding of the
technology yes, and I have observed many expreiments with MO at the local
university. I found the tests they were doing on the durability of MO
quite fascinating.

[In response to better discs = last longer]

> More conjecture?

No, based on experience. The better quality discs I have outlast the
cheaper ones. There are 1 or two exceptions but generally this seems to
ring true.

> Again, you seem to ignore the error correction threshold. Discs with a
> BLER less than or equal to 220 will all carry their digital payload
> identically.

As I said earlier, I did not realise we were restricting this to a
0<BLER<220 scenario. Sorry.

> What? The disc's bit errors are either fully correctable or they
> aren't. If they are, there is no basis for a quality difference. If
> they aren't, you've somehow got a bad MD and you should toss it or
> perhaps return it for a refund.

Or perhaps (as in the case of the several Memorex discs I have had) they
just develop faults very quickly when used extensively. I would like to
know how I can test the BLER on these discs, as they have deteriorated so
much that you *can* hear an audible difference between them and a new
disc.

--
Magic

Location : Portsmouth, England, UK
Homepage : http://www.mattnet.freeserve.co.uk
EMail : mailto:[EMAIL PROTECTED]


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