Blu-Spec CDs

From this Wiki:

Blu-spec CD is a specification for an improved version of a conventional Audio CD, introduced by Sony Music Entertainment. Instead of a traditional infra-red laser, a blue laser is used for recording the pits on the CD master that is needed for disc replication. The blue laser creates more precise pits, causing less distortion in the optical read-out process and supposedly resulting in higher-quality audio. [1]. However, and despite marketing claims, there is no published proof or evidence that this technology actually leads to any improvement in the final audio reproduced, since CIRC, the built-in redundancy and error correction system that is part of the CD standard, already takes care of occasional misread bits.

A Blu-spec CD can be played on all CD players and does not require a blue laser to be read. It is not a Blu-ray Disc.

The Blu-spec CD approach competes with other variants of the CD format, even though the improvements promised by them target different stages of the production process:

* DSD-CD (Sony)
* SHM-CD (Universal Music)
* XRCD (JVC)
* HQCD (Memory-Tech)
* HDCD (Pacific Microsonics/Microsoft)

There's an interesting article in the January 09' TAS by Robert Harley. He writes about the Reference Recordings HRx format, which are basically WAV files on DVD of the master recording which are sampled at 176.4Hz with 24 bit resolution. Of course you need a special card and DAC. He makes a few good points about the high rez formats which I'll try to paraphrase (but do check out the article if this stuff interests you as it's certainly worth reading). He makes three points:

1st High Rez formats do not in any way guarantee good sound - rather those specifications are "an opportunity for good sound". "A well-designed 44.1hz/16bit system will outperform a poorly conceived and executed high-resolution system".

2nd He points out the the systems that resolve 16 and 24 bit material are far more demanding in terms of clocking accuracy, power supply purity and every other subsystem.

3rd Many components advertised as high resolution are not delivering what they claim and are marketing gimmicks (he cites a 24-bit DAC chip delivering only 20 bits of information while the remaining unused 4-bits are cynically referred to as "marketing bits".

Finally he points out that a high-res datastream does no good if the signal has previously been subjected to a standard resolution A/D conversion. Once converted to 44.1./16 it is irreparably compromised. This, he says, will become more of an issue as high-rez downloads become more common.

He also points out, at one point, the obvious; that a poorly recorded performance will not be helped by higher resolution.

Anyway, a good read. The DAC he was using to review the HDx is also reviewed by Harley in the next pages. It is a Berkley Audio Design Alpha DAC capable of decoding sampling rates between 32-192khz and up to 24-bit. He claims it's the best outboard DAC he's heard.

Rja - for the record, I wasn't implying Blu-spec were hi-rez, but the thread seemed to have moved that direction hence the input. I think the price on the DAC was around $4-5K - I'll have to check and get back to you.