SHM-CD: hype or not?

[HighlandDougie]

I know that we've been round the houses on the topic of SHM-CDs several times before but Jayne's comments in the Rachmaninov 3 BaL thread about being dubious about the technical claims of the superiority of SHM-CDs made me wonder something similar. I've rather assumed that the superior sound quality from the SHM-CDs I have over their standard CD equivalents was due to the care with which the Japanese often remaster their discs - in short, it was down to re-mastering of the music files rather than to the inherent superiority of the SHM-CD pressing process.

So, to test this theorem (and I freely admit that the sample is a bit small), I took the Tower Records Japan CD pressings (remastered by Universal Japan in 2009) of Bernard Haitink's Berlin PO Mahler 3 and Mahler 6 and did a straight comparison with the SHM-CD releases (which use the same masters). The SHM-CDs sound perceptibly better. To use that Hi-Fi anorak phrase, there is a width and depth to the soundstage which isn't there on the Tower Records CDs. It's a bit like going from 44 to 96 or listening to a 2-channel SACD rather than the CD equivalent.

I thought that I would also try with Karajan's VPO Nutcracker, where the remastering in the fairly recent big VPO box appears to be the same as in a Universal Japan SHM-CD box of Karajan's Decca recordings. OK, so the big box is a European pressing but one would have thought that the quality of its many pressings should be good, given that one of the languages in the accompanying booklet is Japanese. The SHM-CD is again markedly superior: depth, width, clarity, reduction of 'glare' on the strings.

I'm not advocating the wholesale replacement of one's Universal Group CDs with their SHM-CD equivalents (even bought directly from Japanese suppliers, postage ramps up their cost, and, heaven forbid that any of them use the speedy but dreaded EMS where their European partners are the likes of Parcelforce which whack on duty, VAT and a service charge, taxes and import duties) but I do think that there may be something in the claims about the actual discs representing an advance on standard CDs. So, if HD downloads don't appeal and one yearns for the physical CD in the best possible format, they might be worth more than a quick glance.

[Dave2002]

To use that Hi-Fi anorak phrase, there is a width and depth to the soundstage which isn't there on the Tower Records CDs. It's a bit like going from 44 to 96 or listening to a 2-channel SACD rather than the CD equivalent.

This is quite interesting. Do you think you have particularly good or sensitive hearing?

The trouble with this is that we are discussing in many cases some very fine and subtle differences. I find that I can often hear small differences, particularly when I use headphones, but I have found it hard to tell the difference between CDs and SACDs, though I do tend to feel that SACDs generally give a smoother sound. I would really hesitate to say I could distinguish between 24/96 or 24/192 recordings and CDs reliably. As you have also hinted, some of the differences may be due to mastering or remastering.

If the data on the SHM discs is essentially the same (can that be checked?) then there are only a limited number of reasons why the replay should sound better than equivalent CDs on the same equipment.
One possible reason might be lower error rates in the readout from the disc, and another might be lower jitter - though this really should be sorted by most good CD players - the output rate should not depend on the readout rate from the disc. A now somewhat unlikely possible reason is the switching in of additional circuitry within the CD player. The CD spec does allow for an extra bit of analogue circuitry to be switched in and some early Japanese CDs did that - though in fact I've only ever been aware of one or two. Some early CD players did have a light or indicator which showed when this happened.

I am unaware of any modern CD players having different filtering which is content related, but that might just be a reason too. This could be either determined by programme content, or by explicit flags in the data from the disc.

Do you get the same perceptual difference if you rip the CDs from different sources to different files, and replay them through your computer, or is this something which is only manifest when playing CDs on a CD player?

[HighlandDougie]

Dave

I've never really thought about my hearing but I suppose that it is reasonably sharp (I'm certainly sensitive to noises) - any improvement from 24/96 to 24/192 is, though, well beyond me.

Unlike HDCD, which is an encoding/decoding process where suitably equipped CD players could have a light which illuminated when an HDCD encoded disc was being replayed, the data on SHM-CDs is exactly the same - the difference comes in the physical properties of the discs themselves. To quote the official definition,

"SHM-CD is a digital optical disc data storage manufacturing process. It is an improved compact disc product with the greatest change being a different polycarbonate material that allows more precise physical representation of stored bits during pressing and less laser scatter during reading. These improvements aim to facilitate playback by producing fewer errors and potentially better sound quality."

While I can understand the scepticism expressed (by JLW and many others) that it's all hype designed to prolong the sales of re-marketed CDs to gullible Japanese buyers (but not at inflated prices for bog-standard DG/Decca/Philips SHM-CDs), my ears tell me that there is a definite improvement.