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June 13, 2008

SACD (, )

by fluffy at 11:26 PM
So, after learning that the older PS3 models function as an SACD player, I decided to buy an SACD. I'm listening to it right now. So far I'm not particularly impressed, as it doesn't actually sound any better than a CD (not that I was expecting it to). I think the only thing I can say in its favor is that having true 5.1 multichannel sound makes it sound better than a stereo CD played in PLII Music mode, but I never play CDs in PLII Music mode to begin with and my stereo soundfield is just fine anyway.

Also, it's worth noting that this music sounds like it's overcompressed and clipping, which is surprising considering it's a Rachmaninov concerto.

Of course the SACD purists would scoff at me for listening to the "true" DSD signal converted to (gasp!) PCM at a "lowly" 176KHz. I like how SACD purists say that DSD is "more like" the original signal because if you assign the 1-bit values to +1/-1V and play it on a speaker it'll sound similar to the original signal - well guess what, when you convert the PCM stream to its respective votage levels, it sounds exactly like the recorded signal. Because that's how PCM works.

The only reason DSD is closer to the original analog signal is because they 1) record it at an insanely high frequency (2.8MHz!) and 2) use noise shaping to filter the signal. Well, guess what, PCM DACs don't need to do 1 (because 216 is somewhat bigger than 21) and they also do 2. It's not like the output from a decent PCM DAC will have the stairstepping that DSD people like to claim impacts the sound.

Note that I do realize that DSD does actually fill a very nice role as an analog archival format — after all, it's basically just storing the raw output of the delta-sigma stage of a high-end ADC — but that doesn't make it necessarily any better for output purposes. Plus, the math for manipulating PCM is very simple, whereas the math for manipulating DSD isn't. So, okay, DSD is great for archiving your old analog masters but it's not terribly useful for actually processing the audio in any meaningful way other than basic splicing. You can't even reasonably change the volume on a DSD stream, or mix two DSD streams together! So yeah, it's nice that you can use DSD to get a clean conversion to any PCM format that you want without any weird frequency artifacts, but that's something of a micro-optimization around a problem that doesn't really exist...

Anyway, the thing that annoys me most about this album is that it's a single-layer (i.e. not hybrid) SACD, so I have no way of actually ripping the CD audio to a format I can play anywhere else (ironic considering DSD's previously-stated intent). Oh well.

Comments

#10980 06/16/2008 06:28 pm
I'm an employee of the folks who did the sound for the Moscow concert, now, so I'm learning just a little bit about signal chains and whatnot. Nothing like this, really, but a little bit about the more broad strokes of live audio setups. That's just an asterisk. More broadly, I use PLII Music for CDs and for my iPod--why don't you?
#10981 06/16/2008 10:20 pm
PLII Music kills the stereo separation all in the name of taking a stereo signal which is mastered for two ears and distributing it to 5 speakers to try to do a "better job" of providing a surround soundfield. It's a roundabout way of getting an inferior reproduction of what you had already.

The only plus side I can see to Pro Logic for stereo music is that it gives you a bit more headroom, if you like to listen to your music louder than your amp or speakers can handle it.
#10996 06/18/2008 06:58 pm Which concerto?
Hi Fluffy!
I know this is kind of off the subject but which Rachmaninoff concerto do you like to listen to? My favorite is Piano Concerto No. 2 in C Minor, Op. 18... cranked up of course! Just curious... Very Happy
#10998 06/18/2008 07:20 pm
I'm not versed enough to have a favorite. The one I have on SACD is Piano Concerto no. 3, which I liked but wouldn't consider particularly memorable. I also have a CD with his Symphonic Dances Op 45, Piano Concerto No 4, Sonata for Piano and Cello in G, and a few other shorter pieces of his. I don't really have the attention span to remember most classical works though.
#10999 06/18/2008 11:05 pm
Oh okay. Well I actually had to look up the info on the Piano Concerto that I mentioned... I listen to it all the time and I was pretty sure it was No. 2 but I can never remember the titles and op. numbers. If you had a favorite Rachmaninoff piece I was going to find it and listen to it. I like Rachmaninoff but there's so much classical music out there, even from one composer, that sometimes I just go by recommendations. Anyway, if you have a chance and you're in the classical mood, give Piano Concerto No. 2 a try... don't forget to blast it though! Very Happy