OPPO BDP-103 and BDP-105 Networking Universal 3D Blu-ray Players (part4)

SACDs are 24/176 resolution.

 

AND: if you quit the GUI during a conversion, sacd_extract does not quit, which means your CPU will continue to run hot. You'll need to kill sacd_extract from the Task Manager.

(Sorry - should have specified earlier that I'm running Windows.)

 

Interesting, any idea why? Am I missing a setting on the program? Thanks

 

That's just the industry spec/standard for the format. But I don't know anything about program settings in this case. I haven't tried any extractions. I have an Oppo 105, though, so I'm interested in maybe trying it in the future.

 

No, they are 1/2822.

But when converted to PCM, they are roughly equivalent to 20/96. 24/88.2 is my preferred PCM conversion format.

Direct Stream Digital - Wikipedia, the free encyclopedia »

 

I'm stumped with this. If I rip from an sacd then it should be 24/176 but when I use iso2dvd then dbpoweramp to flac it gives 24/96. Does it matter which format I choose in iso2dsd? Output options are Phillips DSDIFF, Sony DSF, DSDIFF Edit Master. There are no options for sampling on the iso2dsd or dbpoweramp when converting to flac. Any help would be appreciated.
I guess I should ask (since I"m new to this) - will I hear a difference between 176 and 96 on a modest system?
Thanks again!

 

Not sure why you say it "should be 24/176". DSD and PCM are different things. DSD is not 24/176, it is 1/2822. iso2dsd doesn't do any resampling, the native DSD goes into the file. I'm not familiar with dbpoweramp, but that is where you should look for settings as to what resolution to create when converting to PCM. I would recommend 24/88.2.

 

Gardo, that's because the ISO2DSD is "unmanaged code".
Languages like C# etc., have hooks with the OS that make them play nice with system resources.
Unmanaged code, like straight C can take everything it wants, hence when you bust the .iso to .dff & then .dsf it pegs the CPU & goes really, really fast.
It was a bit interesting to note that ripping the .iso file via the Oppo & PC vs. PS3 is about the same rate.
My speculation is the decryption algorithm is the limiting factor and not computer horsepower or I/O.
I'm sure you're all fascinated by my post

 

I think it is more drive speed. If you notice as the rip progresses, the average speed slowly increases. I believe this is because the drive spins the disc at a constant rate. As you get closer to the outside of the disc that means more data per rotation. Most CD drives do the same thing when ripping.

If that is the case, it is the drive rotation speed that is the limiting factor.

 

Could also be that if the drive has any cache, the data rate screams at first, then when full, you are now b/w limited by the actual write speed of the disk.

 

Although the data flow rate is roughly equivalent to 24/132.3 PCM? Still, as you say, they are somewhat different animals and there probably is no direct equivalent

 

Big factor is that almost everything over 40kHZ or so in DSD is noise that has to be filtered out anyway so there isn't much point in converting DSD to anything over 96kHz.

 

Thanks for doing this Bill Mac,
Apparently I was changing between the stereo and MC of the SACD.

So, I made a mistake!

Gardo - thanks for your input too. Although I maintain you wont suffer sonic degradation when playing the SACD layers if Sec. Audio is turned on.

 

Sure, but there remains the possibility that the next stable release, in addition to what was fixed in the beta, will "fix" the SACD ripping "issue" without warning. Oppo has to consider the legal ramifications (potential lawsuits) of continuing to allow customers to rip SACDs.

 

As others have pointed out, SACD uses 1-bit sampling, at a very high sampling rate. So SACD is not 24/176 or 24/96 or anything else like that - those are PCM bit depths and sample rates.

When converting SACD to PCM (like when making FLACs from an SACD ISO, DSF or DFF file or files), the DSD data gets converted to PCM.

Because DSD/SACD samples at only 1 bit of resolution, it has to use aggressive noise shaping to push all the noise into the ultrasonic frequency zone, beyond human hearing. My understanding is that SACDs (or SACD players?) have a steep cutoff at 50kHz, because beyond that frequency is where most of all that noise is.

Because 50kHz is very close to 48kHz, one can say that SACD's sample rate is very similar to 48kHz sample rate for PCM. As for bit-depth, as noted above, SACD's signal to noise ratio is equivalent to about 20 bits of depth.

So 20/48 is probably the closest equivalent to SACD. But, when converting SACD to PCM, it's best to use a sample rate that's an even divisor of SACD's native sample rate. That's why 88.2kHz and 176.4kHz are used (as opposed to 48kHz or 96kHz).

IMHO given the above info, 24/88.2 is plenty for SACD and you get no benefit from converting at 24/176.4 - although the latter certainly couldn't hurt.

 

I'm not so sure they are "allowing" anything. If someone found a way to exploit these players (not just Oppo) then the person taking the action should be held responsible. Since the PS3 was made by Sony, they went through great efforts to stop the hacks but who knows about third party companies....

 

You're forgetting Nyquist-Shannon. That would mean 96kHz PCM sampling—a response up to 48kHz without aliasing—gets close to the effective frequency response of single-rate DSD64. However, 88.2kHz is often favored because it is integer math to get there from 2.882MHz.

 

D'oh! You are right of course - forgot to double b/c of Nyquist.

 

Certainly a dumb question but I'm going to ask it anyway.
Why convert DSD to PCM?
I noticed a pretty substantial difference when I initially got my 105 and selected the option to output SACD discs and DSD input in DSD.

 

Do you use any speaker/bass management from the player? If so, the "substantial difference" could be because you were hearing the lack of said management when in pure DSD mode.

 

Well, I am. Thanks!

 

Agreed.

And with regard to "equivalents" between DSD and PCM, as I understand it there are advantages to DSD beyond sampling rate and bit depth, advantages having to do with AD/DA conversion, timing, etc. that give DSD an advantage on ambience retrieval and soundstaging. On the other hand, Steve and others have noted that the top octave in DSD isn't completely faithful to the source.

All very interesting.

 

I can hear audible differences between DSD and its PCM converted 24-bit/88.2 kHz counterpart, easily favoring DSD. I've found pure DSD sound and its derivative 24-bit/176.4 kHz PCM counterpart are nearly impossible to distinguish in practical terms.

YMMV.

 

Sharp guy.
I don't presently have any subs on my 2-channel system so bass management is not a factor.
I have thought about adding one but for most of the music I listen to my speakers, Revel Studio2s, handle LF pretty well.
They're not flat to 20hz but I don't have much organ music.
IMO, there are some trade offs using a 2.1 or 2.2 vs a straight 2.0 system, like having to buy a sub & amp just to see if I like it better.

For my multi-channel system, I use Anthem ARC as film soundtracks and 5.1 music benefit greatly from the room correction and bass management no matter what the format.

 

I run 2.2 and LOVE it but took forever to get it just right.