Any way to convert DSD 128 files to DSD 64?


#1

So I have recorded a ton of vinyl (over 100 LPs) in DSD 128 with the NPC. Many of these are my brother’s amazing record collection, which is why I got the NPC in the first place. I wanted to archive his vinyl in the best way possible so I could give it back to him without too much wear and tear. The vinyl rips sound amazing and I’m very happy with them. Now I have a problem, and I think may of you suspect what it is. I am getting the Bridge II today and it only plays DSD64 (WHY?!!) so I now have to find a way to down-convert my albums. I tried through Vinyl Studio but you can only record DSD in the original resolution chosen for recording, i.e. DSD 128, in my case. JRiver has a conversion function, but it makes the DSD 64 files at least 10 dB quieter, which is suboptimal. Plus, I wonder if it goes through a PCM intermediary conversion. It probably does. Regardless, do you guys know of another method to down-convert DSD 128 to 64 and keep the same output level? I guess I could convert to PCM 24/192 and then to DSD 64 but that defeats the whole purpose of recording in DSD. The thought of re-recording all of these LPs makes me nauseated. I may just convert to 24/196 in Vinyl Studio and be done with it, honestly, unless I can find an acceptable solution.

Oh, I almost forgot, I guess I could use HQPlayer and output to DSD64 by default, but I’d like to get away from that program and let my DS DAC take care of filtering and noise-shaping and such on it’s own. Thanks.

Adam


#2

Are you getting the bridge to stream from a remote computer where simply using a USB cable to the DS will not be possible?


#3

How have you been listening to those files? Why not get the Bridge installed, compare your options, and if there is no hope of the Bridge II being upgraded to DSD 128, send it back, and optimize your USB signal path. If you do want to use the computer in a remote location just continue using the LanRover.

I had just got about a half dozen SACD rips, and then changed DACs to one that doesn’t do DSD. JRiver converts those to 24/176, and they sound good. Yes, I know they are DSD 64, You might find with Vinyl that 24/176 will be just fine. And finally, if you are going to convert in Vinyl Studio, save the original DSD 128 files to a separate drive, to be used in the future. Don’t do anything that permanently changes those files.

What about Roon? I know very little about it, but I do know the Bridge II works with it. Would that do the conversions? Something to look into.


#4

I’d prefer to not use my USB chain while playing digital music/streaming, if possible, and stream using a supposedly superior method. That’s the whole point of the bridge, isn’t it? I use Roon a lot and would also like to be able to maximize MQA, which I can’t do currently because Tidal won’t play nice with LANRover. Plus, I’d like to keep my USB chain connected from my NPC to my Mac Mini in order to rip vinyl. It’s kind of a pain to switch if back and forth between the NPC and the DS DAC, like I do now. Don’t get me wrong, my USB chain is pretty sweet right now with LR. I’m hoping to hopefully improve SQ a little and add some functionality with Bridge.


#5

Well the point of the Bridge is to take advantage of a second digital lens for improvement of sound quality and to move the “noisy” computer equipment (fans, hard drives, RFI, EMI) out of the listening room. How much perceived improvement the bridge adds in sound quality is purely subjective so only you can determine its benefit. With the DS, the USB input is far better than the PWD and with the Land Rover, well you know about it.

If the computer is going to be physically located in the listening room, which it sounds like yours is for vinyl ripping purposes, then the simplest thing (although not necessarily the cheapest) will be to purchase another USB cable to reside between the Mac and the DS so you can keep the one between the Mac and the DS in place permanently. Using the USB input from the MM to DS, you can play the full DSD 128 file without conversion and just stream Tidal, etc., via the Bridge.

So much of what we audiophiles spend time thinking about is theory, so test the theory. I would recommend that you make the effort to swap the USB from the NPC to the DS then listen to those DSD128 files. If the sound is to your liking there’s your solution. Buy a second USB. Adding another layer of conversion via software may not result in any better sound quality to your ear (or anyone else’s for that matter).


#6
jeffstarr said

How have you been listening to those files? Why not get the Bridge installed, compare your options, and if there is no hope of the Bridge II being upgraded to DSD 128, send it back, and optimize your USB signal path. If you do want to use the computer in a remote location just continue using the LanRover.

I had just got about a half dozen SACD rips, and then changed DACs to one that doesn’t do DSD. JRiver converts those to 24/176, and they sound good. Yes, I know they are DSD 64, You might find with Vinyl that 24/176 will be just fine. And finally, if you are going to convert in Vinyl Studio, save the original DSD 128 files to a separate drive, to be used in the future. Don’t do anything that permanently changes those files.

What about Roon? I know very little about it, but I do know the Bridge II works with it. Would that do the conversions? Something to look into.


I’m not touching those original Vinyl Studio DSD 128 files, trust me! And you’re probably right, I doubt I can tell a difference between DSD 128 and PCM 24/176. And with Vinyl Studio, I could batch convert them so it’s not a big deal. Still, knowing they are not DSD irritates me!

I hadn’t actually thought about Roon down-converting. That might be a good solution! Will have to see how that sounds. Thanks!


#7
speeddeacon said

So much of what we audiophiles spend time thinking about is theory, so test the theory. I would recommend that you make the effort to swap the USB from the NPC to the DS then listen to those DSD128 files. If the sound is to your liking there’s your solution. Buy a second USB. Adding another layer of conversion via software may not result in any better sound quality to your ear (or anyone else’s for that matter).

What's really not to my liking is having to buy a long, expensive USB cable!! I sweat interconnects, USB, and power cables are leading me to financial ruin. As opposed to the DS DAC, P10, LANRover, and NPC (not to mention preamp, power amp, dual subs, and speakers) which are all sound investments! itwasntme_gif

#8

See my last post in this thread for a solution

http://www.psaudio.com/forum/directstream-all-about-it/support-for-dsd256-and-beyond/


#9

@jazznut - Here’s a follow up on my initial problem of having a bunch of ripped vinyl in DSD 128 and not being able to play it through the Bridge II. As a reminder, I use Roon almost exclusively while streaming. Before, Roon would try to default convert to 32/176 after negotiating with the DS Sr, which is a no-go as far as the DS Sr is concerned, giving a bunch of digital harsh as the output. So I restricted the max PCM bit depth to 24 bit and DSD 128 would then convert to 24/176, which was fine. It just wasn’t DSD and I think I lost a tiny little bit in the conversion. Less “air” (hate that term, but that’s what it was missing) and instrument separation. Mandating that Roon downconvert DSD 128 to DSD 64 previously required a PCM intermediary step to 32/176 which taxed the CPU and also sounded like PCM with no benefit to the DSD conversion. Now with Roon ver 1.3, build 216, DSD 128 files are directly converted to DSD 64 and they sound every bit as good as the original! Awesome. No need to re-rip my vinyl or hard convert my files. Plus, I can continue to rip in DSD 128, which is nice. This is why I love Roon. They are constantly addressing ways to improve their product. All of a sudden my main issue with Bridge II is no longer a big concern. Very nice.


#10

Great you found that solution! While I didn’t get, why you not just rip your vinyl directly to DSD64, just the advice to check if Roon downconverts over PCM with a -6dB level drop (as most software does) or not. You can check by manually converting one file with the free Tascam Hire editor, which converts while preceiving the level. Then compare the two in level, you’ll hear the difference immediately.

I think you wouldn’t want to have all your ripped vinyl -6dB lower in level.


#11

Roon does not downsample through PCM, as far as I know, and there is no -6dB penalty. It’s a win-win, as far as I’m concerned. Plus my Mac Mini isn’t overly taxed while converting. I would convert to DSD 64, but I’m running up against space issues on my HD right now and don’t feel like dealing with it, honestly. Plus I have over 60 LPs ripped in DSD 128 so, there’s that. I got better things to do, honestly. Besides, the Roon downsampling sounds great!


#12

From the Roon website regarding build 216, “Support for processing DSD content natively without performing a PCM conversion. This will be turned on by default, but can be disabled if needed.” Also, “Significant performance optimizations to the sample rate converters and sigma-delta modulators (needed to make DSD512 practical).”

I was under the impression that you couldn’t do a DSD sample rate conversion without going through PCM, but what do I know. Way to go Roon!


#13

Just some minor clarifications about DSD conversion mentioned in the recent posts - I don’t have any idea what DSP Roon is using for various DSD work (but they are smart people so they probably are doing a right thing):

In general going thru PCM doesn’t need to take a lot of CPU nor does it require “a -6dB penalty”. Going to PCM only takes a low pass filter and that’s one of the simpler DSP things to do… Going to DSD (whether from PCM or DSD) is the medium expensive thing. Decoding DST (the standard DSD compression format) from, say, an .iso is the CPU expensive thing.

If you convert DSD to fixed point PCM with the standard 0dBFS as the maximum value representable you do indeed need some headroom and 6dB is safe. But converting to floating point PCM or having PCM as an intermediate step in a DSD to DSD conversion doesn’t need to truncate the intermediate top bits any more than any algorithm “needs” to truncate the bottom bits of any intermediate values. It’s only at the final destination that one needs to pick a standard format (e.g. 16 bits, 24 bits… with the maximum value near unity, etc.)


#14

Thanks Ted, but I didn’t fully get it.

Why again is i.e. a DSD conversion with Jriver, Foobar or other converters (except Korg, Tascam and obviously Roon) affected with a -6dB drop in level?


#15
amgradmd said

From the Roon website regarding build 216, “Support for processing DSD content natively without performing a PCM conversion. This will be turned on by default, but can be disabled if needed.” Also, “Significant performance optimizations to the sample rate converters and sigma-delta modulators (needed to make DSD512 practical).”

I was under the impression that you couldn’t do a DSD sample rate conversion without going through PCM, but what do I know. Way to go Roon!


That really sounds promising.

I see Roon as a potential 2nd option with its strenghts and weaknesses besides Jriver (which I also like) for me.

So far I was reluctant because Roon’s told to sound worse due to some part of their software concept. Please anyone to veto if there are new reliable infos.


#16

While I’m attempting to clarify a few things let’s talk about DSD -> DSD vs DSD -> PCM -> DSD.

It’s largely a mater of semantics:

if by “DSD” you mean one bit (and never more than one bit) it’s quite hard to do much math.

if by “PCM” you mean more than one bit, then almost anything you do will involve PCM since PCM is essentially base 2 and computers are almost always base 2…

But here are some more practical definitions:

DSD is very high sample rate and noise shaped

PCM is low or moderate sample rate and not noise shaped - i.e. all frequencies up to 1/2 the sample rate are represented equally.

By those definitions you can apply any reversible sample wise operation on DSD even if it involves more than one bit and not loose anything: It’s still high sample rate and noise shaped.

I think it’s perfectly reasonable to consider doing math on DSD at the DSD’s sample rate (even if it involves filtering, etc.) as DSD operation and not a PCM operation.

If on the other hand the sample rate is lowered (even temporarily) then it harder to claim no PCM involved - especially since that will require a filter with a cutoff below 1/2 that lower sample rate (at least if no aliasing is introduced.)

So my advice is to not get hung up on DSD vs. PCM, “one bit processing”, etc. but instead to see what’s the lowest sample rate or bandwidth involved and how often some sort of sample width narrowing (besides the final dithering for PCM or conversion to one bit for DSD) happens. And perhaps secondarily if any sample rate conversions involved use something other than the brickwall filter at 1/2 the sample rate.


#17
jazznut said Why again is i.e. a DSD conversion with Jriver, Foobar or other converters (except Korg, Tascam and obviously Roon) affected with a -6dB drop in level?
0dBFS is the nominal maximum value representable. In PCM 0dBFS value is usually defined as unity, e.g. the maximum positive PCM value is one least significant bit away from unity (and the maximum negative value is precisely negative unity.)

For SACD 0dBFS is defined as 6 dB lower than all ones or all zeros. It’s also called 50% modulation index, i.e. that 50% of the value represented by all ones or all zeros is the 0dBFS level. That’s because DSD starts distorting when the modulation index gets too high. For SACDs in particular you can’t spend significant time above 0dBFS tho you can get to about +3dBFS with no distortion.

So if you are converting from DSD to a file in PCM format the only way to avoid any possible clipping is to have the output 6dB quieter since then the PCM can represent any possible stream of DSD bits, even all zeros or all ones. For properly mastered SACDs you can probably get away with approx. 4dB of PCM headroom instead of 6dB, but you shouldn’t try to get away with no PCM headroom unless you know that the DSD never exceeds 0dBFS anywhere (very unlikely.)

As I mention in an earlier post, if the conversion step is DSD -> DSD you don’t need to be affected by this. It’s when your final format is PCM or if you use multiple steps with PCM as an intermediate output that the 6dB difference between 0dBFS DSD and 0dBFS PCM matters.


#18

I must say I have a bit of a “man-crush” on Ted for always weighing in before we too far off base with these discussions. What an incredible asset to this community. Plus, I feel just a little bit smarter for having read his posts. Kind of how I feel when I read Shakespeare: I don’t understand it all, but sure do feel smarter for having done so. Thanks Ted!


#19
Ted Smith said
jazznut said Why again is i.e. a DSD conversion with Jriver, Foobar or other converters (except Korg, Tascam and obviously Roon) affected with a -6dB drop in level?

As I mention in an earlier post, if the conversion step is DSD -> DSD you don’t need to be affected by this. It’s when your final format is PCM or if you use multiple steps with PCM as an intermediate output that the 6dB difference between 0dBFS DSD and 0dBFS PCM matters.


But doesn’t your last sentence mean, the programs which cause the -6dB drop use some kind of PCM interim step during DSDxxx->DSD64 conversion, which is what I mentioned in post 10?

#20
jazznut said But doesn't your last sentence mean, the programs which cause the -6dB drop use some kind of PCM interim step during DSDxxx->DSD64 conversion, which is what I mentioned in post 10?
The difference is whether that 6dB drop is required or not. Having a 6dB drop doesn't (necessarily) mean that the sample rate was lowered during processing and conversely, having no drop doesn't mean that there wasn't some bad math or a temporarily lower sample rate involved.

When I mentioned one step vs more than one step I was trying to talk about using one command in some program that does a DSD->DSD conversion vs using multiple commands that do some conversion to, say PCM and then another back to DSD. Most conversion utilities do convert to lower rate PCM when going from one DSD sample rate to another, but that isn’t necessary with a well written program.