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Upsampling PCM or DSD in 2022

The purpose of this post is to ask the collective about the best options for upsampling today, and whether it’s worth doing. I stumbled into this topic after recently considering Paul McGowan’s take on DSD, and after reflecting on the upsampling in my home theater system.

Paul believes that DSD is world’s better than PCM. That caught my attention, because, until now, I have been operating under John Darko’s view that high res (i.e. 24-bit and above) is nice but not worth chasing--CD quality is good enough. But audio does seem analogous video. And 1080p isn't good enough for my video streams. So, I now want to give DSD and upsampling a shot.

In my home theater system, I use an Nvidia Shield TV streamer for its AI upsampling, driven by its graphics processor. Plenty of video content is still being released or only available at 1080p. Although upsampled 1080p isn’t as good as 4k, it’s better than basic 1080p. That upsampling makes a big difference for me. I strongly dislike watching 1080p content on my 4k TV. As far as I’m aware, the Nvidia Shield streamer offers the best video upsampling on the market, and it only costs >$200. It occurred to me that I might get similar gratification by upsampling audio too.

Upsampling can be performed at the DAC, streamer, server, or somewhere in between. Here are the major options I’ve considered so far:

  1. PS Audio’s Direct Stream DAC costs 6k. As an FPGA unit, it has lots of extra power that this manufacturer directs towards upsampling, and upsampling PCM to DSD is a major selling point for this device. Unfortunately, you have to get to the Direct Stream in the lineup to experience that feature.
  2. Chord’s Hugo M Scaler costs 5k. Although Chord builds FPGA DACs too, Chord sells a separate component for upscaling. In the audio chain, the M Scaler sits between a streamer and DAC. Because Chord separates out upsampling functionality into its own component, Chord’s solution is likely more expensive than PS Audio’s.
  3. HQ Player software costs >$300. HQ Player is a software service that can be installed on a server, or on a computer that sits between the server and streamer. Besides being affordable, you can pair HQ Player with Roon. The author of AudioBacon reports HQ Player introducing up to 30 seconds of lag to an audio stream when set to the most demanding upsampling algorithm even when used with a powerful Windows computer. But another commenter mentioned that his M1 Apple device introduced zero lag when running HQ Player.

Because the retail price of the components in my stereo system came out to about 5k (when new), HQ Player is where I’m looking for now. Please comment if:

  • You know about some other upsampling options I ought to consider;
  • You have opinions about the value of high res audio or upsampling; or
  • If you have anything you’d like to add to the conversation.
128x128classdstreamer
hgeifman
2,110 posts
 

As described above, I understand that both the PS Audio DirectStream Mk2 DAC and HQ Player up sample PCM to DSD. Obviously, some people believe this conversion results in improved sound quality and others do not. I have no DSD listening experience so I do not know. I also understand that the other components in the system, obviously, influence the overall sound quality (as described above). My questions are:

1) Are there other devices that also up sample PCM to DSD? For example, can I purchase a device that accepts PCM out from my Aurender, for example, converts it to DSD for input to my DAC that supports true 1-bit DSD for DSD content? Does this really MAKE sense?

2) How exactly does PCM get converted to DSD? I know the PS Audio DirectStream DAC uses FGPA with custom instructions to make this conversion. I assume a combination of software and hardware are required but, in simple terms, how exactly does this conversion work? How much computing power is required for a PCM to DSDS conversion?

3) Once the PCM stream has been converted to DSD, how does the DSD stream get converted to analog? Does it use a filter to make this conversion? Please explain?

4) The most important question is how does listening to PCM streams compare to listening to a DSD Stream that has been converted by one of the above devices?

5) My current audio system only streams PCM so I am looking for more information on these PCM to DSD conversion options. Thanks.

 
classdstreamer's avatar
classdstreamer OP
160 posts
 

@hgeifman

I started this thread over a year ago and have mentally made note of other audio upsampling options. Besides offerings from Chord and PS Audio, Lumin streamers support upscaling to DSD, Emm labs DAC upsamples to DSD. I forget what others upsample off hand.

I like watching Steve Huff’s reviews, and in this review of the Lumin U2, Huff claims to prefer Spotify streams upsampled to DSD through the Lumin over high res streams. That is quite a big claim. If I also found that I preferred Spotify streams upsampled to DSD over streams from Qobuz/Tidal, I would pretty quickly drop my Qobuz, Tidal, and Roon subscriptions. But based on my experience with upsampled DSD via HQ Player, I don’t expect to prefer upsampled DSD via Lumin to native high res PCM.

One takeaway from Huff’s video, however, was that an upsampler placed at the streamer level or farther downstream, would benefit all lossy content -- which arguably would benefit form upsampling the most. My wife and I both love Spotify and haven’t made the jump to Apple Music even though we have Apple devices. Although Apple Music contains high res content, I don’t like Apple Music’s policy of deleting my saved music, artists, and playlists if I ever take a hiatus from it’s subscription.

Regarding HQ Player, I found HQ Player to be a laggy and a clunky experience generally. I wasn’t a fan of waiting 5 seconds for music to begin. Sometimes I would press play and nothing would happen. I used HQ Player to see if DSD was something I would get into, but I preferred the sound of PCM to (upsampled) DSD on my system. And, when I used HQ Player to upsample CD quality tracks from Tidal into high res, I ended up preferring those filters that sounded the same as CD quality streamed from Tidal through Roon.

I never did get around to installing HQ Player onto a computer to sit between the Roon Core and streamer, which may solve the inconsistent experience or reduced lag. I also haven’t installed HQ Player on an M-chip Apple device to see if that removed lag as someone claimed. HQ Player allowed me to experiment with my system and get a taste for (upsampled) DSD. I also found it fascinating how different filter/dither options in HQ Player could alter the sound.

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reg19
80 posts
 

@hgeifman HQP does not do the same thing as the PS Audio new DAC does. It does not just upsample to DSD.

It gives you a vast choice of modulators and filters to suit your room and equipment. That is its defining factor.

rms456
37 posts
 

@reg19 , therein lies the issue with HQPlayer, there are many choices of modulators and sampling rates to choose from. I found the process difficult to narrow down for all different types of music, there was no ‘one’ setting that 

a) worked for the DAC

b) different modulators worked against each other for say jazz, 70’s rock, or vocals. 
 

The process was such that tuning HQPlayer was needed per album. That was the time to stop tinkering and listening instead. For years now, I just let the DAC convert PCM/DSD the sample rate of the album, done. The Playback Designs MPD-3 DAC I own internally converts anything to DSD, I liked the sound of that DAC, it now has a fault, so it’s a dust collector. 
The current DAC, Accuphase DC-950 converts anything, it doesn’t upsample to DSD, whatever they use works really well, very happy with it for many years now.

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reg19
80 posts
 

@rms456 I think that one narrows down to perhaps 1 PCM setting and 1 DSD setting for your equipment / room with HQP and not on a per album basis.

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