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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
inrealtime's avatar
inrealtime
26 posts
 

In my many years of experience with DACs and digital formats DSD is indeed best. And PS Audio's Direct Stream is the best sounding DSD DAC I've heard. Almost always a noticeable improvement of PCM files using it compared to directly through a high quality PCM DAC (both with and without the fiber conversion trick, which I also recommend).

I also highly recommend their SACD transport using I2C to send the DSD layer directly to their DAC.

lordmelton's avatar
lordmelton
877 posts
 

If you have a quality DAC and equipment you shouldn't feel the need to upsample.

Upsampling is OK I guess when you have cheaper equipment because the upsampling algorithm is basically filling in holes with guesses produced by the algorithm.

Therefore the upsampled music is not true to source.

audiojan's avatar
audiojan
406 posts
 

I've been using a PS Audio DirectStream Sr. for a few years now and although I've auditioned quite a few other units, none gets close. The DSS has an organic, almost analog, sound that is truly intoxicating. Feed it a native signal (no upsampling) and it's glorious. If you upsample via Roon (which what I have and use), you can clearly hear that it adds a digital "edge" to the sound. Sounds more detailed at first, but further listening and you realize it's just a harder leading edge.

 

If you really want to hear the best possible DAC, get a DirectStream Sr, upgrade the output transformers to Edcor XS4400 and get an external power supply for the digital side, letting the DSS only power the analog side. That beats everything out there for a relatively cheap investment.!!!

classdstreamer's avatar
classdstreamer OP
172 posts
 

A few takeaways from the discussion so far:

  1. People here have a strong preference for a format, whether it’s PCM or DSD. That tells me DSD is something I need to hear, and I can decide whether I prefer it or not. My current DAC doesn’t support DSD, but all of the upgrades I’m considering do, so I will trial DSD at some point in the future.
  2. People with PS Audio’s DAC-based upsampling solution seem to greatly enjoy it. However, server-side upsampling doesn’t seem to be as polarized--for or against. I’m in the process of replacing the rug in the listening room. Hardwood is exposed for now, but I may try A-B’ing Roon’s (PCM) upsampling before and after with the hardwood, and later with the rug.
  3. I just ordered the components to convert cable to fiber right before internet enters the streamer. I’ll try A-B’ing Roon’s (PCM) upsampling before and after inserting fiber as well. If fiber has the effect I hope it does, fiber may help further reveal the benefits/detriments to upsampling.

I’m expecting fiber to make a big positive difference. But from this conversation, I’m not certain whether Roon’s upsampling will be a net improvement. I have a lot of variables to control for, so I’ll be a bit longer before reporting my findings.

redlenses03
94 posts
 

This (can be) a pretty involved topic in so far as understanding the two different formats and especially upsampling in the correct context, since it (upsampling to DSD) is actually fixing / addressing inherent distortion

"Most" DAC’s that use chips (ESS Sabre for ex) as well as CHORD, upsample everything internally and almost impossible to avoid (there are some exceptions and depending on how the DAC designer implements the "chip" can disable certain functions). So the comment above about "cheaper equipment because the upsampling algorithm is basically filling in holes" and "Therefore the upsampled music is not true to source" is incorrect IMHO.

NOS DAC’s (Holo, Mustec, T+A, last gen Lampi’s) are just that and there are a fair amount of NOS DAC’s available nowadays. These are a prime target for umsampling prior to DAC and a widely used method at this time is HQP. Its a great software with many filters and modulators for both PCM + DSD. The developer is all about DSD (upsampling PCM > DSD and native DSD is HQP wheelhouse) and "usually" best if installed on its own dedicated wkst. If using roon (for lib mgmt and sending to HQP), keeping roon on its own dedicated core wkst is a good idea.

The format hi-res is really irrelevant and is used incorrectly in a lot of topics IMHO. It all has to do with provenance > the masters. There are a lot of great redbook sounding CD’s as well as a lot of crappy sounding re-masterd and upsampled and sold as hi-res from same CD.

If the master / recording was done natively in a higher rate (24/96 for example) or DSD, that’s great and more then likely it will sound very good (or as best as the mastering). My point is the bit rate isn’t automatically the end all - you have to know where it came from (to be absolutely certain). I would venture to say many artists now record in 24/96 and very few in native DSD.

DSD IMHO is anything but hard, brittle etc.. and generally speaking my fav format especially on a DAC meant for it.

The use of the new HQP EC modulators and upsampling to DSD 256 is pretty ridiculously good and I upsample everything to DSD 256 or 512 with the orig modulator.

This is all really to say, there is no right or wrong way to go here and comes down to personal preference and ones system.

If you have a solid wkst you can run HQP on with a quality USB card to go DAC direct OR send HQP to an NAA (opticalRendu, Pi, NUC, Fillet etc..) your golden. Additionally, you can now very easily get HQP in an embedded version (custom ubuntu with HQP installed) OS image. Just burn it to your internal M.2 or boot to a USB stick.

 

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