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.
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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.

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.

 

I’m relatively new to this forum, and I’m certainly not looking to make any enemies here. I’ve always maintained the view that if someone is happy with the sound of their audio system, and it gives them joy listening to music, that is a beautiful thing—and it would be a self-serving, destructive act to attempt to sully that experience for them by criticizing their choices.
 

However, I see a lot of talk on here about the “sound” of a DAC, particularly in favor of PS Audio’s $6,000 take on this technology, and Paul McGowan’s “proprietary” terms he invokes to describe its ephemeral results. And it is a very different thing when one is suggesting to others that the indefensibly priced DirectStream is “the only way to go” if you want to achieve the pinnacle of sound, from a component that shouldn’t have a “sound” to begin with—especially when their claims are as scientifically baseless as the language used by the marketing mouthpiece of the manufacturer himself. Has anyone ever asked themselves what factors justify that price point, for a device that exists almost exclusively in the digital realm?
 

What exactly should a DAC “sound like”? A DAC is nothing more than a computer, designed to convert a digital sample of an original master back into its original form with the least amount of errors possible—errors that take the form of noise, distortion or “jitter” when our amplifiers transmit the signal to our headphones or speakers. If a DAC is doing its job properly, it shouldn’t have a “sound” other than what was intended in the mastering process. If it sounds “warmer” than other DACs, assuming that all other components are unchanged, then that’s either a product of distortion (errors) or of the cognitive bias introduced by having spent $6,000 on the device itself. Logically (and therefore scientifically), the DAC should be an invisible part of the signal chain—reproducing the original master as faithfully as possible, allowing us to tailor the sound to taste in our choice of amplifiers, DSPs/ASPs and headphones.  
 

For those in the market for a DAC, or an audio system in general, please do your research before spending your hard-earned cash on your choice of components, and please be very wary of the advice you receive from others, particularly when they are suggesting to you that you would be a pinhead if you didn’t buy into the marketing claptrap from “premium” brands. A very wise audio engineer once told me to spend my hard-earned cash in the following order of cost, from least to most—and it has always served me well: Cables—>Streamer—>DAC—>Amplifer—>Headphones. The latter component is the most personal one, the one that has the most significant impact on the resulting sound. Find a DAC that has the best measurements (lowest noise, distortion and error rate)—if you do your homework you’ll find that recent advances in technology have brought us options that require a minimum of expense to do the job exceptionally well. Peace.

@srkbear Thanks for trying to save us all from the snakey oil salesmen out there. It's highly appreciated.

However Paul McGowan's SACD/CD transport is a ground breaking product that outputs pure native DSD over I2s to a DAC, eliminating and freeing the user from restrictive conversion processes.

As far as the sound of DACs is concerned it's more of how much more detail, soundstage, presence, realism, imaging etc., not just warm or cold.

We don't tailor sound using amplifiers and other components, we look to find a synergy that will bring us as close to the live event as possible. Whether that's a concert or studio session.

I wasn’t being snarky in my post, so I’d appreciate not being condescended to or demeaned in turn, if I may so ask. I’m well aware of PS Audio’s coup in circumventing Sony’s DRM licensing limitations. Perhaps a little explanation of the back story of this stroke of genius is in order so folks won’t continue to mistake it for “innovation”. 

Sony is the original inventor of SACD technology, as you know. And since the inception of the format, Sony has forced all manufacturers of SACD players to follow their own hardware limitations, namely downsampling all digital audio streams to a maximum of 48 kHz and 16 bit. Sony also owned a majority of the masters originally released in the SACD format, and they invoked this restriction to prevent bootleggers from pirating their own digital masters that far exceeded the resolution of standard Red Book CDs. 

You’ll note that PS Audio, the only outfit who has managed to circumvent these restrictions, did not release their DirectStream DAC in isolation—they did so with the simultaneous release of first their PerfectWave SACD player, that was designed to offer this benefit when coupled with one of their proprietary DACs, via McGowan’s beloved IIS protocol. Then they “upgraded” the technology to their DirectStream line, at even higher prices. 

PS Audio could not have achieved this “innovation” without the express permission and cooperation from Sony, without incurring major lawsuits. Even high dollar Marantz SACD players do not have access to the bit perfect DSD layer, because they are just as restricted by Sony’s DRM rights as any other manufacturer is. So PS Audio did not achieve this breakthrough by any strokes of technological brilliance—they merely bought the rights to supersede the licensing limitations from Sony, who would only agree to this if the format was limited to a non-standard (at the time) transmission protocol—namely, IIS. 

So that $6,000 price tag you paid for to gain access to that DSD layer largely went  to Sony for their licensing rights. There’s no magic otherwise in PS Audio’s DAC or SACD player, nor is there anything superior about IIS over standard USB (despite McGowan’s inscrutable claims to the contrary). It’s all a ruse to get you believe that McGowan has mystical gifts as an engineer, and to convince you to part ways with a month’s worth of salary to buy these two units as a pair accordingly.

Lest you misunderstand my motives, I’ve long been tempted to buy into this just so I could access the only way possible to play my SACDs natively through my headphone setup. If you’re happy with these assets, as I’ve said before, I champion and celebrate that for you, and I have aspired to what you have myself for some time. Where I take exception is when folks start implying that the DAC itself offers superior performance over much less expensive offerings, or when folks pass along McGowan’s unsubstantiated scientific claims that he promotes to obfuscate the truth behind DirectStream’s technology, the “benefits” of IIS, and his profit-seeking motives. PS Audio is inarguably savvy, but their ingenuity is in strategy, not so much on the bench. Peace.