Convert PCM to DSD on the fly to DSD capable DAC

Nobody? Would the conversion process be applying some filters to the mix otherwise I’m struggling to understand how the DSD conversion will sound any different to the redbook given the redbook is a finite set of data to begin with?

Digital filters in the DAC for PCM vs. just an analog filter at 50-70KHz for DSD.

Steep “brick wall” digital filtering which has to be implemented at around 20kHz in Redbook comes with various problems, including pre and post “ringing” of the (ideal) digital square wave, creating timing issues. Upsampling in PCM permits less aggressive digital filters which can reduce such artifacts. DSD permits analog filtering well above audible frequencies doing away with digital filtering artifacts altogether. There’s a free trial available for HQPlayer. Try it and see what you think.

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DSD is always playback natively unlike PCM which required over-sampling digital filter Therefore DSD produces almost perfect impulse response needed to produce complex harmonics. The downside is it produce higher out of band noise. This noise can be reduced by a simple 50kHz filter.

If you read my post from a little earlier I described it as “starkly more musical” - how I describe that in words I’m not sure but it to me it is obviously more enjoyable to playback CD rips (FLAC) as DSD256. Yes, it is to do with the filters used in HQPlayer. Why not try HQPlayer; as long as you already have a suitable computer it’ll cost you nothing.


Yes you did.

I also contacted Signalyst about HQPlayer licensing and I can confirm my understanding is correct, “Roon will be interfacing with HQPlayer via its API, in which case it’s not really an integration as they’ll still be standalone software installs that just happen to know how to talk to each other”. This means that Roon and HQPlayer will continue to be licensed separately and you will not need to purchase another HQPlayer licence when the hook up with Roon comes on stream.


Jaon, I don’t think it is good etiquette to include the email addresses of others in our posts as they’ll be harvested by the bad guys bots.


Good point. I’ve edited the post to delete email details

Hi AndyBob,

Is it possible to add this feature without having to wait for integration of HQPlayer? If I’m not wrong, there’s already a feature in Roon that can convert DSD to PCM on the fly for those who don’t have a compatible DSD DAC?

You mean DSD to PCM already ?

Oops! My mistake. It should be DSD to PCM on the fly for those don’t have a compatible DSD DAC. I’ve corrected.

For information/clarification, carried forward from HQ Player Integration:

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Hi Guy,

At the risk of exposing my inherent technical ignorance, my understanding is that DSD > PCM is simpler than PCM > DSD.

I haven’t heard of plans by Roon to implement PCM > DSD within Roon itself. The planned integration with HQPlayer and existing capacity to send an audio stream to a JRiver zone would seem to me to make it somewhat redundant.

Let’s set a notification for @danny and @brian to let us know of any news in that regard.

Incidentally Archimago looked at some DSD > PCM converters and a couple of others in a follow-up back in April. Always interesting to see his measurements, along with Juergen’s (JRiver) views in the comments.

That’s my understanding, too :smile:

We have no plans to develop our own DSP for PCM->DSD–inventing DSP processes is not our core competency. We would be more inclined to license anything like this from a third party.

We do intend to integrate with HQPlayer, which provides this sort of thing. Many DSD DACs also perform PCM->DSD conversions internally, and offer some of the same benefits in hardware.

While it’s true that many DAC’s convert PCM to DSD internally, the hardware in the vast majority of DACs only has a tiny fraction of the processing power available in a modern computer/music server. In addition, with a DAC, there are typically no options to select the filtering and upsampling algorithms and typically, no software updates to further improve them over time.

HQPlayer provides Jussi’s incredible skill with DSP, along with selectable filters, algorithms and bitrates. In addition, HQPlayer offers different “strengths” of the same type of algorithm, so that you can exploit the full power of a Core i7 processor or get most of the same benefit with an easier load on a lesser powered server. For many of us, HQPlayer PCM > DSD upsampling sounds better than anything else we’ve tried.

All of these HQPlayer options are actually very easy to use. There’s one drop down list, each, for algorithm and filter. You can adjust them and decide which you prefer and which your server can handle comfortably. On the other hand, I find HQPlayer’s interface for selecting music to be terrible. This is why there is so much interest in combining the strengths of Roon with those of HQPlayer. If you like them both, to use either, as great as it is, is to miss the other.

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