Upsampling and filters

While rereading the Rossini manual, I just now found out (page 35) how to properly set the filters while upsampling. However, filters are a personal choice, but you have to make 2 choices in the case of upsampling to DSD.

The Rossini DAC features two sets of digital filters: one set for PCM and one set for DSD.

  • The PCM Filter is applied when the unit is receiving PCM data.
  • The DSD Filter is applied when the unit is receiving DSD data or when the DSD Upsampling feature is active.

While upsampling PCM data to DSD or DSDx2, both filters are active, but only the PCM Filter setting appears on the display.

So, if you are upsampling to DSD or DSDx2, do not forget to set both the desired PCM Filter and DSD Filter in Mosaic (Settings > Audio > dCS Processing Platform - set both filters F to your choice).

Erno this has always been the case as the filter choice available changes with the type and resolution of the incoming data. So not only are there different choices between PCM and DSD ( although they share the same filter numbers in the display, F1 - F5) but they may also be different in accordance with the resolution. The numbers alone do not represent a specific filter type.

Let’s take what always appears as F5 in the display. If the incoming data is DSD F5 has " a relaxed roll off". But if you are playing PCM 16/44.1 F5 is an asymmetrical design. Filter F5 with 176.4 or above PCM is a Gaussian design. The way in which filters are made available goes way back to Elgar and Elgar+. dCS have always only offered filter choices that are considered “reasonable” for the input data type and therefore may alter in their nature in accordance with the latter.

Perhaps you are missing my point. If you play PCM and have your DAC set to DSD upsampling, then not only you have to set a filter of choice for the original PCM file, but also a filter for the DSD upsampling stage. So you could have F3 for PCM + F2 for DSD, at the same time. If you are unaware of this, and just have set a PCM filter, then the default DSD filter in case of DSD upsampling is F1, but you can change that, if you know you have that choice. If you never play DSD files, but have set upsampling to DSD, you might never look at DSD filters, but you have to.

I had an earlier go at this but decided my response was too wordy and unfocussed.

So , you do indeed have to set different filters for PCM ( for each resolution) and DSD ( for both resolutions). You only have to do this once for each resolution that you actually use as Rossini will remember the setting. So as all PCM, if remaining as such, is upsampled to DXD there is one filter setting to set that you prefer and for DSD there is one for DSD 64 and one for DSD 128 ( which may well be the same , it’s up to you).

uote=“Ermos, post:1, topic:3228”]
both filters are active

No, only one is active at any time and it is automatically selected from memory. If you do not make a choice it will be the filter that is the factory default.

Sorry Pete, the Rossini manual says (page 35) clearly both filters are active:

You are right . I was looking at the same page " filter" and did not scroll further down the page to " DSD Filter". What an odd arrangement. You can select between 5 DSD filters but not see what you have chosen as only PCM filter numbers appear in the display - is that what it means? That however is when upsampling from PCM. I presume that if playing native DSD the PCM filter is inactive and the number displayed will be that of the DSD filter.

I understand the PCM filter being active at the same time as this is broadly similar to what happens with the multi box systems where the upsampler provides a choice of filters which are distinct from the DAC filters and run simultaneously.

Yes, indeed. Only in Mosaic you can set and see it.

Yes, indeed. Please note that the displayed DSD filter shows as Fx DSD, whereas a not-upsampled-to-DSD PCM filter just shows Fx in the display.

Can you hear significant differences among the 78 options?

Yes, and you? :wink:

No :cry: I think my hearing isn’t great these days. My headphones are the original HD800 so not great by modern standards.

I am able to hear difference is the various maps. My clock is still in its box waiting until I can work up energy to install it. Maybe that’ll make the filters more distinct?

I do not hear immediate and significant differences between the filters upon switching . I find it necessary to live with them for some time until their characteristics become apparent even if almost subliminally. For example if I switch from filter 4 to filter 2 I either cannot tell the difference or think filter 2 may be a tiny bit sweeter. It is often considered as a great filter for classical music. If I leave it engaged I will guarantee that at some point , maybe a day or two later, I have to switch it out as it has become almost cloying as far as I am concerned ( YMMV).

So even though they may not provide immediate gratification ( e.g. like having a bass boost button) selecting the correct filter for each resolution is necessary as otherwise you may find yourself no longer wanting to listen further in that session yet, due to their subtle effect, be unable to pin down quite why.

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The biggest difference I notice between the different filter(s) / combination(s) I hear because of the discovery in my OP of this topic.

When playing old music from the seventies and eighties (PCM with filter F3), and upsampling to DSDx2, the second active filter is usually F1DSD, but as indicated by the manual, if the music sounds harsh, switching to F2DSD does wonders.

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I would second Pete’s @PAR observation, that filters need time to unfold their effect. Also, finding a difference between settings takes initial time with new equipment. When one gets used to what is changing in music presentation and sound, the subtleties become more obvious.

After having lived with the Vivaldis for a bit, I agree with Erno @Ermos, that filter choice can depend on the actual album aside from or instead of input rates. For some albums I don’t hear meaningful differences between the various settings. And with some, there can be as large an effect as feeling a warm and tingly feeling in the gut. Which says as much as


Here’s a useful mention of a very similar issue by @Andrew from dCS beginning in the middle of post 2:


Don’t forget DSD Filter 5 . This is the most recent addition to the array oi DSD filters and is what dCS currently advise as the default choice for Vivaldi. dCS would not devise a new filter setting and recommend its use if it was not worthwhile.

Marco, frankly I do not recommend changing filters for individual albums even if there is a slight audible difference, This is the type of behaviour where the enjoyment of music takes second place to being an audiophile/ techno nerd. Like in the domain of analogue vinyl audio where I know one guy who changes SRA for each side of an LP. Little musical enjoyment just attention to its medium of sound. As I have said before home audio is entertainment not a scientific experiment. Find a setting that is acceptable for the majority of tracks of that resolution and then leave it alone.


Hello Pete @PAR,

changing settings (sample rate, filter, mapper) per record might not be a wise general recommendation. For the reasons you mention. Beyond that, what you describe is not my own approach to audio. You could for example take what you read from me in the Music section. My posts deal with the music itself, not with sound. Those short writings are a welcome exercise for me to delve deeper into an understanding of music.

As an experienced meditator I am trained in working with my mind. Maybe half of the time when I want to hear an album in its entirety, I purposely leave all everyday issues behind. Then let all accumulated emotions go. And finally dissolve any disturbing thoughts. Thereafter I settle into awareness itself. Until the mind wanders and then I bring it back to gentle, open or focussed awareness.

Resting in awareness can be open or it can have focus. The first useful focus is the body consciousness (body sensations) as it brings the mind into the here and now. Furthermore it serves as a sturdy anchor. The second focus while listening to music in this way is the ear consciousness. It is very interesting for example to stop with the perceived sound (not hifi sound) and intently not go on to let words rise in the mind consciousness. That’s a little bit like stopping with the taste of a strawberry on the tongue without naming the experience ‘sweet’, ‘delicious’ and so on. When doing that, the experience becomes undescribable. The third focus is the mind consiousness. This is the hardest one to keep awareness of. Our tendency to get enthralled with all the many thoughts crossing the mind is heavily ingrained. Awareness of the mind consciousness is somewhat like looking at the sky. In this analogy the sky is the mind and thoughts are the clouds. When we rest in awareness it is like gazing at the sky. There is clarity and knowing.

There are 128 combinations for each sampling rate —> 1,008 configurations. Add in the dithering from the clock we’ve got 2,016 unique sound profiles.

Unfortunately I own Alibaba stock so probably won’t have time to work through this since I’ll be too busy auctioning off my tangible assets to fund the semi daily margin calls. Silver lining is that in a couple of months I’ll likely have to pawn the Rossini so I might be able to entirely avoid this process.

Hello @Katzky I see your point. Too many possible choices, too easy to waste large chunks of time. I don’t know whether dCS gives recommendations as to exact filter settings in the Rossini manual. They do in the Vivaldi manuals. For example they recommend filter 5 for the upsampler plus filter 5 for the DAC when the upsampler receives 44.1 KHz PCM data and delivers DSD data to the DAC. Those recommended values worked very well for me to start off.

Dithering of the clock signal I set on or off a couple of times and left it untouched for a couple of days to hear what difference it makes. I am not sure whether I heard much of a difference between on and off. My slight personal preference is with dither on. Now the clock settings remain constant all the time.

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Thanks Pete. I have just started to experiment with filters on my new Rossini, and did not reach nr. 5 yet :grinning:

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Perhaps we should reread this, and wait for the next chapter: Filtering in Digital Audio