Filter Options in dCS products

Hi,

I am curious that whether dCS products (Rossini or Bartok or Vivaldi in the 2.9 platform) provides any option where one does Not want to select any Filter.

In my (limited) understanding, using filter brings in some sort tone control. In case I don’t want that what is the way to set a ‘No Filter’ setting ?

Regards,
Sourav

All the settings of the filter options in dCS DACs involves some kind of filter. There is no " no filter" option.

I would not view digital filters as tone controls.The filter is there to remove the samples above the Nyquist frequency ( aliases) which is required in order to recreate the original signal that was sampled. However I have read some reviewers describe the subjective effect of some filters as being similar to that of a tonal variation though I think that they are really describing other attributes with a limited vocabulary and have resorted to using the metaphor of a tone control.

Not using any filter could itself also be described as a “tone control” in that it introduces significant levels of high treble energy into the music signal ( those aliases as they haven’t been filtered out). This can be heard by some and its effect will vary subjectively depending upon the programme material. It can introduce harshness or brightness.

I strongly suspect that a preference in some quarters for not using any filter is because the filter that it is being compared with has been less than competently designed in the first place hence the preference for not using it.

Broadly speaking most filter variants are designed to affect the time domain rather than the frequency domain. A digital filter never “brings in” a tone control in a literal sense.

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Or maybe it is about the greatest neutrality of sound reproduction without any interference in processing? So that the DAC only reads zeros and ones and does not change anything. Filters still somehow interfere with the signal and its processing. So maybe such a purist option like the lack of filters would be an interesting solution?
I still do not understand the rules of the filter to the end, although I think I was able to choose the setting that suits me. However, after sending my conditioner to the site, I had to change the settings because I stopped enjoying the sound.
Regards Robert

I’m with Pete Rogers on this one. I’ve heard filterless implementations (one French designer I know was particularly keen on it e.g. for RBCD playback), and apart from the fact that I could hardly sit through a handful songs, to claim it sounds more “natural” when a DAC outputs all kinds of non-musical content, is what it does at all. Filterless sounds more digital. And it’s potentially hazardous for one’s equipment, which is why I don’t know of a single product today that’s filterless. That dCS gives a choice of filters is luxury compared to other products, that’s all. Anyone who’s confused by all the choice may be best advised to go by the recommendations in the manuals:

Greetings from Switzerland, David.

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From your response you appear not to have much knowledge about digital sampling and why digital filters are necessary (not optional). As you say " I still do not understand the rules of the filter".

There is no interference with processing. You are imposing analogue concepts on the digital domain. Digital filters are essential for correct processing and are therefore part of it. It is only possible to correctly reconstruct the original waveform by removing ( filtering) the aliases above the target high frequency ( called the Nyquist frequency in honour of one of the early theoreticians of digital processing, Harry Nyquist) . This has nothing at all to do with analogue filters like you find on a preamp or graphic equaliser.

" So that the DAC only reads zeros and ones and does not change anything" There are actually no zeros and ones in digital processing ( nor anywhere in nature). They are used only in conceptual models as a metaphor for two distinct states that the processor is able to distinguish( which could be called off/on, up/down, left/right, yes/no or 1/0 etc). If there is no filtering of the aliases above the Nyquist frequency, which are created because correct sampling requires a minimum of two samples per sampled frequency, they will be processed by the DAC and form an incorrect part of the resulting analogue music.

Please Google Nyquist and/or Shannon. I am useless at talking about this subject and I am sure that my crude explanation can be improved upon.

Off topic, I do hope that you have read the recent " Bartok Stops Playing in Network Mode" thread as it has provided a solution to the one person other than you who has had trouble with continuous drop outs with Mosaic. The answer is in respect of his network and not Bartok. I strongly suspect that this may be where your solution also lies.

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Pete is spot on, in the realm of digital-to-analog conversion, filters are an essential element for the reconstruction of the original analog signal from digital data. Without a filter, you cannot properly reproduce the original analog signal.

It’s math, not a subjective tone control decision.

Whether the filters are end-user selectable as in the case of dCS DACs, or not, as in the case of Chord DACs with its WTA filter, or PS Audio DS DACs with its passive transformer filter, or EMM Labs DACs with their “active adaptive reconstruction filter” for example, all DACs will have some kind of filter whether they advertise it or not.

There are no DACs without a filter of some kind at the output stage, with perhaps the exception of DAC designers who believe the human ear (or the Speaker) is the ultimate low-pass filter. But I don’t know of any current implementation being sold in the market, probably sounds like crap when coupled with modern high-bandwidth Amps and Speakers :joy:

All this is not to be confused with choice of upsampling/Interpolation filters versus non-oversampling filter-less DACs. Related of course, but a different altogether :wink:

@sourav

I wonder if the “tone control” filters you’re actually thinking of are analog filters applied to analog signals like in Preamps of yore :grin:

My knowledge of D / A processing is small. I did not know that every type of D / A conversion requires a filter to be used for make it correct. My mistake was due to reasoning similar to that in the analog world, filters and color regulators work. I meant to eliminate elements that change the source signal from the audio stream processing path. That is, the most advanced fidelity in mapping the assumptions of the musicians and the producer of the recording.
Regards Robert Tota

If you want to read about digital filters how they affect pre/post ringing and phase these articles by Arcimago is good reading.

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I will read with pleasure to broaden my knowledge about D / A conversion. Thanks to the articles my knowledge will deepen. Maybe I will avoid such dilettant remarks.
Regards Robert

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Thanks to everyone for detailed explanation on this topic.

I believe now my Qs would be what is the default filter for DCS DACs (there should be 2 - 1 for PCM another for DSD) ?

Regards,
Sourav

I am guessing that at this point you do not own a dCS DAC.

There are no default filters. You are able to make up your own mind although dCS do supply suggested settings for a start in the User Manuals. However the available filters vary not only in regard to whether the selected data file is PCM or DSD but also in regard to the resolution. So PCM filter 5 for one resolution is not necessarily the same as filter 5 for another. For example filter 5 is an asymmetric filter for 44.1 but for resolutions of 176.4 and above that type of filter is filter 6 and filter 5 is then Gaussian.

In practice this may only be important during the set up period as once you have decided what filter you like for each resolution the dCS DAC remembers it and and it is automatically applied thereon ( unless you change your preference of course).