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In a digital system how important it an analogue preamp?


DomT
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Digital volume control can be "transparent", it really depends on how it's implemented.
For example, HQPlayer performs its DSP at 64/80-bit floating point, you can easily attenuate 60dB without loss.
Here's an interesting piece on Roon's software-based volume control:
"DSP Volume Control in Roon and XMOS" - Carl-Werner Oehlrich
Does that use "upsampling" to convert a 16/24 bit signal to a higher one? (I use inverted commas as I thought upsampling was done at the sampling rate rather than bit rate but I assume it will in practice lead to the same result of increased resolution.)

I'm suspicious of players/DACs that do that to then apply a reduced bit rate attenuation. The upsampled signal is not a copy of the "original" analogue signal (or sound if recorded entirely in the digital domain) but an interpolated estimate. (Forgive me if that's only oversampling, I can't see any other way than interpolation to upsample but am happy to learn.).

To then reduce the bit rate back towards where it came from must chuck out some of the baby with the bathwater. Unless it's clever enough to be able to separate the two and only take out the interpolated bits. I guess that's possible somehow.. anyone know?
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39 minutes ago, Lawrence001 said:

Does that use "upsampling" to convert a 16/24 bit signal to a higher one? (I use inverted commas as I thought upsampling was done at the sampling rate rather than bit rate but I assume it will in practice lead to the same result of increased resolution.)

I'm suspicious of players/DACs that do that to then apply a reduced bit rate attenuation. The upsampled signal is not a copy of the "original" analogue signal (or sound if recorded entirely in the digital domain) but an interpolated estimate. (Forgive me if that's only oversampling, I can't see any other way than interpolation to upsample but am happy to learn.).

To then reduce the bit rate back towards where it came from must chuck out some of the baby with the bathwater. Unless it's clever enough to be able to separate the two and only take out the interpolated bits. I guess that's possible somehow.. anyone know?

It’s all maths intended to make the output as close to the analogue signal as possible.

Digital music is captured at 24-bit and processed at 32-bit exactly to avoid losing headroom, and then the final mix can be downrezed to 16/44.1

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3 hours ago, Lawrence001 said:

Does that use "upsampling" to convert a 16/24 bit signal to a higher one? (I use inverted commas as I thought upsampling was done at the sampling rate rather than bit rate but I assume it will in practice lead to the same result of increased resolution.)

I'm suspicious of players/DACs that do that to then apply a reduced bit rate attenuation. The upsampled signal is not a copy of the "original" analogue signal (or sound if recorded entirely in the digital domain) but an interpolated estimate. (Forgive me if that's only oversampling, I can't see any other way than interpolation to upsample but am happy to learn.).

To then reduce the bit rate back towards where it came from must chuck out some of the baby with the bathwater. Unless it's clever enough to be able to separate the two and only take out the interpolated bits. I guess that's possible somehow.. anyone know?

99% of DACs perform either up- or over-sampling and many process at 24-bit.

Most ADCs digitise the analogue signal at 24-bit using an SDM chip so the signal is DSD before being 24-bit PCM. And then for distribution purposes it is lossily downrezed to Redbook CD.

Most DACs use sigma-delta chips which also convert PCM to DSD before the A/D conversion.

Bip perfection is a myth.

Edited by tuga
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19 hours ago, tuga said:

You are listening through a system composed of electronic equipment and speakers in a given room.

The same mic feed will sound very different with these systems in these three rooms:

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This was your response to justify why people may not enjoy listening to the actual recording in the mastering suite. I said that was weird and you say it’s normal. The thing is that unless the visitor had been to the actual recording session then they would not be able to comment as they would have no reference point and in any event relying on audio memory as the mastering would happen later  

But nevertheless in your view people may not like the sound that they are hearing in the mastering suite, but you advocate strongly that these same people should spend money on HiFi equipment that is transparent and accurate to the original recording.

Why on earth should people buy neutral and transparent systems if they didn’t even like the sound in the mastering suite? If it’s so very subjective as you say why be so forceful in your comments about neutrality and transparency? 

Edited by DomT
Mastering
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On 23/10/2021 at 08:03, Fourlegs said:

My experience is that using a MFA Baby Ref V2 compared to taking a Chord Dave direct to the power amp was that the Baby Ref did not change sound at all in terms of character, tone etc but there was a very slight (and I mean very slight) difference in absolute transparency with the MFA. I am not being fooled, the MFA as near as makes no difference did not impart any sound of its own on the signal. Also I am not fooled because I have owned many TVCs and yes they are different but to my ears the best of them such as the Baby Ref V2 really are just about invisible from a sonic point of view.

Was this one of the TVCs that you mention you have measured? It would be really useful to the conversation if you could actually be more specific in your claims because at the moment it is just generalisations and which seem to conflict with the specifics which others of us have experienced.

Can we have some specifics named please? Also, it would be really useful to have some more specifics of what you say you measured. The fuzzy photo doesnt really help.

Nick your findings are similar to what a I found when I placed a Creek OBH-22 after my Benchmark DAC; albeit the Creek was not as transparent as yours. The difference though with my active preamp was very distinct in that music had more life. Did you ever try an active preamp with the Dave?

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2 hours ago, DomT said:

This was your response to justify why people may not enjoy listening to the actual recording in the mastering suite. I said that was weird and you say it’s normal. The thing is that unless the visitor had been to the actual recording session then they would not be able to comment as they would have no reference point and in any event relying on audio memory as the mastering would happen later  

But nevertheless in your view people may not like the sound that they are hearing in the mastering suite, but you advocate strongly that these same people should spend money on HiFi equipment that is transparent and accurate to the original recording.

Why on earth should people buy neutral and transparent systems if they didn’t even like the sound in the mastering suite? If it’s so very subjective as you say why be so forceful in your comments about neutrality and transparency? 

I don't force "transparency" or accuracy on people. I think that they should buy what they like.

I try to understand their preference in terms of "presentation" and make suggestions. And I attempt to correlate the description of what they are hearing an liking with the performance of the equipment in question.

You could say that I am forceful on the classification or labelling of something as (more or less) "transparent" or accurate, which as I said depends on the topology and implementation and is assessed (primarily) by its measured performance.

21 hours ago, DomT said:

Listening at the mastering session is listening to the actual recorded performance. People may not enjoy listening to the actual recorded performance but that would be a bit weird wouldn’t it?

It is a bit weird, I agree, but people like what they like and what better proof of that pluralism that the wide array of choices evidenced by us Wammers and audiophiles all around the world?

With our equipment choices we are, in a way, remastering or remixing our recordings. The goal for many is not the accurate reproduction of the recording/signal but a sonic "presentation" which favours aspects we find the most relevant. I have to admit that it took me some time to realise that.

Perhaps trained listeners (e.g. mixing and mastering engineers) would choose the same type of equipment (Toole's research seems to point in that direction) but us audiophiles have tastes as varied as we have individuals. This is why I am critical of purely subjective reviews; they merely describe a tasting session from the perspective of one, hardly something that others can relate to.

Edited by tuga
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2 hours ago, DomT said:

This was your response to justify why people may not enjoy listening to the actual recording in the mastering suite. I said that was weird and you say it’s normal. The thing is that unless the visitor had been to the actual recording session then they would not be able to comment as they would have no reference point and in any event relying on audio memory as the mastering would happen later  

But nevertheless in your view people may not like the sound that they are hearing in the mastering suite, but you advocate strongly that these same people should spend money on HiFi equipment that is transparent and accurate to the original recording.

Why on earth should people buy neutral and transparent systems if they didn’t even like the sound in the mastering suite? If it’s so very subjective as you say why be so forceful in your comments about neutrality and transparency? 

Just to be clear, I am not doubting your assessment that placing the ARC in the signal path in your system sounds better to you.

But, like @Fourlegs, I have reasons to believe that the improvement it brings to the table is an effect that is achieved through the addition of (euphonic) distortion. And there's nothing wrong with that. Such effects are used in music production all the time, either through recording and mixing equipment choices or from the use man of acoustic, electronic and digital tools available to the engineers.

But, in my opinion and experience, placing extra components in the signal path will lead to some degree of degradation, even if/when they bring something "extra" to the "presentation".

So, even though the preamp stage is probably the best place to add euphony, nowadays with "transparent" digital volume control one can bypass the preamp altogether if one doesn't need multiple inputs for analogue sources. That is why I suggested that you look into one of ARC's DACs. I wasn't trying to offend, or doubting your assessment and preference, only trying to help.

Edited by tuga
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6 hours ago, tuga said:

With our equipment choices we are, in a way, remastering or remixing our recordings. The goal for many is not the accurate reproduction of the recording/signal but a sonic "presentation" which favours aspects they find the most relevant. I have to admit that it took me some time to realise that.

This seems spot on to me, recorded music is always a facsimile . Enjoyment is key for me. and if you are listening to music 8 hours a day then you probably need a different sounding system from one which will be used for just 90 minutes of listening. I remember an answer given by the founder of Nottingham Analogue years ago, asked for hifi advice he said “try and hear as much live music as possible“

Also…..as music lovers even the best hardware is limited by the software.  Even if care is taken with recording it feels like the most “transparent” system is too good for a lot of recordings. I do not want to be restricted to just mofi vinyl (etc),  I do not want to be limited to the 1000 albums that meet the standards needed to be enjoyable on an Uber system.

Edited by callen24returns
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2 hours ago, DomT said:

Nick your findings are similar to what a I found when I placed a Creek OBH-22 after my Benchmark DAC; albeit the Creek was not as transparent as yours. The difference though with my active preamp was very distinct in that music had more life. Did you ever try an active preamp with the Dave?

With the Dave I used to use an Icon Audio LA5 TX which is a valve pre amp and this was connected to a pair of Icon Audio MA845 Mk2M power amps. Then I changed to the MFA passive pre because I found it a more natural sound. The Dave direct to the 845 power amps did not work at all. The sound was horrid. In fact I have found that any DAC with volume control always so far with me sounds horrid and flabby when connected direct to any of the valve power amps I have tried. Hence why I was using a pre with the Dave.

However after changing to the ss Pass Labs power amps I found I much preferred Dave direct to them with no pre.

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Interesting thread - I think there's a tendency to apply ideology and/or a particular kind of logic to this - I used to think that fewer components in the signal path = greater fidelity to the original signal (what some might refer to as transparency), but my personal experience has led me to believe that this is an oversimplification - I have tried a number passive preamps, a Music First TVC (admittedly an earlier incarnation than the baby ref referred to in this thread), and experimented with direct connection of DACs when this has been an option, as well as a number of different active pres - I have come to the conclusion that there is something more than just some absurd idea of adding "euphonic distortion" going on - possibly the precise way in which gain is applied to the original signal plays a vital part in preserving its vitality/musicality: the number and topology of the stages involved all playing their part - this obviously means considering the pre and power amps together, and doesn't suggest that either approach to preamplification is necessarily better or worse at achieving a satisfying end result - in the context of my own system, I like to think of the essential elements of the musical signal being gently teased apart by the gain stages of my preamp, and passed across to the power amp to carry out the 'heavy lifting' in the simplest way possible - the results, to my ears at least, speak for themselves :) - MH

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