aussievintage Posted June 7, 2021 Posted June 7, 2021 7 minutes ago, davewantsmoore said: The whole idea that such behaviour from a codec, that while it will "mangle" some signals .... will "sound good" ...... isn't as far fetched as it may sound. As many famous people have said (in varios ways) "what they eye can see the ears don't mind" (or words to that effect) ..... ie. you can measure things which look ugly, which don't sound so bad. Puts me in mind of my beloved low power SET amplifiers.
rantan Posted June 7, 2021 Posted June 7, 2021 (edited) 38 minutes ago, El Tel said: Pro-mqa crowd have an unshakeable argument: it sounds better to them. You can't argue with someone else's subjectivity. Anti-mqa crowd ought ignore any component that can be undone by marketing BS and mealy-mouthed words. You cannot argue against it when obfuscation and moving the goalposts is the standard modus operandi. Instead, the anti crowd should focus on the undeniable fact that this is a solution looking for a problem that just happens to be grasping at owning the entire playback chain and locking us all into a proprietary format. That fact is the killer for the anti argument. I don't give a flying-**** how good it might sound, I am not signing-up to it. I'd rather stop streaming altogether than have no choice but to use it. Exactly. This whole issue is not and has never been, about sound quality. It is about an anti competitive proprietary platform which seeks to lock in consumers to a walled garden where one company controls every level of music production and marketing. We should all be very careful what we wish for. Edited June 7, 2021 by rantan typo 7
Satanica Posted June 7, 2021 Posted June 7, 2021 18 minutes ago, El Tel said: I don't give a flying-**** how good it might sound, I am not signing-up to it. I'd rather stop streaming altogether than have no choice but to use it. I don't quite agree with that. If there was evidence that it sounded better than I would be interested in using it and I would be prepared to pay a bit of money for it. But I'm not paying money for nothing and right now all I see is nothing at best. 1 1
Volunteer Volunteer Posted June 7, 2021 Volunteer Posted June 7, 2021 (edited) 50 minutes ago, Satanica said: I don't quite agree with that. If there was evidence that it sounded better than I would be interested in using it and I would be prepared to pay a bit of money for it. But I'm not paying money for nothing and right now all I see is nothing at best. If it comes all pervasive, you won't have a choice. That's the issue. Its sole reason to exist is to put music buyers back on the treadmill. It happened when we went from vinyl to CD when the physical medium was the only method of distribution. The reinvention of formats has historically helped the record companies maintain their business model which is now going to the wall as margins with streaming are much lower. Reinvention of formats has also helped hifi gear manufacturers too; it gets the punters onto the upgrade path. All things being equal, none of this would concern me; as methods and technology move on, we get the benefit. This being said, if the underlying format is not open (like CD and vinyl physically, or like PCM digitally), then control is not in the hands of the consumer. Supporting it, is in effect providing a case for a closed ecosystem. One of the things that alarms me, is that mqa has reportedly been seeking to get its DAC partners to force all conversion through the mqa decoding path, even the open formats. Why? It's clearly a crap idea to force compliance in this way when manufacturers like Lumin currently push non-mqa streams through a non-mqa DAC path in their kit. If mqa make this happen, they will have the ability to influence the sound of non-mqa streams and potentially provide a false picture of format superiority. I'll let you join the dots on that one. Edited June 7, 2021 by El Tel Punctuation and spelling. And idiocy. Again. 4
LHC Posted June 7, 2021 Posted June 7, 2021 7 hours ago, El Tel said: One of the things that alarms me, is that mqa has reportedly been seeking to get its DAC partners to force all conversion through the mqa decoding path, even the open formats. Are there any real evidence that DAC manufacturers are "force" to take this route? Evidence of such coercion would strengthen the case you are making.
Volunteer Volunteer Posted June 7, 2021 Volunteer Posted June 7, 2021 1 hour ago, LHC said: Are there any real evidence that DAC manufacturers are "force" to take this route? Evidence of such coercion would strengthen the case you are making. It is under consideration for the mqa roadmap apparently. The position is that it could become a prerequisite for future mqa certification (in a similar way that mqa certification precludes a digital-out post-MQA processing from the DAC so as to prevent analysis). I've read so much on this topic in various repositories that I can't always find info a second time around. By all means take it with a pinch of salt, but I am not into hyperbole or misrepresentation of information.
LHC Posted June 7, 2021 Posted June 7, 2021 Worth watching PS Audio as a MQA partner. They have stated their preference for DSD over MQA. If PS Audio is strong-armed into running all non-MQA streams through a MQA decoder/pathway, then we have a real problem.
TP1 Posted June 8, 2021 Posted June 8, 2021 7 hours ago, LHC said: Worth watching PS Audio as a MQA partner. They have stated their preference for DSD over MQA. If PS Audio is strong-armed into running all non-MQA streams through a MQA decoder/pathway, then we have a real problem. As I understand it, MQA can only work on PCM streams.
davewantsmoore Posted June 8, 2021 Posted June 8, 2021 2 hours ago, TP1 said: As I understand it, MQA can only work on PCM streams. MQA as a format involves "augmenting" PCM, per se. ie. MQA is PCM. The filtering that MQA applies in the playback device, OTOH .... could be applied to a 1-bit audio format, although it takes a fair amount of computation to do that.... and so most converters would not have the ability.
zippi Posted June 8, 2021 Posted June 8, 2021 2 hours ago, TP1 said: As I understand it, MQA can only work on PCM streams. My understanding is that this is one of the reasons DSD streams often get converted to PCM in the processing before DA conversion. (ie for MQA process or any other digital post processing/filtering applications in the DAC)
Grant Slack Posted June 17, 2021 Posted June 17, 2021 On 08/06/2021 at 2:46 PM, zippi said: My understanding is that this is one of the reasons DSD streams often get converted to PCM in the processing A DSD file can’t be edited, so any signal processing requires conversion to PCM. A DSD file that seems to have had signal processing has inevitably been converted to PCM (or DXD, which is just a misleading name for PCM files to placate DSD fans who think PCM is inferior), edited, then converted back to DSD for distribution (sometimes with a higher-than-PCM price tag). cheers 1
davewantsmoore Posted June 17, 2021 Posted June 17, 2021 5 hours ago, Grant Slack said: A DSD file can’t be edited, so any signal processing requires conversion to PCM. This is not technically true..... it just that it requires significant computational power to modify DSD.... nobody built a custom chip to do it (not enough market) .... and until the last ~10 years general purpose computer chips (ie. PCs, etc) were not fast enough, especially not in a form which could be put inside a DSD workstation, and run many channels of edits in real-time (and so "traditionally" any DSD edits were => more bits / less samples, ala PCM) Today, it can be done. Something like HQplayer (for example) allow you to do with a powerful computer. 2
Grant Slack Posted June 17, 2021 Posted June 17, 2021 (edited) 2 hours ago, frednork said: Roon does it too That would, in Roon, require converting to PCM, or its proxy, DXD, as I mentioned above. cheers Edited June 17, 2021 by Grant Slack 1
zippi Posted June 17, 2021 Posted June 17, 2021 3 hours ago, davewantsmoore said: This is not technically true..... it just that it requires significant computational power to modify DSD.... nobody built a custom chip to do it (not enough market) .... and until the last ~10 years general purpose computer chips (ie. PCs, etc) were not fast enough, especially not in a form which could be put inside a DSD workstation, and run many channels of edits in real-time (and so "traditionally" any DSD edits were => more bits / less samples, ala PCM) Today, it can be done. Something like HQplayer (for example) allow you to do with a powerful computer. This whole spiel above by @davewantsmoore boils down (for most currently practical purposes) to @Grant Slack quote below: 9 hours ago, Grant Slack said: A DSD file can’t be edited, so any signal processing requires conversion to PCM.
frednork Posted June 17, 2021 Posted June 17, 2021 1 hour ago, Grant Slack said: That would, in Roon, require converting to PCM, or its proxy, DXD, as I mentioned above. cheers not according to Roon brianBrian LuczkiewiczRoon Labs: CTO Oct '17 We do indeed process DSD without performing a DSD->PCM conversion first. The signal path is reflecting that accurately. I’m going to explain how it works–keep in mind that there are some subtle technical details here, and some background knowledge is required to understand them fully. Processing DSD isn’t nearly as straightforward as processing PCM. With the exception of a few simple operations, you can’t process it directly in the 1-bit representation. There are more steps involved, but it’s possible to perform those steps in a way that keeps all of the important properties of DSD intact. First, I’ll explain DSD->PCM conversion, because it helps to understand the other technique in a relative sense. DSD->PCM conversion starts with a with a DSD signal and produces a signal with two characteristics: PCM representation (lower sample rate, wider samples) Low noise floor throughout the frequency domain of the PCM format that is as flat as possible. The first one is obvious–we need a PCM-like representation at the end. The second goal is more subtle–it is saying that the content of the signal must look like a PCM signal. It must be accepted and played properly by PCM equipment. It must be processable by downstream DSP processes that expect to work with PCM data, and so on. It must not cause damage to equipment that’s expecting PCM. This is accomplished in three steps: Start with a DSD stream, and widen from 1 bit-per-sample to 64 bits-per-sample Downsample it by 8x (so DSD64 -> 352.8kHz, DSD128 -> 705.6kHz, etc). Apply a low pass “reconstruction filter”. This filter also exists in a DSD DAC, but since we are effectively simulating the DAC, we must simulate that aspect here too, since PCM DACs do not have this filter. The reconstruction filter removes the noise inherent to the DSD signal before it can reach equipment that might not be prepared to handle it. Most of the energy in a DSD signal lives in this noise (well over 95%), so even though the noise is all at inaudible high frequencies, it’s important to filter it out so that your gear is not asked to turn that energy into loud, high frequency sound. If you look at a spectrogram of DSD->PCM converted data, it looks like a PCM signal. Depending on the source material, and the sensitivity of your spectrogram, you might see a bit of a very quiet noise floor in the area where the transition band of the noise shaping filter used during mastering crosses over with the transition band of the DSD->PCM low pass filter (30-60kHz for DSD64). OK, so now that DSD->PCM is explained, lets talk about the case you’re actually interested in–the one where we process and output DSD without converting it to PCM. This works like this: Start with a DSD stream, and widen from 1 bit-per-sample to 64 bits-per-sample Apply a low pass filter to remove the bulk of the inherent noise energy from the widened signal. Apply processing steps to the wide intermediate format. Send the signal through a sigma-delta-modulator to re-render the “wide” 64-bit stream into a 1-bit DSD stream. The low pass filter (2) in this process might sound like the reconstruction filter we discussed above, but it is very different. It is much more lenient, less steep, and it only attenuates frequencies over 100kHz–and these already have a very poor SNR because of the inherent noise shaping in DSD, so we can be sure that no meaningful information existed there in the first place. Without the filter, sound quality suffers significantly or the sigma delta modulator risks becoming unstable (i.e. starts outputting horrible sounds that ruin your ears and if you’re unlucky your gear too). At step (3) the signal is structurally similar to a PCM signal–in that it is comprised of a series of multi-bit samples. However, it does not have content typical of PCM signals and it maintains the DSD sample rate. If you looked at a spectrogram of the intermediate format in (3), it would look just like DSD, except with the bulk of the noise above 100kHz severely attenuated by the low pass filter. By maintaining the original sample rate through processing, the time-domain characteristics of DSD are maintained. By designing the filter to stay far away from musical content, the frequency-domain characteristics are maintained too. Sometimes this form of processing, or this intermediate format is referred to as “DSD-Wide”. We didn’t use that term because some people have defined DSD-Wide as an 8 bit intermediate format (whereas we use 64 bits…a luxury of precision afforded to us by running on modern desktop-class CPUs) and I didn’t want to create confusion.
Grant Slack Posted June 17, 2021 Posted June 17, 2021 Actually, according to Roon, “Roon currently does not support processing DSD signals directly--if the processing is requested, Roon begins by converting DSD into an extremely high-resolution form of PCM called DXD” IMO the quote you showed definitely loses DSD which is 1-bit by definition. It is just a bit (pun) of word-smithing to say that the exact form of multi-bit that they lost DSD to, wasn’t exactly the conventional definition of PCM. Big deal. That’s what the DSD cohort used to say about DXD: “let’s insist it isn’t PCM so we can say we are better than PCM” sort of claim. 1
davewantsmoore Posted June 17, 2021 Posted June 17, 2021 10 hours ago, Grant Slack said: That would, in Roon, require converting to PCM, or its proxy, DXD, as I mentioned above. Not necessarily. https://help.roonlabs.com/portal/en/kb/articles/hqplayer
davewantsmoore Posted June 17, 2021 Posted June 17, 2021 (edited) 8 hours ago, Grant Slack said: That’s what the DSD cohort used to say about DXD: “let’s insist it isn’t PCM so we can say we are better than PCM” sort of claim. Sure, but lots of people say lots of silly things. Let's not base the whole thing around the idiocracy (?!?!, ok ) Roon also say: Quote If you are interested in processing DSD content from Roon without converting the DSD to DXD first, it is possible to use Roon with HQPlayer--an external piece of software that specializes in this sort of processing. As to whether or not Roon can do a similar thing themselves (without HQplayer) ..... seems a bit ambiguous to me (using only 5 minutes of sluthing). Some quotes imply the use of "DSD wide" .... others imply "DXD using 64bit @ DSD512 sampling rates, and the need for a very high power CPU (which is akin to what HQplayer does ...... but drops the extremely ill defined and confusing "DXD" moniker in there" (why they would say DXD there is beyond me). ... and other sections of their forums and docs imply convert to 384khz PCM. While it might be neat to define "DSD as 1bit" .... the important thing here is the sampling rate (and how any conversion is done, and/or lack of). Why does it seem everything that I ever encounter that involves Roon over the past few years, leaves me doing a massive face palm? So close, yet so far. Edited June 18, 2021 by davewantsmoore 1
Grant Slack Posted June 18, 2021 Posted June 18, 2021 2 hours ago, davewantsmoore said: While it might be neat to define "DSD as 1bit" .... the important thing here is the sampling rate (and how any conversion is done, and/or lack of). Hi Dave, While I am in full agreement, the reason I fully agree is because I don't see any harm in making competent conversions from 1-bit to multi-bit. OTOH I sense that some in the audiophile community are less agnostic than I, and are convinced that DSD is preferable to PCM (or any "PCM-like" multi-bit variety) from a purity and simplicity perspective, including simplicity of conversion to analog, and convinced that this ultimately leads to purity of sound. To which I say, people are kidding themselves with notions that such purity and distinction exists in the real-life digital audio processing world. (As John Siau has written, in commercial DSD releases, the direct path is a myth.) All 1-bit music data is promptly converted to sigma delta at various stages, and all PCM music data is promptly converted to sigma delta at various stages. Digital audio is all mixed-blood; there are no pure heritages. No point in kidding ourselves. And you know what? It works brilliantly, even though each conversion is lossy. The reason studio techs aren't carrying long sad faces that their workflow involves compromised conversions, is because it works so well, and the intermediate conversions are what's best for the outcome. Also, I believe HQPlayer uses DXD as its intermediate format. There are very limited things it can do in 'direct DSD'. If so, case closed. cheers Grant 1
davewantsmoore Posted June 18, 2021 Posted June 18, 2021 (edited) 5 hours ago, Grant Slack said: While I am in full agreement, the reason I fully agree is because I don't see any harm in making competent conversions from 1-bit to multi-bit. If you are ONLY adding more bits.... then this is, sure... totally lossless. If you are also talking about adjusting the sampling rate..... then the devil is in the detail. Quote OTOH I sense that some in the audiophile community are less agnostic than I, and are convinced that DSD is preferable to PCM (or any "PCM-like" multi-bit variety) from a purity and simplicity perspective, including simplicity of conversion to analog, and convinced that this ultimately leads to purity of sound. Yeah, I don't think that. DSD can be as good as any other bit depth / sampling rate...... they can all easily store music. As to wether something would sound better than something else..... it depends on the damage that's been done to it. Changing sampling rates, can do that damage. Quote All 1-bit music data is promptly converted to sigma delta at various stages, and all PCM music data is promptly converted to sigma delta at various stages. I don't agree that this is always true..... but when it is...again, the devil is in the detail as to how that is done. Quote Digital audio is all mixed-blood; there are no pure heritages. Eh? Plenty of digital audio is created in a certain sampling rate/depth ..... and then released to the consumer at this same rate/depth. Quote The reason studio techs aren't carrying long sad faces that their workflow involves compromised conversions, is because it works so well, and the intermediate conversions are what's best for the outcome. What would some of those conversions be, for example? Quote Also, I believe HQPlayer uses DXD as its intermediate format. You can ask HQplayer to output in PCM. ... but it's focus is "DSD". Sometimes people call what they do "DSD wide" ..... .but people should be very careful jumping to conclusions about what HQPlayer (and similar) are doing based on any "name". As I said before, the important thing is that the sampling rate does not change.... and a sufficiently well performing SDM is used. Quote There are very limited things it can do in 'direct DSD'. If so, case closed. ? What is something that is cannot do in "direct DSD" ? (ie. without modifying the sampling rate). Edited June 18, 2021 by davewantsmoore 2
Grant Slack Posted June 19, 2021 Posted June 19, 2021 Hello Dave, AFAICT one thing HQPlayer Pro can do in Direct DSD, is to modify the sampling rate. Don't ask me how, but the product feature list says so. But if you were to suggest it could apply PEQ in Direct DSD, I would ask for proof that it doesn't jump to intermediate DXD. Which, regardless of sample rate change or not, represents a conversion from pure 1-bit to SDM multi-bit. Anyhoo, I'm mainly reading this thread to learn. I just wanted to chip in to the discussion about attempting MQA in 1-bit, as if it was really important and an advantage, to which I pointed out that multi-bit/PCM will almost certainly have crept into the path from studio microphone to home loudspeaker, (especially for all-digital recordings). Hence the purity idea is more theoretical than anything. cheers Grant
davewantsmoore Posted June 20, 2021 Posted June 20, 2021 18 hours ago, Grant Slack said: AFAICT one thing HQPlayer Pro can do in Direct DSD, is to modify the sampling rate. Don't ask me how, but the product feature list says so. Sure.... it can remodulate anything into DSD.... including DSD. 18 hours ago, Grant Slack said: But if you were to suggest it could apply PEQ in Direct DSD, I would ask for proof that it doesn't jump to intermediate DXD. Which, regardless of sample rate change or not, represents a conversion from pure 1-bit to SDM multi-bit. Yes.... it does... but would fear you would read things into that you shouldn't. How it is done: 1. Start with DSD (eg. ~2.8mhz samples, 1 bit per sample) 2. Convert to 64bits per sample (80 bits per sample?). So, yes - at this point you have "multibit" audio. Is this "DXD"?! (No) ..... Some people call this "DSD-wide". Yes, there is the potential for distortion here.... but the high sampling rate and enormous precision (bit depth) make the infinitesimally small. 3. Apply the EQ/change to the 64bit audio 4. Apply a SD modulator to convert to 1bit "DSD". One could rewrite the above steps.... 1. Start with DSD (1-bit) 2. Apply SD modulator to generate new 1-bit audio (and baked into this specific modulator, is the distortion that you wanted, ie. your EQ). Voila.... no intermediate conversion to "multibit". What would the problem be with "converting to multibit"..... the same as any "bucketed measurement system". Quantisation distortion. Using a high bitrate completely dodges that. The 64 bit granularity is 1,099,511,600,000 (1 trillion) times more than 24bit 18 hours ago, Grant Slack said: Anyhoo, I'm mainly reading this thread to learn. I just wanted to chip in to the discussion about attempting MQA in 1-bit, as if it was really important and an advantage, to which I pointed out that multi-bit/PCM will almost certainly have crept into the path from studio microphone to home loudspeaker, (especially for all-digital recordings). Hence the purity idea is more theoretical than anything. cheers Grant
davewantsmoore Posted June 20, 2021 Posted June 20, 2021 19 hours ago, Grant Slack said: Anyhoo, I'm mainly reading this thread to learn. I just wanted to chip in to the discussion about attempting MQA in 1-bit, as if it was really important and an advantage, to which I pointed out that multi-bit/PCM will almost certainly have crept into the path from studio microphone to home loudspeaker, (especially for all-digital recordings). Hence the purity idea is more theoretical than anything. The advantage is not in any "bitness" .... it simply in the lack of distortion. Resampling audio on under-powered realtime hardware implementation is a large potential source of distortion.... and really where both MQA and DSD are coming from. ie. "go fast, don't resample". Using a computer (gaining vastly more power, and/or sidestepping real-time) lets this be avoided.
frednork Posted June 20, 2021 Posted June 20, 2021 3 hours ago, davewantsmoore said: How it is done: 1. Start with DSD (eg. ~2.8mhz samples, 1 bit per sample) 2. Convert to 64bits per sample (80 bits per sample?). So, yes - at this point you have "multibit" audio. Is this "DXD"?! (No) ..... Some people call this "DSD-wide". Yes, there is the potential for distortion here.... but the high sampling rate and enormous precision (bit depth) make the infinitesimally small. 3. Apply the EQ/change to the 64bit audio 4. Apply a SD modulator to convert to 1bit "DSD". One could rewrite the above steps.... 1. Start with DSD (1-bit) 2. Apply SD modulator to generate new 1-bit audio (and baked into this specific modulator, is the distortion that you wanted, ie. your EQ). Voila.... no intermediate conversion to "multibit". What would the problem be with "converting to multibit"..... the same as any "bucketed measurement system". Quantisation distortion. Using a high bitrate completely dodges that. The 64 bit granularity is 1,099,511,600,000 (1 trillion) times more than 24bit Just for my own info, isnt this exactly what the roon guy says they do? If not, how do they differ from HQplayer aside from more filters as most people seem to think they are different.
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