Jump to content
IGNORED

Upsampling to anything other than your DAC's internal conversion rate


Recommended Posts

I wonder why, with all the positive feedback of audiophiles using software upsampling and filtering, there aren't more manufacturers producing NOS filterless DACs...

 

Does it somehow disturb the status quo?

 

R

 

More expensive parts than using a commodity DAC chip, and puts you on your own as to how to implement the circuit (thus requiring engineering time and again more expensive). And to reach what fraction of an already small market?

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment

Generally, to use internal DAC filters/modulators least, feed the highest DSD rate the DAC will accept. For Chord and DACs that don't accept DSD, feed the highest PCM rate they'll accept.

 

Now for the exceptions...

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment
This is going to be a very unpopular statement around here. Let me quailfy it by saying that my NAD M51 DAC does not do DSD. However, it upsamples all PCM input to 844kHz PWM.

 

I have experimented extensively with Audirvana's iZotope settings, as well as HQPlayer, which I also own. If there is any audible benefit with software upsampling, I'm just not hearing it. It always sounds veiled or muted. Maybe I'm just not using the right upsampling settings. Or, perhaps this is because my system and/or my ears are not sensitive enough, but the question that newbies and others here like myself want explained is how does upsampling add any enhancement to music from its native format? You can't add detail that's not there, and if we are talking about ultra-high frequency noise or artifacts, who can hear that, anyway? Is there inherent distortion with PCM at Nyquist frequencies when played "straight"? Miska has explained it in theory, but, is it audible? if so, I would LOVE for someone to suggest some specific Audirvana or HQPlayer PCM upsampling setting for my particular DAC that will enhance the SQ.

 

So what external sample rate will it accept?

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment
I know it's not often people take the time to make the distinction. I use it this way:

 

native streaming vs DoP streaming (that's until the USB interface).

 

native DSD DAC or non-native DSD DAC (DAC-level).

 

What do you classify as native vs. non-native DSD DACs?

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment
Yeah as far as I know . I could be wrong but I think the Yggy upsamples all files to 24/192 .

 

I believe Yggy upsamples to 358/384KHz, but the max it will accept is 176.4/192KHz, so it does do at least one round of upsampling on any signal fed to it. Miska's software offers two "closed form" filters, which are the same general type as those used in Schiit's multibit DACs, so if you have one of these Schiit DACs you might wish to experiment with them.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment
The Teac UD-H01 that I used to own upsampled everything to 192k with its ASRC, it says so in the website literature.

But when I moved from BitPerfect to HQPlayer and fed the DAC with upsampled redbook the improvement in sound quality was quite noticeable, which means that the ASRC was rubbish.

 

I have recently ordered a custom designed and built NOS filterless DAC which can be fed PCM at 384k, making the most of HQPlayer's PCM processing capabilities.

The alternative would have been a DSD-able NOS DAC.

 

Which commercial DACs besides the Teac 501 can have filtering and possibly the ASRC turned off?

 

R

 

The easy alternative is to find a DAC whose highest input rates aren't upsampled internally. In other words, say you have a PCM DAC that would upsample lower rate inputs to 352.8/384KHz, but allows you to feed it 352.8/384KHz and doesn't do any further resampling. Or, more typical these days, you have a DAC that accepts DSD128 and won't do any further resampling to input at that rate. So you just feed these DACs the max rate and it's the same as using an NOS DAC.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment

 

If we assume (which may not be a fair assumption) that all of the upsampling is bit perfect in that it applies no DSP or other changes to the signal except duplicating data points exactly, then the differences you hear will all be due to the choices of filters applied (chosen for you in the case of Schitt/Chord/Wyred and chosen by you in the case of HQPlayer/Audirvana).

 

It's never bit perfect, since part of the idea is to change the sample rate (i.e., add more bits). And this is true of DAC internal sample rate conversion and filtering as well. But now think of what Miska said regarding the fact that the data is not the signal. As you mention below, what is being done is that the (digital) data is being changed in service of getting the (analog) signal closer to the performance, whether that was live or as it came from the studio.

 

Most of these conversions are "lossy" in the mathematical sense that the original data points cannot be recovered by a mathematical operation from the converted data. A few (the Schiit filters and a couple of Miska's) are "closed form," which means the original data points can be recovered. So they are not "lossy" mathematically, but they are still not bit perfect. As to whether such filters sound better, I'll leave this to the listeners and developers.

 

Given the range of opinions expressed about filters/upsampling, I think it is fair to assume that the filters DO have an impact on the resulting sound. Now, if you chose the DAC(s) you have by comparatively listening to them against other DACs, part of what you were doing was showing a preference for that manufacturer's choice of filters. Thus, if you "love" that particular sound, it would not be surprising that you would prefer it over a set of filters that produce a different sound. For most folks who use their DACs with HQPlayer or Audirvana but chose no upsampling, I think that all they are really saying is "I like the filtering choices made by my DAC manufacturer."

 

The next level up though would be to ask, which of the above is closest to the original recording? I think Miska has clearly shown why upsampling data to a higher rate allows a set of filters to be applied (whether by him or by your DAC manufacturer) that produces fewer artifacts in the audible range (so has nothing to do with higher frequency hearing/response beyond 20kHz/steeper transients, etc. that often get referenced to say upsampling can't make a difference).

 

Exactly. There are still disputes over whether some aspects of filter differences are audible (for example, differences of thousandths of a second in transient response). I don't have the tools or knowledge to carry out measurements, but let me say two things from a subjective point of view:

 

- The first time I used HQPlayer, I was shocked at how different from each other the various filters sounded to me. I was not expecting anywhere near that level of difference.

 

- Something very similar happened when I first tried the "Plus" version of Audirvana. I was surprised at how much difference even small adjustments in some of the parameters could make in the audible results. Now since I didn't know what I was doing (and still don't in any real sense), it's quite likely some of the settings I experimented with were "pathological," i.e., stuff that people who know about filters would never do. So of course some of the changes I made were going to create very audible differences. Still, it was very interesting to me that I felt I could hear changes of a percent or two in some parameters.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment
So it's easier to find a DSD-able commercial DAC that doesn't upsample?

 

R

 

Yes, just because there are more delta-sigma than PCM DACs these days.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment
Great discussion.

 

But I do want to bring this back to the central point about DAC knowledge. How do we know what the magic sample rate is for each DAC that minimizes the DAC's internal proceeding?

 

I doubt DAC vendors are willing to disclose this, are they? For example, my Ayre Codex DAC supports up to DSD128 for DSD, but 32/384 for PCM.

 

Even if I accepted your point that something like HQPlayer is going to sound better, what would I set the upsampling to?

 

 

Sent from my iPhone using Computer Audiophile

 

It's not really that complicated. As I said before upthread somewhere, the choices are essentially two:

 

- For most DACs, set the upsampling rate to the highest input rate the DAC will accept. Easy peasy.

 

- For a few DACs that will accept DSD, you may want to send the highest PCM rate.

 

That's pretty much it. The only other decisions you would need to make, and probably the harder ones, are what filter and modulator to choose if using HQPlayer; what filter parameters and modulator to choose if using A+; or with XXHighEnd on Windows (since the filtering is pretty well set and it doesn't do DSD), your choices from among the myriad OS tweaks XXHE allows you to make.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment
The DAC may not understand where the 192 came from, but 'we' know the file has undergone sample rate conversion. It may be all numbers in the mathematical domain, but we are not multiplying any easy equation, like 2 x 4 =8. The algorithms for SRC are surely as complex for upsampling process as they are for the downsampling process.

 

There maybe more processes out in the wild but I only know of Izotope that's built into Sound Forge and Audirvana +. The Izotope SRC can be change the steepness, max filter length, cutoff scaling, alias suppression and Pre-Ring. I don't have much of a clue how to set them (the point of another thread), let alone make conclusions how they work. On the occasion I do SRC to create a CD from a 96/24 file, there's nothing much lost, so by luck SRC works.

 

Actually it's more difficult to try to downsample with audible transparency than it is to upsample. Your intuition that "there's nothing much lost" when you create a CD from a 96/24 file is not correct. Once again this has to do with unavoidable mathematical tradeoffs between time domain and frequency domain performance that become more problematic the closer one gets to the audio band. Upsampling moves you away from the audio band (that's why it's been standard in the digital audio industry since before separate DACs even existed), downsampling gets you closer to it and thus is more difficult to do without audible problems.

 

By inference, you're telling me that upsampling SRC is transparent? If you apply mathematics, no matter how 64bit precision you make it, there will be a difference.

 

Nope, though some people may find it to be. Just saying that unless you choose from among a tiny handful of true NOS DACs, your choice is to upsample in software or in your DAC. Upsampling with competently done software is usually measurably better than doing so in the DAC by reason of greater computing resources when using the former. And if you do choose a true NOS DAC and run Redbook through it, there is a significant, measurable increase in harmonic and intermodulation distortion versus using upsampling. (Again, that's why upsampling has been standard in the digital audio industry for decades.)

 

Others have posted that they prefer not to upsample and I would agree after listening to various sample rates for HQPlayer, including DSD256 for 18 months. I don't believe it is problem that the computer is working harder and is noisier as a result, it's the FLAC (uncompressing) vs WAV argument, no. Maybe Izotope is better. Maybe I drag out the TASCAM DA-3000 recorder and make some comparisons. Now, which filter to use?

 

Certainly no one can argue with personal preference.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment
Jud: as you can see my feeble lawyer/VC mind struggles with the precision of these engineering concepts :)

 

Yeah, I often feel like I'm attacking the problem with a blunt instrument too. :)

 

The part I found interesting in playing around with the A+ parameters in iZotope were the necessary tradeoffs and learning much more about my own personal sensitivities to a) ringing, b) decay, c) transient attack, d) frequency flatness and others. Quite often things that sounded great on day one became tiresome after a few days or weeks. The longer I listened, the more less was more (I think you experienced some of the same in your progressive leaning toward less-invasive flatter filter slopes). It was that learning with iZotope that then allowed me much more quickly to choose which filters I liked in HQPlayer (even if I didn't know what fine-tuning parameter tradeoffs Jussi had made).

 

I also have to assume that in choosing some of these filters we are "making up" for limitations elsewhere in our system -- for example a bookshelf sized set of speakers might seem much larger with a bit more reverb and slower decay. With my giant Magnepans, exactly the opposite was true -- I tended toward leaner, more nuanced presentations.

 

I would rather think of one part of the system "working with" other parts. An example I've used before is that my main system speakers are set up (including the crossover filters) to be time and phase correct, which may be a reason I prefer linear phase to minimum phase filters there. It seems to me subjectively that this results in better imaging (and in fact I've done a bit of blind testing where I've preferred linear phase).

 

One area where Miska in particular has tried to make up for deficiencies elsewhere in the chain is by providing among the HQPlayer choices "apodizing" filters, to substitute the better transient performance of the HQPlayer filters for worse transient performance that is often characteristic of the filters used in the creation of CDs. On the other hand, there are people who don't particularly like apodizing filters, which leads to what I say below.

 

All that being said, I do think there is value in us collectively trying to come up with a list of starting points for different DACs. Put differently, I'd like to make sure I'm going through filter choices that make the greatest possible impact because I have chosen a DSD512 or 24/384 starting point wherever that is possible and thus knowing where to start then pushes the learning over to the other filter choices rather than choice of upsampling.

 

As noted before, I think choosing software upsampling rates is really as easy as upsampling to the max input rates for most DACs, with the exception of certain DACs (like the Chords) that accept DSD input but should be fed the highest possible PCM rates.

 

Beyond that, I doubt we'll find a lot of consensus, because people not only have different tastes, we actually hear differently from each other. As you said, a lot of choice in DACs comes down to filtering preference, and there's hardly unanimity in choice of DACs. But for me it's nice to try to find a better understanding of what the different filters and their choices of parameters are doing, so at least I have some idea of *why* I may prefer one filter to another.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment
Even order harmonic distortion is a good thing then, music has gobs of harmonics, so makes sense to add it in, rather than being clinically cold.... any plans to add it as a "filter"? A+ does, I believe it's Mode 2.

 

 

Where did you get that from? "Mode 2" isn't even a filter, let alone designed to add gobs of harmonic distortion. If you want that, don't oversample or use any filters at all.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment

Mode 1 and Mode 2 are "integer modes" in Audirvana Plus. These have to do with avoiding OS audio processing rather than harmonics or the topic of this thread, upsampling.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment
You gotta proof better than simply saying[/url] :

 

He's provided quite extensive proof in many comments and blog posts with test results.

 

It would therefore seem to be up to you to read what he's written rather than demanding he repeat himself for your benefit.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment

Agreed, so rather than any further complaints, let's get back on track.

 

The majority of DACs seem to work pretty nicely with upsampling to max input rate. Miska has mentioned Chord as exceptions. What are other possible exceptions?

 

- I'd nominate DACs with ASRC (asynchronous sample rate conversion) that take all inputs and convert them to a single PCM sample rate (prior to SDM) as a jitter minimization technique. Benchmark does this, as do many older USB DACs. Any other newer DACs in this category?

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



×
×
  • Create New...