Upsampling


What’s the purpose of upsampling DACs?

Previewlordrootman
Same purpose as all other tech specs, to get you thinking they matter. The more thinking the less listening. Ad copy is a lot easier to write than it is to make sound quality you can hear.
Two fold.  One, the filter behavior improves, hopefully pushing any aberrations out of the audible spectrum. Second, the DAC chip itself may perform better with more data, even if that data doesn't actuall increase the content of information from the original.

Upsampling is not all the same however, there's linear extrapolation and curve fitting with the latter requiring quite a bit more math and compute horsepower to do right.

In the end, only your ears matter though. :)
right on the money Erik. I stream at DSD 512. To my ears it creates an airer more detailed presentation that I like. Not all gear can do this successfully.
Hey @tuberist,

I tried this with my Brooklyn. I did not like it at all, especially compared with original DSD files from Blue Coast.

YMMV,

Erik
mr millercarbon... you’re so cynical. why do you post here? i don’t think you’re having fun with audio. how is advertising for golf or cars any different than audio? both have new and improved merchandise every year in order to move more product. is the new stuff better than last year’s? i doubt it but it’s up to me to decide.
mr millercarbon... you’re so cynical. why do you post here?
To learn. For example I learn who is capable of reading and thinking and who is having a hard time with it.
i don’t think you’re having fun with audio.

I get PM'd all the time from people who read my posts and find them both informative and entertaining, in pretty much equal parts. There's even ones who appreciate my "wordsmithing". Who'd a thunk? I'm thinking of starting my own YouTube Channel. Have you tried reading my reviews? So much great stuff! My system is better than I ever even thought possible. I'm having the time of my life!

how is advertising for golf or cars any different than audio?

Golf balls you hit. Cars you drive. Audio you hear.

both have new and improved merchandise every year in order to move more product. is the new stuff better than last year’s? i doubt it but it’s up to me to decide.


Nice, but you got your work cut out for you catching Captain Irrelevant.

I write, almost always, to make a serious point. Only instead of boring blah blah blah I write in a style that tweaks and instigates and provokes thought. Like right now you are thinking, well who knows. Whatever. Point is you are thinking. At least I hope you are. Way too little of that going on these days. Way too little.

You inadvertantly got one thing right. Upsampling is like ad copy: irrelevant. You can explain it all any way you like. At the end of the day someone will simply plug in some non-upsampled player that will sound unambiguously better and that will be the end of your upsampling story. When you have lived through as many pure copper long grain crystal heterodyne monolithic cryogenic nano silver coating geometry phase timing synchronized stuff as I have it may begin to dawn even on you that I do indeed have a point.

The next day someone will ask what is the point of having a lot of watts? Or edge wound voice coils. Or MOSFETs. Or DSD. Or whatever. My answer will always be:
Same purpose as all other tech specs, to get you thinking they matter. The more thinking the less listening. Ad copy is a lot easier to write than it is to make sound quality you can hear.

When just over-sampling, it is to reduce the analog filter requirements pretty much exclusively. Though there is certainly a "following" for non-oversampling DACs, most of us want to hear what is on the CD or in the digital source, and not artifacts that were never part of the music. 

If your sample rate is 44.1KHz, and the audio bandwidth is 20KHz, there is only a 2KHz band between sample bandwidth (44.1/2 = 22.05KHz), and music 20Khz. To eliminate all the artifacts requires a very high order analog filter (many stages), which is going to itself create large phase artifacts in the audio bands.

When you upsample audio, you don't interpolate between samples (or shouldn't), you insert 0's between samples. 20-30-40 would become 20-0-0-0-30-0-0-40-0-0-0 (for 4x oversampling). This shifts the spectrum of the artifacts to 4x the sample frequency. Then you can use mainly digital filters to remove the artifacts. These digital filters can be something called linear-phase that does not wreck the relative timing of different frequencies. This is then followed by a much simpler analog filter which has much less impact on the phase response.

Almost all modern audio DACs chips have built in over-sampling. Most that build their own DACs, also use over-sampling, sometimes at very high frequencies. There are "claims" made w.r.t. some using FPGAs about the size of their digital filters and an improvement in "accuracy" but for all the hand-waving, good luck getting a number pinned down (to justify).
Miller
You really do like the sound of your own voice don't you ( convert voice to type for this media).


Don't stop the signal!
Thanks for great responses I’m learning something new 
I have Cambridge Azur 851N is upsampling 
I stream from tidal Qobuz and Spotify 320kb 
the fact is when I stream 16/44.1 on both tidal and Qobuz vs Spotify 320kb same original recorded music / version can’t tell the difference 
I can easily see the difference in 24/96 ,24/192 and MQA  but not on 16/44 vs 320kb
 is because of upsampling? my system includes Klipsch KLF 30 Parasound A21+ Michi P5 preamplifier Parasound P6 Sony Z1 a pair of SVS SB16 ultra and PC13 ultra and MacBook Pro thanks 
Way way larger differences between uncompressed 16/44.1 and Spotify 320kb, then between 16/44.1 and 24/96 or 24/192. 24/96 and 24/192 may be different versions. Oversampling would have nothing to do with it.
The 851n does feature 24/384 Upsampling but that surely is not default.
It has to be in the settings to choose what level of Upsampling you desire or run native.

I can clearly hear a big difference between Spotify and even base Qobuz of 16/44.
Upsamples everything to 24/384. If they didn't, they would have to use more aggressive analog filters and/or selectable filters. This makes it easier and may make the clock easier.