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Is big better? (A data into DAC musing)

Jimbob54

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so this is an odd thing…

software transport: Apple Music (lossless)

computer: A) AppleTV B) MacBook Pro

connects: A) Optical B) USB

DAC Displaying: A) PCM 48 B) PCM 768

now assuming the streams are being streamed at X resolution then processed via the (computer) which determines what encoding the DAC interprets.

and considering that these differences should only be minor and arguably almost unnoticeable (apart from by cats and dogs).

The reality is that the sound is far superior via the MacBook, it’s unsurprising really given the computer processing comparables, and the difference in PCM conversion?

listening to Prince’s Sign o’ the times the soundstage is much wider, the instruments more defined and the actual sounds/notes are clearer with more timbre and texture. And yes whist distracting myself and the wife from the worry of our cat being at the vets I roped the poor Lass into helping me conduct blind tests, the difference is unmistakable.

and as we’re still awaiting news about the cats health I’ll try and get her to help me test it with the MacBook output set to PCM48 so it matches what’s being sent via the AppleTV (which sounds compressed)

curiouser and curiouser….

Its possible one of the streams has a degree of volume levelling/ normalising that the other doesnt so (possibly) what comes out of the DAC isnt at the same level for the Apple TV vs the Mac
 
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Headchef

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Its possible one of the streams has a degree of volume levelling/ normalising that the other doesnt so (possibly) what comes out of the DAC isnt at the same level for the Apple TV vs the Mac

ah, I thought of that, turned off all levelling, sound reduction, eq, etc. But you’re right there’s little to actually tell if Apple are applying some kind of “loudness” hokum to the TV output but as far as the volume levels I used a db meter (avg 55db)
 

Jimbob54

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ah, I thought of that, turned off all levelling, sound reduction, eq, etc. But you’re right there’s little to actually tell if Apple are applying some kind of “loudness” hokum to the TV output but as far as the volume levels I used a db meter (avg 55db)

Yes, analysing whats actually happening in the chain is far harder on non computer devices. Another interesting point is something is obviously upsampling the Mac / USB feed to the max setting as clearly Apple Music goes up to "lossless" 44.1 and/ or 48 khz sample rate (EDIT- actually I think they do have or will have soon limited amounts of higher res stuff), nothing remotely near 768 khz sample rate. Whether thats something you have elected to do, default setting somewhere I know not. Based on prior discussions and reading the posts of others, knocking that down to 44/48 or something inbetween that and 768 shouldnt be the reason for the significant perceived differences in the 2 sources. But who knows!
 
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Yes, analysing whats actually happening in the chain is far harder on non computer devices. Another interesting point is something is obviously upsampling the Mac / USB feed to the max setting as clearly Apple Music goes up to "lossless" 44.1 and/ or 48 khz sample rate, nothing remotely near 768 khz sample rate. Whether thats something you have elected to do, default setting somewhere I know not. Based on prior discussions and reading the posts of others, knocking that down to 44/48 or something inbetween that and 768 shouldnt be the reason for the significant perceived differences in teh 2 sources. But who knows!

and here we come full circle :) the MacBook receives Apple Music at “lossless upto 24-bit/192kHz” but then when you configure the Aune S8 DAC through Audio MIDI Setup it gives the option to use the DAC’s XMOS internal clock at 32-bit integer 768.0kHz which the DAC is showing as PCM768 there’s certainly no perceivable increase in noise however it sounds discernibly better.

Which makes me wonder if those that are buying these lovely DAC’s and just plugging them in might be missing the best operation that their device is capable of, by relying on the source to pass through the processing instruction (native) rather than setting the DAC manually (forced).

And it’s not just Apple, I’m now listening to Lou Reed on Tidal which the DAC is processing as PCM768 even though it’s streaming as “HiFi” (which I think is CD Redbook) and it sounds superb….
 

Jimbob54

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and here we come full circle :) the MacBook receives Apple Music at “lossless upto 24-bit/192kHz” but then when you configure the Aune S8 DAC through Audio MIDI Setup it gives the option to use the DAC’s XMOS internal clock at 32-bit integer 768.0kHz which the DAC is showing as PCM768 there’s certainly no perceivable increase in noise however it sounds discernibly better.

Which makes me wonder if those that are buying these lovely DAC’s and just plugging them in might be missing the best operation that their device is capable of, by relying on the source to pass through the processing instruction (native) rather than setting the DAC manually (forced).

And it’s not just Apple, I’m now listening to Lou Reed on Tidal which the DAC is processing as PCM768 even though it’s streaming as “HiFi” (which I think is CD Redbook) and it sounds superb….
You're not configuring the dac in that set up. You're configuring what the mac feeds the dac. Windows has a similar settings which you can either get to from the os sound settings or the driver control panel specific to the dac driver. By selecting 32 /768 that's what the mac sends it, that upsample happens on the mac. Which isn't the same as what clock is used.

Edit https://audiosciencereview.com/foru...end-audio-from-macbook-to-external-dac.14245/
 
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audio2design

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well that probably explains why the S8 runs hot compared to other DAC’s which I’ve used that tend to be cool to the touch. But then is noise figures in the review all came back as pretty good. Do you think DAC/Noise is subject to a sort of Moores Law?

No, I would say it is reaching an asymptotic best case.
 
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You're not configuring the dac in that set up. You're configuring what the mac feeds the dac. Windows has a similar settings which you can either get to from the os sound settings or the driver control panel specific to the dac driver. By selecting 32 /768 that's what the mac sends it, that upsample happens on the mac. Which isn't the same as what clock is used.

Edit https://audiosciencereview.com/foru...end-audio-from-macbook-to-external-dac.14245/

see that’s what I was wondering, is the Mac upsampling/oversampling? I’m damned if I can find anything online suggesting that it is, as a musician I’ve always understood (in a simplistic way) that MIDI is a transport rather than a processing engine? Which leads me (perhaps incorrectly) to the Audio MIDI Setup being little other than a way of selecting the DAC to do the processing??
 

Jimbob54

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see that’s what I was wondering, is the Mac upsampling/oversampling? I’m damned if I can find anything online suggesting that it is, as a musician I’ve always understood (in a simplistic way) that MIDI is a transport rather than a processing engine? Which leads me (perhaps incorrectly) to the Audio MIDI Setup being little other than a way of selecting the DAC to do the processing??
Let's put it another way, if you were talking about the rme dac, think I linked earlier the rme guy categorically stating that no upsampling (as opposed to oversampling) happens in that dac, yet at the os level I can select (in Windows) various sample rates. I assume on mac I would have the same options
 
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Let's put it another way, if you were talking about the rme dac, think I linked earlier the rme guy categorically stating that no upsampling (as opposed to oversampling) happens in that dac, yet at the os level I can select (in Windows) various sample rates. I assume on mac I would have the same options

I’ve just found this! Currently digging through it, I feel we might be getting warmer….

EDIT WRONG LINK: https://developer.apple.com/audio/

EDIT MAYBE CLOSER: https://developer.apple.com/documentation/audiotoolbox
 
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Not really, your dac isn't a midi device. It's midi and audio settings on the mac isnt it?

almost, Mac seem to confuse the definition of MIDI

ugh, seems to be an even deeper rabbit hole, I’m now sat here wondering if Audio MIDI Setup uses the deferred renderer setting or if the incoming file is fed through an algorithm in OSX to change the encodin.

that said it appears to use the DAC’s clock and gives the option to set the format fed to the DAC.

I guess the main question would be as to capability and quality of the OSX encoder Vs the likes of Roons DSP. In theory OSX would be professional grade as it’s the same software transport a lot of Audio production suites are built upon, in fact it might well be that the likes of Roons DSP is simply a front end offering easier user access to those settings??

ugh, goes off to hurl another can of worms at the wall.
 
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Right so assuming that, actually I’ve gotten to the point of not really caring about the nuts and bolts of it, but here’s a thing.

I figured I’d use Tidal masters as the audio source files for this test. Did a series of blind a/b tests (thanks to the long suffering better half again!) ensured volume was an equal avg 65db. Came to the following conclusions.

”forced” PCM768 sounds best, more open spacious, better instrument and voice definition.

“Native” Exclusive mode is quieter (much to the Wifes annoyance as she had to match the levels whilst I was out of earshot (and pretend that she was matching them when she wasn’t)

The lower rates have a kind of compressed overall sound to them in comparison to the upscaled/oversampled “forced” rates.

I don’t know why this is the case but ultimately if it sounds better (more open, clearer, more dynamic with a wider soundstage) one way than the other then I’m going to listen to it that way.
 
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