1 Topic by arnaoldobartolini (edited by arnaoldobartolini 2021-10-04 18:07:06)

  • Registered: 2021-10-04
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Topic: Apple Music bit test

Hello,


I'm running Mac OS 11.6 (Big Sur) on a 2014 Mac mini. My ADI-2 DAC FS is connected via USB.

I would like use Apple Music as a single application for lossless streaming and storing my CD's (a lot of releases of older music on streaming services are "re-masters" with low dynamic range or outright clipping so I want to import my own older CD's).

With Apple Music the bit-test passes only for 44.1 kHz files (with 32 bit showing as 24 bit passed)
Switching to 48 kHz or higher in the audio MIDI setup and playing the corresponding bitrate does not pass the test.

Is this behaviour normal?

Thanks,

Arno

2 Reply by fisico (edited by fisico 2021-10-04 17:34:37)

  • Registered: 2019-12-12
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Re: Apple Music bit test

Not normal, all bitrates should pass the test. 1) did you set Music volume at max? 2) did you uncheck Music>Preferences>Playback>Sound Check?

  • Registered: 2021-10-04
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Re: Apple Music bit test

Yes, volume is at max (otherwise 44.1 kHz would not pass).
Also Sound Check is switched off in the Music app preferences.

  • Registered: 2021-10-04
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Re: Apple Music bit test

It seems the Music App does not change sampling rate when I change the sample rate of the ADI-2 in the MIDI settings.
I need to restart the Music app when I change to a different sampling rate. That way the bit tests pass.

Not really user friendly when streaming music with different sampling rates.

I guess I could leave it at the highest rate the Apple Music offers leaving the Mac to oversample lower rates.

Would it be better to downsample higher rates to 44.1 or oversample 44.1 to a higher rate in the computer as far as aliasing or out of band images is concerned. (If I downsample a high resolution file to 16/44 using audacity I don't hear a difference so 16/44 is good enough for me).

5 Reply by MC

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Re: Apple Music bit test

You are wrong here - the way this software works is the most user friendly one, because it makes the least problems when playing back dozens of different file formats and sample rates - that might not be supported by the used DAC. Even switching between them can cause annoying mute times plus pop sounds.

Of course people in the know want their music fully original, for these it's disappointing. But they are a small minority, and they can easily get better players that do what they want.

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6 Reply by KaiS (edited by KaiS 2021-10-05 07:14:58)

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Re: Apple Music bit test

arnaoldobartolini wrote:

Would it be better to downsample higher rates to 44.1 or oversample 44.1 to a higher rate in the computer as far as aliasing or out of band images is concerned. (If I downsample a high resolution file to 16/44 using audacity I don't hear a difference so 16/44 is good enough for me).

Use the samplerate that the majority of your music has.

Bit depth can be left at max., i.e. 24 or 32 bit.
If you play 16 bit files the missing lower bits are treated as zeros with no adverse effect.

KaiS's Website

7 Reply by arnaoldobartolini (edited by arnaoldobartolini 2021-10-05 17:19:57)

  • Registered: 2021-10-04
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Re: Apple Music bit test

MC wrote:

You are wrong here - the way this software works is the most user friendly one, because it makes the least problems when playing back dozens of different file formats and sample rates - that might not be supported by the used DAC. Even switching between them can cause annoying mute times plus pop sounds.

Of course people in the know want their music fully original, for these it's disappointing. But they are a small minority, and they can easily get better players that do what they want.

You have a point in that automatic switching of bitrate's in the midi settings (like the Qobuz app) will cause the DAC not to play if it doesn't support that rate. There are however more elegant solutions like being able to select a maximum bit rate and sample depth your DAC supports.

Having to restart an application in order for the app to actually change it's bit rate after manually changing the midi settings (and DAC changing it's sample rate accordingly) remains user un-friendly and potentially confusing.
Suppose the midi setting is not supported by the DAC and it won't play. Changing the MIDI settings will not help until the app is restarted. Or suppose you are you are playing an RME bit test after changing the MIDI settings to the correct bit rate and it doesn't pass.... This behaviour is not obvious and makes it seem there's another problem.

Yes, I can use another app but I'm not aware of another singe app for streaming and playing my own CD catalog so I'm contemplating a switch from Qobuz to Apple Music. I can set the MIDI settings to the maximum bit rate that the Apple Music app offers and have lower rate's oversampled by the Mac Mini. Problem solved.

8 Reply by KaiS (edited by KaiS 2021-10-06 07:28:58)

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Re: Apple Music bit test

arnaoldobartolini wrote:

... automatic switching of bitrate's in the midi settings (like the Qobuz app) will cause the DAC not to play if it doesn't support that rate.

Did you find any Samplerate / (bitrate) that ADI-2 doesn‘t support?

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  • Registered: 2021-10-04
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Re: Apple Music bit test

No, this was a remark about the general behaviour of the Apple Music App with a DAC not supporting all bit rates.

10 Reply by ramses (edited by ramses 2021-10-06 08:29:48)

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Re: Apple Music bit test

arnaoldobartolini wrote:

No, this was a remark about the general behaviour of the Apple Music App with a DAC not supporting all bit rates.

Then you should change the sentence, it doesn't reflect what you intend to say.
BTW I am wondering why you refer to MIDI settings .. what has MIDI to deal with playback of audio ? Maybe a typo ?

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
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Re: Apple Music bit test

I am running Mac OS 11.6 (Big Sur) on a 2014 Mac mini with ADI-2 DAC FS is connected via USB or toslink, I do not have any problem.

Pacifist, dumb, not stupid
Listen music out from a box which sounds
Reading words on paper/ screen
  • Registered: 2018-06-12
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Re: Apple Music bit test

KaiS wrote:
arnaoldobartolini wrote:

Would it be better to downsample higher rates to 44.1 or oversample 44.1 to a higher rate in the computer as far as aliasing or out of band images is concerned. (If I downsample a high resolution file to 16/44 using audacity I don't hear a difference so 16/44 is good enough for me).

Use the samplerate that the majority of your music has.

Bit depth can be left at max., i.e. 24 or 32 bit.
If you play 16 bit files the missing lower bits are treated as zeros with no adverse effect.

If letting CoreAudio resample everything to one output sample rate, need to reduce Apple Music app volume by 3dB?

For digital headroom for resampling? To avoid digital clipping before it even reached ADI-2?

  • Registered: 2021-07-25
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Re: Apple Music bit test

ramses wrote:
arnaoldobartolini wrote:

No, this was a remark about the general behaviour of the Apple Music App with a DAC not supporting all bit rates.

Then you should change the sentence, it doesn't reflect what you intend to say.
BTW I am wondering why you refer to MIDI settings .. what has MIDI to deal with playback of audio ? Maybe a typo ?

For MacOS, the Audio Midi Setup application is where all input/output interfaces with audio devices are configured.   Audio devices are set up within the Audio Midi Setup app, which can be confusing, to be sure.

https://support.apple.com/guide/audio-m … 5/mac/12.0

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Re: Apple Music bit test

sberry2018 wrote:
KaiS wrote:
arnaoldobartolini wrote:

Would it be better to downsample higher rates to 44.1 or oversample 44.1 to a higher rate in the computer as far as aliasing or out of band images is concerned. (If I downsample a high resolution file to 16/44 using audacity I don't hear a difference so 16/44 is good enough for me).

Use the samplerate that the majority of your music has.

Bit depth can be left at max., i.e. 24 or 32 bit.
If you play 16 bit files the missing lower bits are treated as zeros with no adverse effect.

If letting CoreAudio resample everything to one output sample rate, need to reduce Apple Music app volume by 3dB?

For digital headroom for resampling? To avoid digital clipping before it even reached ADI-2?

Usually yes, how much depends on the resampling algorithm.

Give it a try:
• Bring down volume to -10 dB in Apple Music.
• Play some different high res tracks, preferable those that are mastered for permanent full-scale.
• Note the highest peaks in ADI-2’s Peak Meter, set to “Pre-FX” in Setup/Options/Display/Hor. Meter.
• The value you got is how far you can go up from -10 dB.
I.e., if you see -6.5 dB highest peak, you can go up to -3.5 dB volume in Apple Music.
Leaving an extra 1/2 dB doesn’t hurt, so -4 dB would be the one.

• Report back, we like to know!

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  • Registered: 2018-06-12
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Re: Apple Music bit test

KaiS wrote:
sberry2018 wrote:
KaiS wrote:

Use the samplerate that the majority of your music has.

Bit depth can be left at max., i.e. 24 or 32 bit.
If you play 16 bit files the missing lower bits are treated as zeros with no adverse effect.

If letting CoreAudio resample everything to one output sample rate, need to reduce Apple Music app volume by 3dB?

For digital headroom for resampling? To avoid digital clipping before it even reached ADI-2?

Usually yes, how much depends on the resampling algorithm.

Give it a try:
• Bring down volume to -10 dB in Apple Music.
• Play some different high res tracks, preferable those that are mastered for permanent full-scale.
• Note the highest peaks in ADI-2’s Peak Meter, set to “Pre-FX” in Setup/Options/Display/Hor. Meter.
• The value you got is how far you can go up from -10 dB.
I.e., if you see -6.5 dB highest peak, you can go up to -3.5 dB volume in Apple Music.
Leaving an extra 1/2 dB doesn’t hurt, so -4 dB would be the one.

• Report back, we like to know!

"Play some different high res tracks, preferable those that are mastered for permanent full-scale."

Can you share one specific example?

Or maybe I can create a sweep file 0dBFS using REW and play that in Apple Music app on macOS.

  • KaiS
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Re: Apple Music bit test

sberry2018 wrote:
KaiS wrote:
sberry2018 wrote:

If letting CoreAudio resample everything to one output sample rate, need to reduce Apple Music app volume by 3dB?

For digital headroom for resampling? To avoid digital clipping before it even reached ADI-2?

Usually yes, how much depends on the resampling algorithm.

Give it a try:
• Bring down volume to -10 dB in Apple Music.
• Play some different high res tracks, preferable those that are mastered for permanent full-scale.
• Note the highest peaks in ADI-2’s Peak Meter, set to “Pre-FX” in Setup/Options/Display/Hor. Meter.
• The value you got is how far you can go up from -10 dB.
I.e., if you see -6.5 dB highest peak, you can go up to -3.5 dB volume in Apple Music.
Leaving an extra 1/2 dB doesn’t hurt, so -4 dB would be the one.

• Report back, we like to know!

"Play some different high res tracks, preferable those that are mastered for permanent full-scale."

Can you share one specific example?

Or maybe I can create a sweep file 0dBFS using REW and play that in Apple Music app on macOS.

Most contemporary pop recordings are mastered like this.
A sine sweep won’t do, as it cannot exceed 0 dBFS intersample peak.

Music can, i.e.:
Tori Amos - Speaking With Trees
CHVRCHES - Asking For A Friend (2‘20“ ff, extreme)

KaiS's Website

  • Registered: 2018-06-12
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Re: Apple Music bit test

Thanks.

I think -3dB is generally accepted figure to cover most music. -4dB adds more safety margin.

If one is only listening to classical and jazz then probably you can get away without any digital headroom but for modern more popular music, it is essential when doing DSP I think.

18 Reply by KaiS (edited by KaiS 2021-10-30 15:35:29)

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Re: Apple Music bit test

sberry2018 wrote:

Thanks.

I think -3dB is generally accepted figure to cover most music. -4dB adds more safety margin.

If one is only listening to classical and jazz then probably you can get away without any digital headroom but for modern more popular music, it is essential when doing DSP I think.

3 dB is about the maximum intersample peak.
You can add up to 2 dB for the SRC process, so 5 dB total.
These are “worst case” values out of practical evaluation.

Peaks this high are very short, few and high-pitched.
Therefor clipping them a little usually is inaudible, if you have a reason to squeeze out the last few dB’s of loudness.

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