How is Apple Lossless ALAC output to PCM

[vddobrev]

I have a question on Apple lossless and high-resolution lossless. How exactly are these formats converted to PCM? Is this done in hardware or in software?
Asking because I am largely disappointed by the new M1 Mac mini output via HDMI to receiver. I can clearly hear worse quality compared to a 2014 Mac mini output.
M1 mini is limited to only 48KHz, and it sounds worse than 2014 mini, set to 48khz (even though it can do 192KHz) to match the M1 mini for comparison purposes.
So something in the M1 mini is inferior - what is it, what hardware/software is responsible for ALAC to PCM?

 

[gigatoaster]

Why don’t you use a USB DAC, then?

You won’t get DSD but DoP which is considered the same, apparently.

 

[chabig]

I believe audio decompression is handled by a hardware decoder on the M1.

 

[vddobrev]

I am not sure what is DSD or DoP... I will check it though...
Why would I need to buy a USB DAC? And how will it help me? All I need is to be able to use an HDMI connection from the M1 mini to my receiver just like the 2014 mini and get a good audio.

 

[vddobrev]

Well, regardless how exactly audio gets converted from ALAC to PCM, I have established a fact that the M1 mini has an inferior sound output, be it via HDMI to receiver or Bluetooth to AirPods. The sound is worse compared to both Mac mini 2014 and iPad Pro 12.9 2021.

So for my use case, where the Mac mini M1 was supposed to be my media player connected to my receiver, it seems that it does not cut it. My 2014 Mac mini is superior in HDMI sound output.

 

[gecko579]

Interesting and disappointing. Can you specify what’s changed (anything objective like volume, sync, inability to decode various signal types or more subjective presence, soundstage)?

 

[vddobrev]

Yes I will describe. First let me list my equipment:
1. Receiver: NAD T785 7.1, 120W per channel.
2. Front Speakers: Martin Logan Preface
3. Subwoofer: Martin Logan Descent i

Objectively nothing seems changed, apart from that M1 Mac mini output is only 48KHz. Other than that there are no volume, sync, or other changes noticed.

Subjectively, though, I can hear the following changes compared to my 2014 Mac mini or Mac Pro 2013. Both 2104 mini and Mac Pro 2013 were set to output 192KHz, while the M1 can only do 48KHz. I also experimented with setting the 2014 mini and MP 2013 to 48KHz. Here is what I observed in my tests, M1 mini compared to my other macs

1. Low frequencies - lack of low extension, the bass frequencies are less thumping and lack impact.
2. Mid frequencies - lack of presence, vocals are not impressive and convincing, soundstage is not very well formed.
3. High frequencies - harsh and dry, to the point being irritating.

I heard all of the above right the first time when plugged in M1 mini. I have probably switched between the two at least 30 times to listen for differences, just to eliminate the chance that I might be imagining things. I even involved my wife, asked her to pick the better sounding of the 2, without telling her which is which - she said every time that M1 is worse, especially she said the guitars are very harsh, and the other source is more pleasant and mellow.

So that's it from my observations of listening to the M1.

Edit: forgot to mention what I was listening to: Toto (lack of low extension is especially obvious on the Album Tambu), BB King, Eric Clapton, Chicago. Other music played which is not critical, but still sounded worse: Sabaton, Iron Maiden.

 

[gecko579]

Looks like others have noticed what they describe as degraded sound output from M1 vs Intel (though not via HDMI it appears)…

MIDI Audio Output on M1 Mac MacBook Pro ?

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