What sounds better: FLAC or WAV

Despite both FLAC and WAV are lossless formats and supposed to be bit perfect they sound differently. FLAC – more congested, WAV – “easier” and more airy.

Here’s one of the reasons why. Let’s see what “top” on the PS-Audio Bridge (a network player) says:

24/88.2 FLAC (-4):

/bin # top -b -n20 | fgrep idle | fgrep -v fgrep
CPU: 6% usr 13% sys 0% nic 80% idle 0% io 0% irq 0% sirq
CPU: 14% usr 9% sys 0% nic 76% idle 0% io 0% irq 0% sirq
CPU: 24% usr 9% sys 0% nic 65% idle 0% io 0% irq 0% sirq
CPU: 23% usr 7% sys 0% nic 69% idle 0% io 0% irq 0% sirq
CPU: 23% usr 7% sys 0% nic 67% idle 0% io 0% irq 0% sirq
CPU: 23% usr 9% sys 0% nic 66% idle 0% io 0% irq 0% sirq
CPU: 23% usr 6% sys 0% nic 69% idle 0% io 0% irq 0% sirq
CPU: 21% usr 9% sys 0% nic 69% idle 0% io 0% irq 0% sirq
CPU: 22% usr 9% sys 0% nic 67% idle 0% io 0% irq 0% sirq
CPU: 24% usr 6% sys 0% nic 69% idle 0% io 0% irq 0% sirq
CPU: 25% usr 7% sys 0% nic 66% idle 0% io 0% irq 0% sirq
CPU: 23% usr 7% sys 0% nic 68% idle 0% io 0% irq 0% sirq
CPU: 22% usr 9% sys 0% nic 68% idle 0% io 0% irq 0% sirq
CPU: 25% usr 7% sys 0% nic 67% idle 0% io 0% irq 0% sirq
CPU: 23% usr 6% sys 0% nic 69% idle 0% io 0% irq 0% sirq
CPU: 21% usr 10% sys 0% nic 68% idle 0% io 0% irq 0% sirq
CPU: 23% usr 7% sys 0% nic 69% idle 0% io 0% irq 0% sirq
CPU: 23% usr 7% sys 0% nic 68% idle 0% io 0% irq 0% sirq
CPU: 22% usr 6% sys 0% nic 70% idle 0% io 0% irq 0% sirq
CPU: 26% usr 6% sys 0% nic 66% idle 0% io 0% irq 0% sirq

24/88.2 FLAC (-0 – no compression):

/bin # top -b -n20 | fgrep idle | fgrep -v fgrep
CPU: 13% usr 13% sys 0% nic 73% idle 0% io 0% irq 0% sirq
CPU: 13% usr 10% sys 0% nic 75% idle 0% io 0% irq 0% sirq
CPU: 11% usr 9% sys 0% nic 77% idle 0% io 0% irq 1% sirq
CPU: 9% usr 7% sys 0% nic 81% idle 0% io 0% irq 0% sirq
CPU: 11% usr 4% sys 0% nic 82% idle 0% io 0% irq 0% sirq
CPU: 10% usr 7% sys 0% nic 81% idle 0% io 0% irq 0% sirq
CPU: 9% usr 6% sys 0% nic 83% idle 0% io 0% irq 0% sirq
CPU: 13% usr 6% sys 0% nic 79% idle 0% io 0% irq 0% sirq
CPU: 12% usr 6% sys 0% nic 80% idle 0% io 0% irq 0% sirq
CPU: 10% usr 7% sys 0% nic 80% idle 0% io 0% irq 1% sirq
CPU: 10% usr 6% sys 0% nic 82% idle 0% io 0% irq 0% sirq
CPU: 9% usr 7% sys 0% nic 81% idle 0% io 0% irq 0% sirq
CPU: 10% usr 7% sys 0% nic 80% idle 0% io 0% irq 1% sirq
CPU: 11% usr 6% sys 0% nic 82% idle 0% io 0% irq 0% sirq
CPU: 12% usr 7% sys 0% nic 79% idle 0% io 0% irq 0% sirq
CPU: 9% usr 6% sys 0% nic 83% idle 0% io 0% irq 0% sirq
CPU: 12% usr 7% sys 0% nic 79% idle 0% io 0% irq 0% sirq
CPU: 9% usr 7% sys 0% nic 82% idle 0% io 0% irq 0% sirq
CPU: 9% usr 7% sys 0% nic 82% idle 0% io 0% irq 0% sirq
CPU: 7% usr 7% sys 0% nic 85% idle 0% io 0% irq 0% sirq

24/88.2 WAV:

/bin # top -b -n20 | fgrep idle | fgrep -v fgrep
CPU: 0% usr 14% sys 0% nic 85% idle 0% io 0% irq 0% sirq
CPU: 11% usr 7% sys 0% nic 81% idle 0% io 0% irq 0% sirq
CPU: 8% usr 9% sys 0% nic 82% idle 0% io 0% irq 0% sirq
CPU: 7% usr 4% sys 0% nic 87% idle 0% io 0% irq 0% sirq
CPU: 6% usr 6% sys 0% nic 86% idle 0% io 0% irq 0% sirq
CPU: 5% usr 6% sys 0% nic 87% idle 0% io 0% irq 0% sirq
CPU: 6% usr 5% sys 0% nic 88% idle 0% io 0% irq 0% sirq
CPU: 8% usr 6% sys 0% nic 85% idle 0% io 0% irq 0% sirq
CPU: 5% usr 5% sys 0% nic 88% idle 0% io 0% irq 0% sirq
CPU: 7% usr 6% sys 0% nic 85% idle 0% io 0% irq 0% sirq
CPU: 8% usr 5% sys 0% nic 85% idle 0% io 0% irq 0% sirq
CPU: 8% usr 5% sys 0% nic 86% idle 0% io 0% irq 0% sirq
CPU: 6% usr 7% sys 0% nic 86% idle 0% io 0% irq 0% sirq
CPU: 8% usr 5% sys 0% nic 86% idle 0% io 0% irq 0% sirq
CPU: 6% usr 6% sys 0% nic 85% idle 0% io 0% irq 0% sirq
CPU: 7% usr 5% sys 0% nic 87% idle 0% io 0% irq 0% sirq
CPU: 5% usr 5% sys 0% nic 88% idle 0% io 0% irq 0% sirq
CPU: 7% usr 6% sys 0% nic 85% idle 0% io 0% irq 0% sirq
CPU: 7% usr 6% sys 0% nic 85% idle 0% io 0% irq 0% sirq
CPU: 6% usr 6% sys 0% nic 87% idle 0% io 0% irq 0% sirq

AIFF:

/bin # top -b -n20 | fgrep idle | fgrep -v fgrep
CPU: 14% usr 28% sys 0% nic 57% idle 0% io 0% irq 0% sirq
CPU: 9% usr 7% sys 0% nic 82% idle 0% io 0% irq 0% sirq
CPU: 8% usr 8% sys 0% nic 83% idle 0% io 0% irq 0% sirq
CPU: 32% usr 33% sys 0% nic 33% idle 0% io 0% irq 0% sirq
CPU: 41% usr 57% sys 0% nic 0% idle 0% io 0% irq 1% sirq
CPU: 15% usr 18% sys 0% nic 66% idle 0% io 0% irq 0% sirq
CPU: 7% usr 6% sys 0% nic 86% idle 0% io 0% irq 0% sirq
CPU: 8% usr 6% sys 0% nic 85% idle 0% io 0% irq 0% sirq
CPU: 5% usr 7% sys 0% nic 86% idle 0% io 0% irq 0% sirq
CPU: 8% usr 6% sys 0% nic 84% idle 0% io 0% irq 0% sirq
CPU: 9% usr 4% sys 0% nic 86% idle 0% io 0% irq 0% sirq
CPU: 7% usr 7% sys 0% nic 85% idle 0% io 0% irq 0% sirq
CPU: 8% usr 6% sys 0% nic 85% idle 0% io 0% irq 0% sirq
CPU: 6% usr 7% sys 0% nic 86% idle 0% io 0% irq 0% sirq
CPU: 7% usr 6% sys 0% nic 85% idle 0% io 0% irq 0% sirq
CPU: 5% usr 7% sys 0% nic 86% idle 0% io 0% irq 0% sirq
CPU: 9% usr 6% sys 0% nic 84% idle 0% io 0% irq 0% sirq
CPU: 8% usr 6% sys 0% nic 85% idle 0% io 0% irq 0% sirq
CPU: 7% usr 5% sys 0% nic 86% idle 0% io 0% irq 0% sirq
CPU: 8% usr 6% sys 0% nic 85% idle 0% io 0% irq 0% sirq

Basically, the same as WAV.

And this is the Bridge load when nothing is playing:

CPU: 3% usr 4% sys 0% nic 92% idle 0% io 0% irq 0% sirq
CPU: 2% usr 5% sys 0% nic 91% idle 0% io 0% irq 0% sirq
CPU: 3% usr 3% sys 0% nic 93% idle 0% io 0% irq 0% sirq
CPU: 3% usr 4% sys 0% nic 91% idle 0% io 0% irq 0% sirq
CPU: 5% usr 2% sys 0% nic 91% idle 0% io 0% irq 0% sirq

It takes the CPU from 3 to 5 times more cycles to decode FLAC stream than WAV. The higher the FLAC compression the more CPU cycles it takes. Hence more power is consumed andmore EMI is emitted.

And this is, just in case, 24/192 FLAC

CPU: 42% usr 11% sys 0% nic 45% idle 0% io 0% irq 0% sirq

That’s why the transcoding and all other digital conversions should be done on the server with enough CPU power, not on the player.

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