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M1 Internal Audio round-trip latency is off

MacOSX and iOS
#1

Hi,
As we review things on M1s machines,
We’ve noticed that round-trip latency is wrong on those machine.
While this simple test is imperfect,
We got worse results with M1 machines vs pre-2015 Macs
(I will also test my 2018 MBP 13" with T2 and update)

We tested:
(44.1khz / 512buffer size), Internal Audio Device, using Microphone (so round trip is expected to be imperfect)

  • MacBook Air M1
    image
    image810×1278 44.8 KB

    Samples: ~2518
  • MacBook Pro M1
  • MacBook Pro 13" 2014: Samples ~281
  • MacBook Pro 13" 2018 (T2): Samples ~1286

How we’ve tested:

  • Open an audio app (eg Logic Pro X)
  • Insert an audio track
  • Mute it while arming it.
  • Toggle a metronome / percussive sample.
  • Record
  • Unarm/record.
  • Unmute
  • Play the recorded audio.

The amount of offset we see is quite noticeable.

Notes:

  • We’ve tried Rosetta and this isn’t arch related.
  • We’ve tried several apps and all severe from same issue.

Anyone else seeing this?

Thanks!

2 Likes
#2

Without knowing what/how you record this is meaningless. Is this using the internal soundcard?

#3

Is this using the internal soundcard?

Yes. I wouldn’t expect perfection.
But ‘close’ to time (eg. see MBP 2014 result) rather than huge offset.
It is also not random (we did those rough trials few times)

#4

Thanks for the reply. I can add some testing later myself. The most important thing is that round trip works with external sound cards, so I’ll check that. The drivers of the m1 internal audio stuff do glitch in a number of ways for me. I’d guess the problem is there, but better be sure. Problems I’ve seen so far:

  • no sound at all until reboot
  • sound coming out of the speakers although headphones are connected
  • no internal volume control after unplugging an external display with speakers
#5

That’s seems to work as expected. but since the T2s Apple’s internal audio on Macs seems to worsen.

On iPad/iPhone devices we don’t see such a major regression.