Review and measurements of MacBook Air (2024) headphone output

[ceedee]

for MacBook Air only from M2 ongoing. Surely M3 has it because I own it and it drives HD650 also very loud

I have an M3 MacBook Pro and it does well at driving the HD650, but the oratory1990 EQ correction requires a -9.3 dB preamp gain, so the perceived volume goes down quite a bit. Without the EQ applied they are pretty loud. An external amp is still needed for some music that's mastered more quietly, or when I'm doing music production with lower levels.

 

[crappypanther]

We can safely use the headphone output of modern laptops and not worry about the horror stories told to us by audiophiles

 

[visanj]

I actually wrote the driver for this headphone amplifier at Apple which was my last job there around 2020. It was done during the Covid time and I thoroughly enjoyed it just because I have some old AKG k240/K501 at 600ohm/120ohm lying around somewhere. I remembered I specifically set the max output to 4Vrms, but it became 3.2Vrms when released which was after I left, I am still curious why.

One issue was planar magnetic headphone has low impedance but requires high output voltage, I raised this issue but the consensus seems like very few customers has planar and they probably have dedicated amplifier already.

That is one heck of a job you had at Apple. I haven't communicated with anyone working in Apple's audio team before. Pleasure to be in this forum.

Back to the topic, just a question, Is headphone jack same for all MacBook Pros released after M1?

 

[stefanovesa]

Mainly because it might damage some headphone (or your hearing) considering the customer base is so big.

I think you might already noticed it in your test, the impedance detection is done at the time 3.5mm plug is inserted. In theory, you can fake it by plug a 300ohm fake load and swap it to 32ohms real headphone.

Do you know why Apple ha decided to limit to 96 kHz the sampling rate of the internal DAC? Thanks

 

[xxie]

Back to the topic, just a question, Is headphone jack same for all MacBook Pros released after M1?

I don't know the answer as I left before M1 releasing. From driver point of view, headphone jack is quite complex as so many different headphones out there (i.e. mic/button detections, different standards on pins etc), I'd be surprised if there is major change.

Do you know why Apple ha decided to limit to 96 kHz the sampling rate of the internal DAC? Thanks

The audio routing inside the computer could be fairly complex, i.e. you might need share same audio bus for different devices; there might be also signal integrity concern too. I imagine a dedicated DAC has no such concern and able to reach 192khz.

 

[amper42]

Do you know why Apple ha decided to limit to 96 kHz the sampling rate of the internal DAC? Thanks

Apple didn't want to pay the tariff on frequencies over 96kHz.

 

[stefanovesa]

Apple didn't want to pay the tariff on frequencies over 96kHz.

LOL

 

[schmalgausen]

Received a brand new M4 version from our IT few days ago. Today I was faced with the issue when the laptop can't recognize headphones on 3.5 out (HD6XX by the way). It was fixed with reboot. Anybody has the same?

 

[AudioSceptic]

Received a brand new M4 version from our IT few days ago. Today I was faced with the issue when the laptop can't recognize headphones on 3.5 out (HD6XX by the way). It was fixed with reboot. Anybody has the same?

If one reboot has been a permanent fix, I don't have an explanation and I'd say it's "just one of those things!" (anything more would be a wild guess). We have one MacBook Air M4 here and it's fine.

 

[schmalgausen]

On Reddit some people report the same behaviour.

 

[schmalgausen]

Keep getting no sound from 3.5 out after sleep even updated to macOS 26

I actually wrote the driver for this headphone amplifier at Apple which was my last job there around 2020.

Keep getting no sound from 3.5 out after sleep even updated to macOS 26. Maybe the driver creator can comment?

 

[plant550]

I've got a pair of headphones just at the 150ohms threshold (hd550) which I think is occasionally weaving between the 1.25v and 3v modes (music gets suddenly quieter after some time listening to music). A somewhat undesirable behaviour.

Is there any way I can easily measure the voltage output from the headphone jack whilst headphones are plugged in?

 

[staticV3]

Is there any way I can easily measure the voltage output from the headphone jack whilst headphones are plugged in?

E1DA Cosmos Load board + gneral purpose Multimeter would do the trick.

Just keep in mind that you cannot measure voltages while playing music. For the measurement you'd have to temporarily play a 60Hz sine tone.

 

[plant550]

E1DA Cosmos Load board + gneral purpose Multimeter would do the trick.

Just keep in mind that you cannot measure voltages while playing music. For the measurement you'd have to temporarily play a 60Hz sine tone.

I have a DMM and a 3.5mm splitter. Any way to measure using that + a blank 3.5mm jack?
I.e. plug splitter into the Mac mini headphone jack, hd550 into 1 of the split and a blank 3.5mm jack in 2nd split.


I don't want to buy that board just to check this curiosity

 

[staticV3]

I have a DMM and a 3.5mm splitter. Any way to measure using that + a blank 3.5mm jack?
I.e. plug splitter into the Mac mini headphone jack, hd550 into 1 of the split and a blank 3.5mm jack in 2nd split.

A splitter would work, too.

 

[schmalgausen]

Any ideas if MacOS resample the stream from 44.1 to 48? What are preferable settings for Spotify lossless?

 

[staticV3]

Any ideas if MacOS resample the stream from 44.1 to 48? What are preferable settings for Spotify lossless?

It resamples to the sample rate that you've selected in the MIDI Control Panel.

 

[schmalgausen]

If Spotify plays 44.1 and there is 44.1 in MIDI then it is not double resample?

 

[staticV3]

If Spotify plays 44.1 and there is 44.1 in MIDI then it is not double resample?

it'll still resample.

IIRC there are ways in which developers can get exclusive audio output in macOS, so w/o resampling, but Spotify doesn't use them.

 

[mcdn]

Any ideas if MacOS resample the stream from 44.1 to 48? What are preferable settings for Spotify lossless?

It’ll resample to the rate you set in Audio/Midi settings, but it doesn’t matter, you can’t hear the difference.