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Review: Apple vs Google USB-C Headphone Adapters

For the record, this is what the settings look like in Moode Player's ALSA Options menu. ALSA volume is set to 100.

moOde_ALSA-ctrl_00.jpg


Here is alsamixer in a terminal, which was already set at 100 when I got in.

AlsamixerStatus100.jpg


It looks like the Moode ALSA Options directly control the alsamixer, as their level settings exactly matched (both pinned at 100).

Therefore, the alsamixer was set to 100 when I did my casual, non-scientific auditioning of the Apple dongle.

I'll have to go back and do a more controlled comparison, with levels matched using a 1kHz sine wave test tone and a DMM to measure AC volts rms across the speaker terminals, etc. (Yes, I have an rms voltmeter).
 
Thinking that the Apple dongle might be a fake, I found a freeware USB device ID viewer to check it out. Looks legit.

Apple_dongle_legit.jpg


Upon installation in Windows, the Apple dongle's volume is set to 25% by default. Maybe that's how it gets installed in Linux too.
 
Do you guys know what version of the Apple adapter is being sold in Japan? I'm assuming that is the A2049 version but can't find the confirmation anywhere. I have a friend there at the moment and I might ask him to bring me one. Thanks for your help!
 
That's the same one you get from Amazon in the U.S. @bezae welcome to the forum. Where are you located?
Great, thanks!
I'm based in London, UK, and have been lurking on this forum for years. ASR remains my main source for hi-fi reviews, as I appreciate Amirm's scientific approach over reviews filled with pseudo-acoustic jargon. Excited to finally join the conversation!
 
Great, thanks!
I'm based in London, UK, and have been lurking on this forum for years. ASR remains my main source for hi-fi reviews, as I appreciate Amirm's scientific approach over reviews filled with pseudo-acoustic jargon. Excited to finally join the conversation!

I'm also in the UK and a recent member of the forum. It's a breath of fresh air in a world bogged down by flowery descriptions and reviewers who don't give a second thought to the psychology of listening.

I'm not a measurement purist but it is an essential baseline. I quite like some distortion in my listening experience. It'd be a better world if audio companies could admit they have a 'house sound' rather than all of them claiming absolute purity and perfection.
 
Due to the current state of the art, absolute purity and perfection of sound reproduction is an impossibility. There are compromises, starting all the way at the beginning, at the microphones.
 
Can someone confirm this regarding gain levels?

Code:
    PC
EU 50%
US 100%

    Android
EU 13%
US 25%

    Android w/ 3rd-party SW
EU 45%
US 90%
 
Can someone confirm this regarding gain levels?

Code:
    PC
EU 50%
US 100%

    Android
EU 13%
US 25%

    Android w/ 3rd-party SW
EU 45%
US 90%
In a nutshell:
  • US output voltage is 1V @0dBFS.
  • EU has 5.8dB reduction hardcoded into the chip (only some Apple devices can bypass that)
  • EU and US have -20dBFS default HW volume (on top of hardcoded reduction)
  • Different ROMs have different digital headroom for mixing.
    At 100%, OneUI 3.1 will output 0dBFS, LineageOS 21 will output -1.5dBFS, OxygenOS 11 will output -1.4dBFS)
dBr
A2049A2155
Bit-perfect playback w/ UAC2 controlReference-5.8
PC Default-0-5.8
Lineage OS 21 default-21.5-27.3
Lineage OS 21 UAC2 maxed-1.5-7.3
Oxygen OS 11 default-21.4-27.2
Oxygen OS 11 UAC2 maxed-1.4-7.2
OneUI 3.1 default-20-25.8
OneUI 3.1 UAC2 maxed-0-5.8

Voltage Percent
A2049A2155
Bit-perfect playback w/ UAC2 control100%51%
PC Default100%51%
Lineage OS 21 default9%4%
Lineage OS 21 UAC2 maxed84%43%
Oxygen OS 11 default9%4%
Oxygen OS 11 UAC2 maxed85%44%
OneUI 3.1 default10%5%
OneUI 3.1 UAC2 maxed100%51%

Loudness Percent
A2049A2155
Bit-perfect playback w/ UAC2 control100%67%
PC Default100%67%
Lineage OS 21 default23%15%
Lineage OS 21 UAC2 maxed90%60%
Oxygen OS 11 default23%15%
Oxygen OS 11 UAC2 maxed91%61%
OneUI 3.1 default25%17%
OneUI 3.1 UAC2 maxed100%67%
 
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Couple of questions, using the Apple dongle as long as the volume is loud enough your headphone is being powered to it maximum capability, Bass impact/control for example will not be improved on an amplifier with higher voltage/current at the same volume level?

Quoting Amirn from the original post,

"Switching to high-impedance 300 ohm Sennheiser HD-650 nearly killed performance. The sound was OK but bass is week and dynamic range just not there. Here my reference is more powerful desktop and battery operated portables."

So what's happening here?
 
Couple of questions, using the Apple dongle as long as the volume is loud enough your headphone is being powered to it maximum capability, Bass impact/control for example will not be improved on an amplifier with higher voltage/current at the same volume level?
Below 20Ω load impedance, the US dongle can clip hard when pushed to 100%, which can result in poor sound.

If you have the EU dongle, or headphones above 20Ω impedance, and you're happy with the volume you're getting out of it, then no money spent on a beefy external headphone Amp will increase impact, control, slam, dynamics at the same volume.

To actually increase these things, you'd have to turn up the volume or use DSP.
 
Below 20Ω load impedance, the US dongle can clip hard when pushed to 100%, which can result in poor sound.

If you have the EU dongle, or headphones above 20Ω impedance, and you're happy with the volume you're getting out of it, then no money spent on a beefy external headphone Amp will increase impact, control, slam, dynamics at the same volume.

To actually increase these things, you'd have to turn up the volume or use DSP.


Thing is though the quote from @amirm doesn't seem to indicate a low volume issue as otherwise I'm sure he would've said so, he talks about exactly which you say shouldn't be effected, "bass is weak and dynamic range just not there", the devil is in the details as they say and I think details like this need to be clarified to make sure there is no confusion, is Amirm saying simply the Apple dongle ran out of volume so was clipping, or was there other reasons as to why the sound was effected?

I 'used to' assume that more voltage was required to give better control over the bass and improved dynamics etc, even at lower listening levels but reading this forum has made me question that but not absolutely.
 
he talks about exactly which you say shouldn't be effected, "bass is weak and dynamic range just not there"
Bass is weak due to how human ears perceive low volume (equal loudness contours) and dynamic range is not there because volume is low (compared to external Amps).

If you were to match volume on an external Amp to the Apple dongle and record the HD600 from both the external Amp and the Apple dongle, the result would be identical.
 
Bass is weak due to how human ears perceive low volume (equal loudness contours) and dynamic range is not there because volume is low (compared to external Amps).

If you were to match volume on an external Amp to the Apple dongle and record the HD600 from both the external Amp and the Apple dongle, the result would be identical.

Well it would be nice to have clarification from @amirm as to whether his impression was because of low volume or not because as I said he doesn't seem to be indicating as such, unless it's expectation bias, I know for me personally it would be hard for my brain to accept a HD600 is being fully powered on an Apple dongle!

Hopefully amirm will reply :)
 
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