USB-C DAC + IEM: Huge Volume Difference Between Two Sources — Why?

[Soyel Afridi]

Hello everyone totally new here.. kindly need ur help..

I have 2 phone 1.Oppo reno 2f 2. Xiaomi pad 7

1st one has Usb c charger port and 3.5 mm jack, but 2nd one has usb c port...

I have a IEM KZ CASTOR PRO improved bass and separate type c to 3.5mm Dac Audiocular D07..

The problem is when i use the the 1st one phone..meansthe oppo one.. listings sometimes using the type c dac and iem through the phone type c charger port... I got more louder sound then 2nd one phone means pad 7 ..

For example.. using same setup(Audiocular D07 + kx castor pro improved bass) 6% volume level is enough in oppo one .. But in 2nd phone getting the volume level i have to use 24% volume ... ...in both cases I'm not using any equilaiser. ..i) so that's the main problem.. ii) now i have doubt even after i match the volume level physically in the 2nd device by increase volume.. Am i loosing audio quality in the 2nd device...bcz i am a audiophile that's i bought dac and iem .. a)if not..why not..b )if yes, how solve this issue..
...
even i have 2 use more volume level ..I'm ok...but main doubt is if there not sound quality loss ..so why 2nd device giving less sound in same volume level.. nearly 70 % less volume....

Iem impedance= 16-22Ω
Sensitivity = 100-103dB

Used chatgpt got more confused

 

[staticV3]

Hi @Soyel Afridi! Welcome to ASR.

Digital volume sliders like those built into different Android ROMs do not all behave the same.

The volume level achieved with 10% volume on one ROM, may require 20% or 30% on another.

To match levels, it's not enough to match the volume slider position.

In addition, different Android ROMs leave different amount of digital headroom, likely to account for signal gain due to mixing.

For example, OneUI 3.1 can output the full 0dBFS whereas Oxygen OS 11 and Lineage OS 21 will only allow up to -1.5dBFS output from a single source.

None of this is really an issue though. You're not losing sound quality by turning up the volume.

If anything, the only time I experienced sound quality degradation due to Android volume was when I used a sensitive IEM with a high gain headphone adapter.

For comfortable volume, I had to set my phone to the bare minimum, one click of the volume rocker up from silent.

That exposed a quite nasty noise gate that was built into the Android audio pipeline at the time, which in that scenario ended up cutting off like the bottom 30% of my tracks in terms of loudness, with an awful digital artifacting noise in the mix.

The solution at the time, because my headphone adapter supported UAC2 Hardware volume control, was to launch USB Audio Player Pro, use it to reduce the headphone adapter's hardware volume effectively reducing its gain, and then I could turn up the Android volume to compensate.

This pushed the noise gate far below the audibility threshold and restored clean playback.

Ever since, I've made a habit of ensuring that the native Android volume slider is turned up a good bit when playing through Aux or USB just for peace of mind, though I must admit it's possible that the audio pipeline has improved since then. I have not checked in years.

Of course, another solution is to use playback Apps like USB Audio Player Pro, HiBy Music, FiiO Music, or Neutron Player, which will bypass the Android audio pipeline completely and send the audio straight to your headphone adapter.

This also bypasses any issues that the Android pipeline may or may not have.