Why Android resamples your music to 48 kHz

One mixer, one rate

Android’s audio system, AudioFlinger, mixes every app into a single stream per output: music, notifications, games, navigation. A mixer needs one rate, and on most phones that rate is 48 kHz. A 44.1 kHz track is converted to 48 on the way in; a 96 kHz track is converted down. The conversion is decent on modern phones, but the DAC receives something other than the file.

It used to be worse: 16 bits

Many Android players, and some media frameworks by default, also process audio as 16-bit integers. A 24-bit file loses its bottom eight bits before the mixer ever sees it. That is a player choice, not an Android limit: a player can process in 32-bit float and hand float to the system. MP95 for Android does, and 24-bit files stay 24-bit.

What Android 14 changed

Android 14 lets an app ask the system to run the mixer for a USB audio device with specific attributes, including the sample rate, chosen from the list the device reports. A player that uses it can switch the DAC to 44.1 for a CD rip and to 96 or 192 for hi-res, track by track. MP95 does this when Match output sample rate is on.

On Android 13 and older

There are two ways around the mixer: accept its rate, or bypass Android’s audio system entirely with an app that ships its own USB driver. USB Audio Player Pro is the best-known example. It works on any version, at the cost of fighting other apps for the device. MP95 vs UAPP.

The speaker and Bluetooth

The built-in speaker and headphone jack run at the phone’s fixed rate. Bluetooth re-encodes everything with its own codec. For these outputs, rate matching does not apply; a clean float path is the best a player can do. What the player controls over Bluetooth.

How to check

A DAC with a rate display is the simplest check. In MP95, Settings → Sound → Hi-Fi shows the live Output line: the rate the device actually runs at, and whether anything is processing.