Note: Shairport Sync can take configuration settings from command line options. This is mainly for backward compatibility, but sometimes still useful. For normal use, it is strongly recommended that you use the configuration file method.
**Raspberry Pi**
+
The Raspberry Pi has a built-in audio DAC that is connected to the device's headphone jack. An updated audio driver has greatly improved the quality of the output – see [#525](https://github.com/mikebrady/shairport-sync/issues/525) for details. To activate the updated driver, add the line:
```
audio_pwm_mode=2
```
to `/boot/config.txt` and reboot.
-Apart from a loud click when used for the first time after power-up, it is quite adequate for casual listening. A problem is that it declares itself to have a very large mixer volume control range – all the way from -102.38dB up to +4dB, a range of 106.38 dB. In reality, only the top 30dB of it is in any way usable. To help get the most from the DAC, consider using the `volume_range_db` setting in the `general` group to instruct Shairport Sync to use the top of the DAC mixer's declared range. For example, if you set the `volume_range_db` figure to 30, the top 30 dB of the range will the used. With this setting on the Raspberry Pi, maximum volume will be +4dB and minimum volume will be -26dB, below which muting will occur.
+Apart from a loud click when used for the first time after power-up, it is quite adequate for casual listening. A problem is that it declares itself to have a very large mixer volume control range – all the way from -102.38dB up to +4dB, a range of 106.38 dB. In reality, only the top 40dB of it is in any way usable. To help get the most from the DAC, consider using the `volume_range_db` setting in the `general` group to instruct Shairport Sync to use the top of the DAC mixer's declared range. For example, if you set the `volume_range_db` figure to 40, the top 40 dB of the range will the used. With this setting on the Raspberry Pi, maximum volume will be +4dB and minimum volume will be -36dB, below which muting will occur.
From a user's point of view, the effect of using this setting is to move the minimum usable volume all the way down to the bottom of the user's volume control, rather than have the minimum usable volume concentrated very close to the maximum volume.