19. Instructions for Settings->Audio menu

3.5Output selection

PO (Power output), generally used when connecting to earphones and speakers

LO (Line out), generally used when connecting to power amplifiers

SPDIF (Coaxial out), generally used when connecting to DACs

2.4.4Output selection

BAL.PO and BAL.LO available

3.SPDIF out (it only needs to be set in this way when the coaxial output is used)

D2P mode: when playing PCM signals, it will output raw PCM signals; when playing DSD signals, it will first convert DSD to PCM and output PCM signals.

DoP mode: PCM will be output as PCM signals while DSD will be output as raw DSD signals.


Select DoP first. For some devices that are not supportive of DoP, please select D2P.


There are 4 levels, Over-ear headphone mode, High, Medium and Low, corresponding to 4 levels of output voltages. You can select different Gains according to the earphones used.

When the M15S is connected to fast charging adapter, the enhanced over-ear headphone mode could be enabled.

5.Lowpass filters mode

There are 7 different filters built in the M15S for your preference.

Filters are the sound effects born with the chip, which only has slight adjustments for the sound. Here are some introductions to some filters. These are only for reference since actual listening also has something to do with the matched device.

1) fast roll-off,linear phase filter: Most Common filter with clean suppression and high rejection, best for music with high transients. Provides crisp clean highs

2) slow roll-off,linear phase filter: coherent and clear sounds, positioned near the middle. It is suitable for classical music.

3) fast roll-off, minimum phase filter: Minimal Pre- Ringing, preferred for Imaging and soundstage. No aliasing in frequency domain. Stronger bass than Linear Phase,clean highs

4) slow roll-off, minimum phase filter: Non-Symetrical filter designed to minimize pre-ringing. Strong punchy bass with good transient attacks

6.Bluetooth Audio Encoder

The Bluetooth transmission takes the highest codec by default. You can choose the highest codec supported for the Bluetooth connection by this option.


If there is any imbalance between the left and right channels when playing music, you can adjust the channel balance here. It has up to 10 levels available.

8.All To DSD

When the All To DSD function is turned on, the PCM signals will be converted to DSD for output with sound quality further improved.

【Principle】All To DSD is mainly about switching digital signals from PCM to DSD format. So when making digital-to-analog conversion, it can use DSD format, enriching music styles with clearer and natural sound quality. In addition, since the lowest format of the DSD is DSD64, i.e. 4 times of the 44.1k/16bit (just looking at the data size), the All To DSD function is upsampling the 44.1k/16bit audio signals. Third-party apps also support All To DSD.

【Notes】 When the All To DSD function is turned on, the CPU will consume more power, which will shorten the play time of the M15S with obvious heating on the body.

During the process of using, if you notice that the total battery life is much shorter than that written on the specification table on our website, please check if the All To DSD function is turning on. It is suggested to turn off the All To DSD function and follow the provided test conditions to check the battery life of the M15S again.

9.Adjustable volume at LO

When it is turned on, the volume will be adjustable in LO mode. If it is turned off, the volume will be fixed as maximum.