18. Instructions for the M27 system settings-audio menu

修改于星期二, 十一月 18 在 11:24 AM

1.Optical/Coaxial output: When using the optical or coaxial output port, please enable the Optical/Coaxial Output switch in the Settings - Audio menu, as this feature is turned off by default. Once the switch is enabled, playback will follow the standard SPDIF protocol specifications. The coaxial output supports up to PCM 384kHz and DSD128, while the optical output supports up to PCM 192kHz. Audio files exceeding these sampling rates will be processed through SRC (Sample Rate Conversion).

2.3.5 output selection: PO/LO available, PO as default

3.4.4 output selection: BAL/BAL.LO available, BAL as default

Note: When switching to LO/BAL.LO, a pop-up prompt will show up saying that Line output is not affected by volume control, and switching to line output will set the output volume to maximum, potentially causing harm to headphones and human hearings! Please unplug the headphones and select the appropriate device for correct connection before switching to line output. When turning on "Adjustable volume for line output," there is no prompt.

Output priority

3.5&4.4&6.35 analog output could output simultaneously

4.SPDIF OUT: DoP/D2P (DoP output as default)

This setting applies only when playing DSD tracks via coaxial output.

In D2P mode, PCM signals are output in their original PCM format, while DSD signals are converted to PCM before output. (Currently, DSD64/128 is converted to 88.2kHz PCM, and DSD256 is converted to 176.4kHz PCM.)

In DoP mode, both PCM and DSD signals are output in their native formats. (DoP output supports up to DSD128.)

Note: DoP is preferred, and D2P needs to be selected if some devices do not support DoP.

5.Gain

There are five gain levels: ultra high, super high, high, medium, and low gain modes, corresponding to five levels of output voltage. You can choose different gains according to your headphones.

Note: The Ultra high gain mode is hidden by default and available only when inserting a fast charging power supply.

6.Digital filters

There are seven different filters on the M27. You can choose them according to your listening preference. Filters are some effects that come with the original DAC chip, and the adjustment is subtle for the sound.

7.Bluetooth codec

When transmitting via Bluetooth, the device will by default connect using the highest supported codec. You can use this option to manually select the preferred highest supported codec.

The M27 supports LHDC,LDAC,aptX Adaptive,aptX HD,aptX,AAC and SBC. You can switch the codec on the menu of Settings->Audio->Bluetooth Audio Encoder. Note that it needs to be disconnected and reconnected to enable the new codec after changing it.

8.Bluetooth audio codec LDAC (playback quality)

Allows switching between different playback quality modes for LDAC, including options for prioritizing audio quality (990kbps/909kbps), balancing audio and connection quality (660kbps/606kbps), emphasizing connection quality (330kbps/303kbps), and providing optimal sound quality whenever possible (Adaptive Bitrate). Only available for Bluetooth transmission.

9.Bluetooth audio codec LHDC (playback quality)

Allows switching between different playback quality modes for LHDC, including options for prioritizing audio quality (900kbps), balancing audio and connection quality (500kbps/560kbps), emphasizing connection quality (400kbps), prioritizing low latency (256kbps), and providing optimal sound quality whenever possible (Adaptive Bitrate). Only applicable for Bluetooth transmission.

10.Bluetooth volume adjustment mode

This function is only available for Bluetooth transmission, which features “Sync Bluetooth volume” and “Indep Bluetooth volume”. The Sync Bluetooth volume should also be supported by the receiving device, otherwise, it will be unavailable. The Indep Bluetooth volume means the volume adjustment of the receiver and transmitter is independent of each other. The Sync Bluetooth volume mode can solve the issue of overly small volume when connecting to some Bluetooth headphones, such as AirPods.

11.Channel balance

Channel balance means, by adjusting the output amplitude of the left or right channel individually to build up a special listening condition suitable for the users. For users who have no difference in hearing between left and right ears, there is no need to use this function, as the output of the left and right channels of the device is balanced. The default value of channel balance is 0, each of the left and right channels can be adjusted by 20 levels, and each level has a fixed difference of about 0.5dB.

12.All to DSD

After turning on the All to DSD, the global PCM audio will be converted to DSD for output, and the sound quality will be further improved.

Principle: The most important thing of All To DSD is to convert the digital signal in PCM format to DSD format, so that the DSD format can be used when performing D/A conversion to obtain different styles of sound, more clear and natural sound. In addition, since the lowest DSD format is DSD64, which is 4 times the data of 44.1k/16bit only calculated from the amount of data, All to DSD is also equivalent to up-sampling the PCM signal. The effect of All to DSD also supports third-party apps.

Enabling the All to DSD function increases CPU power consumption, which may result in reduced battery life for the M27 and more noticeable device heating.

If the overall battery life of your M27 is significantly shorter than the official specifications, please check whether the “All to DSD” function is enabled. It is recommended to disable this function and retest the battery life under the reference conditions provided on the official website.

13.Lineout volume adjustable

When Lineout volume adjustable is enabled, the volume during LO will be controlled by the buttons (including both single-ended and balanced LO).

14.Adjustable system USB output volume

When this option is enabled, the output volume of USB Audio can be adjusted directly from the M27 device.

15.Second harmonic adjustment

This feature emulates the unique distortion characteristics of tube amplifiers by intentionally adding even-order harmonics (second harmonics) that do not exist in the original signal. Three levels are available, and changes take effect immediately.

Level 0: Minimum harmonic content, lowest distortion.

Level 1: Moderate harmonic content, medium distortion.

Level 2: Maximum harmonic content, highest distortion.

16.Equalizer

The 31-band global PEQ function supports EQ superposition of the FIIO Music and other third-party apps. Here are the processes after enabling the PEQ on the system.

(1) Over 192k sampling rate- SRC processing;

(2) Priority: All to DSD>PEQ>MQA.

PEQ is only effective for the analog output in Android, Pure Music, AirPlay, Roon Ready mode. It does not work with Bluetooth Receiving mode or USB DAC Mode.

17.Auto pause without headphones

When this function is enabled, under Android and Pure music modes, if the M27 is in music playback state without headphones connected, the system will automatically pause playback after 2 minutes.