Tone2 Pro - Bit Perfect Linux Audio

Guide from @hyphop for Linux users on how to get bit-perfect audio going for your Tone2 Pro!

How to get Maximum Performance from your Tone2 Pro and Tone1 on Linux


System Preparation

For maximum performance, you need to use the native Linux-ALSA stack! Please avoid PulseAudio if you want to obtain the best audio quality from your Tone2 Pro or Tone1.

1. Disable PulseAudio for Tone2 Pro, Tone1, and other Khadas Audio Devices

NOTE: You can skip this step if PulseAudio not installed in your system. To check, use the command:

which pulseaudio || echo PulseAudio not installed

If PulseAudio is installed, it is very easy to create a custom configuration file!

sudo tee /etc/udev/rules.d/89-pulseaudio-usb.rules <<END
# Disable PulseAudio for next usb-audio devices by usb-id
# Tone2 Pro
ATTRS{idVendor}=="3353", ATTRS{idProduct}=="a002", ENV{PULSE_IGNORE}="1"
# Tone2
ATTRS{idVendor}=="3353", ATTRS{idProduct}=="a004", ENV{PULSE_IGNORE}="1"
# Tone1 
ATTRS{idVendor}=="3353", ATTRS{idProduct}=="a001", ENV{PULSE_IGNORE}="1"
# Tea
ATTRS{idVendor}=="3353", ATTRS{idProduct}=="a005", ENV{PULSE_IGNORE}="1"
# Tea Pro
ATTRS{idVendor}=="3353", ATTRS{idProduct}=="a006", ENV{PULSE_IGNORE}="1"
# Tone1 with XMOS usbid
ATTRS{idVendor}=="20b1", ATTRS{idProduct}=="000a", ENV{PULSE_IGNORE}="1"

# just one line for all XMOS devices
ATTRS{idVendor}=="20b1", ENV{PULSE_IGNORE}="1"
# just one line for all Khadas Audio devices
ATTRS{idVendor}=="3353", ENV{PULSE_IGNORE}="1"


Now just re-plug your Tone2 Pro or Tone1 device to your machine for the new configuration to take effect.

2. Check If Native DSD Playback is Supported on Your Tone2 Pro or Tone1

Enter the following command into Terminal:

grep -H DSD_U32_BE /proc/asound/card?/stream0 && \
echo Native DSD support - ok

3. What should I do, if DSD is not supported?

Your Linux system is using an old kernel! Please check your kernel version using the command uname -r, and check this topic Does the v2.00 Firmware sound better? - #6 by hyphop, and then upgrade your Linux kernel.

How to Display All Supported Formats

Get a list of all supported audio file formats using Terminal:

grep "" /proc/asound/card?/stream0
# or 
grep -e usb -e Format -e Bits -e Rates /proc/asound/card?/stream0

Example Output:

Khadas Tone2 Pro at usb-0000:03:00.4-1, high speed : USB Audio
    Format: S32_LE
    Rates: 44100, 48000, 88200, 96000, 176400, 192000, 352800, 384000, 705600, 768000
    Bits: 32
    Format: S32_LE
    Rates: 44100, 48000, 88200, 96000, 176400, 192000, 352800, 384000, 705600, 768000
    Bits: 24
    Format: SPECIAL DSD_U32_BE
    Rates: 44100, 48000, 88200, 96000, 176400, 192000, 352800, 384000, 705600, 768000
    Bits: 32

Use MPD Audio Player with Tone2 Pro and Tone1

About MPD

Music Player Daemon (MPD) is a flexible, powerful, server-side application for playing music. Through plugins and libraries it can play a variety of sound files while being controlled by its network protocol.

Why MPD?

MPD User Manuals

Install MPD (example)

sudo apt-get install mpd mpc ncmpc

Prepare MPD (example)

Create music folders and the mpd config file (your music library must be accessible from these folders)

mkdir -p ~/mpd/music ~/mpd/playlists

Minimal MPD Config File (example)

MPD searches for a config file in $XDG_CONFIG_HOME/mpd/mpd.conf then ~/.mpdconf then /etc/mpd.conf or … read more man mpd

nano ~/.mpdconf

# ~/.mpdconf - minimal mpd configuration for bit-perfect DSD playback

music_directory "~/mpd/music"
playlist_directory "~/mpd/playlists"
db_file "~/mpd/base"
log_file "/dev/null"
pid_file "~/mpd/"
state_file "~/mpd/mpd.state"
sticker_file "~/mpd/sticker.sql"

group "audio"
#bind_to_address "localhost"
bind_to_address "any"
bind_to_address "~/mpd/mpd.socket"
follow_outside_symlinks "yes"
follow_inside_symlinks "yes"
auto_update "yes"
auto_update_depth "6"

#zeroconf_enabled "yes"
#zeroconf_name "Music Player @ %h"

audio_output {
type "alsa"
name "Tone2"
# use only hardware devices for bit-perfect playback
device "hw:CARD=Pro,DEV=0"
# optimal buffer/period size for maximum performance
# about 2% system usage only ;)
buffer_time "409600"
period_time "40960"
# only use hardware volume control
mixer_type "null"
# software volume control, you may/may not need this ;)
# mixer_type "software"

# disable all format conversions
auto_resample "no"
auto_channels "no"
auto_format	"no"
# Disable DSD over PCM, as we have native playback from the Linux kernel
# dop		"yes"

audio_output {
type "alsa"
name "Tone1"
device  "hw:CARD=Control,DEV=0"
buffer_time "409600"
period_time "40960"
mixer_type "null"
auto_resample "no"
auto_channels "no"
auto_format "no"
#dop "yes"

audio_output {
	type "null"
	name "NULL"

filesystem_charset "UTF-8"
audio_buffer_size "512"
#buffer_before_play "5"

How to Get the Proper ALSA Device Name for Bit-Perfect Playback

Full List:
aplay -L|grep -A1 ^hw:

Only USB List:
aplay -L|grep -A1 ^hw:|grep USB -B1

Only for Tone Board:
aplay -L|grep -A1 ^hw:|grep Tone -B1|head -n1

MPD Test/Check Foreground Run Mode

To detect problems and run more checks, input the following command:

mpd -v --stderr --no-daemon ~/.mpdconf

MPD Start/Stop

  • mpd ~/.mpdconf - start
  • mpd - start
  • mpd --kill - stop
  • sudo pkill mpd - stop everywhere

Basic MPC Usage Example

mpc is a command-line client for the Music Player Daemon (MPD). It connects to a MPD and controls it according to commands and arguments passed to it. If no command is given, the current status is printed (same as “mpc status”).

mpc add DSD_test_512.44100.2.dsf
mpc add '09 - Faith No More - Be Aggressive.flac'
mpc add
# play it
mpc play
mpc repeat on 
mpc outputs
mpc stop 
mpc clear
mpc update
# get full commands list 
mpc help

How to Check Which Output Format and Rate is Currently Used for My Tone Board?

cat $(dirname /proc/asound/card?/stream0)/pcm?p/sub?/hw_params

Native 512-DSD output example:

format: DSD_U32_BE
subformat: STD
channels: 2
rate: 705600 (705600/1)
period_size: 28902
buffer_size: 131072

MPD Client Interfaces

All are welcome to give comments, replies and suggestions for improvement!


For someone with basic skills, what do you plug into what to access the command line or whatever it is that you type into?

I didn’t understand this to be so hands on when I bought it? Sorry…

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The Linux Terminal App, also known as the “Shell”.

p.s ctrl + alt +t is a shortcut to open it
p.s.s yay @hyphop voice reveal :grin:

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