The Marshall London comes with a dedicated button at the top of your device that launches a custom interface to give you access to some of the most common music features on your phone
MARSHALL M- BUTTON 
MUSIC CONTROLLER
Now you can control your streams and local music from one interface easily accessible by one click of the M-button.
The following can be done:
Player Selection
Select local or streaming player
Music Control
Play/Pause selected tracks
More Info
Get access to artist information where available
Host Player
Go to host player for more controls
MARSHALL FEED
Get all the latest Marshall news and information specifically for Marshall London users and customised for your region
VOLUME CONTROL
If you have more than one headset or headphone connected then you can control the individual outputs.
Set Volume
You can adjust the volume for the individual audio outputs. The second volume slider will only appear if a second headphone or headset is connected. When using the volume scroll wheel, you will adjust both outputs at once.
Mute
You can easily mute and unmute the device
EQUALIZER
Adjust equalizer settings for most of your music streams. Some music players and VOIP applications will not be affected by these settings.
The equalizer comes with pre-installed settings that can be managed from the Equalizer+ default music player installed on your phone.