Balance control

[user24024]

Checklist

• [X] I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• [X] I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• [X] I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• [X] I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• [X] This issue contains only one feature request.
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Feature description

Add playback balance control functionality.

Why do you want this feature?

To be able to adjust the balance.

Additional information

Ideally, balance control should basically lower the volume of a channel, instead of moving both channels left or right.