Feature request: Software volume control for USB S/PDIF output devices

[ThilliMilli]

Short summary

Add software volume control for USB S/PDIF output devices that do not expose macOS volume control.

Why is this needed?

Hi,

first of all: I really like BetterAudio. The overall usability is excellent, which is why I just purchased a license.

However, there is one crucial feature missing for my setup: volume control for USB S/PDIF output devices.

In my setup, I use a “USB SPDIF Adapter” as an audio output device when my MacBook is connected to my monitor on my desk. BetterAudio detects the device correctly, but the output volume cannot be adjusted through the app. This is also not possible through the standard macOS volume control, as the device does not seem to expose hardware volume control to macOS.

FineTune (https://github.com/ronitsingh10/FineTune) has implemented software volume control for the same USB S/PDIF adapter, so I was wondering whether it would be feasible to implement something similar in BetterAudio as well.

This matters because I prefer BetterAudio’s overall usability and would like to keep using it as my main audio control app. However, this missing feature means that I am currently switching back and forth between BetterAudio and FineTune.

Proposed solution / behaviour

BetterAudio to provide a software-based volume control for USB S/PDIF output devices when hardware volume control is not exposed to macOS.

Expected behavior:

• The USB S/PDIF output device should show a usable volume slider in the BetterAudio menu.
• Adjusting the slider should change the perceived output volume for that device.
• The interaction should feel consistent with volume control for other output devices in BetterAudio.
• If possible, this could be implemented as software attenuation for devices that do not support native macOS hardware volume control.
• Ideally, this should also work with per-app volume control and multi-output setups, if technically feasible.

A simple UI approach could be to display the USB S/PDIF adapter like any other output device, but with a normal adjustable volume slider instead of only showing the device as selected/fixed.

Platform

macOS

Related issues or PRs (optional)

no issue or PR but kind of a feasibility proof :) -> FineTune has implemented similar software volume control for the same type of USB S/PDIF output device: https://github.com/ronitsingh10/FineTune

Mockups / screenshots / notes (optional)

I’ve attached screenshots showing:

• The USB SPDIF Adapter in BetterAudio, where the device is detected but volume control is not available.
• FineTune, where the same USB SPDIF Adapter can be controlled through a software volume slider.
• A mockup for BetterAudio how a possible solution could look like

A possible BetterAudio implementation could look similar to the existing BetterAudio output device list, but with a usable volume slider for the USB SPDIF Adapter as well.