Always show DSP volume in the “signal path” if not set to full volume.
Changes to the “signal path” are not shown when DSP volume is being used to alter the signal. This is inconsistent: the “signal path” shows additional steps when R128 volume leveling is enabled, when a preset adds headroom management, or when Procedural EQ Volume is enabled.
The second last screenshot of the “signal path” in this blog post https://blog.roonlabs.com/signal-path/ shows DSP volume with a green dot.
A post by Brian (DSP Enable lowers Sound Quality) says it should be displayed and this is probably a bug.