Top toolbar RTA (spectrum analyzer)

The idea is to add a Foobar-like spectrum analyzer to the top panel of LMMS. There's some space there I think it might be useful to quickly check a frequency, a simple 100Hz/1kHz/10kHz grid could also be added to provide precise reference (why not?) so it's less of just a cool looking toy and more of a real tool. Here's a quick mockup:


I often find myself adding a spectrum analyser to the master bus and setting it to "Always on Top" - it helps me build the sense of where every sound resides and helps me plan my mix and even composition. very useful.

What do you think? Of course it should be possible to switch that off if the user doesn't need it and it drains his resources too much.

Start by reviewing the proposed top-panel spectrum analyzer and the linked mockup, then compare it with the existing master-bus spectrum analyzer workflow described in the issue. Define how the analyzer, optional 100Hz/1kHz/10kHz reference grid, and resource-saving switch should behave; the work is done when the feature is available in the top panel and can be disabled.

Written by the indexing model from the issue text.