In this simple example (see video) instead of measuring loudness I'm measuring CPU and memory usage.
CPU and memory consumption are obtained from kernel's /proc filesystem and top command.
Buffers and Cached memory can be excluded or included from the count long pressing on the memory VU meter.
While the application was running a background process was launched and thus why the CPU usage increases.
I've found this example interesting and wanted to share it.
I hope you find it interesting too.