PMC 22 with Sub

Welcome aboard James. I have a similar sized room and bought a REL sub in the 1990's. Very good sub. It filled in the lowest frequencies well when I had stand mount speakers but less so when I got larger speakers with extended response. The PMC speakers I have heard had deep bass as well as the detail. In a square room of that size the acoustics are challenging as I know from years of moving and measuring the acoustics. You may find moving the 22's nearer the back wall gives some more bass extension without the hassle of a sub.

If you are having problems with room effects, it's often said that a pair of smaller subs can help tame room modes. Maybe not go as low as a single larger sub but better for poor room acoustics. Having said that, I found integrating a pair of REL Tx5s with my little Harbeth P3s to be really difficult. I must have spent 6 months fiddling with settings using the REL instructions and not satisfied. I then opened up a rabbit hole and started measuring with REW (free) software and UMIK mic. This revealed how much the room was damaging the bass with my prefered speaker placement. A lot of measurements and researching best speaker positioning resulted in far better response, removing the worse of room effects. I now use dsp to integrate the subs but keep a 'pure GS' route to mains only. So I have the option to include subs for some music but to be honest even though the P3s now only go down to 90Hz, I usually prefer the clarity of mains only.

Hi James.