When the bass drops

At the end of my tether here, looking for any advice or people’s previous experiences in a similar situation. I’m in a terraced house which I own. One one side there’s an family of four, also homeowners, who I rarely hear a peep from and get on well with, and on the other side a homeowner family of four (kids are under 7) where the parents are fond of loud parties and subwoofers. I have already asked them on previous party nights to turn down the music but this has never gone down well with them and relations are unfortunately now non-existent. They now appear to have bought a fairly powerful subwoofer that pumps out bass which comes directly through my wall and is causing me immense stress, tension, and is severely impacting the quiet enjoyment of my property that I am supposedly entitled to. I am going to FLAC this week for advice and will be contacting the local council too. They have neighbours on the other side who I’m going to have a word with and see if they are affected as much as me, but I don’t think so as the layout of their house is different to mine. I don’t want to revert to pumping up the bass on my side as ‘a taste of their own medicine’ and see if that works but as this stage I’m fairly desperate and the only other options appear to be 1) move (can’t afford to) 2) invest in expensive soundproofing that may or may not work 3) quickly go insane

I would sincerely appreciate anyone else’s POV on this. I realise noisy neighbour threads are ten-a-penny but I also rent out a room in my house and my renter has told me they will move out if this isn’t solved in some way as they can’t sleep and find the sound as intrusive as I do. Thanks for reading if you made it this far!