Hi there,
So, born 77, wife and two kids. My son (8) and I are doing a DIY project with volumio amongs other things. I´ve been running volumio a few years with raspberry and a hat-amp.
The base was kind of thin, so now we are buildning a subwoofer. I almost got the raspberry/volumio to work now. The setup (when finished) should be something like:
transformer - amp - raspberry - pi dac pro w filters - mono speaker +mono sub.
Right now, it´s just a test rig 
hi! welcome 
Ok, some (hopefully) inspiration
This is one carlsson OA5 restored with new drivers and such. This speaker was designed for mono, but often sold as pairs as a result of the new trending stereo concept (in the mid seventies). I had one box left as I was satisfied with the mono setup. I was running this with volumio on a raspberry and a hat-amp for some years.
I recently decided to make something of the remaining box, so here we are (almost). One sub with builtin amp, driven by a raspberry with pi dac pro and volumio. I made some physical “limiters” (the pots) to be able to fine tune filters and also have them as just limiters (so no one blows any drivers or so by mistake). The sub is a vented one using a monacor driver sph200ke. It kinda looks like a stereo setup, but this is a dual mono, or 1.1 setup.
I fiddled around with a lot of filters, but I´m close to finish now, or even done, time will tell. The original OA5 now has a HP filter @ 60Hz second order. I found this to be the best for that speaker. The sub is using HP@80 with a butterworth @ 42 oct for a quick rollof.
Left to do:
Get my head around the volstereo2mono plugin. This is taunting me at the moment.
Some cosmetics, like a new (vintage) on/off switch as well as a vintage wall plug.
