I had the opportunity to visit Vic of Trans-Fi fame the other night to have a listen to his OB's,which I'd discovered whilst having a mooch around the net looking for info on my Bastanis. Thanks are due for hosting me and allowing me to listen to his creations - thanks Vic!
Short version - Wow. Just wow..
Long version - Vic took me upstairs to his living room, quite a large space, around 30ft. by 15ft. so room for speakers to breathe. We had a chat about the construction of the speakers and the various earlier iterations that are scattered around the room. Some photos below, but basically he uses some miniature scaffolding parts from a company near Huddersfield I think it is - total cost for all the parts and for them to cut the tubing to length was £99 delivered, so a bit of a bargain there. I'll try and find a link. The bass drivers are bolted together facing each other using some spacers of around 4-5", and hang in a cradle of the scaffolding supported by some small loops of cable. This seems to work really well - I checked to see if any vibrations were making there way from the drivers to the scaffolding and couldn't really detect anything, so this arrangement appears to work really well. The PRV mid/top drivers are hung from a U shape bracket, again with a loop of cable under the top drivers' magnet. Vic made some fish plates, more or less the shape of a dog bone to connect the four drivers together, all just hanging there from the top driver. The weight of the drivers keeps them steady. They are connected series/parallel a la Edingdale stylee.
It was all digital files we listened to, one particular track that struck me was a live version of Man/Machine. I can honestly say I've never heard a speaker in a living room get closer to how a live gig sounds ( or at least how I imagine it would sound not having been there). The scale, dynamics and sheer drive to the bass has to be heard to be believed - I've certainly never heard anything like it in a living room, it really is like being at the gig. The funny thing is though, the bass is in no way overblown, nor does it interfere with the mid/tops in any way, it's just there when it needs to be, and boy is it there! As Vic commented, you can't really appreciate music like this until you hear it with the full frequency range reproduced, and having now heard this for myself, I have to agree.
The 4" PRV drivers appear to be quite a bargain- I think they are around £75 each?
Mids and tops were very well reproduced, huge soundstaging too. Very clean and clear, and I didn't miss a tweeter at all.
Further details - The bass drivers are Dayton Audio UM18, crossed at 275hz to suit the PRV drivers, using the DSP in the Behringer amps. I was surprised to learn there is no DSP used to tweak the low bass response due to the lack of baffle, these drivers are so capable that none is required - I can certainly vouch for that. Only caveat is sensitivity is not great, but as Vic again commented, watts are cheap - he's using a couple of 6000w NX Series Behringers which he paid £300 each- all he does is up the gain by 10db to match levels with the PRV's. Other than that they are run open, as I believe are the PRV's - they are run with a pair of Temple Audio boards, powered with a pair of supercap power supplies.
Well that's about it, just like to say thanks again to Vic, it was a pleasure to meet you. My plan now is to copy the bass side of this and use it with the Bastanis mid and tweeter.
EDIT - link to the metal store - https://www.themetalstore.co.uk/