TiMBoZ's Passive FAST couple of photos

[TiMBoZ]

Just thought I'd post a couple of pics. I've posted this is in full range because I figure it's most likely of interest to full range enthusiasts.

The design is inspired by/similar to Troels Gravesen's 'Acapella' except sans tweeter and with parallel/butt jointed sides for a smaller footprint, easier construction. I also really like the Thiel 2.7/3.7s also I've been working on them for 3 years. They're done, finally!

They're 1.2m tall. 28cm wide & 70kgs each. They are a composite of MDF, porcelain tiles, rubber, aluminium, epoxy you name..it I tried it.

They have lime washed paper backed maple veneer skin. 2 coats clear urethane. Propellor posts, side mounted outrigger legs.

The 8' alloy SBA on the bottom is on reflex loaded box approx 40+L. I tuned the port by ear. I started listening with a very short port, then a very long one. I decided I wanted about 30% of the short ported, 'slammy' sound and 70% of the longer ports more mature, refined, modulated sound. So I chopped 30% off the long port

XO is at approx 400Hz I started with a LPF then fitted the HPF by ear. You can here when there's too much overlap, the sound gets kinda woolly/muddified and when there's not enough overlap the sound is too stark and etched and the vocal too recessed in the mix. The end result is kind of 'tuned to taste' I guess.

The Alpair is 10.3M but I used 10.2M's as well. (I have an old pair of these). The newer 10.3 is a lot brighter than the 10.2. and has the arrestor. A better fit for this situation IMO. I settled on a 3.9 Ohm padding resistor but there wasn't much in it between a 3.3 or the 3.9. I spray painted the rings to make em look a bit classier.

They took me 3 years of spare man cave time. They are a my own personal statement/take on the FAST concept that I just had to realise. But I'm glad they're done I can sit. listen an enjoy em

[Bigun]

Congrats !

[Bare]

Those do bear a 'resemblance' to Theils.
Look good actually.
You didn't do the Cast Concrete Baffle :-)

[TiMBoZ]

Thanks Bigun!

Well Bare, I like the idea of a concrete baffle but I didn't go that far. I shaped/made the baffle from solid MDF & plywood slab I guess. Layer of each. Routed the driver holes etc., then carved the arched profile with a plane. Then I took a 25mm drill bit and drilled lots & lots of holes to form a crude 'honeycomb'. Then I filled the holes with small gravel, then backfilled with slow cure epoxy, stirred with a toothpick Then a smoothing coat of epoxy putty, then sanded back to the wooden honeycomb, as best I could. I don't think I'll do this again