My bassbins project

No pics yet for you visual thinkers, I'll post some later this week.

I got a quad of peerless HDS woofers, 8"s (so does it count as a sub? prolly not). These are a customized unit that was being used by Fried loudspeakers a year and a half ago, they've since changed owners, and being friends with the new guy, got some of his old stock on barter. They're similar to the regular HDS 8"s, just a touch nicer, and some slightly changed parameters.

Now, I wanted sealed cab bass. I'd been using some ported Vifa 7"s, as a stopgap, but they weren't making me happy, the extremely dynamic high sensitivity speakers I use on the top side of my actively biamped rig needed something to match better. So I modeled them up, and knocked up a pair in some 20L cabs I had sitting around (3/4" ply with some bracing) and used an opamp equalizer to set them to model flat to 30 then roll off. This didn't sound so good, so I adjusted the filter pot to put it to about 37 (f3) and it was much better. Natural F3 was more like 75Hz in these boxes. After happy results with this setup, I built another set, in larger (1 ft^3) boxes, with more bracing and better build quality.

Right now, they're stacked, running up to 200Hz with a 2nd order active filter. I'm going to fiddle with different arrangements of the XO, maybe run them bipolar or whatever. But I'm very pleased with the initial results here, they move as much air as I ever need (equivalent surface area to a 12" per side) with decent Xmax (8mm 1 way linear)

Soooo, if anybody has a powerful amp, and wants sealed bass without the size, an active EQ'd driver can do it for you. BTW, these are low Q alignments, both between .5 and .6.

Questions, comments, moans and groans welcome.
 
Pic

Here's a pic. Ugly cabinets from the outside, but they're sturdy. Up top is an open baffle with two audax PR17OMO and an Eminence APT80. Actively crossed over by a marchand XM127 (between bass+OBs, the mid/tweet is first order at 5k) The little red box you see to the left of the speaker is an active EQ to compensate for sealed box rolloff, little opamp unit built in a chinese cookie tin. Amps are a Fi X running 45s with magnequest OPTs, and an old phase linear, serving duty while I rework my PWM amp. Not the most elegant setup, but it makes good music. Preamp is a White follower 6922 stage, sources are either LP12/Ittok LVII/Sumiko Virtuoso Boron into bel canto phono1 or Sony DVP-S9000ES into a poth audio dac.
 

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