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Even BIGGER than Bigger, Badder BIB...
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Old 2nd October 2018, 05:11 PM   #21
BHD is offline BHD  United States
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A pair of JBL 2220A woofers have been purchased. I'm gonna do this!
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Old 4th October 2018, 07:44 PM   #22
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B&C DE250-8 1" compression drivers have arrived along with crossover components... woofers have been shipped. Almost there!
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Old 5th October 2018, 08:51 PM   #23
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Thanks for weighing in GM!

What were the dimensions that you came up with? I'm just curious.
You're welcome!

Hmm, just now seeing this!

Good Q, not sure which one I was referring to at this point..........

GM
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File Type: txt 12TRXB_BIB.txt (1.0 KB, 4 views)
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Old 5th October 2018, 09:00 PM   #24
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If SE amps won't work with high Qts drivers in a BIB that is definitely something I'm looking to learn NOW rather than later after buying ten sheets of plywood.
BIB [conical or parabolic] pipe horns are specifically designed for matching impedance amps, so for optimal bass you may need to add some series resistance for it 'to be all it can be' , though in reality it may already have too much bass, requiring some extra damping.

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Old 5th October 2018, 09:30 PM   #25
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One thing is that the woofer is a very low Qts driver and I seem to remember that when using a driver of that sort with amplifiers with a low damping factor you should oversize the cabinet cross sectional area by putting in a higher Qts into the BIB calculator. I'm sure that I read that but can't find the info anywhere.

Thoughts? Ideas?
Correct; between me and a few others posting this on various forums, but mostly here, surprised you couldn't find it: Qts' = Qts + any added series resistance: mh-audio.nl - Home

All things considered though and assuming a nominal 8 ohm driver, then just use a 0.403 Qts where in a reflex, Vb = Vas, Fb = Fs, so 300L would be the absolute minimum in a BIB and ~900 L the point of diminishing returns with 125 dB/37 Hz transients/30 W/1pi per HR.

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Old 6th October 2018, 12:12 AM   #26
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Thanks GM, I promise that I did look for it. The BIB thread is one hell of a long thread now so things can get lost. Plus, it is me looking for it after all.

Building a super efficient deluxe econowave into a BIB instead of the Jensen (Brociner) horns seems like such an amazing idea I'm surprised no one else has done it - 101 db efficient BIB's that should go DEEEEEEEP...

Should put my Sachikos in the shade in a few areas.

Components have arrived and I'm debating whether to build a test cabinet out of chip board or just dive in and build a plywood enclosure. I've gotta hear these!
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Old 6th October 2018, 12:48 AM   #27
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You're welcome!

Well, admittedly one has the best luck finding stuff when just searching for the core 'theme', so I just did a search of the BIB thread for 'matching impedance' and the first 'hit' gave essentially what 'we' were looking for in post 130, so wouldn't have needed to even scan very far in this case : Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks?

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Old 6th October 2018, 10:10 PM   #28
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Building a super efficient deluxe econowave into a BIB instead of the Jensen (Brociner) horns seems like such an amazing idea I'm surprised no one else has done it - 101 db efficient BIB's that should go DEEEEEEEP...

Components have arrived and I'm debating whether to build a test cabinet out of chip board or just dive in and build a plywood enclosure. I've gotta hear these!
Actually....... the pipe horn variants I did way back when were almost all Econowave concepts using various cheap 12-15" wide range [mid] woofers and usually just a 1200 Hz wide range 40x90 horn capped off with a 2.2 uF, a popular combo used in floor standing and [stereo] consoles and always seemed to sound fine as long as they were coupled to the electronics they came with.

Did some smaller ones using 8" + 1" cheap Radio Shack drivers with the initial response that I was nuts to put an 8" into an 8 ft^3 cab until I cranked up Rick Wakeman's 'The Six Wives of Henry VIII'/'Jane Seymour' that is .

There was some folks 'threatening' to build some BIB versions, but don't recall it happening. 'Hope Springs Eternal' though............

I had occasion to get a little involved in a local system build using chip/flake board recently and found that its properties have changed quite a bit over the decades since I last used it and with the 3/4" having a MOE not that much less than BB, etc., ply that combined with the latter's price hikes in recent years I see no reason other than cosmetics to waste the $$$ on it and just add a little more bracing.

GM
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Old 8th October 2018, 10:16 PM   #29
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I got the inspiration from Wilberforce's "What would you do with this cabinet" thread. I'd been wanting to build a the same cornerhorns he built but things got in the way - I kept trying to get cabinet makers interested, they'd say they'd do it until it came time to start and then they were "busy" or they'd "lost their woodworking space" etc.

The BIB calculator gives dimensions of 28 deep by 19.75 width 87.65 height and that's just perfect for efficient use of materials. I should be able to build a pair of them with five sheets, and I'm definitely going to build the first set out of OSB like the ones Variac did with the Pioneer BOFU 8" drivers back in the day. It should allow me to get an idea if the concept works and what it will sound like. I'll make a more ambitious build later or wrap the existing cabinet with 1/4" maple ply. Even though they're big they should be a lot easier to build than my Sachikos were.

JBL 2220A drivers have arrived intact and look like new.
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Old 8th October 2018, 10:26 PM   #30
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Here is a picture of some of the components.
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