Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks? - Page 16 - diyAudio
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Old 12th March 2006, 11:16 PM   #151
dmason is offline dmason  United States
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Remember, what it SIM's like and what it winds up sounding like are often two different things. OneSpeed put the Fostex 168EZ into that rather large TQWT meant for Supravox 215RTF, and it worked extremely well, with plenty of balance and bass. The same driver shouldn't work as well as it does in the BIB, but it surely does, and is, as I write. I would not be surprised if the Hempster wasnt a champ.

Scott -- I found the US Dist for Acuhorn off Audio-Gone, and asked him why I couldnt see any mouths or vents like the others, and he explained that it was a simple folded, floor loaded horn. So it is BIB upside down, I guess. If it is impressing so many people in using the Monacor...
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Old 13th March 2006, 12:24 AM   #152
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Greets!

Ah, I didn't realize he had already done a design.

Good size, the room I'm sitting in is very close to these dims so know the acoustics well.

Thanks, glad you liked them! I'm a big fan of corner loading, especially with triangular cabs, which among other things will negate the need for any BSC.

Yes, it is, if it has enough Vb. Shrinking it to your dims makes it too small IMO though.

Anyway, do you know the amp's DF or actual output impedance? It can make a big difference in the design, especially with a medium Q driver.

GM
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Old 13th March 2006, 12:38 AM   #153
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Quote:
Originally posted by Scottmoose
The little Monacor looks like it could be the long-awaited replacement for the 1354 BTW guys -I was running a few sims on it earlier. Great little driver, especially at the price. I'll have to look at their other units.
Greets!

WRT cab alignments, I agree. I plugged its specs into a known, measured, 40-1354 tower design and it sims identical except for being ~1 dB less efficient, but of course this says nothing about how its mids/HF compares.

GM
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Old 13th March 2006, 01:14 AM   #154
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Quote:
Originally posted by dmason
Remember, what it SIM's like and what it winds up sounding like are often two different things. OneSpeed put the Fostex 168EZ into that rather large TQWT meant for Supravox 215RTF, and it worked extremely well, with plenty of balance and bass. The same driver shouldn't work as well as it does in the BIB, but it surely does, and is, as I write. I would not be surprised if the Hempster wasnt a champ.
Greets!

Oh so true, but there's no way you're going to overcome the effects of a grossly too small pipe, but too large OTOH is almost impossible, so little wonder 168 did OK in the 215's pipe. Indeed, as I previously noted, my pre-T/S designs were all made under the assumption that the cab's Vb was theoretically too large since it's easier to damp a cab than it is to enlarge it.

GM
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Old 13th March 2006, 03:26 AM   #155
dmason is offline dmason  United States
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So Bigger is Definitely Better!!

This means that the 168EZ perhaps represents an even BETTER candidate, because @ 66X15X7.5 it isnt all that large, and in fact its width, in aspect, seems to narrow. Perhaps it needs to be rebuilt (by someone) wider than the existing design, perhaps taller as well.

...listening to the very occasional rock recording, (Yes Live at the House of Blues) and the durn things are KICKING, definitely a Rickenbacker bass in the other room; all with 2 wpc Parafeed, built, incidently, by Terry Cain & Co. A surprisingly good, BIG sounding speaker, let there be no doubt. His original encouragement was "just build it." Now we are into the real stuff.

Thanks as always Greg for the enlightenment.
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Old 13th March 2006, 07:51 AM   #156
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Those who don't believe that bigger cabinets (and drivers, let's be honest) properly applied, will take a small ones to the cleaners should take a listen to Tannoy's monster Westminster, or it's direct ancestor, the GRF Autograph... I've yet to meet anyone who wasn't impressed.

Dan -given the amount we've learned from Greg over the last week, and the fact that thanks to Andrew, I've finally got the original plans, I can confirm your suspicions: you can go larger. Comparing the dimensions for Terry's box to the Fostex original, they are basically identical, being fractionally enlarged in TC's case to account for his using 1" material rather than the 18mm. The Fostex original is just over 1" longer too, again because it's metric, not Imperial (Aha! The Dark Side!). However, that box was for the FF125K. With that dinky little thing Sm=6.4209Sd. So a heck of a lot more cab volume. Keeping the same Fostex ratio, these would give the 'required' Vb: 11" x 14.75" (WxD external, assuming 3/4" material) or juggle to suit. I'd keep it at 66" tall (1/2 Fs), though you could try going up a bit. Your existing one should still be streets clear of the original version with this driver though, expecially if mounted in corners. It would also explain why my FF165K versions were not exactly lacking in the LF department.

Floor venting? I was wondering as the cab volume looked a bit small. I'll see what I can come up with for the 8" Monacors BIB-wise.

Cheers
Scott
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Old 13th March 2006, 11:03 AM   #157
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And now for one especially for Dan.

Supravox 165LB time. Well, you'll certainly have a suckout in your existing boxes, fine though the are for the FE168ESigmas. Here's one which doesn't though (well, OK, it drops about 4db, which is around 1/5 the loss of the other combinations I've tried). It won't go as low as the 168ESigma, obviously, given it's 65Hz Fs, but it still reaches down to ~28Hz, and with room-gain from corners, it should be usable to 40Hz.

53" tall (106" total line length)
9" wide (external)
16" deep (external)
31.8" up from internal base.
Terminate internal baffle 6.875" from front and rear walls and internal base.

As usual, you can juggle the WxD to suit your own taste and room, so long as Vb stays the same. This is Sm=5Sd if you're interested. Only one I've found with an acceptable mid-bass in the sims for this driver.

Onward!
Scott
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Old 13th March 2006, 03:05 PM   #158
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Default Output Impedance

GM,

Good Morning. I am currently running an Antique Sound Lab Orchid 3.5 wx2 2A3 integrated amp. It has output taps for 4, 8 or 16 ohms. I have not measured the actual output impedance. Hope that answers your question.

James
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Old 13th March 2006, 06:35 PM   #159
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This might be the best thread over this forum. I have been quite impressed with all I have read so far, gone several times over what Scott, Martin, Terry, GM and others had to say about the BIB, nice contributions, thanks guys.

Even though I have made quite a number speaker projects in the past Iím not a qualified designer (not smart enough as Nelson puts it) and have follow others ideas with not very good results in my opinion. I see I have to try harder.

Some 4 years ago I tried the FE164ís on a BR box, the big ones suggested by Fostex with poor results on the low end, they start to roll off at 200Hz and the BSC didnít help much either.

After reading this thread I was wondering how these FE164 would do on a BIB box, Can someone give me a hand to figure this out? I would like to try these seemingly strange boxes.

FE164 parameters as published by Fostex are;

Fs 50 Hz
Qts 0.31
Qms 4.0
Qes 0.34
Vas 32.2 L
Xmax 1.0 mm
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Old 13th March 2006, 07:07 PM   #160
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They'll work in Terry's original fairly well, being the predecessor to the FE17E. Could do with being larger though...

When I get home from work I'll run some numbers

Best
Scott
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