Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks? - Page 12 - diyAudio
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Old 8th March 2006, 06:16 PM   #111
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Impressive, I think, will be the word. You up for building a pair with the hempsters then Dan?

Interesting site -I didn't know anyone had made a commercial version. (proves how much attention I pay to most manufacturers doesn't it?) I think I prefer Terry's cabinet work though... and you're right Dan -that Tesla driver does look suspiciously like a (slightly) tweaked Monacor: http://www.monacor.com/int/en/produk...7&spr=EN&typ=u

Best
Scott
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Old 8th March 2006, 06:31 PM   #112
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Default Hempster BIB

All right. Scott and Dan have me convinced that the hempster in a BIB is the greatest thing since sliced bread. I will start construction as soon as E-Speakers ships me a pair of FR8s. Scott have you made any adjustments to the parameters you previously posted? Thanks. James
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Old 8th March 2006, 07:08 PM   #113
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Jimmy

You cannot go wrong. It may be that they drop your jaw. I consider the BIB's a true musical instrument; they resonate in the good way, like an organ pipe or so. ...As long as you avoid MDF, that is...

If you value music over the current charade of so called high resolution MY-fi, which sounds decreasingly musical in my experience, and you combined the BIB load with the energetic, emotional, aura-enriched organic-ness of the hemp cones, you are truly in for a treat. The result I honestly suspect will be right over the top. Add an SET amp and sit back and listen for the rest of your life. 2 watts with a strong source signal will drive the daylights out of the hemps, and sounds gorgeous.
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Old 8th March 2006, 08:22 PM   #114
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Greets!

Quote:
Originally posted by planet10


Well more like alot of people repeating the accepted wisdom. GM designed an 1194 ML-Voigt that purposely have S0 = 0 to disprove the point, I believe Woody has the prototypes -- they placed fairly well at an Atlanta diyFest.

dave
Yes, he does. They did OK, all things considered, but I didn't enter them to be officially judged in the separate auditioning room, instead only setting them up on top of some large Goodmans? Lowboy cabs in the 'greatroom' for a short time using several full coffee creamer cups to space them up for the bottom firing vent since I didn't have time to make a proper stand/base for them, so only a fraction of the folks actually got to hear them before voting. Factor in that we are visually oriented creatures and their crude looks IMO had to have affected some folk's subjective opinion of how they performed: http://www.patcave.com/diy2k4/spk_7198a.jpg

Still, the cab is ideally just there as a platform for the driver to 'work' from, with your tweaked 40-1197s being much better overall than stock and these Tangband drivers IMO: http://www.patcave.com/diy2k4/spk_7223.jpg (don't recall the model #), so placing 3rd behind BB's FE167E demo MLTL: http://www.patcave.com/diy2k4/spk_7222.jpg and JC's FE108EZ/dual driver sub two way: http://www.patcave.com/diy2k4/spk_7221a.jpg 'tells the tale' IMO.

Quote:
Originally posted by Scottmoose


Regarding the So=0, I agree. Generally best avoided unless there are specific reasons for having it, like to increase pipe-gain, but it's not the great evil of the Western (or any other) World either.

Dan -I agree about the B200 not being an ideal match with that hefty Q. Not impossible either; as I say, I tried it a few days ago with some interesting results. It wouldn't be my first choice either though -Fostex of hempsters for me.


Cheers
Scott
FWIW, I've repeatedly strongly disagreed with this generalization since its alledged 'shortcomings' go away with proper design, leaving only its positive attributes, with better overall performance and slightly easier to build layout than Weem's or MJK's popular truncated variant. The trade-off is that it's harder to get the design 'right' if you're not fairly well versed in horn design. Still, I've built very few over the decades since a straight pipe works 'good enough' for the vast majority of apps, with the added benefits of being easier to build and typically somewhat smaller.

WRT 'BIB' style cabs and high Q drivers being mutually exclusive, ya'll are completely 'missing the boat' IMO. For instance, to make the semi-high Q 40-1197 pipes 'sing' required nearly 9 ohms of series resistance............ the trade-off is size since the cab's Vb must 'swamp' the driver's Vas. Indeed, my interpretation of a 'BIB' (wasn't aware of the Japanese concept during my building years) design only requires knowing the driver's Sd and a general idea of its Fs. The trade-off is that I derived it based on the high Vas drivers of the day, so it's even more unsuited than T/S derived pipe designs for any of the space saving low Vas drivers of today.

GM
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Old 8th March 2006, 09:23 PM   #115
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I have to agree with GM regarding the use of a variant of drivers. (based on things I've heard) I believe it was earlier in this thread, (or another) where we discussed someone on this board using the Isophon 8x12" drivers in a larger version of the BIB with great success. I measure mine (though roughly) and they came out to a Qts. of about 1.0. Seemingly too high, but then again, maybe not.

I did originally build the BIB boxes for a 6" cheap rat shack driver, 1042 maybe? Anyway, it wasn't bad, but I'd guess has a higher Q as well.

One other thought, though strange to me, is I put the 168E Sigmas on an OB recently as an experiment. And to my surprise, while they don't have much low end, they didn't sound like an entirely different speaker either, (which I expected).

This tells me the BIB box isn't as boxy sounding as expected.

On a similar note, one could visit the Supravox TQWT. I've heard it with the 168s, and it sounded amazing. This was designed for the 215 variants, which range in Q from .23 to .8 or so. And the 168, at a much smaller size, comes in at .28 or so. I know it's been used with the 206E with success as well.

I'm only stating this as it seems the box could work with most anything to some extent. The Supravox box is similar in a quarter wave treatment.

Anyway, enough rambling...
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Old 8th March 2006, 09:44 PM   #116
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Hi GM... I think your 1197 speaker is a rather pretty ugly duckling.

Closing your eyes or turning out the lights may have one thinking they are involved with a great beauty.

Noticing the cute phase plugs on the 1197's i wondered if you've heard the Pioneer B20's with phase plugs? I love my B20's and had them cranking late last night before running off to krav maga training.

They sound just fine stock to me but i wondered about any improvements in midrange clarity phase plugs may offer.

I may just cut those dustcaps out one day. Any thoughts?

Godzilla
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Old 8th March 2006, 10:02 PM   #117
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Quote:
Originally posted by one1speed
someone on this board using the Isophon 8x12" drivers in a larger version of the BIB with great success
Shoog... unfortunately he "broke" the drivers :^(

I haven't yet measured any of those -- but do have a mismatched pair of the co-ax version downstairs.

dave
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Old 8th March 2006, 10:05 PM   #118
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Quote:
Originally posted by Godzilla
I may just cut those dustcaps out one day. Any thoughts?
Of course i'm biased, but i haven't had a bad sonic experience yet -- i have had a bad experience with FE127 -- 4 dead -- while they were playing with PP it was definitely an improvement -- i wonder how many drivers you'd have to order off Fostex to have them leave the dust caps off?

dave
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Old 8th March 2006, 11:05 PM   #119
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James -they're great. But I'll say this again: remember to build for the right reasons: they are not monitors, and don't pretend to be. Interesting that the original design was for the FF125K: it looks like Terry altered the dims for 1" material for his RS versions, but left the rest pretty much alone, at least for those (not for his 168Sigma versions though!)

Quote:
Originally posted by GM
WRT 'BIB' style cabs and high Q drivers being mutually exclusive, ya'll are completely 'missing the boat' IMO. For instance, to make the semi-high Q 40-1197 pipes 'sing' required nearly 9 ohms of series resistance............ the trade-off is size since the cab's Vb must 'swamp' the driver's Vas. Indeed, my interpretation of a 'BIB' (wasn't aware of the Japanese concept during my building years) design only requires knowing the driver's Sd and a general idea of its Fs. The trade-off is that I derived it based on the high Vas drivers of the day, so it's even more unsuited than T/S derived pipe designs for any of the space saving low Vas drivers of today. GM
That's very interesting Greg. As I say, the B200 surprised me by actually working, though they peaked a bit ( a lot) at circa 55Hz. Going by what you say, it might have been more a case of the box not being optimised rather than a fundamental mis-match of cabinet type and driver, as the rest of the Fr was pretty good. I'll look into that some more. Could you share any of your own methodology that you mention? As I said to Martin earlier, I like to learn new (to me) methods whenever I can.

Regards
Scott
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Old 9th March 2006, 01:38 AM   #120
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I know folks have said bracing is unneccessary. However, it seems to me that it couldn't hurt, especially for larger versions. How about vertical panels between the divider and the front and back? I'd swiss cheese them of course. Could there be any harm?

In the original, the quarter wave tuning is an octave below the Fs right? That would put the second mode right at the drivers Fs. Does making it shorter than ideal (for example, a Hemp BIB 70" tall mean the driver isn't as damped at resonance as it should be? I know that the driver gets too high if it is taller, but what if one extended the enclosure above where the divider attaches to the baffle?
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