Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks? - Page 103 - diyAudio
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Old 16th July 2006, 11:02 AM   #1021
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Zek, the reason some of the theory is a bit hazy is that Jeff, GM and I have deliberately chosen to keep it that way as we don't wish to be responsible for any possible loss of commercial revenue. For example, when Terry came up with his new FE108ESigma floor-loading BIB enclosure, Jeff pulled the sugested dimensions for this driver from the pages. Also, they're checked and occasionally tweaked in MathCad (though the initial sizing is not done in his software), which means that he is also involved too. Sadly, there are dishonest people out there. A real shame, but we can't ignore the reality, more's the pity. Nothing to stop them from using the suggested dims up on the pages of course, but no sense in giving them everything and making their loathsome lives a breeze. If any private individual wants a particular driver doing, they can always ask here, and one of use will help out. That said, these things are easy enough to figure out if you do some reading on conical horns and TQWTs. Enthusiasts with a genuine interest will find this all part of the fun. Vile enclosure design thieves can rarely be bothered. It's not an easy situation, but we've done our best to take a middle ground. I'll answer a few of the points you raise though as there's nothing particularly startling about them; if anyone wants to investigate further, you can take it from here.

1) Drivers if you're running full-range want to be Fs 40-60Hz, lowish Vas to keep Vb reasonable, and preferable of a middling Qt. Low Q will also work fine -just make sure you have a low DF amp and / or some series resistance. High Q will also work, but the necessary Vb will be somewhat higher.

2) 1/2 Fs or a little lower. No news there.

3) Not so much to do with T/S parameters as it happens. Vas and to a lesser extent Qt are the critical factors. You want a Vb sufficient to swamp the Vas of the driver. See traditional enclosure design formulas / proceedures from the pre T/S parameter era.

4) See TQWT / QW theory. Have a read of Martin King's white papers on www.quarter-wave.com for more on driver positioning.

5) There are two Excel sheets which will help you here. Use the first to determine enclosure height (or alternatively, just use H=Fs/2) and Greg's to establish optimal expansion (i.e. W & D)

6) Totally room dependant. Start with some stuffing in the point above the driver, a felt or similar pad behind the driver, and a 1in layer on the base. Adjust room position and internal damping from there. Remember these are nominally corner horns, so they need at least 1 boundary near them, behind, or to the side, or both. As I say, depends on the enclosure you've built, your system, your room, and your own taste.

7) Subjective. Great bass for the driver size is a given. Excellent imaging is usual, as is a freedome from 'boxy' colourations. The rest depends on the individual listener's perception. Dan and I experience a sort of dipole sound in the low registers; odd because these are about as far removed from dipoles as you can get, but there you go. That's what it sounds like to us. Other people might not experience this, or have a different perception of it.

Regards
Scott
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Old 16th July 2006, 06:05 PM   #1022
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Hi there,
been away for a while due to hard disk breakdown.
I agree totally regarding dipole bass from BIB`s. My listening room is an acoustical nightmare. The only speaker that works here are dipoles and BIB`s.

Been listening to track 4 on Red hot chilipeppers new album today. It is stunning the amount of bass one can get out of a mere 10 cm`s driver. Plus it is fast and without "overhang".

My Monacors BIB`s were a low-cost-first-time-fullrange project for me. Amazingly my Genelec 1030 got replaced by these 60 EURO/pair speakers.
I am not saying these BIB`s are better in all area`s than my Genelec`s, but for me it has always been a pain to listening to music when I have fever. I had high fever a few weeks ago and found out it was possible to listening to music thru these fullrangers. I simply find that it is more enjoyable to listen to these cheap bastards.
Now it is time to step up the stakes a little higher, I`m thinking of building new ones with either Neo-fones or 168ES. Are there anyone who have built BIB`s with Neo-fones yet?

Best regards/Peter
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Old 16th July 2006, 07:07 PM   #1023
dmason is offline dmason  United States
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Peter

If you have some tubes, I would recommend the 168's, whose sound will only be enhanced. They do quite well on as little as 2 watts, and from 4-10 really come on. If you have SS power, the Neofones look pretty interesting, and Brian Cherry, bias ignored, seems to think they are a very good wideband driver, as does Thorsten Loesch.

My vote goes with the FE168, which is almost ideal for this type of alignment and sounds wonderful after the scant 1,000+ hours of play.
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Old 16th July 2006, 07:21 PM   #1024
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Hi dmason
For the moment I`m running Monacor`s with a NAD 7020e as my Naim amp need a doctor. I am more interested in UCD180 than a tube amp. Reports from others says that Hypex amps sounds smother than expected from a class D amp. What`s your opinion about Sigma`s and SS amps. Anybody else who`s running Sigmas with SS or class D amps
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Old 16th July 2006, 07:56 PM   #1025
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I'm in agreement with zeb up above there that a nice
how-to for the bibs is called for.


Quite frankly, anyone who thanks that the BIB will
be somebody's meal ticket into speaker manufacturing
and design is whistling in the paranoid dark.

As a matter of fact, I'd like to see where virtually any DIY
project was stolen for commercial gain. I've seen no evidence
of it and I've been reading these forums for 6 years.


Also, Scott, the calculator that GM has repeatedly posted
has no file extension. It downloads as a zip, is opened
and then not executable. Perhaps a program has to open it
but there should always be a file extension for program
clones that are Excel compatible.


Lastly, I think that the open source model is still the
appropriate one and that all efforts to that end will bring
people into the hobby rather than discourage them from it.
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Old 16th July 2006, 08:57 PM   #1026
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Quote:
Originally posted by loninappleton
Also, Scott, the calculator that GM has repeatedly posted
has no file extension. It downloads as a zip, is opened
and then not executable. Perhaps a program has to open it
but there should always be a file extension for program
clones that are Excel compatible.

Download the file, then edit the name to BIB.zip. Now it will unzip as as BIB Folding.xls

Bob
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Old 16th July 2006, 09:03 PM   #1027
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Quote:
Originally posted by Bob Brines



Download the file, then edit the name to BIB.zip. Now it will unzip as as BIB Folding.xls

Bob

Thanks Bob.

I thought it might be something like that but I do not
use Excel and s would be trying it out in 602 suite to see if
that works.

Maybe someone can repost because I took it off system
already.

No rush though. My BIB project is developing slowly.
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Old 16th July 2006, 09:20 PM   #1028
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Quote:
Originally posted by Bob Brines



Download the file, then edit the name to BIB.zip. Now it will unzip as as BIB Folding.xls

Bob

Readers will be happy to know that the procedure
worked fine and opens in Open Office by default.

Neat.

:-)

I forgot how to recalc in spreadsheets but that
should be a small problem.
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Old 16th July 2006, 09:47 PM   #1029
dmason is offline dmason  United States
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Peter

I haven't heard the UCD amps but they get glowing reports. I do know of at least three people using the FE168 in Abbys and BIB's with a variety of T amps, tube pre amps, etc with fantastic results. My BIB's with the new Red Wine Audio Signature 30 T amp sounds terrific, so UCD would as well, I would imagine, lots of dynamics, and snap, zero bass overhang with additional bottom end due to high damping factor, pseudo dipole bass phenomenon, you could NOT go wrong.

Last night we watched "Pirates of the Caribbean" on TV and the guests couldn't believe the bottomless bass sound coming from these things powered by a 30 watt T amp.
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Old 16th July 2006, 10:21 PM   #1030
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Cheers Bob -good tip. Perhaps there's a way to build it into the pages without eating up your space Jeff?

Glad Dan and I aren't the only ones Peter -I wondered if we were going mad or not! No Neophones yet AFAIK, though I'd be fascinated to hear a pair -I like the specs of that driver. However, the safest option are the Sigmas, as Dan advises. Just ensure you're running a highish resistance wire and you should be in business. There's also supposedly a 6 1/2in Hemp driver coming that should be very interesting indeed.

Dan -is that that new RWA amp? Methinks when finances allow I'll be looking into getting one of those.
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