Hi Lon, I think it's cool that ilewis33 worked the problem from both ends (baffle step and line length). Plus he appears to be using several guitars as resonators. 
It's no longer a BiB of course.
But the BiB is a proven design. It will work! I'm not sure I'd want to shorten the line length because that also has the effect of increasing the distance to the ceiling (so double whammy of higher tuning, less boundary reinforcement).
Glad it worked out for ilewis33 though. It resembles a Bob Brines straight pipe that got folded unevenly:
http://www.geocities.com/rbrines1/Pages/Straight_Pipe.html
It's no longer a BiB of course.But the BiB is a proven design. It will work! I'm not sure I'd want to shorten the line length because that also has the effect of increasing the distance to the ceiling (so double whammy of higher tuning, less boundary reinforcement).
Glad it worked out for ilewis33 though. It resembles a Bob Brines straight pipe that got folded unevenly:
http://www.geocities.com/rbrines1/Pages/Straight_Pipe.html
rjbond3rd said:Hi Lon, I think it's cool that ilewis33 worked the problem from both ends (baffle step and line length). Plus he appears to be using several guitars as resonators.
But the BiB is a proven design. It will work! I'm not sure I'd want to shorten the line length because that also has the effect of increasing the distance to the ceiling (so double whammy of higher tuning, less boundary reinforcement).
Glad it worked out for ilewis33 though. It resembles a Bob Brines straight pipe that got folded unevenly:
http://www.geocities.com/rbrines1/Pages/Straight_Pipe.html
Yes I've seen that one over the years. It's the Noogi's older sibling
and all are children of the Voight Pipe which was used for 8 inchers of various sorts. Means of construction is great because you can get 2 sides out of one sheet and one diagonal cut. I thought about doing these ages ago.
rjbond3rd said:Hi Lon, I think it's cool that ilewis33 worked the problem from both ends (baffle step and line length). Plus he appears to be using several guitars as resonators.
But the BiB is a proven design. It will work! I'm not sure I'd want to shorten the line length because that also has the effect of increasing the distance to the ceiling (so double whammy of higher tuning, less boundary reinforcement).
Glad it worked out for ilewis33 though. It resembles a Bob Brines straight pipe that got folded unevenly:
http://www.geocities.com/rbrines1/Pages/Straight_Pipe.html
Ha! Yeah, if I put my electric guitar amp in that corner and turn it up, you can indeed hit a chord, mute it, and hear the acoustic guitars on the wall ringing in sympathy... pretty cool.
My BIBs started out life normally:
However, after reading that the 126e Fs measured out at 90 Hz as opposed to 70 Hz, I made the decision to cut the line length down to match. It really did tighten up the bass, and I have a sub with crossover point set at about 80 Hz, very low gain. Since the 4.5 inch driver BIBs are so short , I don't think it was doing much ceiling loading anyway.
I like the one-armed bandit description. I just need to clean them up a bit, as they look incredibly "agricultural" now. I recently moved them into my sunroom, where there are no obstructions between the speakers, and wow, that really does make a huge difference in the soundstage.
I've been thinking of different folding patterns - a BIB is basically just a folded linear expansion horn/resonator, right? I thought one which had the horn mouth pointing straight back at the wall, on the floor, would be neat. Just trying to stay in the spirit of as few cuts and pieces of wood as possible.
Re: wool dampening
Should do.
These measurements of a pair of BIBs were posted here some time back, but I can't for the life of me remember who did them, or exactly where. Sorry about that. But I thought it would be a good idea to have them up again as a reference. Illustrates the point that they are intended as corner horns, as well as roughly the kind of response you can expect.
Should do.
These measurements of a pair of BIBs were posted here some time back, but I can't for the life of me remember who did them, or exactly where. Sorry about that. But I thought it would be a good idea to have them up again as a reference. Illustrates the point that they are intended as corner horns, as well as roughly the kind of response you can expect.
Attachments
ilewis33 said:
Herein lies the crux of the matter in that the driver's 'Fs' has no real bearing on its performance if proper corner loading is achieved until its 'Flm' cut-off is reached, which for most drivers used in BIBs will be down in the <10 Hz BW which will normally put it below the room's first mode, so within reason the driver will be somewhat protected to below audibility and with a useful BW to well below its 'Fs'.
AFAIK. Anyway, buried in this thread I discuss the fact that the few 'BIBs' I built were all floor corner loaded to get the max gain BW like an early day corner BLH by simply adjusting the pipe's distance from the corner since I didn't know the math to work it out empirically, though to do it right you have to use triangular shaped cabs. Still, decent corner loading can be achieved by just cutting off a narrow cab's lower back at an angle since you're trying to load the corner's apex as much as practical.
GM
Hemp FR6.5c BiB without too much of the first 'B'?
Hi everyone,
This is an awesome thread with a TON of info... thanks!
I have a question that doesn't seem to have been asked yet. What about the Hemp FR6.5c driver? I used GM's calculator and came up with this:
Fr=50.0
Vas= 45.30 liters (!)
Qts = 0.44
LL = 134.65
Zdriver = 29,22
Sm = 294.29(!!)
W = 14,43
D = 20.40
H = 67.32
I am surprised by the Sm... it's the same as what I've heard for the FR8 driver. I've also seen mention of an Sm of 200 and it seems to have worked for the FR8. Does anyone have any experience with this driver or suggestions on how I could get this a bit smaller? I like the idea of the Hemp drivers but maybe my size (wife?) limit will put me closer to the 168 Sigmas.
Thanks!
Hi everyone,
This is an awesome thread with a TON of info... thanks!
I have a question that doesn't seem to have been asked yet. What about the Hemp FR6.5c driver? I used GM's calculator and came up with this:
Fr=50.0
Vas= 45.30 liters (!)
Qts = 0.44
LL = 134.65
Zdriver = 29,22
Sm = 294.29(!!)
W = 14,43
D = 20.40
H = 67.32
I am surprised by the Sm... it's the same as what I've heard for the FR8 driver. I've also seen mention of an Sm of 200 and it seems to have worked for the FR8. Does anyone have any experience with this driver or suggestions on how I could get this a bit smaller? I like the idea of the Hemp drivers but maybe my size (wife?) limit will put me closer to the 168 Sigmas.
Thanks!
On those spreadsheets I've found that the qts. has a really big impact on the sm. If you wanna see big, model the Pioneer B20. That sucker is huge!
Try redoing it but put in 45Hz for the Fs. That should give you a longer line but a smaller sm. If that's not small enough try 40Hz. At that frequency though your looking at a seven foot tall bib.
Try redoing it but put in 45Hz for the Fs. That should give you a longer line but a smaller sm. If that's not small enough try 40Hz. At that frequency though your looking at a seven foot tall bib.
gurley123 said:
Combination of Q & Vas actually.
Anyway, to quote Gene Hunt, don't be such a Jessie. If you want big, run the Eminence Beta 12LTA wide band unit through one of the spreadsheets. If you don't feel so inclined, then expect a cabinet Vb of ~41.5ft^3 & a terminus CSA of ~958in^2.
gurley123 said:
And a very high driver position, though I personally prefer them since in a live app most often the musicians/sound system are much higher than your ears. Of course with a FR driver you need to tilt it down as required, which has the added advantage of lowering the floor bounce frequency as well as reducing the bad side effects of distributed reflections.
An all around win-win scenario IMO, though as always YMMV.
GM
>>> A dirty little part of me wants to build these really big BiBs. My house is a little on the small side...
BIBs can be really slim and take up about the same floor space as typical monitors or floorstanders. I was amazed how little they intrude into my room once in corners. They are pushed as close to the wall and corners as you can get them. Soundstage is big and wide. My suggestion is to get a little dirty.
BIBs can be really slim and take up about the same floor space as typical monitors or floorstanders. I was amazed how little they intrude into my room once in corners. They are pushed as close to the wall and corners as you can get them. Soundstage is big and wide. My suggestion is to get a little dirty.
The Beta 12LTA isn't gonna be slim no matter how you slice it. The spreadsheet spits our 26" wide x 36 7/8" deep internal. I don't think I can sneak those by the wife.
Don't get me wrong. I wanna build it. I just need a place for them before I commit. I also want to do a multiway with a big prosound 15". Maybe I could donate those to the local roller derby for PA duty.
Don't get me wrong. I wanna build it. I just need a place for them before I commit. I also want to do a multiway with a big prosound 15". Maybe I could donate those to the local roller derby for PA duty.
Here is the Beta 12 LTA BIB
the BBBIB- Bigger Badder BIB
https://www.diyaudio.com/community/threads/bbbib-bigger-badder-bib-speaker.88104/
One pair has been made, and a friend of mine is just finishing his cabinets! They make the Pioneer cabinet look tiny!
Here's the plans:
https://www.diyaudio.com/community/threads/bbbib-bigger-badder-bib-speaker.88104/post-1031054
And some photos:
https://www.diyaudio.com/community/threads/bbbib-bigger-badder-bib-speaker.88104/post-1266924
the BBBIB- Bigger Badder BIB
https://www.diyaudio.com/community/threads/bbbib-bigger-badder-bib-speaker.88104/
One pair has been made, and a friend of mine is just finishing his cabinets! They make the Pioneer cabinet look tiny!
Here's the plans:
https://www.diyaudio.com/community/threads/bbbib-bigger-badder-bib-speaker.88104/post-1031054
And some photos:
https://www.diyaudio.com/community/threads/bbbib-bigger-badder-bib-speaker.88104/post-1266924
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