Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks?

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loninappleton

Member
Joined 2004
Scottmoose said:
Sounds like a plan.

Just looked up the bazooka thing from 'they who shall not be named.' I see a 12ft length of 12in diameter pipe, available from all good plumbers. I particularly like the description of the cabinet material in their technical literature (chuckle). Nice. Custom Extruded polyvinyl chloride. I imagine most of their buyers will probably never make the connection with PVC. Oh well.

Well, anyway, I tried. The idea itself doesn't actually strike me as being so bad -Nelson has done a non resonant version with 21in woofers after all -and I believe El Pipe-O works well enough for what it is. I just object to the (I won't say it) around it.

One DIY version. 12in diameter pipe 12ft long. Driver at the apparant 1/4 length, jusging by the photographs. No damping applied. I tried to find a 12in woofer with a lowish Vas, but the Eminence Delta 12A was the best I could do. I suspect it's a heck of a lot better than the original driver.

Overall, I'd say it's actually not too bad, all things being considered, asuming hefty Eq, corner loading, and a quick prayer that the PVC pipe doesn't decide to make like an anaconda. So, that's about $95 for the driver, including postage. Call it $25 for the pipe. Another $5 for a can of spray paint. Hmm. I make that $125US so far. Add a cheap equaliser; maybe $50 or so & we're at $175. How much do these things sell for, new? On second thoughts, don't tell me. I'm sure I don't want to know.

Give me a BIB any day. More efficiency, just as easy to make, shorter and decent horn loading. It'd make a good potato gun though, with a few simple changes.
Click to expand...

Scott, where's the link to the Bazooka thing?


I love pvc designs and actually made the pvc
periscope before getting into MLTL.

Also bought some stock for BIB but I'm undecided
as to use the FE127e's again or one of the 6 in.
Fostex. As a sample, I'm think remounting the
127e's will give me a a good idea of BIB performance.
 
gychang

gychang

Member
Joined 2005
peterbrorsson said:
Hi!
I'm pretty sure the midrange problem I have is due to the chip board I used. There's a lot of resonances when pressing ear to the side panels. It calls for a better building material or damping panels with bitumen plates........

Cheers
Click to expand...

I plan to use hardi backer (used when installing shower stall) to dampen the sound per Bob Brines suggestion, what do u think?

gychang
 
GM

GM

Member
Joined 2003
Godzilla said:
http://www.zillaspeak.com/BIB-RadioShack.asp

Original dims for TC's 1354 BIB.

Peace,
Godzilla
Click to expand...

Greets!

Which if I calc'd it correctly equates to:

L = 138"
Sm = 55"^2
zdriver = 30"

Note that if you build it per T.C.'s dims, it's not a smooth expansion transition through the bend compared to what the Excel WS calcs, but I don't know if there's an audible difference. Anyway, using the same 'L', 'Sm', the bottom inside width/depth becomes:

W = ~6.194"
D = ~8.879"

GM
 
GM

GM

Member
Joined 2003
GM

GM

Member
Joined 2003
stroop said:
I got 2 daybeds right...now say I build the BIB in one and use the other as an artificial corner...........

GM I think I'm going to have to read your posts about ten times!

By the way, I gotta say thanks so much for the help..........
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Greets!

You're welcome!

Yes, I try to answer as best I can, but alot of this stuff requires a good grounding in basic acoustics, so requires the reader to either ask for specific clarifications, or better still, do the research.

Sorry, even if the couch has a solid base, it doesn't have enough rigid surface area to do much at midbass/bass freqencies, which are very large when not confined by a pipe or horn.

GM
 
GM

GM

Member
Joined 2003
Re: damping material, hardi backer?

gychang said:
found the hardi backer (cement based lining used for shower install) great for my 1st DIY per Bob Brines suggestion. Anyone have opinion on its use in the BIB speaker project?

thanks,

gychang
Click to expand...

Greets!

If doubled up to make a 1" thickness, it can be used for the entire cab if you want, but the weight may be a bit much for most folks, so making it from a single thickness and skinning it with a nice 1/2" void free plywood would work well and provide more finishing options.

GM
 
P

peterbrorsson

Member
Joined 2006
did u finish building?, how did it turn out?, what demensions did u use?
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Hi gychang!
Yes I finished them but slightly bigger than Scott suggested. There is a post with dimensions further back. I do not have them right now. Search my postings and you will find them.

They work surprisingly good considering the price. I have them in a 50 sqm room and they manage to fill the room completely with real fast and heavy bass. I have them against a wall which is not recommended, but when put in corners, as they should be, the bass over powers completely. Consider if you should try SPH60X/AD which mcfabs (see post 1429) are building.

There are some issues with the whizzers that I'm going to work with but over all I'm satisfied with them. Doing it more for fun than necessity so to say.

Good luck/Peter
 
S

stroop

Member
Joined 2005
Hi GM,

What the mattresses lay on is basically 2 slabs of 27mm solid birch 200cm x 80cm, I'd use the same for the rest of the enclosures I'd say. It's pretty sturdy stuff! I could reinforce it with MDF. As I said it may just be a whole easier to make a couple of sealed enclosures and put them where it is best.

I gotta do a bit more reading yet....

Cheers Stroop
 
Scottmoose

Scottmoose

Member
Joined 2005
wodendesign.com
The bazooka remark was my rather wry definition of the (I won't name the company, but the first letter is 'B') Acoustic Cannon subwoofer type thing. Not actually too bad a design in some ways, but, I'm sure, massively over-priced for what it is.

To prevent any confusion between the different dimensions Greg & I refer to regarding TC's original cabinet, it's casued by the fact that I deliberately converted to 3/4in material while preserving the external dimensions, to provide a bit more box volume. Greg's are the original dimensions that TC & Fostex came up with, using 1in material. One of these days, I'm going to plug these things into the Sections worksheet & see what difference the expansion rates make. Problem is, my geometry etc., is apalling. I'll have to draw the things out on the floor & get my old ruler out to measure things. On the whole, I'd rather stick with the 1:1.414 conical profle Greg defined for safety, but there might be something interesting to discover.
 
P

peterbrorsson

Member
Joined 2006
Hi gychang!
I found the dims for my BIB's at post 1082

width 12.7 cm

depth 26.2 cm (with internal baffle)

height 142.5 cm

Speaker 64.5 cm down from closed end

internal baffle ends 13 cm from bottom,back and front baffle(forgot to mention in post 1082)

All these are internal measures. I think you can make even numbers to make measurments easier. These dims are what I ended up with in reality due to some small mistakes while cutting.
What you should also consider is what height you have in your listening position. For me this height is good but then my sofa is quite low... You could add a base that is thicker to get the right height if it is to low + it would make it more rigid and stable


Good luck! Peter
 
gychang

gychang

Member
Joined 2005
Re: Re: damping material, hardi backer?

GM said:


Greets!

If doubled up to make a 1" thickness, it can be used for the entire cab if you want, but the weight may be a bit much for most folks, so making it from a single thickness and skinning it with a nice 1/2" void free plywood would work well and provide more finishing options.

GM
Click to expand...

GM, that was exactly what I was thinking, use 1/2" and add 1/4" hardi backer as extra support and damping material. I will go ahead and try.

thanks,

gychang
 
M

McFaBs

Member
Joined 2006
Hi Peter!

I'm not totally sure due to the rough and smaller cab I'm using for breakin-in the drivers BUT, yes, monacors SPH68X/AD have more HF and with a better texture. What I also felt was a slightly better bass and even better image.

Have you tried Dammar or similar treatments to the cone? Scott suggested few post ago Planet10 Phase Plugs....If RadioShack models are fitting Monacors, in the near future I'll try!

Hope that Planet10 will read this and give a hint....

So, you think that "de-wizzer" mod is not arguable?

Ciao. Fab.
 
M

McFaBs

Member
Joined 2006
Re : Monacors Dims

Hi Gychang!

I'm also building a Monacor based BIB but I'm using Zilla's Dims which are closer to TC original one.

The result is a slightly bigger and taller cab, nearly 65" high, 6.2" wide and 8.85" deep.

You see, many options on the recipe book...

Tell us if HardyBacker internal lining gives good effects

Ciao. Fab.
 
gychang

gychang

Member
Joined 2005
best cost effective BIB, which?

Love to build BIB, not very good with woodwork, just learning about speaker building in general.

I have t-amp to drive the speakers, and since the cost is an issue, I would like to get suggestions on the speaker choice. What would the DIY community think is the most cost effective solution in USA? (monacor cost a bit with shipping from Europe).

thanks in advance.

gychang
 
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