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

Dave,
The cones are accurate in the first picture...the one in the backyard. The picture next to the Eames chair is not the true color.

GM,
I still can't make it work. I get the link to copy but it will not work after I paste it on the message area. Sorry to be a pest but can you give me a little more detail on the procedure?

Thanks,
Ray
 
gychang said:



that's great!, exactly what I was looking for.

gychang


Over at the craft store (Ben Franklin's etc) they
have a variety of plaques for people who want to
paint them or mount (small) fish. :)
I found some eliptical ones of decent size at
Hobby Lobby on sale. These are USA stores but I imagine
that this type of stuff is available all over.

I've also seen sets of eliptical 'trivets' as well as
interesting shaped and inexpensive bread boards which
could be adapted without a lot of cutting.
 
th_03268_Final_Spot_122_511lo.jpg


Test

Thought you would enjoy a picture of the Dummy!

If this works.....I have it!

Ray
 
loninappleton said:



Over at the craft store (Ben Franklin's etc) they
have a variety of plaques for people who want to
paint them or mount (small) fish. :)
I found some eliptical ones of decent size at
Hobby Lobby on sale. These are USA stores but I imagine
that this type of stuff is available all over.

I've also seen sets of eliptical 'trivets' as well as
interesting shaped and inexpensive bread boards which
could be adapted without a lot of cutting.


that's very helpful, I will check out the craft stores in Irvine, CA and see if I can find one, will save me buying a router and extra work...

gychang
 
Scottmoose said:


You've helped with something else here though. Remember we mentioned the Polish AcuHorn's; specifically the 125 which is apparantly an inverted BIB? Well, both Dan and I speculated at the time that the driver was likely the Monacor SP-200X 8in unit going by a different name (Tesla), although for the driver Fs, the horn length seemed a bit short. OK, fast forward to last night when I finally ran across your post, and decided to have a gander at those TVM ARZ 6608 drivers you linked to.

MathCad model of AcuHorn enclosure assuming these TVM drivers is below. Given that they are inverted and floor-firing, I suspect bass should be considerably boosted over what is indicated below 80Hz, and the ripple mostly flattened out.

Best
Scott

Hi Scott,
As I have find in my basement an old pair of ARZ6608 :D
I simulated both combinations - floor-firing - which seems to have more bass in 80-150 region but lot of irregularities after 100Hz (driver position ratio set to 0.3) and top-firing (driver position ration = 0.191) which is rather nice (I've got same graph as you shown). I used my old copy of ML TQWT.mcd (I hope it's still legal to use it…) with params :

Fd := 71.4 Hz
Re := 7.5 Ohm
Lvc := 0.5 mH
Bl := 5.2
Sd := 189 cm2
Vad := 27 liter
Qed := 1.17
Qmd := 3.12

L:= 95.6 in (70Hz)
Xi := 0.3 (bottom oriented or 0.198 top oriented)
S0 := 0.001 Sd
SL := 4.1 Sd
Density := 0.0001 lb ft-3
R port := 6.19 in
L port := 0.0001 in

Maybe I will try to build it but I can't decided which one - top or bottom firing? Do you have any information how original AcuHorns is build- It's not clear from their site.
 
vladimir said:
I simulated both combinations - floor-firing................

..............I used my old copy of ML TQWT.mcd (I hope it's still legal to use it…)

Greets!

How can you sim floor loading with WSs that are based on half space loading (speaker flush mounted in an infinite wall)? Even then the WS's calcs are simplified in that the vent's terminus is at the same x/y point as the driver and why the HF portion of the plot gets increasingly off.

Since these were in the public domain, we can legally use or copy/share them, though I prefer not to do the latter.

GM
 
GM said:


Greets!

How can you sim floor loading with WSs that are based on half space loading (speaker flush mounted in an infinite wall)? Even then the WS's calcs are simplified in that the vent's terminus is at the same x/y point as the driver and why the HF portion of the plot gets increasingly off.

GM

Hi,

no I haven't simulate floor loading - I only changed the position of the driver (I use only mathacad explorer so I don't think that I'm able to modify anythink in the WS). Btw, Isn't floor loading exactly the half-space situation ?
 
I think I might have found a suitable driver for a subwoofer BIB..

8 inch driver (fairly low sd for a smaller overall size).

VERY high (or low depending on your viewpoint) mechanical compliance. (..prob. should say very compliant - but that sounds a little redundant.)

LOTS of excursion.

LOW fs.

Fairly low cost.

Ta' Da!:

http://www.mcminone.com/product.asp?catalog_name=MCMProducts&category_name=&product_id=55-2421

of course the power could come from this:

http://www.mcminone.com/product.asp?catalog_name=MCMProducts&product_id=50-6272
 
I've got one of the 55-2421s. They are a clone of the Tang Band W8-740C. The Tang Band is better built. Don't trust MCM's specs. The 55-2421 is more like Fs 30hz, Vas 40 liters, Qts .3 They are an amazing driver for the money. I'm using one in a tube a la El Pipe-o. It works decently, but is not ideal. I built a friend an EBS enclosure with a passive radiator that worked really well for its size and cost.

I too have been curious to see a BIB for them, though I imagine it would need to be mass loaded due to the low Fs.

Paul
 
gychang said:



that's very helpful, I will check out the craft stores in Irvine, CA and see if I can find one, will save me buying a router and extra work...

gychang

I was talking about fish earlier. Perhaps any taxidermy
outfits have mounting blanks that would give some
size options too.

Store names are Ben Franklin, Hobby Lobby plus any
local businesses.


The Home Depot has some (albiet flimsy) round
'coasters' for flower pots of various sizes. Those
are made out of fiberboard.

Eventually you'll want a router though. :)