iBIBk developement thread.

Jump to Latest
planet10

planet10

frugal-phile™
Joined 2001
planet10-hifi.com
Paid Member
FlorianO said:
At the moment I will try to dig up my old math skills and -- while respecting the width and length of the slot in your drawing -- draw the parabolic curvature such that I get the right area.
Click to expand...

What i drew was just a freehand approximation. The height can probably change (i think i had a reason for the height i chose but can't think what. The Area is important becasue it adds to the height of the box off the floor to give Sm.

Am I on the right track ? What is tried and what not ?
Click to expand...

At this point yes. JohninCR is our sole example so far.

dave
 
M

moray james

Member
Joined 2003
morayjamescables@yahoo.com
I did a series of tapers...

a few years back and the triangle did not work. I found that the top part of the taper and the bottom were the most influential parts. I ended up with a curve that looked a lor like a tractrix expansion which I had terminate at the top edge of the driver on the canted baffle. I that case i was loading a Fostex FE166/7 driver and wanted full range output from the driver wizzer not firing into the tapers.
I have a bunch of pictures of Dutch designs but either they are too large to post or in the wrong format to post and I am getting frustrated trying to post them now. Sorry.
 
F

fred76

Member
Joined 2005
johninCR said:
Here's my iBIBk's using 127's. I've been too busy with a bunch of construction projects to tune them, experiment with supra-baffles, or apply finish. They're definitely the deep bass champs of the small driver lineup, and Dave's idea for the extension to make the 3 point stance is a great use for driver cutouts which add nice visual appeal, especially for those of us lucky enough to have some real wood cutouts. They make even an unfinished cab appealing, even though my pic may not show it.

My limited understanding of the K is that only the higher frequencies fit through the smaller portion (readily audible with your ear near a K-slot), and this results in a terminus that is variable in size based on frequency (someone please correct me if I'm out in left field).

An externally hosted image should be here but it was not working when we last tested it.
Click to expand...

Hi John,

Very nice job. I'm eager to read a follow-up after you've fine tuned it, and what supra baffle you'd use. I think the truncated pyramid would be nice. But maybe with just 2 layers (~1.5" thickness) so it wouldn't be too top heavy.

regards,
fred
 
G

G

Member
Joined 2002
johninCR said:
Here's my iBIBk's using 127's. I've been too busy with a bunch of construction projects to tune them, experiment with supra-baffles, or apply finish. They're definitely the deep bass champs of the small driver lineup, and Dave's idea for the extension to make the 3 point stance is a great use for driver cutouts which add nice visual appeal, especially for those of us lucky enough to have some real wood cutouts. They make even an unfinished cab appealing, even though my pic may not show it.

My limited understanding of the K is that only the higher frequencies fit through the smaller portion (readily audible with your ear near a K-slot), and this results in a terminus that is variable in size based on frequency (someone please correct me if I'm out in left field).

An externally hosted image should be here but it was not working when we last tested it.
Click to expand...

How do they sound?
 
G

G

Member
Joined 2002
It seems to me that I have seen something similar somewhere but how about a IBiB built like this.
 

Attachments

  • fe127e ibib.jpg
    fe127e ibib.jpg
    7.8 KB · Views: 780
G

G

Member
Joined 2002
Isn't the Voight Pipe a 1/4 wave and the BIB a 1/2 wave enclosure? Is there an advantage of one over the other? I would like to use a enclosure like this for the 4.5" hemp acoustics that will be available one day or for a pair of FE127Es. Just looking for an opinion. I am limited in available space in my listening room but I would like to try a BIB with a small driver like the 127E. I will post a diagram of my other idea. Maybe one of them has merit.
 
G

G

Member
Joined 2002
Here is another idea. It is not to scale and obviously my skills in Paint could use some help:). The front and rear baffle would be extended to mount to a base plate with cutouts on the side for venting. Maybe it should just vent torwards the nearest corner? I know that this is similar to the version using the Karlson slot but I get the impression that the slot tuning fro a Karlson is more luck than solid formula.
 

Attachments

  • ibib2.gif
    ibib2.gif
    4.7 KB · Views: 720
vitalstates

vitalstates

Member
Joined 2006
vitalstates.org
G said:
Here is another idea. It is not to scale and obviously my skills in Paint could use some help:). The front and rear baffle would be extended to mount to a base plate with cutouts on the side for venting. Maybe it should just vent torwards the nearest corner? I know that this is similar to the version using the Karlson slot but I get the impression that the slot tuning fro a Karlson is more luck than solid formula.
Click to expand...


Hi Gavin

Looks like a vofo to me, that is if you really mean the driver to be in that position. Check out my website if you want some dims.


Hi Scott

In the supra design the driver rear fires off into the void which to my mind creates too many I/f waves to be predictable. just a thought!.

Regards

Ed
 
Shoog

Shoog

Member
Joined 2002
Someone commented a while back that they thought the terminus on the design was a little small. My experience with the original BIB design is that they are prodigious bass producers and the terminus has to be heavily restricted to keep things in proportion.
Restricting the terminus also helps smooth things out.

Shoog
 
Scottmoose

Scottmoose

Member
Joined 2005
wodendesign.com
vitalstates said:
Hi Scott
In the supra design the driver rear fires off into the void which to my mind creates too many I/f waves to be predictable. just a thought!.Ed
Click to expand...

Hi Ed
It was the vent layout I was primarily referring to. No argument from me though -the driver positioned like that is a bad idea IMO. Yet another reason why so many of the old folded TQWTs were rubbish. Too much HF leakage down the rear of the line, right where you don't want it. Not good. Worse, those Supravox cabinets (which I suspect were based on the old Weems calculations, which were never much cop) don't have anything like enough volume for the driver.
 
You must log in or register to reply here.
Top Bottom