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Old 26th January 2013, 03:58 AM   #1111
IG81 is offline IG81  Canada
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Seems to me like most of the K-slots pictured on the various iBIBk builds were small enough that a straight cut would have about the same effect. Too really do its thing, the K-slot has to be significantly large compared to the pipe it's trying to de-Q. Here is the K-slot in its purest form:

brass_tube_1.jpg

Transylvania Power Company "The Tube" and a similar-sized brass tube I made.

IG
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Old 26th January 2013, 09:03 AM   #1112
xrk971 is offline xrk971  United States
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The Transylvania Pipe would be an easy build in PVC pipe. Does it sound good and what kind of tweeter do you couple it to? A dome type or is that a compression driver underneath? Doesn't it have a strange spatial output profile? Looks very interesting though.
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Old 26th January 2013, 10:50 AM   #1113
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Quote:
Originally Posted by IG81 View Post
Seems to me like most of the K-slots pictured on the various iBIBk builds were small enough that a straight cut would have about the same effect. Too really do its thing, the K-slot has to be significantly large compared to the pipe it's trying to de-Q.
Yes, I believe they were largely for aesthetics rather than any supposed acoustical benefits. Might help a little.
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Old 26th January 2013, 11:07 AM   #1114
rock12 is offline rock12  United States
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I am in. bought some board yesterday finished reading post today Now to decide on some speakers. This should tide me over while I wait on Edcors lead time.
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Old 26th January 2013, 11:11 AM   #1115
rock12 is offline rock12  United States
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what if I double the the thickness and glue together for the 72 centimeter size
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Old 26th January 2013, 12:14 PM   #1116
xrk971 is offline xrk971  United States
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Rock12,
What are you building? The Cornu?
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Old 26th January 2013, 12:28 PM   #1117
xrk971 is offline xrk971  United States
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In case anyone is interested, I started the build on the flat BIB or FIB, it's in the BIB thread. Pretty straight forward build so far.
Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks?

Last edited by xrk971; 26th January 2013 at 12:31 PM.
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Old 26th January 2013, 02:59 PM   #1118
IG81 is offline IG81  Canada
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Quote:
Originally Posted by xrk971 View Post
The Transylvania Pipe would be an easy build in PVC pipe. Does it sound good and what kind of tweeter do you couple it to? A dome type or is that a compression driver underneath? Doesn't it have a strange spatial output profile? Looks very interesting though.
The K-Tube is a real good and natural-sounding waveguide IMO. Karlson-evangelist Freddy has been recommending them for years, stressing how easy it is to replicate it with schedule 40 PVC, yet very few people seem to have actually tried it. In the spirit of this thread, easy enclosure replication with foam-core, I'll also recommend an easy K-Tube replication with PVC. It's as easy as printing out and cutting a half-ellipse pattern to wrap round your tube and mark where to cut. The TPC tube is 5.3" long, 1" I.D. It really needs a compression driver IMO, but might work with a dome tweeter of the same diameter, I have not tried though. The radiation pattern is indeed asymmetric, with a wide dispersion. Listening angle is usually ~30 "down the slot side". It's probably what matches a Karlson bass/mid enclosure best and should work well with direct radiators or other midbass/midrange horns too.

IG

Last edited by IG81; 26th January 2013 at 03:02 PM.
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Old 26th January 2013, 03:16 PM   #1119
IG81 is offline IG81  Canada
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I had a few sheets of foam-core left, so I built a small pipe for FF85WK yesterday, for kicks mostly. 30" long, which actually tunes right to driver Fs, 115Hz. I just wrapped the 20"x30" sheet into a 5"x5" square tube, driver located at 1/5 down the line, sealed with duct tape. It had decent bass output with my ear to the pipe's mouth, but even in corners, it would not couple this into the room much. My small BLH design for FF85WK works much better, does not even need corner placement and can work in the room center, placed on the floor. Plays decent down to 70-80Hz.

I also built a mini RJ cabinet for the old FF125K, with some heavy corrugated cardboard some years back.

IG
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Old 26th January 2013, 03:39 PM   #1120
xrk971 is offline xrk971  United States
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Ig,
Cap the end with a tube (paper tissue roll) and make it a mltl. Bass will be lower better and couple well if wall loaded.

Last edited by xrk971; 26th January 2013 at 03:46 PM.
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