http://www.diyaudio.com/forums/showthread.php?postid=1134724#post1134724
A post in the main BIB thread to someone using a k-solt-like opening in their pipe.
dave
A post in the main BIB thread to someone using a k-solt-like opening in their pipe.
dave
Thanks for that link Dave. More along the lines I had in mind. I was a great admirer of the thought behind the Impulse speakers too. Never had the chance to hear them in New Zealand though. We had small thread about these Impulse speakers a short time ago and I gathered what I could on the net about them. Ahhh for some money to some experimenting. I have picked up quite a few old speakers, no classy ones, from hard rubbish collections around here and hope to do some experimenting with them. Have to find out their specs. first. Also picked up enough pieces to make a complete stereo and a computer so the first job is a dedicated test centre.
Maybe soon I will be able to contribute more than ideas.
jamikl
Maybe soon I will be able to contribute more than ideas.
jamikl
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).
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.
One idea I had was to simply extend the front baffle and rear piece of the cabinet a yet to be determined length and let the pedestal part load the speaker. Does anyone truly understand how to determine the contour of the kslot? Trial and error seems kind of haphazard. Beatiful job BTW. I really like your cabinets John. Please give us some updates on your experiences with the iBIBk.
This is exactly the sort of project I want to do next, though I'm thinking of making the suprabaffle removeable so I can use them as test mules for various drivers in this class (FE103/7/8/126/7, FF125, Tang Band bamboo 4", Pioneer 4.5" elcheapo, some random leftovers I have laying about, etc.). Figure that done with 4' lumber, it should be a bit long for the 103/7 and maybe a touch short for the 125/6/7 or Tangband. If I make the feet of adjustible height and cut a k-slot in the back to provide at least a minimal mouth opening, I should be able to tune it to about anything that I can fit into it.
I'm thinking the face will be 6" wide (technically 7.5" given the side panels) and 10" deep to get close to that 1:1.41-ish ratio that the folks in the know keep mentioning. Would there be any problem with moving up say 8" wide front panel so that I could play around with larger drivers in an admitedly high tuned BiB? I could obviously try the FE166/7/8 class drivers, or basically 6.5" drivers of any sort I might come across, but I could also shoehorn in an 8"er like a B20 or FE206/7/8 or FF225. Other than the tuning being obviously higher than the recommended for any of these drivers, would there be function issues with attempting such a thing?
Kensai
I'm thinking the face will be 6" wide (technically 7.5" given the side panels) and 10" deep to get close to that 1:1.41-ish ratio that the folks in the know keep mentioning. Would there be any problem with moving up say 8" wide front panel so that I could play around with larger drivers in an admitedly high tuned BiB? I could obviously try the FE166/7/8 class drivers, or basically 6.5" drivers of any sort I might come across, but I could also shoehorn in an 8"er like a B20 or FE206/7/8 or FF225. Other than the tuning being obviously higher than the recommended for any of these drivers, would there be function issues with attempting such a thing?
Kensai
Thanks for the explanation of "bump" Kensai and G. johninCR, the original articles on the Karlson slot are based on a quarter wave tube, not a half wave like the BIB. I think He wanted the slot to pass as many frequencies as possible as it came down to a very narrow opening indeed and extended 0.66 to 0.75 of the length of the tube from the open end. He used exponential formulae. Whether the same as those giving the horn dia. for a given frequency I don't know.
There was a link to a spreadsheet on one of the recent Karlson threads. As set up on the spreadsheet it calculates a 64 inch slot and a 31 inch slot. It uses the horn theory and the slot is made to equate to the dia. of the horn. I wonder if the slot can be terminated at some wider opening so that it does not help the higher frequenies passing through the BIB.
The interesting thing is why he used the slot in a bandpass box, or at least it appears that way. I want to try it in a tube, with a compression chamber like a horn behind the driver and the slot at the open end. I would imagine that the BIB would be quite close to this anyway although the resonances would be different. This is all just a gut feeling as I am not an engineer and don't understand all the ramifications of what is going on. Struggling with the theory on The Deuland filter at present. I'm so ignorant I dont understand how the square root of minus one is used.!!!
jamikl
There was a link to a spreadsheet on one of the recent Karlson threads. As set up on the spreadsheet it calculates a 64 inch slot and a 31 inch slot. It uses the horn theory and the slot is made to equate to the dia. of the horn. I wonder if the slot can be terminated at some wider opening so that it does not help the higher frequenies passing through the BIB.
The interesting thing is why he used the slot in a bandpass box, or at least it appears that way. I want to try it in a tube, with a compression chamber like a horn behind the driver and the slot at the open end. I would imagine that the BIB would be quite close to this anyway although the resonances would be different. This is all just a gut feeling as I am not an engineer and don't understand all the ramifications of what is going on. Struggling with the theory on The Deuland filter at present. I'm so ignorant I dont understand how the square root of minus one is used.!!!
jamikl
Kensai,
What you mentioned trying is exactly my plan. Make the cutout hole large, and use a supra-baffles as mounting plates for different drivers. I could be way off base, but my gut is telling me that the cab is too big for this driver. It's proven to have the length to generate deep bass, so I want to try some other bass shy drivers. Also, despite the few cm opening all around the bottom + the K slot, the terminus seems restricted to me. Part of my tuning process will include stacking some blocks under the three legs. I also wonder if some type of deflector is warranted, centered on the floor under the cab.
What you mentioned trying is exactly my plan. Make the cutout hole large, and use a supra-baffles as mounting plates for different drivers. I could be way off base, but my gut is telling me that the cab is too big for this driver. It's proven to have the length to generate deep bass, so I want to try some other bass shy drivers. Also, despite the few cm opening all around the bottom + the K slot, the terminus seems restricted to me. Part of my tuning process will include stacking some blocks under the three legs. I also wonder if some type of deflector is warranted, centered on the floor under the cab.
