I suspect with my aging ears that I don't hear more highs. I like the cool look when I can form a cover w/o wrinkles. I started making them when my son left his K-15 cab (loaded with 12" guitar speaker) in a friend's basement and it supposedly was struck by a ping pong ball. I made him a new one and tacked it in place with Pliobond cement just on the edge.
I have yet to see if I can form a quality small one. In looking around the house for a suitable die I am eyeing a measuring spoon of a suitable size.
At present I am trying to get the PA-130s into my K-5 (scaled from K-12 plan) boxes. I removed the wings but the shelf interferes with front mounting and the magnet size prevents rear mounting. I am going to try carving an arc in the shelf to see if I can do a front fit.
I have yet to see if I can form a quality small one. In looking around the house for a suitable die I am eyeing a measuring spoon of a suitable size.
At present I am trying to get the PA-130s into my K-5 (scaled from K-12 plan) boxes. I removed the wings but the shelf interferes with front mounting and the magnet size prevents rear mounting. I am going to try carving an arc in the shelf to see if I can do a front fit.
IIRC, GregB used thin aluminum foil on the entire cone of a Beta12cx and there was a guy who did one before Greg, which had very thin gold leaf on both sides of the cone !. (GregB is a skilled luthier and K-hip 😀)
The "Espresso" cabs are really nice.
Is it espresso? I mean like ... coffee?
Please explainn a little more detailed.
I might try that, too ....
Is it espresso? I mean like ... coffee?
Please explainn a little more detailed.
I might try that, too ....
Literally called "Espresso" stain. The one I used is from Varathane, but other manufacturers use the same name. Basically a very dark brown.
https://www.homedepot.com/p/Varathane-1-qt-Espresso-Classic-Wood-Interior-Stain-339719/305501997
I don't have the latest photos - but with 3 coats of BLO and wet sanded in between with a bit of the stain added to the BLO and applied and let dry for 4 hours and then buffed with crumpled bond paper - the finish is satiny smooth and nicely matted but sort of shiny if you look at it at the right angle. Same color though just deeper and richer. I really like how the BLO and Espresso stain turned out.
https://www.homedepot.com/p/Varathane-1-qt-Espresso-Classic-Wood-Interior-Stain-339719/305501997
I don't have the latest photos - but with 3 coats of BLO and wet sanded in between with a bit of the stain added to the BLO and applied and let dry for 4 hours and then buffed with crumpled bond paper - the finish is satiny smooth and nicely matted but sort of shiny if you look at it at the right angle. Same color though just deeper and richer. I really like how the BLO and Espresso stain turned out.
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xrk, your nipped PA-130 looks like it would be a natural for experimenting with either an Al dome or a paper whizzer cone just edge glued above the void.
BTW, this whole thread has been one of the most interesting I have ever read. I keep going back to it.
BTW, this whole thread has been one of the most interesting I have ever read. I keep going back to it.
I have a couple of PA130-8’s not doing anything. So you guys think adding an aluminum dustcap vs a treated cloth or paper dustcap can extend HF range? I think the coaxial dome tweeter is a more sure thing to get HF’s. The 5.5kHz breakup is what I would like to take a little better on the PA130.
I gave this to a friend and he still uses it as the kitchen radio all these years.
It’s a pity that the CX150 is no longer offered.
Dayton Audio CX150-8 5-1/4" Coaxial Driver with 1" Silk Dome Tweeter 8 Ohm
I gave this to a friend and he still uses it as the kitchen radio all these years.
It’s a pity that the CX150 is no longer offered.
Dayton Audio CX150-8 5-1/4" Coaxial Driver with 1" Silk Dome Tweeter 8 Ohm
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concerning use of Eminence's Beta8cx, it might help to either use a 0.5mH coil as lowpass, or 2nd order lowpass such as 1-1.2mH with 20-30uF cap to "boost" its high end (by lowering input Z, thus pulling more power)
I'd still love to have this size XKi.
I'd still love to have this size XKi.
Xrk, what is the duct height for the PA130-8 in the post above? When I zoom it the rule is blurred on my screen.
I am almost to the point of building the duct in my hybrids and will have to open my vent a bit as it is now approx ⅜" high.
I am almost to the point of building the duct in my hybrids and will have to open my vent a bit as it is now approx ⅜" high.
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hey Eddie, some time ago I took a K8 copy and hacked a slot vent at its top - it already had a removable "shelf" so moved it up to form a short duct,
I had a W8-1772 stuffed in it and like that driver in smaller K than "K12"
There was tape over the distributed vent's slits
No damping in the front chamber and what you see in the rear
here's how it tuned and played - if links work
https://i.imgur.com/NKE9Zwm.gif
https://i.imgur.com/mGp4fK5.jpg
https://i.imgur.com/n2ExXWU.jpg
https://i.imgur.com/lQZBqaw.gif
I had a W8-1772 stuffed in it and like that driver in smaller K than "K12"
There was tape over the distributed vent's slits
No damping in the front chamber and what you see in the rear
here's how it tuned and played - if links work
https://i.imgur.com/NKE9Zwm.gif
https://i.imgur.com/mGp4fK5.jpg
https://i.imgur.com/n2ExXWU.jpg
https://i.imgur.com/lQZBqaw.gif
That's interesting! It's amazing what further experimentation can bring out of K boxes. I think if John Karlson had lived forever he would never have stopped experimenting. A lot of speaker work is empirical with a search for mathematics to model it. I think the patent office is overwhelmed by all the wording in a patent application.
Since my duct (beginning at the shelf) will reach its length w/o the downturn I am tempted to cut a K-slot into the horizontal portion. It would be easy enough to cover if it detracted from performance.
Since my duct (beginning at the shelf) will reach its length w/o the downturn I am tempted to cut a K-slot into the horizontal portion. It would be easy enough to cover if it detracted from performance.
looking at my Z plot, tuning ~83Hz, F6 maybe 90Hz - good for sub - sat situation. It would be good to make a new kabinet roughly twice its size to get to around 70Hz or better for stand alone application.
John Karlson died Jan. 18, 1973.
A K-slot in a shelf vent would effectively tune somewhat higher than a plain duct.
XRK971 suggested through Akabak simulation a 60 liter total XKi alignment for W8-1772.
That would reach plenty low.
I wonder if the following would work in about half that size ? - I would not want the cavity peak as high as BP sim shows
John Karlson died Jan. 18, 1973.
A K-slot in a shelf vent would effectively tune somewhat higher than a plain duct.
XRK971 suggested through Akabak simulation a 60 liter total XKi alignment for W8-1772.
That would reach plenty low.
I wonder if the following would work in about half that size ? - I would not want the cavity peak as high as BP sim shows
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Enlarging an existing vent is easier said than done, using a 4-in-hand farrier's file/rasp and a hunting knife I have finally reached ½" in one box. I will do the same with the other box then decide if I want to go on to ¾". It may get easier if I can get a larger rasp into play.
I can make the duct longer (up to 12" total L) to make up for K-slot if I decide to try it.
I can make the duct longer (up to 12" total L) to make up for K-slot if I decide to try it.
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to hack that top vent, I used a cheap "multi-tool" which pretty much can cut flush (if not straight with my poor skills)
one can only tune "so low" vs back chamber volume and T-S. It is cool X can get so much out of relatively small XKi boxes. Does having the vent at the top of the front chamber do some "de-Q-ing" effect against cavity peaking? (IF a peak were significant, that's when a smoothing stub could be of benefit plus reduction of deep dips would remove some "echo" effects - but I say the front chamber shape vs volume may have effect on those in the first place - ??)
one can only tune "so low" vs back chamber volume and T-S. It is cool X can get so much out of relatively small XKi boxes. Does having the vent at the top of the front chamber do some "de-Q-ing" effect against cavity peaking? (IF a peak were significant, that's when a smoothing stub could be of benefit plus reduction of deep dips would remove some "echo" effects - but I say the front chamber shape vs volume may have effect on those in the first place - ??)
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I can see where a multi tool could be useful also a little 4½" circular saw, not for this but for cutting sheet goods.
I would think a K-slot in a duct (of sufficient length) would make tuning less critical and broaden the range.
I would think a K-slot in a duct (of sufficient length) would make tuning less critical and broaden the range.
My problem is everything will be subjective as I have no test equipment or lab access, just tones off youtube.
I have enlarged both vents to ½" and the next step will be to clamp one in my Rockwell Jaw Horse and work on the vent with a longer file and/or rasp being able to use both hands. That should go pretty fast compared to one-handed work. So my vent area will be around 4.73 in² if I open to ¾". Should I stop at ¾" or try to go to 1"?
My 50W per channel blue tooth amp is getting closer according to aliexpress emails so I have some incentive to finish the speakers.
I have enlarged both vents to ½" and the next step will be to clamp one in my Rockwell Jaw Horse and work on the vent with a longer file and/or rasp being able to use both hands. That should go pretty fast compared to one-handed work. So my vent area will be around 4.73 in² if I open to ¾". Should I stop at ¾" or try to go to 1"?
My 50W per channel blue tooth amp is getting closer according to aliexpress emails so I have some incentive to finish the speakers.