what effect would building the keyhole the same height and depth as the plans,
but narrower for an 8" have,
theoretically?
but narrower for an 8" have,
theoretically?
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What keyhole?
The cabinet is called the Keystone, which looks nothing like a keyhole or an A hole.
Cutting the width down will (kinda) work, if the driver has decent Bl (around 20 or more) and an Fs around 35, both of which are unlikely for 8 inch drivers found laying abound the house.
You will spend just as much time building it, and only saved a few bucks on wood, and won't have anything useful.
There are tons of used 15", 18", 12" that will "work" in the Keystone cabinet.
go ahead and build Art's Keystone with cutout to accommodate 18" then make whatever adapter rings are needed - its a handsome design and "Karlsonish" in style 😛
I'd imagine it would whup the USC1 which is similar (a bit narrower IIRC) in bulk & form factor
this is a one-sheet K-coupler loaded with old cheap but cheerful Eminence 18 vs UCS1 - K15 would measure better as it had a front shelf
to deflect some of the first dip. The K was much cleaner and more hit but not much LF extension
I'd imagine it would whup the USC1 which is similar (a bit narrower IIRC) in bulk & form factor
this is a one-sheet K-coupler loaded with old cheap but cheerful Eminence 18 vs UCS1 - K15 would measure better as it had a front shelf
to deflect some of the first dip. The K was much cleaner and more hit but not much LF extension
An externally hosted image should be here but it was not working when we last tested it.
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Drawing_Correction_#1
Hi Art,
I took another stab at drawing your Keystone sub from the work sketches you provided in Post #63. I added mm dimensions per djim's request.
It would be interesting to see if the same Keystone exit would work with a front loaded horn as well. What's your gut feel?
Regards,
Hi Art,
I took another stab at drawing your Keystone sub from the work sketches you provided in Post #63. I added mm dimensions per djim's request.
It would be interesting to see if the same Keystone exit would work with a front loaded horn as well. What's your gut feel?
Regards,
Post #79
Hi freddi,
I took a quick look at Eminence's Sigma Pro 18-2, Delta PRO18A and PA460-8, and they are all really close to each other in the basic response (see: Post #62).
Regards,
Hi freddi,
I took a quick look at Eminence's Sigma Pro 18-2, Delta PRO18A and PA460-8, and they are all really close to each other in the basic response (see: Post #62).
Regards,
Hi Y'all,
The pdf in Post #48 has some errors in it (haste makes waste) - don't use, use the one in 85, or even better use Art's from Post #63.
Regards,
The pdf in Post #48 has some errors in it (haste makes waste) - don't use, use the one in 85, or even better use Art's from Post #63.
Regards,
TH are quite different from FLH, I don't think the keystone exit would be useful in a FLH even in a slim form factor. In a "W" or "C" or spiral horn shape, a keystone exit shape would probably have detrimental effects, causing reflections back in to the horn, which would cause peaks and dips.
With the TH using an air column on both sides of the cone, the keystone exit has the opposite effect, smoothing out the response.
Art Welter
Hi Art,
I agree in a true FLH the Keystone exit may do more harm than good, but we are talking about terminating what amounts to be a foreshortened expanding duct that is terminated by a heavily undersized mouth. I just wish I could model the Keystone exit in AkAbak, but sofar the light has not come on.
Regards,
I agree in a true FLH the Keystone exit may do more harm than good, but we are talking about terminating what amounts to be a foreshortened expanding duct that is terminated by a heavily undersized mouth. I just wish I could model the Keystone exit in AkAbak, but sofar the light has not come on.
Regards,
Oliver,
The corrections you made in the plans in Post # 85 (Drawing Correction #1) look good, nice job, thanks again.
Only difference of note is the bottom of the Keystone exit is 12.75 inch as built (323.85 mm), not 12.5 inch.
The difference of 1/4 inch there is not a concern.
The Keystone exit should be rounded over both sides.
Also, the braces are important, anyone attempting to build a similar cabinet should refer to the pictures in post #63.
Art Welter
Hi Art,
I added your comments in note form to the drawing, if you find anything else, or want to add anything let me know.
Regards,
I added your comments in note form to the drawing, if you find anything else, or want to add anything let me know.
Regards,
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Hi Oliver,
Can you add dimensions or HR input values to the pdf so we may look for alternate drivers?
Can you add dimensions or HR input values to the pdf so we may look for alternate drivers?
Hi NEO Dan,
It'll take me a little bit of time to do that, and I don't quite know if I'll have the time today. Anyway, I'll attach my Hornresp Input screen for the original drawing I made. As far as the tapped horn aspect is concerned, there should not be enough difference between the two drawings to matter. Be warned though, Hornresp does not have any way (I know of) to model the Keystone exit, so all you're going to get is a general idea for a tapped horn with a similarly sized mouth located at the front at the end of the horn path.
Regards,
It'll take me a little bit of time to do that, and I don't quite know if I'll have the time today. Anyway, I'll attach my Hornresp Input screen for the original drawing I made. As far as the tapped horn aspect is concerned, there should not be enough difference between the two drawings to matter. Be warned though, Hornresp does not have any way (I know of) to model the Keystone exit, so all you're going to get is a general idea for a tapped horn with a similarly sized mouth located at the front at the end of the horn path.
Regards,
Attachments
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