hi X - do you have any further thoughts on making Beta 8cx XKi's vent and other details? - its such a nice size to place or carry plus already have the cx part - how poorly does your foamcore Beta 8cx XKi fare against the recent Scanspeak/Dayton "FAST"? -does the little K have some strengths ? - (I would run a passive xover)
Hi Freddi,
I was wondering the same thing and plugged my XKi Beta 8cx in for a listen. The coloration of the K aperture is very aparent compared to a flat response ref monitor. The XKi of course is way more sensitive at about 93 to 95dB so is way louder. I am thinking it may be better to go with an open faced Beta8cx if you want more accuracy.
The problem is if you want deep bass you need a long vent and I get cancellation at the vent resonance. About 1kHz. Need short vent above xo frequency. Maybe multiple shorter vents will work better.
I was wondering the same thing and plugged my XKi Beta 8cx in for a listen. The coloration of the K aperture is very aparent compared to a flat response ref monitor. The XKi of course is way more sensitive at about 93 to 95dB so is way louder. I am thinking it may be better to go with an open faced Beta8cx if you want more accuracy.
The problem is if you want deep bass you need a long vent and I get cancellation at the vent resonance. About 1kHz. Need short vent above xo frequency. Maybe multiple shorter vents will work better.
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hi X --from the description of the little Scanspeak, I don't know if a Beta 8cx even as direct radiator, could match it. Maybe the Karlsonator8 would be less colored than the XKi 8cx - ? here's something you might try on a larger FR or coaxial as a broadening lens (JBL EON)
I see DJK indicating they probably work best with 12" and up for matching with a waveguide
I'd guess they would work with some FR
some years back I tried an oval lens in front of a 15" woofer -- think I hit the wrong smoothing button but you can get the picture
I see DJK indicating they probably work best with 12" and up for matching with a waveguide
I'd guess they would work with some FR
some years back I tried an oval lens in front of a 15" woofer -- think I hit the wrong smoothing button but you can get the picture
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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regarding the ~1K cancellation dip, as we know, Eminence's data shows a mild weakness in that area - I don't know if a dual chamber reflex would offer any advantage over regular or not subjectively. How high do you think the XKi Beta8 would have to be tuned to have negligible cancellation? - it does quite well where a regular K8 would dip
Hi Freddi,
The 1k dip is problematic if you want to use with a CD crossed at or above 1k. It can work well if you can have a CD tweeter that can cross low around 700Hz. I don't know any 1in throat CD that can do that though. I was listening to the Beta8cx XKi last night driven with my 200w IRS2092 amp and it takes being driven loud and hard very well with nice punchy bass down to 60Hz. I had a separate high power full range serving as mid and tweeter (5MR450NDY). They sound good together but more like a FAST.
If you wanted it to do real coax duty I would look at a better 8in coax like a B&C without the 1k dip as that is close to where the vent resonance is.
The 1k dip is problematic if you want to use with a CD crossed at or above 1k. It can work well if you can have a CD tweeter that can cross low around 700Hz. I don't know any 1in throat CD that can do that though. I was listening to the Beta8cx XKi last night driven with my 200w IRS2092 amp and it takes being driven loud and hard very well with nice punchy bass down to 60Hz. I had a separate high power full range serving as mid and tweeter (5MR450NDY). They sound good together but more like a FAST.
If you wanted it to do real coax duty I would look at a better 8in coax like a B&C without the 1k dip as that is close to where the vent resonance is.
I'm on travel and going to be without my akabak computer for the next week so won't be able to answer these questions until I get back. If it's a driver with a powerful motor (Qts < 0.4) and is flat thru 1k probably a good chance it will work.
hey XRK971
wonder what the sweet spots are for 8 inch fullrange driver and 10" coaxial k-couplers? can the XKi offer advantages ? the larger couplers can somewhat stand alone without subwoofer augmentation - K8 is marginal in bass but fine for a lot of older vocal-centric music.
Karlsonator8 with a cusp at the aperture's top might be next for my collection - ?
my Karlsonator 12s have worked well with whatever driver has been mounted - when
clutter is reduced, I'll try them with a good Eminence 12CX
your Beta8cx XKi is still an attractive size and low frequency extension
Karlson factory K8 - 1960's with FE206EN
Factory K8 size as "X8" by Carl Neuser with 1"ID x 5.3" long K-tube
Art Welter's Dad's K8 based on Karlson's K12 is nice
HAK8 (extended height K8) next to a 1960's factory K12
One of Carl's HAK8 test boxes with laminated veneer K-tube and curved
reflector
"SK8" next to a factory K8
K10 size with BOFU and K-tube helper tweeter
K15 scaled to K10 size (0.65) with Beta10cx awaiting a better crossover
AmadeusMozart's K6.5 scaled 1.22 would be a HAK8
TheJessMan's Karlsonator 8 pair
wonder what the sweet spots are for 8 inch fullrange driver and 10" coaxial k-couplers? can the XKi offer advantages ? the larger couplers can somewhat stand alone without subwoofer augmentation - K8 is marginal in bass but fine for a lot of older vocal-centric music.
Karlsonator8 with a cusp at the aperture's top might be next for my collection - ?
my Karlsonator 12s have worked well with whatever driver has been mounted - when
clutter is reduced, I'll try them with a good Eminence 12CX
your Beta8cx XKi is still an attractive size and low frequency extension
Karlson factory K8 - 1960's with FE206EN
Factory K8 size as "X8" by Carl Neuser with 1"ID x 5.3" long K-tube
An externally hosted image should be here but it was not working when we last tested it.
Art Welter's Dad's K8 based on Karlson's K12 is nice
An externally hosted image should be here but it was not working when we last tested it.
HAK8 (extended height K8) next to a 1960's factory K12
An externally hosted image should be here but it was not working when we last tested it.
One of Carl's HAK8 test boxes with laminated veneer K-tube and curved
reflector
An externally hosted image should be here but it was not working when we last tested it.
"SK8" next to a factory K8
An externally hosted image should be here but it was not working when we last tested it.
K10 size with BOFU and K-tube helper tweeter
An externally hosted image should be here but it was not working when we last tested it.
K15 scaled to K10 size (0.65) with Beta10cx awaiting a better crossover
AmadeusMozart's K6.5 scaled 1.22 would be a HAK8
TheJessMan's Karlsonator 8 pair
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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FE126EN? W5-2143? - FE166EN? PA130 doped? W8-1772 might play in a Karlsonator 8 - be worth a try as that measured
very well with BG20 plus at some point I may buy FE206EN as its lively in Ks - these are
expensive little speakers - - I need to experiment with rear chamber damping of the small K's in my collection - can
Ultratouch insulation be split to get ~1" or so thick without shredding apart? L. Cao's F6 is a great FR - it could stand more motor but that won't happen.
I like to know your and Anthony's thoughts on the shape of the front cavity as how that may affect overall resonance buildups.
why might a whizzer "fail" behind a K-slot compared to a whizzerless design?
http://www.fostex.jp/wp/wp-content/uploads/2014/08/FE126En.pdf
http://www.tb-speaker.com/uploads/editor/files/W5-2143 datasheet.pdf
very well with BG20 plus at some point I may buy FE206EN as its lively in Ks - these are
expensive little speakers - - I need to experiment with rear chamber damping of the small K's in my collection - can
Ultratouch insulation be split to get ~1" or so thick without shredding apart? L. Cao's F6 is a great FR - it could stand more motor but that won't happen.
I like to know your and Anthony's thoughts on the shape of the front cavity as how that may affect overall resonance buildups.
why might a whizzer "fail" behind a K-slot compared to a whizzerless design?
http://www.fostex.jp/wp/wp-content/uploads/2014/08/FE126En.pdf
http://www.tb-speaker.com/uploads/editor/files/W5-2143 datasheet.pdf
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hi X - I've used Dayton's PA130 in a "K5" size so know it would be pretty lively in your XKi alignment - here's your note from earlier in a mini Karlsonator thread along with a poorly drawn/mislabeled sketch below - how far forwards would you cant the upper board for best results and proper volume?
description of size plus your XKi simulation which looked very good
http://www.diyaudio.com/forums/full...onator-0-53x-dual-tc9fds-134.html#post4277373
description of size plus your XKi simulation which looked very good
http://www.diyaudio.com/forums/full...onator-0-53x-dual-tc9fds-134.html#post4277373
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hi X - I've used Dayton's PA130 in a "K5" size so know it would be pretty lively in your XKi alignment - here's your note from earlier in a mini Karlsonator thread along with a poorly drawn/mislabeled sketch below - how far forwards would you cant the upper board for best results and proper volume?
description of size plus your XKi simulation which looked very good
http://www.diyaudio.com/forums/full...onator-0-53x-dual-tc9fds-134.html#post4277373
Hi Freddi,
I hope you build it, but here is a sketch of the XKi for the PA130-8 for you. Internal width is 7in. Note that the 8.5 in high dimension of where the break angle is adjustable to suit the angle of the driver that you like and to allow for more or less magnet clearance in the back. Moving it up or down actually doesn't change the volume ratios as it is a triangle so volume is based on depth or 2.75in dimension.
X
Attachments
thanks X - I appreciate your time and work - for clarification, the 2.75" dimension is from the panel break to the back side of the wings (?) do you think 9mm Baltic birch would be sufficient ? would hot glue hold BB?
this should be a fun and inexpensive project for a lot of FR-ers
I have a saw with no dust collection system and its in a cluttered area around a lot of open gap drivers - maybe I can staple a plastic tarp "tent" around it
this should be a fun and inexpensive project for a lot of FR-ers
I have a saw with no dust collection system and its in a cluttered area around a lot of open gap drivers - maybe I can staple a plastic tarp "tent" around it
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Yes, backside of wings. All dimensions are internal. 9mm BB should be fine and you can get away with not accounting for its effect on the volume given that there is the vent wall and front divider wall. With 3/16in thick foam core, I routinely did not account for it in volume calcs. I don't know if hot melt will hold plywood well. You can certainly use it to tack together in spot glueing and add a bead of Titebond for main joint strength. I have done this and it works well.
Sure you can try to put the vent at the break point, but just like I said to Tb46, having the vent at the top allows the K aperture to be utilized to gradually expand to provide an impedance match and make the response smoother.