Since you are into redesigning the Karlson design, how about a subwoofer-style Karlson where the baffle that the speaker is mounted on is constructed in a push-pull configuration. Maybe the drivers are not directly opposing, but instead mounted on a V-baffle. This may allow for multiple drivers being mounted in a smaller Karson box.
Retsel
Retsel
I did that already which was sort of the inspiration for this latest box. More info here
http://www.diyaudio.com/forums/subwoofers/264737-pp-slot-loaded-sub-alpine-swr-12d2.html
You can imagine a K aperture covering the two drivers.
WOW Nice development! This is very significant.
- Increased LF bandwidth
- similar k-dispersion
- similar efficiency,
- similar cone control / loading
*All in a smaller footprint yeah?
Seems a new class of PA boxen and LF enclosures started here.
Only question is how much the +/-5dB W portion of the response affects instruments and voices in that range... I guess it will fall in freq as the design scales larger and having some dips in the 180hz-280hz range on PA or home theater version could be advantageous (in that scooping that region can help both with apparent mud and reduce common room modes that increase said mud).
- Increased LF bandwidth
- similar k-dispersion
- similar efficiency,
- similar cone control / loading
*All in a smaller footprint yeah?
Seems a new class of PA boxen and LF enclosures started here.
Only question is how much the +/-5dB W portion of the response affects instruments and voices in that range... I guess it will fall in freq as the design scales larger and having some dips in the 180hz-280hz range on PA or home theater version could be advantageous (in that scooping that region can help both with apparent mud and reduce common room modes that increase said mud).
the original Karlson from 1951 and even large klam-"projector" type can sound subjectively better than direct radiator. Metro's T15 is squat and rather cubical with a nice published response. I'm guessing Metro's PHL 15" woofer was close in parameters to say a B&C TBX100
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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Alright! Great work xrk971! 
I'm thinking this might be most useful for a mini subwoofer, given that it has retained the excursion control of the larger K15. How about try it with that little Tangband 5" sub?
The wrap around vent is IMHO a better idea than the T15 port. When several of us were experimenting with ways to scale down the K several years ago, it became apparent that this sort of vent configuration minimizes the peakiness and coloration from the front chamber.
Thanks to IG81, Moray, and many others who I am forgetting for early research work into this issue.
I'm thinking this might be most useful for a mini subwoofer, given that it has retained the excursion control of the larger K15. How about try it with that little Tangband 5" sub?
The wrap around vent is IMHO a better idea than the T15 port. When several of us were experimenting with ways to scale down the K several years ago, it became apparent that this sort of vent configuration minimizes the peakiness and coloration from the front chamber.
Thanks to IG81, Moray, and many others who I am forgetting for early research work into this issue.
Thanks for all the great feedback and kind words guys.
This was one of those moments of inspiration where I ran a sim and it was past midnight. It was just too good of a result that was almost unbelievable that I had to make it. Luckily I had one sheet of FC left and 2 hours later I had the measurement to confirm it works.
The 5in Tang Band will be next. I think some of you may also jump on this and try it for yourself with a favorite driver.
I agree it resembles the T15 a bit but the vent layout is very different and closer to GregB's K'nator. I am glad it is supposed to be better with less peakyness.
This was one of those moments of inspiration where I ran a sim and it was past midnight. It was just too good of a result that was almost unbelievable that I had to make it. Luckily I had one sheet of FC left and 2 hours later I had the measurement to confirm it works.
The 5in Tang Band will be next. I think some of you may also jump on this and try it for yourself with a favorite driver.
I agree it resembles the T15 a bit but the vent layout is very different and closer to GregB's K'nator. I am glad it is supposed to be better with less peakyness.
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Ken Lehman (KenL) experimented with conventional vent but a tapered Nautilus style "stub" at the very top of the front chamber to smooth his K-type. I added a simple extra chamber to a little coupler which had two 4.5" x 4.5" vents and there was some smoothing.
besides akabak, what software can one use to get the chamber sizes, etc? - which if any version of WinISD works properly?
besides akabak, what software can one use to get the chamber sizes, etc? - which if any version of WinISD works properly?
An externally hosted image should be here but it was not working when we last tested it.
maybe the cheap and cheerful MCM 55-1465 12 inch dvc woofer could be used in a new design -? - here's Marshall Leach's TS measurements - mine of one purchased a year ago are close - (its really not too shabby in a Karlson K12 with vents sealed with tape)
Voice Coil Resistance RE = 6.47 ohms per coil
Resonance Frequency fS = 28.1 Hz
Total Quality Factor QTS = 0.326
Electrical Quality Factor QES = 0.374
Mechanical Quality Factor QMS = 2.52
Volume Compliance VAS = 4.80 cubic feet
A Three-Way Satellite Loudspeaker System
Voice Coil Resistance RE = 6.47 ohms per coil
Resonance Frequency fS = 28.1 Hz
Total Quality Factor QTS = 0.326
Electrical Quality Factor QES = 0.374
Mechanical Quality Factor QMS = 2.52
Volume Compliance VAS = 4.80 cubic feet
A Three-Way Satellite Loudspeaker System
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XRK, can do you do some dims and sims for the XKI using a pair of vifas. I've got a CNC guy cutting some glass and graphite skinned honeycomb and foam core for me, in trade for a couple of vifa driver and a small TPA3116 amp. If this reaches lower and still is low distortion, it might be a better design.
Freddi,
It is technically a quasi 6th order bandpass - a regular 6th order bandpass like on WinISD or one of the popular online calculators has two chambers each with a vent to the outside. As far as I can tell, akabak is the only way. I will keep looking but if anyone else knows please show us. Maybe a way to fake it with HR?
It is technically a quasi 6th order bandpass - a regular 6th order bandpass like on WinISD or one of the popular online calculators has two chambers each with a vent to the outside. As far as I can tell, akabak is the only way. I will keep looking but if anyone else knows please show us. Maybe a way to fake it with HR?
I believe the BassBox program Partsexpress sells will do 6th order series bandpass, among other configurations. Starts at $69 instead of free... Might be a good option for those that don't want to devote the time to learning akabak, like me...
There is one online calculator that will do series BP6, but I don't recall the url offhand. I think it was some German dude?
There is one online calculator that will do series BP6, but I don't recall the url offhand. I think it was some German dude?
Vifa TC9FD has too high of a Qts and too large of a Vas to take advantage of this alignment - I will be very peaky in response. Need Qts of about 0.5 or less, preferably around 0.3 to 0.35 and low Vas to keep it compact.
XKi thread started
I started a new thread to discuss the 6th order bandpass Karlson aperture speaker here:
http://www.diyaudio.com/forums/full-range/268524-xki-xs-ab-initio-karlson-6th-order-bandpass.html
I started a new thread to discuss the 6th order bandpass Karlson aperture speaker here:
http://www.diyaudio.com/forums/full-range/268524-xki-xs-ab-initio-karlson-6th-order-bandpass.html
woo hoo - my cutter has resumed a bit on the 0.65 scale K15 made of 5/8" Baltic tirch - hopefully it will be fun with 10CX and wideband/woofer + K-tube on top (plus helper sub)
it would be interesting to compare a dedicated XKi 10 vs a K10 size scaled from K15
it would be interesting to compare a dedicated XKi 10 vs a K10 size scaled from K15
An externally hosted image should be here but it was not working when we last tested it.
Jessman Rocks = true !! - perfectly mated lock-mitre corner joints
a Transylvania "The Tube" would be appropriate to try on top of the new K10 - here's one of my old K10 loaded with an Eminence Delta10A and topped with a lovely tube made by IG81 - I've lost a port piece to the other cabinet and need to make a new one to have a matched pair.
other than the X15 with internal K-tube, this is the standard way to do a K other than coax or fullrange
Delta10A has a rise which needs to be dealt with in the lowpass section - but its in the ballpark of what a small K
likes to get good performance
when running a Delta10A in free air with pink noise, that peak and whatever else sounds horrendous in coloration. I'd like
to try a B&C but not sure if the bolt circle and cutouts are compatible.
a Transylvania "The Tube" would be appropriate to try on top of the new K10 - here's one of my old K10 loaded with an Eminence Delta10A and topped with a lovely tube made by IG81 - I've lost a port piece to the other cabinet and need to make a new one to have a matched pair.
other than the X15 with internal K-tube, this is the standard way to do a K other than coax or fullrange
An externally hosted image should be here but it was not working when we last tested it.
Delta10A has a rise which needs to be dealt with in the lowpass section - but its in the ballpark of what a small K
likes to get good performance
when running a Delta10A in free air with pink noise, that peak and whatever else sounds horrendous in coloration. I'd like
to try a B&C but not sure if the bolt circle and cutouts are compatible.
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interesting - my 1960's K8 once had the University coax shown below - that pincushion basket's hole centers are exact (!) for a Fostex FE206EN - if I can find 4 nuts then will give the Fostex a whirl in this tiny K
An externally hosted image should be here but it was not working when we last tested it.
