hi X thanks for the simulations - I have in pairs: 12lta, Beta 8cx. Beta10cx, Eminence stamped frame 12cx 54oz magnet - Eminence 12cx in cast frame at: 54oz/80oz/109oz, Kappa12A, Beyma12cx, Nirvana stamped frame 10", Beyma 10G200 , P-Audio SN10C coax plus pairs of BetsyK, BG20, W8-1772, and stamped frame Super10 and Super8. Commonwealth 12 - have single 12pe32, Altec biflex, P-Audio BM12CXA and Cannabis Rex The 109oz magnet TSG Eminence 12cx may be close to a "fullrange" Definimax 12HO
I've always perceived 12LTA as weak on bass transients - it has high sensitivity, is relatively smooth - but its overhang is only 0.08" plus qts is somewhat high - it would sound really dull without a helper tweeter.
in a regular Karlson 12, Beta 10cx will deliver a lot more "bass" punch than 12LTA. There may be space to add an internal K-tube to the Karlsonator 12 using a bolt on compression driver in the stub. The tail of the stub removes for better access. I have mounted K-tubes on top of cabinets as high as 4 feet up and they blended well.
I've always perceived 12LTA as weak on bass transients - it has high sensitivity, is relatively smooth - but its overhang is only 0.08" plus qts is somewhat high - it would sound really dull without a helper tweeter.
in a regular Karlson 12, Beta 10cx will deliver a lot more "bass" punch than 12LTA. There may be space to add an internal K-tube to the Karlsonator 12 using a bolt on compression driver in the stub. The tail of the stub removes for better access. I have mounted K-tubes on top of cabinets as high as 4 feet up and they blended well.
An externally hosted image should be here but it was not working when we last tested it.
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Freddi,
The Beta 12CX I sim'd did not have deep bass extension (started rolling off at 90 Hz). It may be the particular model shown on the PE website. It seems you have three different magnet variations. Which one has a magnet closest to the Definimax and can you get me the T/S params for the 12CX you want to use? Let me look at the Kappa 12A and the Beyma 12CX to start.
The Beta 12CX I sim'd did not have deep bass extension (started rolling off at 90 Hz). It may be the particular model shown on the PE website. It seems you have three different magnet variations. Which one has a magnet closest to the Definimax and can you get me the T/S params for the 12CX you want to use? Let me look at the Kappa 12A and the Beyma 12CX to start.
I'll try to dig out the specs - the TSG and a custom 54oz Eminence are the least sensitive - my Beyma 12cx is the model with APT50 size HF driver and like lots of drivers, its T-S is off and Qts ~0.5
TSG 12-1844 COAX 12” inch with 4 Inch Voice Coil And 1 3/8” Screw on Compression Driver mounting.
Re = 5.52 ohms, Le = 1.68 mH, Qms = 9.95, Qes = .27, Qts = .27, Xmax = 4.8 mm, BL = 17.96 T*M
VC Diameter = 4 inches, Gap Height = 9.52 mm, .375", No (Efficiency) = 2.75 97 db, Fs = 44.41 Hz
Zmax = 206.1 ohms. Mms = 57.4 g, Mmd = 50.4 g, Cms = .2239 MM/n, Rms = 1.6088 N*sec/M
Sd = 532.36 Cm2, Vd = 253.54 ccEBP = 162.2Magnet Weight = 109 oz.
Winding Length = 19.0 mm, .75 inches -Calculated Sensitivity = 97 db
TSG 12-1844 COAX 12” inch with 4 Inch Voice Coil And 1 3/8” Screw on Compression Driver mounting.
Re = 5.52 ohms, Le = 1.68 mH, Qms = 9.95, Qes = .27, Qts = .27, Xmax = 4.8 mm, BL = 17.96 T*M
VC Diameter = 4 inches, Gap Height = 9.52 mm, .375", No (Efficiency) = 2.75 97 db, Fs = 44.41 Hz
Zmax = 206.1 ohms. Mms = 57.4 g, Mmd = 50.4 g, Cms = .2239 MM/n, Rms = 1.6088 N*sec/M
Sd = 532.36 Cm2, Vd = 253.54 ccEBP = 162.2Magnet Weight = 109 oz.
Winding Length = 19.0 mm, .75 inches -Calculated Sensitivity = 97 db
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thanks again - there are adapters for 10" with Beta10cx in mind - IIRC for whatever reasons, Beta10cx sim-ed very strong in the stock Karlsonator (12) - how does 12LTA sim?
in the little original Karlson 12's I like the strong motor coax and 12pe32 - latter better overall than a 54oz 12cx - 12pe32 is very sensitive
in the little original Karlson 12's I like the strong motor coax and 12pe32 - latter better overall than a 54oz 12cx - 12pe32 is very sensitive
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The Beta 10CX sims well in a fullsize Karlsonator (15 in driver sixe), but in a 12 inch size the bass extension is not great. The 12 LTA has a bass hump. What is a 12pe32?
Beta 10CX in fullsize:
Beta 10CX in 12 in K'nator:
Beta 12LTA in fullsize:
Beta 12LTA in 12 in K'nator:
I don't know - up to you I guess. It is interesting how the smaller 3 inch or 4 inch full range drivers can get lower bass extension. Probably due to higher Qts and larger relative volume.
Beta 10CX in fullsize:
Beta 10CX in 12 in K'nator:
Beta 12LTA in fullsize:
Beta 12LTA in 12 in K'nator:
I don't know - up to you I guess. It is interesting how the smaller 3 inch or 4 inch full range drivers can get lower bass extension. Probably due to higher Qts and larger relative volume.
Attachments
Freddi,
My mistake then - if this drawing uses a 12 in driver then all my sims for what I call a "Fullsize" are indeed scaled 15/15. I assumed it was for a 15 in driver so when you say it is a 12 in Karlsonator I scaled to 12/15. So go with the sims of the fullsize above.
X
Here is what I thought was meant for 15 in driver and what I called Fullsize:
Thank you very much. Currently he has the BG20's in the stock Karlsonator-8 - is that a mismatch? - I'm trying to figure out which commonly available fullrange will work in the Karlsonator 8.
Carl builds with curved reflectors per Fig.6 of 3540544 and also thinks a roundover on the inside of the wings is useful - what might the latter accomplish?
https://lh6.googleusercontent.com/-...0g/hi5Qd7SIw6Q/w878-h690-no/Karlsonator-8.png
"AmadeusMozart"'s build of SK6.5 with a curved reflector profile like Carl uses-
seems like this would behave different than the Karlsonator series with regards to bounced and reflected sound.
Carl builds with curved reflectors per Fig.6 of 3540544 and also thinks a roundover on the inside of the wings is useful - what might the latter accomplish?
https://lh6.googleusercontent.com/-...0g/hi5Qd7SIw6Q/w878-h690-no/Karlsonator-8.png
An externally hosted image should be here but it was not working when we last tested it.
"AmadeusMozart"'s build of SK6.5 with a curved reflector profile like Carl uses-
seems like this would behave different than the Karlsonator series with regards to bounced and reflected sound.
An externally hosted image should be here but it was not working when we last tested it.
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BG20 in Karlsonator 8
Freddi,
This is a scaled Karlsonator model to approximate the overall height, width and depth of the Karlsonator 8 (that is, I did not re-build the model from scratch based on the dimensions of the drawing above). I did take into account the fact that the K-aperture doesn't start until a certain distance from the top. I found that you can get a smoother response if you make the K-aperture go to a zero width cusp rather than a slot. Here are the sims:
With slot width K-aperture:
With cusp K-aperture:
It looks like a fine performer with nice "hifi" capability given the flat response and very gentle bass roll-off which should give a great impulse response and group delay. Here is the Impulse Response with cusp K-aperture:
Freddi,
This is a scaled Karlsonator model to approximate the overall height, width and depth of the Karlsonator 8 (that is, I did not re-build the model from scratch based on the dimensions of the drawing above). I did take into account the fact that the K-aperture doesn't start until a certain distance from the top. I found that you can get a smoother response if you make the K-aperture go to a zero width cusp rather than a slot. Here are the sims:
With slot width K-aperture:
With cusp K-aperture:
It looks like a fine performer with nice "hifi" capability given the flat response and very gentle bass roll-off which should give a great impulse response and group delay. Here is the Impulse Response with cusp K-aperture:
Attachments
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thanks - I'll get Jesse to do some response and impedance measurements of his BG20 in both the Karlsonator 8 and 12. Will some 6.5" such as my L.Cao F6 which sounds good in a Karlsonator 6 prototype, behave well in a Karlsonator 8?
would you have an illustration of the cusp aperture as a building guide?
would you have an illustration of the cusp aperture as a building guide?
Just make the aperture go to a zero width at the top instead of a finite slot width. I have seen this on several photos of various builds that you have shown. Mathematically, I modeled the K-aperture with a quadratic equation of the form y=ax^2+bx+c where y is the K-aperture width and x is the axial distance starting at the top (beginning) of the aperture. Simply set c=0 (whereas c normally equals the width of the slot).
The non-dimensional equation describing the K-aperture that I used is:
y=ax^2 + bx + c where a=0.974, b=0.00874, and c=0.0207.
This can be obtained from the 1955 Karlson aperture plan by simply shifting the slot over evenly from both sides until the top comes to a zero cusp.
I sim'd an LCAO F6 somewhere earlier in this thread - it looks good as I recall.
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good - the next build will have that feature - - btw, can't find F6 sim in the Karlsonator 8 via searches - here's F6/Karlsonator 6 in a rather poor room position vs a non-factory K8 loaded with an 8" Crunch car speaker
would you extend a Karlsonator 8's slot all the way to the top ? - or stop at the bottom of the vent?
would you extend a Karlsonator 8's slot all the way to the top ? - or stop at the bottom of the vent?
Can anyone provide me with a hi-res copy of the Karlsonator "8" plans?
I have a pair of Fostex Fe203-EnS that I wanna give a chance at making some sound
The image above in post 613 is pretty good and should enable you to build it. GregB may be able to point you to a better one on his "Stupid Hifi Tricks" image server.