When I measure my BG20s in the Karlsonator 8 and Karlsonator 12 I'll be sure to post the results here.
here's Greg B's Karlsonator 8 plan page -- the larger plan is downloadable under "more" https://plus.google.com/photos/1005...5900892929503929170&oid=100545049816297868412
Great, thanks!! I look forward to seeing it. Those renders make everything look so nice!
And thankyou Freddi, that link is much higher res.
Any input as to how well the FE-203En-S might fare in this box? I believe seeing somewhere you said a rising response was good for a Karlson?
It has a reeeelly low Qts; .14
20cm Full Range (8")
Impedance: 8 ohm
Resonance Frequency (Fs): 43Hz
Frequency Range: F0 to 20kHz
Sensitivity: 99dB @ 1W/1M
Music Power Handling: 100W
Moving Mass (Ms): 12g
Qts: 0.14
Effective Vibration Radius: 8.1cm
Magnet Weight: 1,836g (4.04 pounds)
And thankyou Freddi, that link is much higher res.
Any input as to how well the FE-203En-S might fare in this box? I believe seeing somewhere you said a rising response was good for a Karlson?
It has a reeeelly low Qts; .14
20cm Full Range (8")
Impedance: 8 ohm
Resonance Frequency (Fs): 43Hz
Frequency Range: F0 to 20kHz
Sensitivity: 99dB @ 1W/1M
Music Power Handling: 100W
Moving Mass (Ms): 12g
Qts: 0.14
Effective Vibration Radius: 8.1cm
Magnet Weight: 1,836g (4.04 pounds)
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
Freddi is right. If you download the png file using the 'more' menu, you'll get the high resolution 1/2 scale plans. You can easily build from these using a scale or ruler.
Or, go to a print shop and have them printed out at 200% for full scale plans. Printers usually distort slightly, but it's typically close enough for this sort of thing.
Wow, the Fostex FE203-EnS is a pretty extreme driver for this. That's practically like putting a Lowther in there. Normally a driver like this would go in a large high gain backhorn with a high (acoustic) crossover. Still, I suspect it will be a reasonable match, especially if you are running a SET or current source SS amp.
Some control can be exerted over the general frequency balance by changing the wing profile. You may want to leave some room for experimentation with different shapes. My best guess would be to use the truncated slot, but go to a subtle exponential curve, so that the wings cover just slightly more of the driver.
I am finding that lining the wing and inside walls with felt really helps the clarity on the small Karlsonators I'm playing with, and gets rid of most of the reverby coloration.
(I'll post an update soon on my CHR70 mini-Karlsonators...
)Freddi pionted me to the hi-res file, should be fine.
The Fostexes have been sitting in their boxes.... I have 2 pair and they are silent
I bought them before I was a father; back when I knew what a disposable income was
I cant see myself building the recommended backhorns for these and I am at a loss for a different cab that would be suitable with the Qts.
Any suggestions? (that don't need 4 sheets of BB and months of glueing like the horns...)
I have a Tubelab 300b, a single ended KT88, a few small SE 6BQ5, and a few others; output impedance is no problem
The Fostexes have been sitting in their boxes.... I have 2 pair and they are silent
I bought them before I was a father; back when I knew what a disposable income was
I cant see myself building the recommended backhorns for these and I am at a loss for a different cab that would be suitable with the Qts.
Any suggestions? (that don't need 4 sheets of BB and months of glueing like the horns...)
I have a Tubelab 300b, a single ended KT88, a few small SE 6BQ5, and a few others; output impedance is no problem
FE206EN in a classic K12 sounds punchy and John Lapaire made a Karlsonator 8 prototype (about 1.5" less deep than the plan) which seemed to do well with FE206EN and his solid state amps so 203 with a tube amp may be pretty well balanced.
I don't have a Karlsonator yet other than the prototype for the Karlsonator6. I do have a regular vented K-coupler with similar dimensions and when compared to a K12 when both were loaded with a W8-1772, the classic K had 2-5dB more output in the 110-220Hz octave - the original aspect and volume gave more "hit", the taller aspect = more neutral I believe.to
don't forget to put polyfil in the stub behind the Karlsonator's driver - I don't think Lapaire had that section damped in the prototypes - that will reduce coloration quite a bit
"XK8"
I don't have a Karlsonator yet other than the prototype for the Karlsonator6. I do have a regular vented K-coupler with similar dimensions and when compared to a K12 when both were loaded with a W8-1772, the classic K had 2-5dB more output in the 110-220Hz octave - the original aspect and volume gave more "hit", the taller aspect = more neutral I believe.to
don't forget to put polyfil in the stub behind the Karlsonator's driver - I don't think Lapaire had that section damped in the prototypes - that will reduce coloration quite a bit
"XK8"
An externally hosted image should be here but it was not working when we last tested it.
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Like I said, I think these will work, but if you ask xrk971 very nicely, perhaps he will run a sim for you. IIRC, he did a sim of the Lowther DX3 which was very promising, though I can't immediately find it. It may take some tweaking and playing around with stuffing and wing profiles etc, but that's par for the course in DIY audio.
Sounds like you have no shortage of output impedance.
Karlson chambers tend to reduce the shout region (~ 1kHz to 4kHz). That quality will also work in your favor with those extremely underdamped drivers.
IIRC, he did a sim of the Lowther DX3 which was very promising, though I can't immediately find it. It may take some tweaking and playing around with stuffing and wing profiles etc, but that's par for the course in DIY audio. I have a Tubelab 300b, a single ended KT88, a few small SE 6BQ5, and a few others; output impedance is no problem
Sounds like you have no shortage of output impedance.
Karlson chambers tend to reduce the shout region (~ 1kHz to 4kHz). That quality will also work in your favor with those extremely underdamped drivers.
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McTavish,
Get me the detailed T/S params of the FE203En-S and I will run a sim for you. Can't seem to find it on the web - must be a rare driver. Of the top of my head, the Qts of 0.14 is awfully low meaning the driver will basically be un-bounded in a Karlsonator on the low end unless you have a high pass filter down there around 30 Hz to prevent over excursion. The bass may be a bit anemic in this particular cabinet. Something may be possible to extend the Karlsonator cabinet length to improve bass.
I have been thinking of doing a 'clean sheet' design inspired by the Karlsonator specifically made for low Qts drivers with a very high compression ratio in order to more efficiently couple with the driver motor and cone.
Get me the detailed T/S params of the FE203En-S and I will run a sim for you. Can't seem to find it on the web - must be a rare driver. Of the top of my head, the Qts of 0.14 is awfully low meaning the driver will basically be un-bounded in a Karlsonator on the low end unless you have a high pass filter down there around 30 Hz to prevent over excursion. The bass may be a bit anemic in this particular cabinet. Something may be possible to extend the Karlsonator cabinet length to improve bass.
I have been thinking of doing a 'clean sheet' design inspired by the Karlsonator specifically made for low Qts drivers with a very high compression ratio in order to more efficiently couple with the driver motor and cone.
This is all I have, it came with the drivers.
Seems the Japanese do not place much value in T/S parameters, or measurements in general for that matter.
"Tone" is more valued than accuracy
Does anyone have T/S measurements of this driver? Looking at that impedance curve all I can say is Dang! that is wide. We could estimate T/S parameters visually from looking at an impedance curve to get Qms and Qes, etc. We have Sd, Re, Qts, Mms, and fs, but why did Fostex not just measure it?
You are right, they must nor believe in T/S parameters - just stick it in a very complex back horn and hope for the best.
Edit: I was going to go in and manually pull off the impedance curve from the Fostex pdf to calculate Qes and Qms but the impedance curve has no absolute units so I don't know what the peak or Re value is. Thus can't get r0, F1s, F2s, hence no Qes or Qms. Ugghhh...
A little more digging on the net yielded a measurement supposedly from Klang and Ton:
FOSTEX FE203En-S Special Limited Edition GT Fastback Bells & Whistles
Her kommer etterspurte måledata for Fostex FE203En-S (hentet fra Klang & Ton 6/2011) post 380 (http://www.hifisentralen.no/forumet/diy-og-utvikling-ha-yttalere-forsterkere-etc/56400-fostex-fe203en-s-special-limited-edition-gt-fastback-bells-whistles-19.html):
Z: 8 Ohm
Z 1 kHz: 10 Ohm
Z 10 kHz: 21 Ohm
Fs: 45 Hz
Re: 6,65 Ohm
Rms: 1,33
Qms: 3,46
Qes: 0,21
Qts: 0,20
Cms: 0,76
Mms: 16,2 g
BxL: 12,0
Vas: 45 l
Le: 0,38 mH
Sd: 206 cm2
You are right, they must nor believe in T/S parameters - just stick it in a very complex back horn and hope for the best.
Edit: I was going to go in and manually pull off the impedance curve from the Fostex pdf to calculate Qes and Qms but the impedance curve has no absolute units so I don't know what the peak or Re value is. Thus can't get r0, F1s, F2s, hence no Qes or Qms. Ugghhh...
A little more digging on the net yielded a measurement supposedly from Klang and Ton:
FOSTEX FE203En-S Special Limited Edition GT Fastback Bells & Whistles
Her kommer etterspurte måledata for Fostex FE203En-S (hentet fra Klang & Ton 6/2011) post 380 (http://www.hifisentralen.no/forumet/diy-og-utvikling-ha-yttalere-forsterkere-etc/56400-fostex-fe203en-s-special-limited-edition-gt-fastback-bells-whistles-19.html):
Z: 8 Ohm
Z 1 kHz: 10 Ohm
Z 10 kHz: 21 Ohm
Fs: 45 Hz
Re: 6,65 Ohm
Rms: 1,33
Qms: 3,46
Qes: 0,21
Qts: 0,20
Cms: 0,76
Mms: 16,2 g
BxL: 12,0
Vas: 45 l
Le: 0,38 mH
Sd: 206 cm2
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FE203EN-S in a Karlsonator
Ok, here is a sim based on Klang and Ton measurements which have a slightly higher Qts than the factory 0.14.
In a regular Karlsonator 8, you will have a bass peak and a sagging response followed by a very eat your ears off high mid range (stuffing or felt added behind the wings in the front cavity can help with this):
If I make the box smaller to get the volume down by scaling height and depth by 0.81x and width by 0.53x, we get this:
If you made the K-aperture go to a sharp cusp instead of a slot you can get some deeper bass extension but at the cost of a very imbalanced low vs high response:
Looking at the cone excursion, it is as I expected , a runaway at low freq so a high pass filter is needed or XO, or just be careful with stuff that has content below 40 Hz:
Here is Impedance of the 0.81x version with slot front aperture:
Ok, here is a sim based on Klang and Ton measurements which have a slightly higher Qts than the factory 0.14.
In a regular Karlsonator 8, you will have a bass peak and a sagging response followed by a very eat your ears off high mid range (stuffing or felt added behind the wings in the front cavity can help with this):
If I make the box smaller to get the volume down by scaling height and depth by 0.81x and width by 0.53x, we get this:
If you made the K-aperture go to a sharp cusp instead of a slot you can get some deeper bass extension but at the cost of a very imbalanced low vs high response:
Looking at the cone excursion, it is as I expected , a runaway at low freq so a high pass filter is needed or XO, or just be careful with stuff that has content below 40 Hz:
Here is Impedance of the 0.81x version with slot front aperture:
Attachments
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Wow, that was fast! Thanks for the effort xrk971.
It looks like it could work with the felt you mentioned and a high enough output impedance/some series resistance...
I knew this was going to be a tough driver to work with but I have a soft spot for those fostex special edition drivers
I have a pair of Seas Fa22RcZ as well, I guess if the Fostex does not work out I could always toss these in
I am going to build them.
I already have a sheet of 18mm baltic birch and the wife and kid are going out of town for a few days...
That means sawdust will fly!
I figure even if they don't work out with the fostexes I can always find a suitable 8" driver for them. I do have the FA22RCZ's.
Plus it is such a cool concept that I wanna hear for myself what they are all about
I already have a sheet of 18mm baltic birch and the wife and kid are going out of town for a few days...
That means sawdust will fly!
I figure even if they don't work out with the fostexes I can always find a suitable 8" driver for them. I do have the FA22RCZ's.
Plus it is such a cool concept that I wanna hear for myself what they are all about