McTavish,
Very cool - I understand how that goes when SWMBO and kids are out how sawdust, or in my case, foam core dust, flies
. That means you will have something to report back soon. If you want to have ability to try other drivers then stick to the regular Karlsonator 8 rather than the 0.81x scaled version. As you can see, a simple and inexpensive BG20 can work out very well. Good luck!
X
Very cool - I understand how that goes when SWMBO and kids are out how sawdust, or in my case, foam core dust, flies
. That means you will have something to report back soon. If you want to have ability to try other drivers then stick to the regular Karlsonator 8 rather than the 0.81x scaled version. As you can see, a simple and inexpensive BG20 can work out very well. Good luck!X
Here is a link to the SketckUp file with all three Karlsonator designs in it.
https://dl.dropboxusercontent.com/u/1642665/Karlsonators.skp
Let me know if it works out for ya!
https://dl.dropboxusercontent.com/u/1642665/Karlsonators.skp
Let me know if it works out for ya!
Awesome! Thanks Jessman
Tis' the season for box building!
Its always the season for box building!
Anyway I got a chance to measure the Karlson 8 vs. the Karlson 12. First off here is some pics of my Visaton BG20 in the Karlson 12:
Here are the impedance graphs, first up is the Karlson 8:
And here is the Karlson 12:
Its pretty windy today so I wan't able to measure frequency response outside like I prefer to do. I had to measure it inside my woodshop, which is pretty horrific acoustically, so take what you see here with a big grain of salt:
The red line is the Karlsonator 8, the green line is the Karlsonator 12, and the blue line is a measurement of my Karlsonator 8 that I took outside several months ago for comparison.
I'm going to really try to retake the measurements outdoors if I can get a chance in the next day or so.
)
hi Jesse - it looks for all practical purposes that the Karlsonator 8 does as well or better than the 12 for BG20 - did your mic point right on the dustcap axis? - that will usually show more top end. I really like GB's mini build (is that a sock lurking in the front chamber?) Which fullrange might suit the Karlsonator 8 better than the little Visaton? In K12, FE206EN had better quality on drums than my Klipschorns.
that's a very low tuning for the Karlsonator8 - Karlson's K8 tunes ~95Hz, the little SK8 ~65Hz, and I think my XK8 almost the same size as the Karlsonator8, somewhere in the low 50s (?)
Jesse - which K sounds better with your BG20?
that's a very low tuning for the Karlsonator8 - Karlson's K8 tunes ~95Hz, the little SK8 ~65Hz, and I think my XK8 almost the same size as the Karlsonator8, somewhere in the low 50s (?)
Jesse - which K sounds better with your BG20?
Last edited:
GregB,
Those are very nice looking 0.53x scale mini's. I recall running a sim for Illusus a while back for CHR70.3 - not sure if he ever made them but the dimensions were about the same. How do they sound?
X
Yeah, I basically used your suggested dimensions. Thanks!
RE: the sound - The bass is much much much better than when they were in BR boxes, and they will play quite loud for a 3" full range. Also, there is no longer a need for BSC, as the bandpass gain of the couplers is doing its job. The passive filters I used to need with these CHR70 really kind of zapped the life out of them.
Vocals (mids and treble) are a little colored if left in this raw state with minimal damping, but I think I can fix it. A serious issue IME with Karlsons is that the 'reverb' and coloration in the mids and treble from the front chamber gets worse as the size gets smaller. I am experimenting with felt lining and the other ideas to reduce or eliminate this. So far the experiments seem very promising, and I am getting a very open and clean sound, while retaining the effortless and powerful thing. I'll update again after some more tweaking.
When I took the measurements I had the mic about a meter away and it was pretty much pointed at the dustcap. Tomorrow I'm really going to try to get an outside measurement. I'm pretty sure being inside really tainted the results.
So far I haven't done a good head to head comparison to see which cabinet I like better. When I do I'll let you know.
it would be interesting to see in the impedance with wings removed - wonder how much adjustment to the vents would be needed to move the tunings up a bit? - that info could be added to the plans. Perhaps a change in the first part of the slot on the 12 inch Karlsonator would be enough.
what might the blue aperture trace on the Karlsonator 8 plan do to the input impedance? response? "tone"?
what might the blue aperture trace on the Karlsonator 8 plan do to the input impedance? response? "tone"?
Last edited:
Jesse, That's a really awesome job you did on those!! I like the little sub base feature. That type of base would have been typical on vintage Karlsons. Very cool.
Freddy, I think my initial sim/guesses for the Karlsonator 8 took the vent edge radius into consideration. A little bit of change here can make a pretty big difference in tuning, at least in sims.
Speaking of sims, xrk has a much better model than I used, obviously.
X - if I understand correctly, you have replaced the original 13(?) step approximation for the K slot aperture with a quadratic function? If so, that's the long time dream of K enthusiasts everywhere...
I like the little sub base feature. That type of base would have been typical on vintage Karlsons. Very cool. Freddy, I think my initial sim/guesses for the Karlsonator 8 took the vent edge radius into consideration. A little bit of change here can make a pretty big difference in tuning, at least in sims.
Speaking of sims, xrk has a much better model than I used, obviously.
X - if I understand correctly, you have replaced the original 13(?) step approximation for the K slot aperture with a quadratic function? If so, that's the long time dream of K enthusiasts everywhere...
GregB,
The quadratic fit describing the Karlson aperture has always been there - I use it to set the width of the vent at the particular location in the front. There are still a finite number of rectangular aperture vents. I originally used 12, and did a sensitivity analysis by reducing the number of segments to see if there was a large effect. I found that I could go as low as 9 and it was pretty accurate. Although if you have a non-standard profile with a rapid change, more segments may be needed. It would be a good experiment to build a K-aperture using discrete rectangular segments (like stepped staircase - pixelation effect) and compare with a smooth edged one in both listening tests and measurements. Easy enough to try in FC I suppose but I have not had a chance to do so.
If I did not have a 53 node limit in Akabak I would use a lot more to make it as smooth as possible (maybe 50 or 100 even).
Thanks!
But without your original design for the Karlsonator, which I have to say, is one of the most scalable designs ever, none of this would have been possible. I think that all the positive feedback from builders on this thread is a testament to the universality of the Karlsonator as a timeless classic.What did you use to model your Karlsonator? I have seen a version in Hornresp by IG81 that may capture many of the essentials. I have been thinking that I can simplify the Akabak K15 (bandpass) by going with a generic "Enclosure" volume chamber elements for the internal chambers and a segmented waveguide for the front as usual. This may save on nodes and let me go with more segments on the front. For the Karlsonator though, you need the segmented waveguides in the back as it really is a TL/Horn rather than a band pass like the K15.
hi X - it would be great if hornresp could handle the original Karlson using a few assumptions. Would a Tangband W8-1772 work in the Karlsonator 8 or the 12 better? In Karlson's 1954 K12, I prefer FE206EN to W8-1772 - but 1772 sounded very good in a little "SK8" K-coupler - its like K12 was too large or something.
Bob Brine's WT2 averages for two W8-1772
Re ohms 7.28996
Fs Hz 42.59512
Zmax ohms 28.85236
Qes 0.44508
Qms 1.31602
Qts 0.33256
Le mH 0.04414
Diam mm 165.5
Sd mm^2 21512.25
Vas L 72.76948
BL N/A 7.4432
Mms g 12.6453
Cms uM/N 1106.912
Kms N/M 905.7046
Rms R 2.57074
Efficiency % 1.1911
Sensitivity dB(1 watt) 92.76138
Sensitivity dB(2.83 volt) 93.166
Bob Brine's WT2 averages for two W8-1772
Re ohms 7.28996
Fs Hz 42.59512
Zmax ohms 28.85236
Qes 0.44508
Qms 1.31602
Qts 0.33256
Le mH 0.04414
Diam mm 165.5
Sd mm^2 21512.25
Vas L 72.76948
BL N/A 7.4432
Mms g 12.6453
Cms uM/N 1106.912
Kms N/M 905.7046
Rms R 2.57074
Efficiency % 1.1911
Sensitivity dB(1 watt) 92.76138
Sensitivity dB(2.83 volt) 93.166