I like them but can't seem to find them smaller than ¼". I am going to look in Lowes but may settle on truss head or hex washer head #6 screws.
You must be playing very loud - I have never heard wind noises on 0.53x Karlsonator with dual 3FE25’s. Do you have some loose polyfill in the lower chamber behind the drivers? The melamine foam along the entire aperture is interesting. Let us know how that sounds.
Your cabinets look great!
I think it's not as bright as before, the highs are less harsh comparing to the partial/lower damping, the cymbals seem to be more defined, more like cymbals less like a noise... or maybe it's an effect of burning in. Can't hear any difference in the low frequencies. I think it is worth trying if someone complains about harsh hf.
I did an experiment, I placed the speakers facing each other, connected each speaker to the same channel in parallel, reversed polarity in one of them, the base was gone completely, the mids were also much quiter. They seem to be quite equal.
I would like to check the SPL as a function of freq in a professional anechoic chamber.
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Only to the extent that the cutout hole is for a real driver. Seems like it should fit.
Basic Karlsonator physics?
I ended up in this thread searching for an explanation of the Karlsonator design. Did I understand correct that at its basis, Karlsonator is a driver coupled with a quarter-wave tube. But the tube is special in that it's topology allows it to behave like a quarter-wave pipe over a range of frequencies rather than just one fundamental frequency?
I ended up in this thread searching for an explanation of the Karlsonator design. Did I understand correct that at its basis, Karlsonator is a driver coupled with a quarter-wave tube. But the tube is special in that it's topology allows it to behave like a quarter-wave pipe over a range of frequencies rather than just one fundamental frequency?
GregB came up with the Karlsonator as hybrid of TQWT and K-coupler.
The wedge shaped front chamber is excited by the driver, which is at the "bottom" of the wedge where chamber volume is nil and aperture widest. The top of the chamber is driven by the TQWT vent.
The narrowing width of the aperture tends to spread horizontal dispersion.
If the front chamber is sizable enough to resonate at harmonics of typical musical bass instruments, then the front chamber can reinforce those frequencies while reducing cone excursion vs direct radiator.
XRK971 may elaborate.
The image below shows GregB's TWQT for Eminence's Beta12LTA. A simple K-coupler
is added to the front and voila - a "Karlsonator".
The wedge shaped front chamber is excited by the driver, which is at the "bottom" of the wedge where chamber volume is nil and aperture widest. The top of the chamber is driven by the TQWT vent.
The narrowing width of the aperture tends to spread horizontal dispersion.
If the front chamber is sizable enough to resonate at harmonics of typical musical bass instruments, then the front chamber can reinforce those frequencies while reducing cone excursion vs direct radiator.
XRK971 may elaborate.
The image below shows GregB's TWQT for Eminence's Beta12LTA. A simple K-coupler
is added to the front and voila - a "Karlsonator".
Attachments
Thanks for the intro. K-coupler physics explained a lot.
I understand that the slot is exponential (according to Karlson). Is there a formula or algorithm to:
1) Design a quarter-wave tube to a range of frequencies with an exponential cut at the end
2) Design an exponential profile acoustic lens for a range of frequencies?
I'm still searching and am yet to come across any.
you might look at Raymond Bates article
Vintage article "A Tuned Pipe for Bass Enhancement" by Raymond Bates
For low frequency, back loaded has been employed with Fulmer, Bates, and Bill Woods K-slotted BLH. I'm not sure if it would have much use front loaded.
Karlson had a drawing for a 12 foot long klam for 2-15". IIRC the tapered slot portion was 8 foot long with the 15" drivers placed closer to the open end than closed. That was apparently meant for permanent build-in with drivers infinitely baffled into a wall or ceiling space.
That double 15 klam's form incidentally reminds me of a 1944 patent
Vintage article "A Tuned Pipe for Bass Enhancement" by Raymond Bates
For low frequency, back loaded has been employed with Fulmer, Bates, and Bill Woods K-slotted BLH. I'm not sure if it would have much use front loaded.
Karlson had a drawing for a 12 foot long klam for 2-15". IIRC the tapered slot portion was 8 foot long with the 15" drivers placed closer to the open end than closed. That was apparently meant for permanent build-in with drivers infinitely baffled into a wall or ceiling space.
That double 15 klam's form incidentally reminds me of a 1944 patent
Thanks for the reference. Meanwhile, I started simulating simple 3D quarter-wave pipe in FEA but with randomly placed hole on the side, at the end, like a flute. I'm beginning to see how well the acoustic impedance can be controlled with holes and slots.
Guys, so I build Karlsonator 0.53x with dual 3FE25-16 based on XRK recommendations over 2 years ago. I'm super happy with them. I got all what I needed: amazing soundstage (despite position), details and fantastic separation of instruments, super tight bass, wonderfull female voices, even harsh high frequencies are gone, the cymbals sound realistic, these are super hot speakers! The bass fade out quickly somewhere between 55Hz and 60Hz - the fs of my speakers is about 10Hz higher than on the specs. I plan to build another pair made of 12mm plywood but with some 6mm internal bracing.
But it can't be the end. I need to build something new, something "better"? It doesn't have to be as efficient as 96dB (it would be great if so), but I would like to go lower with the bass.
I own a pair of Markaudio Alpair 12P matched at fs=44Hz (my T/S measurements are identical to the specs), Qts is at the range where Karlson/Karlsonator might be the way to go... or maybe something else?
But it can't be the end. I need to build something new, something "better"? It doesn't have to be as efficient as 96dB (it would be great if so), but I would like to go lower with the bass.
I own a pair of Markaudio Alpair 12P matched at fs=44Hz (my T/S measurements are identical to the specs), Qts is at the range where Karlson/Karlsonator might be the way to go... or maybe something else?
Build the 10F/RS225 TLs. They are an endgame speaker for many people, I think. I certainly cannot complain about lack of bass or anything. They do everything well. Just not super efficient so need a 50w to 100w amp.
Latest build by Mas Penk looks wonderful.
Latest build by Mas Penk looks wonderful.
thank you XRK 
Unless... the specs of 3FE25-16 says "Sensitivity (1W/1m) 90 dB", to get 1W from 16 Ohm speaker we need to provide 4V (not 2.83V) (4V*4V)/16Ohm = 1W.
If I am not mistaken at 2.83V we get 3dB less, sqrt(2) times less, which means 3FE25-16 has 87dB 2.83V 1m and with two (8 Ohm) theoretically we are getting +6dB which is 93dB 2.83V (1W) 1m. Please correct me if I am wrong.
Unless... the specs of 3FE25-16 says "Sensitivity (1W/1m) 90 dB", to get 1W from 16 Ohm speaker we need to provide 4V (not 2.83V) (4V*4V)/16Ohm = 1W.
If I am not mistaken at 2.83V we get 3dB less, sqrt(2) times less, which means 3FE25-16 has 87dB 2.83V 1m and with two (8 Ohm) theoretically we are getting +6dB which is 93dB 2.83V (1W) 1m. Please correct me if I am wrong.
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Hi Ripson,
I think you are right and that explains why they probably are closer to 93dB st 2.83v. The confusion for me came from the Parts Express website description which says 90dB at 2.83v and 1m.
The Faital Pro factory datasheet indeed says 90dB at 1W and 1m.
Thanks - and we now see why. But 93dB is still pretty good and why you get less than perceived 91.5dB of your other speaker, might be that the other one has more mid and end presence (less baffle step correction) and sounds louder. A microphone and REW will tell you.
I think you are right and that explains why they probably are closer to 93dB st 2.83v. The confusion for me came from the Parts Express website description which says 90dB at 2.83v and 1m.
The Faital Pro factory datasheet indeed says 90dB at 1W and 1m.
Thanks - and we now see why. But 93dB is still pretty good and why you get less than perceived 91.5dB of your other speaker, might be that the other one has more mid and end presence (less baffle step correction) and sounds louder. A microphone and REW will tell you.
No probs X, they sound great with Mr. Nelson Pass F5, I need to find plans for some super sensitive speakers for 45 tube amp, it's going to run without global negative feedback so it should play at lower levels before harmonics rise too much.
X, did you have a chance to measure T/S of 3FE25-16? My method is quite precise as I got exactly the same results with Alpair 12P as manufacturer specs says, but measured fs for 3FE25-16 are: 131Hz, 129Hz, 130Hz, 125Hz. The specs says 110Hz. Is it normal or I got some worse sort? :/
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Or maybe a layer of dammar oil improve them a bit :O
X, did you have a chance to measure T/S of 3FE25-16? My method is quite precise as I got exactly the same results with Alpair 12P as manufacturer specs says, but measured fs for 3FE25-16 are: 131Hz, 129Hz, 130Hz, 125Hz. The specs says 110Hz. Is it normal or I got some worse sort? :/
EDIT:
Or maybe a layer of dammar oil improve them a bit :O
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seems about normal to see fs and qts somewhat higher than spec. A 45 and ~90dB for two 3FE25 in parallel might not go far dynamic-wise.
I ran a SE 6L6 into a 99dB rated coax in K15 and that was tragic. Percussion with a good 12" and K12 can use over 100 watts on a peak and not sound "loud". I do admit some of the Japanese daiko drums can be startling - partly from the way the music is timed - partly from impact with 15 and 18 inch Karlson. K15 is very adept with percussion.
TPA3116 or better would probably sound very good with those beautiful Karlsonator.
I ran a SE 6L6 into a 99dB rated coax in K15 and that was tragic. Percussion with a good 12" and K12 can use over 100 watts on a peak and not sound "loud". I do admit some of the Japanese daiko drums can be startling - partly from the way the music is timed - partly from impact with 15 and 18 inch Karlson. K15 is very adept with percussion.
TPA3116 or better would probably sound very good with those beautiful Karlsonator.
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