built for me by John Lapaire will examine several aperture including these two wildly different scenario and impedance openings suggested by Carl Neuser. This coupler's hieght is 20" Carl has a 26.5" high coupler with Fe206E. In accordance with Karlson patent 3540544 it features a curved upper reflector, and its rear lowpass choke shelf is variable. There's a slight stub to the shelf to allow adding an incremental front deflection shelf.
Slow taper
Slow taper parameters - 83.6 square inch total aperture
Gap Slope p q Area Length Wmax
0.25 1.5 3 12 83.6 18.5 12
x w
0.00 0.50
1.00 0.50
2.00 0.52
3.00 0.55
4.00 0.62
5.00 0.74
6.00 0.92
7.00 1.16
8.00 1.49
9.00 1.91
10.00 2.43
11.00 3.07
12.00 3.84
13.00 4.74
14.00 5.78
15.00 6.97
16.00 8.29
17.00 9.73
18.00 11.24
18.50 12.00
********************
Fast taper
Fast taper parameters, 131.9 square inch aperture
Gap Slope p q Area Length Wmax
0.5 2.9 1.08 9.5 131.9 18.5 12
Aperture
x w
0 0.50
1 0.78
2 1.10
3 1.43
4 1.76
5 2.11
6 2.46
7 2.81
8 3.17
9 3.54
10 3.91
11 4.30
12 4.72
13 5.18
14 5.73
15 6.43
16 7.38
17 8.72
18 10.69
18.5 12.00
back of cabinet
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.
Slow taper
An externally hosted image should be here but it was not working when we last tested it.
Slow taper parameters - 83.6 square inch total aperture
Gap Slope p q Area Length Wmax
0.25 1.5 3 12 83.6 18.5 12
x w
0.00 0.50
1.00 0.50
2.00 0.52
3.00 0.55
4.00 0.62
5.00 0.74
6.00 0.92
7.00 1.16
8.00 1.49
9.00 1.91
10.00 2.43
11.00 3.07
12.00 3.84
13.00 4.74
14.00 5.78
15.00 6.97
16.00 8.29
17.00 9.73
18.00 11.24
18.50 12.00
********************
Fast taper
An externally hosted image should be here but it was not working when we last tested it.
Fast taper parameters, 131.9 square inch aperture
Gap Slope p q Area Length Wmax
0.5 2.9 1.08 9.5 131.9 18.5 12
Aperture
x w
0 0.50
1 0.78
2 1.10
3 1.43
4 1.76
5 2.11
6 2.46
7 2.81
8 3.17
9 3.54
10 3.91
11 4.30
12 4.72
13 5.18
14 5.73
15 6.43
16 7.38
17 8.72
18 10.69
18.5 12.00
back of cabinet
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
Hi there: The box and coupler look fantastic. Is the total box volume about 1.5 cf and the back volume (behind the driver board and curved panel) about ).7 cf? How is the back volume calculated from driver T/S parameters? Is the 0.5-inch x 12-inch gap calculated as a port? Hope you will post your listening experiences. ...regards, Michael
hi Michael - you've got a keen eye - that's about the rear volume and that slot will be the rear port - hope its large enough. I had someone's ancient 8" driver coupler laying around about this size that have pretty good impact on a drum. K-builder Carl gives a rough estimate of rear chamber volume to be (Vas*Qts*fs)/50
Carl doesn't post nor give out full details - here's an old Sigma coupler with a 2/3 height slot and another 8"/10" coupler (perhaps 28" tall) with laminated veneer K-tube waveguide. He has a 26.5" tall coupler for FE206E with the same cross-section as the test box being built for me but not seen a picture yet.
radial arc wings will be tested on mine along with those two extremes. I think the fast flare aperture may work with weaker drivers such as B20. Tighter and slower flaring apertures add more mass load so require stronger motor.
Best, Freddy
Carl doesn't post nor give out full details - here's an old Sigma coupler with a 2/3 height slot and another 8"/10" coupler (perhaps 28" tall) with laminated veneer K-tube waveguide. He has a 26.5" tall coupler for FE206E with the same cross-section as the test box being built for me but not seen a picture yet.
radial arc wings will be tested on mine along with those two extremes. I think the fast flare aperture may work with weaker drivers such as B20. Tighter and slower flaring apertures add more mass load so require stronger motor.
Best, Freddy
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.
Last edited:
Here's fresh pictures of 3 apertures for the coupler - I'd expect the fast opening to work with weak motor fullrange (B20?) thanks to John Lapaire for great and patient work.
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.
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
radial wings in place
FE206EN/etc. coupler on top of John Lapaire's K15 home/pa system
An externally hosted image should be here but it was not working when we last tested it.
FE206EN/etc. coupler on top of John Lapaire's K15 home/pa system
An externally hosted image should be here but it was not working when we last tested it.
Hey Freddi, are you sure that isn't a Tapped Horn?
If I recall my 1957 15 inch, some parts were shellacced and the only damping was a curved segment of paper-covered kapok (ancient house insulation batt?) stapled on the floor of the chamber behind the driver covering maybe 1/2 of the surface.
What a cello sound! Organ music too, at least for E. Power Biggs' low notes of the time.
If I recall my 1957 15 inch, some parts were shellacced and the only damping was a curved segment of paper-covered kapok (ancient house insulation batt?) stapled on the floor of the chamber behind the driver covering maybe 1/2 of the surface.
What a cello sound! Organ music too, at least for E. Power Biggs' low notes of the time.
re: tapped - have to ask Tom Danley on that one but K15 might be looked partly as one with a short path. I've built an 18" driver sealed rear chamber "klam" and as there's no rear wave contribution its working as coupled cavity. Karlson and Wayne Green's K15 had 3 damping pads with the thickest pad under the rear lowpass shelf.
It's a 6th order bandpass variation. At least, that's how I tend to class it, with the Klams as 4th order BP.
Henry Lang gave early analysis of bandpass enclosures"
SOUND REPRODUCING SYSTEM - Google Patent Search
If the baffles, etc in a Karlson-type are arranged favorably, there's no upper bandpass corner. The resonator is different than a BP chamber with non-flared aperture. I'll measure within limitations those two oddball apertures effect on impedance and response to see if Carl N. can correlate the data with his K-programs. I don't know much about Carl but know he did FEA development of engine blocks. At some point common graphs fail. A speaker may make a decent graph yet not sound right on transients. A speaker may make a poor graph yet work subjectively on dynamic transients.
what are better alternatives to FFT?
SOUND REPRODUCING SYSTEM - Google Patent Search
If the baffles, etc in a Karlson-type are arranged favorably, there's no upper bandpass corner. The resonator is different than a BP chamber with non-flared aperture. I'll measure within limitations those two oddball apertures effect on impedance and response to see if Carl N. can correlate the data with his K-programs. I don't know much about Carl but know he did FEA development of engine blocks. At some point common graphs fail. A speaker may make a decent graph yet not sound right on transients. A speaker may make a poor graph yet work subjectively on dynamic transients.
what are better alternatives to FFT?
They are all band-pass alignments with the Klam being a simple 4th order. The rest are either 6th or 8th order depending on whether or not they have a shelf in the front like the K15. Since a basic TH is a 6th order taken to its logical extreme we can say that Ks with two chambers in back and one in front are a variation of a TH and if the TH has a separate filter chamber as some do, then it's an 8th order same as the K15.
IOW, instead of a long TL or horn expansion connecting the front and rear wave of the driver, the Ks approximate it by adding different size resonant cavities together in series to shorten its path-length considerably and of course since net Vb governs max SPL the typically larger TH will outperform it.
GM
Yes!
Principles for dealing with rear wave is different but result is the same.
I can't believe there is any horn-impedance-matching benefits in those little THs. Just a matter of getting a piece of the rear wave out front in support of the front wave (like a TL) and working over 1 to 1.5 octaves. Even a bass reflex would work good over 1.5 octaves.
Yeah, as you know, its vent/final chamber shape is what makes or breaks a Ks performance, especially its mids/HF BW, so where the bulk of research needs to be directed. Still, I don't ever see myself as accepting them as suitable for HIFI apps unless XO'd right above its gain BW, though one of these days before my hearing goes away too much more I would like to audition an Altec Duplex loaded K15 (preferably the period correct 604B) that IIRC you said it or similar was designed for, i.e. a coax driver with a ~1 kHz XO or about 2-3x higher than used with a typical BP of the same gain BW.
GM
Drat. Forgot about that K15 shelf making it up to 8th order. Thanks (as always) Greg.
You're welcome! I remember it from PWK's remark that it's a 'poly-resonant four cavity box'. Anyway, hope all's well at your end........
GM
Aha, that makes sense.
Not bad cheers; sorry I haven't been in touch for a bit -right when I thought I was getting on top of things, I had to start re-writing my old naval modules to bring them into line with the new departmental format my boss & I worked out. Other than that, pretty good thanks. How're things at your end -hopefully better than when we last spoke?
Not bad cheers; sorry I haven't been in touch for a bit -right when I thought I was getting on top of things, I had to start re-writing my old naval modules to bring them into line with the new departmental format my boss & I worked out. Other than that, pretty good thanks. How're things at your end -hopefully better than when we last spoke?
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.