Kees,
In the above - segment 1 is 0.7 meters long - is that intentional? I usually don't make any segment that long, especially the first one at the throat where it is critical to have an accurate profile. Also, as I recall, the tractrix actually has a slight contraction about 1/4 or 1/4 of the way down from the throat. I don't see any contracting elements here. Otherwise looks pretty good. What I did with E Forker's spreasheet was to extract the area and length every 2.5cm or so. That ended up with maybe 15 segments. You probably don't need 24. In the CAD program, I was able to approximate the tractrix curve with a single spline element with minimal error. Single splines are nice because there are no discontinuities on the tangent slope (or derivative) along the profile.
In the above - segment 1 is 0.7 meters long - is that intentional? I usually don't make any segment that long, especially the first one at the throat where it is critical to have an accurate profile. Also, as I recall, the tractrix actually has a slight contraction about 1/4 or 1/4 of the way down from the throat. I don't see any contracting elements here. Otherwise looks pretty good. What I did with E Forker's spreasheet was to extract the area and length every 2.5cm or so. That ended up with maybe 15 segments. You probably don't need 24. In the CAD program, I was able to approximate the tractrix curve with a single spline element with minimal error. Single splines are nice because there are no discontinuities on the tangent slope (or derivative) along the profile.
Hi X
it is a 60 hz horn in free air, so long and big, it is atest case, but you are right I miss also the contraction on the throat start. I go mention that.
Furter it is nice, I have done myself the ; on the end of the S1T, S1M and L1 etc and send the program back to erik.
I send your reaction also. O yes it is a round tractrix, maybe then it is different what concerns contraction. I did'nt see it.
I have included a picture of the original, the as you see there is a contraction but only in the height part and not the conic width part
(not possible because one piece) what did you use for akabak S1T and S1M ? did I right al the way hahaha.
for me akabak do use mcubic meter one section at a time as hornresp does. I did use the cm2 last row in the table this is height x width in the table,
then you see not the contraction? look at cm2 last row of table.
I need the right way then if program is changed we have a nice tool.
regards
it is a 60 hz horn in free air, so long and big, it is atest case, but you are right I miss also the contraction on the throat start. I go mention that.
Furter it is nice, I have done myself the ; on the end of the S1T, S1M and L1 etc and send the program back to erik.
I send your reaction also. O yes it is a round tractrix, maybe then it is different what concerns contraction. I did'nt see it.
I have included a picture of the original, the as you see there is a contraction but only in the height part and not the conic width part
(not possible because one piece) what did you use for akabak S1T and S1M ? did I right al the way hahaha.
for me akabak do use mcubic meter one section at a time as hornresp does. I did use the cm2 last row in the table this is height x width in the table,
then you see not the contraction? look at cm2 last row of table.
I need the right way then if program is changed we have a nice tool.
regards
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I have look at the program, when I do free air or floor, it have contraction, when do wall and corner it has not.
The corrected program for 24 lines (I can copy and paste in one go so 24 lines is not a problem) it have no contraction whatsoever.
I have mail Erik to point it, maybe because of lower resolution this happend.
Coming week I go get a wood lathe, I have bought one so I can make plugs more easy, he was quite cheap so it is not that big mony eater..
Post 1382 you see it has contraction.
regards
The corrected program for 24 lines (I can copy and paste in one go so 24 lines is not a problem) it have no contraction whatsoever.
I have mail Erik to point it, maybe because of lower resolution this happend.
Coming week I go get a wood lathe, I have bought one so I can make plugs more easy, he was quite cheap so it is not that big mony eater..
Post 1382 you see it has contraction.
regards
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Kees,
The above output does looks very useful - now just a copy and paste operation into Akabak for the tractrix horn profile.
Thanks,
X
The above output does looks very useful - now just a copy and paste operation into Akabak for the tractrix horn profile.
Thanks,
X
Yes but it is the round horn calculator?, is there no difference? that is what confuse me and Erik. I see different outcome, so the low end is much lower als with reactangle output.
regards
You say only length and cubic meter sections are needed, just convert area cm2 row to m2 and use for S1t S1M and the length of the horn in meters is all
I have tell this to erik, using the round output do not work wel because it is round base, also on speaker connection in throat, but will get oke.
regards
I have tell this to erik, using the round output do not work wel because it is round base, also on speaker connection in throat, but will get oke.
regards
Disover that or round or rectangular give same output in cubic cm who I have convert to cubic meter for akabak, so the round version can just also be used, akabak do not see this, just looks to waveguides.
This means Erik can just put in the formulas in the rectangualr sections recacl the cm2 to m2 and length from guide to huide.
regards
This means Erik can just put in the formulas in the rectangualr sections recacl the cm2 to m2 and length from guide to huide.
regards
But the volume of a rectangular horn is different than a round horn. Akabak doesn't give volumes like HR does.
When i do calculate rectangualar or round, it give the same output in cm2 and length only the width and heigth get different output because it is a round version, with the same surface as square ones, also ration of the square horn give a different outcome in the widthh and heigth part, so it looks oke to use the cm2 row of the round horn in akabak.
Akabak do not volumes i new, it does length in meters, area in m2, I did recalc or better program did recalc cm2 to meters, round of square do not give differenties, only heigth and width, so problem solved.
regards
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Oke X I have start to put a woofer on, to see what happens.
and a new throat adaptor, from round to square.
As you see I have a compression in the throat, the new calculations from peter with less numbers do jump over that compression part.
regards
kees
and a new throat adaptor, from round to square.
As you see I have a compression in the throat, the new calculations from peter with less numbers do jump over that compression part.
regards
kees
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Oke I have simulate the devine BA08 woofer after measuring it.
looks quite good and get 100 dB, theoritical speaking. not bad for this cheap speaker who sound also quite nice on that frequency.
regards.
looks quite good and get 100 dB, theoritical speaking. not bad for this cheap speaker who sound also quite nice on that frequency.
regards.
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size is 8 inch and sold by a german company it is a devine BA08.
Bax-shop.nl | Online shop & muziekwinkel in pro audio, verlichting, DJ gear, studio apparatuur, muziekinstrumenten en video or de I think more places.
17,50 each.
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Hi,
I don't really understand how phase plug work (both type, on cone, and as part of horn mouth), but i feel their effect (a bit playing siming with akabak), so from you experiences and knowledges, would a "phase plug driver" as dayton rs100 for example would benefit of added radial ring phase plug at horn mouth ??
Is it worth a try ? I feel that with the on driver phase plug it's maybe a nonsense ...?
I don't really understand how phase plug work (both type, on cone, and as part of horn mouth), but i feel their effect (a bit playing siming with akabak), so from you experiences and knowledges, would a "phase plug driver" as dayton rs100 for example would benefit of added radial ring phase plug at horn mouth ??
Is it worth a try ? I feel that with the on driver phase plug it's maybe a nonsense ...?
The latest results from the XBush horn thread seems to show that working on getting a very smooth transition from the driver to the horn throat is critical to smooth response. Cone drivers don't have enough motor BL to push air through small phase plug channels. Also choice of driver also seems to be significant. For example the FR58EX has bad resonances when horn loaded. Whereas the SB65WBAC25-4 does not have the same issues. A well damped stiff cone seems to be ideal. I would not bother with phase plug for cone driver.
That makes intuitive sense. Makes me wonder if the ideal driver wouldn't be something like the SB65 with stiff well damped dome, instead of a cone??
Sheldon
The SB65 is at the moment one of the ideal drivers for horn loading and getting smooth output to 20k and above. I think I had good success with the 10F/8424 regarding high frequency extension to 20k. I did not have the smooth 3D printed driver to throat adapter at the time but imagine smoother output could have been had. Note that a horn with a round throat will intrinsically have better luck getting a smooth transition from a round driver cone.
This is precise why I get when using a small channels faseplug damp the lower tones to get more high, really I get no more high I get a capasitor effect I did use before you still remember? the motor of a speaker is very important, maybe a titanium mid dome who can go also to the high earea can work, we need such small channels to get effect we need to "compress" the air through it and this need strong dome and magnet.
However when using a K tube and let a faseplug help to get 3.5 khz we can overcome this and still have a single point horn who is 103 dB watt meter..
SB65 is interesting because of upgoing respons in the highs and is available here.
regards
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