Freddi ,
After a lot of refinement the Karlflex's vent velocity is pretty reasonable now ... A 13.5" width standard Karlflex loaded with A PA-310 stays below 20m/sec at full power (using a mass loading vent of 200sq cm) , and the 1.5x width (19" to 20" wide) standard Karlflex (with the Freddi-mod) which i plan to build next for these Daytons has reduced air velocity at the vent coming in at around 13 to 15m/sec (and uses a main vent area of 300sq cm due to the extra cab width) .......................
The 13.5" width Karlflex with the ported parasitic resonating chamber (like the prototype i built) also has an air particle velocity figure of no more than 13 to 15m/sec at full power because it behaves much like a DCR/ABC cabinet at FB with the parasitic chamber's vent acting as a second vent for the entire system at around FB (very near the fundamental is where the air particle velocity peak occurs) ....
For that 8th order design using a PA-310 I would go with no less than 200sq cm on the longest vent (the vent attached to "chamber 1" the one most responsible for generating the fundamental) ............. This means that the vent may end up being pretty long... If you were to make the vent's CSA even larger it just ends up needing to be longer in order to get the same tune and becomes a Quarter Wave Pipe like the 8TH order eigenmode cab sketches from post #17 , and that works too..... Even the version with 200cm sq would probably end up with enough path length to have some amount quarter wave action so this won't be a purely Helmholtz based box, but there is nothing wrong with that!
...... The 8th order 40hz tuned simulation for the Definimax12 in post #34 has a path length of up to 4 feet (depending on how the ports are arranged and the aspect of the chambers)
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after a fairly long BP4 vent I get a bit scared - for BP boxes, seems like this 8th can resonate louder than a BP6 (?) maybe if you wouldn't mind providing details, I'll have a little Karlflex made as it could reach higher and also double as bass guitar bin. Still a BP8 should be made and tweaked - I want the option of pvc ducts so one could be trimmed/tweaked
looks like I had a bandpass filter "on" in this little bp6 sim
here's with no filter
- for BP boxes, seems like this 8th can resonate louder than a BP6 (?) maybe if you wouldn't mind providing details, I'll have a little Karlflex made as it could reach higher and also double as bass guitar bin. Still a BP8 should be made and tweaked - I want the option of pvc ducts so one could be trimmed/tweakedlooks like I had a bandpass filter "on" in this little bp6 sim
here's with no filter
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Hi freddi,
That's what I like to hear - people having fun with Hornresp
.Kind regards,
David
BP8 & Karlflex
Freddi ,
Doing some comparisons
between the HR BP8 sim, and the Karlflex sim (in Akabak because Hornresp cannot model a K-slot)... I think you are right , the 8th order box does produce a bit more resonant gain and is a little more efficient... Unfortunately the BP8 also seems to have less cone control (and because of that cannot take quite as much power), and of course has less bandwidth while requiring a slightly larger box ( about 20% larger when tuned to a 40hz FB and loaded with a Dayton Pa-310) ....... The Karlflex is more of a 6th order design so i suppose these results sound about right ...
The simulations i used were a 100L Karlflex and the BP8 in hornresp was around 120L for the Dayton-Pa310 but of course tuning up to 50hz FB (like you did in your sim) allows the box to be made quite a bit smaller and the output capability increases.........
I realize that this was a sort of "apples & oranges" comparison since it is between two different softwares but this is fun nonetheless ..
Using a driver with a strong motor is where this BP8 really excels, with the Definimax12 the box can be made small at around 85 liters net even if tuned to 40hz ........
Perhaps since we are talking about only having to reproduce up to no more than 200hz with the BP8 i could look into a plugging a few of the cheap subs with high motor strength like the Soundqubed HDS212 into this model just to see what happens ...
after a fairly long BP4 vent I get a bit scared
Freddi ,
Doing some comparisons
between the HR BP8 sim, and the Karlflex sim (in Akabak because Hornresp cannot model a K-slot)... I think you are right , the 8th order box does produce a bit more resonant gain and is a little more efficient... Unfortunately the BP8 also seems to have less cone control (and because of that cannot take quite as much power), and of course has less bandwidth while requiring a slightly larger box ( about 20% larger when tuned to a 40hz FB and loaded with a Dayton Pa-310) ....... The Karlflex is more of a 6th order design so i suppose these results sound about right ...The simulations i used were a 100L Karlflex and the BP8 in hornresp was around 120L for the Dayton-Pa310 but of course tuning up to 50hz FB (like you did in your sim) allows the box to be made quite a bit smaller and the output capability increases.........
I realize that this was a sort of "apples & oranges" comparison since it is between two different softwares but this is fun nonetheless ..
Using a driver with a strong motor is where this BP8 really excels, with the Definimax12 the box can be made small at around 85 liters net even if tuned to 40hz ........
Perhaps since we are talking about only having to reproduce up to no more than 200hz with the BP8 i could look into a plugging a few of the cheap subs with high motor strength like the Soundqubed HDS212 into this model just to see what happens ...
would like to - health issues - no real place for the saw and no mobility - got hands full just organizing the current mess http://i.imgur.com/Aa5VtH6.jpg
hey MMJ - how difficult is it for you to sim a regular K12 with an added cavity "above" the front chamber? - is there a way to fudge its effects and proper size without Akabak?
hey MMJ - how difficult is it for you to sim a regular K12 with an added cavity "above" the front chamber? - is there a way to fudge its effects and proper size without Akabak?
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Possibly if i am not distracted by a DCR spinoff idea after Finishing the Karlflexs
I am still in the middle of my Karlflex project .... Prototype is built , just doing a little more testing, measuring and listening before i build a few more ...... Details at : http://www.diyaudio.com/forums/subw...flex-simple-build-series-tuned-6th-order.html
After i am done with this i might look into trying an 8th order , it is tempting because of it's high efficiency in a small cabinet (with specific drivers) ..... I have a couple of old blown out Definimax12s sitting here, i would probably get them reconed and use them if i decided to give the 8th order idea a go ...
I am still in the middle of my Karlflex project .... Prototype is built , just doing a little more testing, measuring and listening before i build a few more ...... Details at : http://www.diyaudio.com/forums/subw...flex-simple-build-series-tuned-6th-order.html
After i am done with this i might look into trying an 8th order , it is tempting because of it's high efficiency in a small cabinet (with specific drivers) ..... I have a couple of old blown out Definimax12s sitting here, i would probably get them reconed and use them if i decided to give the 8th order idea a go ...
Modeling softwares and special features and shtuff, and things
I tried to figure out how to sim the classic K box with Hornresp but there is no way that i can find to properly model the K-slot section , and the Freddi-mod cavity is something that might also be tricky in Hornresp as well ..... Not to say that it isn't possible, i just haven't figured out how yet ............
I ended up just switching to Akabak to model those features .... Your Freddi-mod cavity idea does work, it works very well in fact! it is an excellent solution for cleaning up the midbass and midrange (if trying to squeeze extreme bandwidth out of that cab) ...
The offset of the driver in the main path was used to flatten the 3rd harmonic ripple, then the Freddi-mod was used to tame the 5th and 7th harmonics .... Worked like a charm! I just need to quit procrastinating and stick the K-slot on the front instead of using this silly plank aperture....damn this phoenix heat
... I could potentially extend the usable bandwidth from 600hz up to 1khz with the K-slot (if so i could then just stick one of my transformer driven 2k Frankenpiezos on it and call it a day, if it could keep up) ....
I tried to figure out how to sim the classic K box with Hornresp but there is no way that i can find to properly model the K-slot section , and the Freddi-mod cavity is something that might also be tricky in Hornresp as well ..... Not to say that it isn't possible, i just haven't figured out how yet ............
I ended up just switching to Akabak to model those features .... Your Freddi-mod cavity idea does work, it works very well in fact!
it is an excellent solution for cleaning up the midbass and midrange (if trying to squeeze extreme bandwidth out of that cab) ...The offset of the driver in the main path was used to flatten the 3rd harmonic ripple, then the Freddi-mod was used to tame the 5th and 7th harmonics .... Worked like a charm! I just need to quit procrastinating and stick the K-slot on the front instead of using this silly plank aperture....damn this phoenix heat
... I could potentially extend the usable bandwidth from 600hz up to 1khz with the K-slot (if so i could then just stick one of my transformer driven 2k Frankenpiezos on it and call it a day, if it could keep up) ....
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(maybe the heat will be traded for bitter cold) - I'm not sure if the K-aperture would measure any better than your plank - but is worth investigating - I'd like a K12 for my Kappa12A but not sure what to do - experimenting in wood with movable parts would help - fwiw I think winisd gave some hints of how large to size the front chamber so the extra cavity could be guessed.
Carl N. is a great believer in the words of John Karlson and uses curved cavities per 3540544 - the little test K below has a "bass clef" shaped cavity, its vent is a gap above the laminated reflector. How does front chamber frontal aspect affect response? - have you seen noticeable changes as the front aspect is varied from classic K to tall and skinny?
when does a layout as below help?
) - I'm not sure if the K-aperture would measure any better than your plank - but is worth investigating - I'd like a K12 for my Kappa12A but not sure what to do - experimenting in wood with movable parts would help - fwiw I think winisd gave some hints of how large to size the front chamber so the extra cavity could be guessed.Carl N. is a great believer in the words of John Karlson and uses curved cavities per 3540544 - the little test K below has a "bass clef" shaped cavity, its vent is a gap above the laminated reflector. How does front chamber frontal aspect affect response? - have you seen noticeable changes as the front aspect is varied from classic K to tall and skinny?
An externally hosted image should be here but it was not working when we last tested it.
when does a layout as below help?
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oops - pasted my hak8 with simple port board instead of Carl's
An externally hosted image should be here but it was not working when we last tested it.
Freddi is a Karlson Wizard
.... hehe .... Actually , despite all of my kvetching we have had it pretty easy here this summer , the heat started late and we are about to get some relief when the monsoon rains come 
Freddi ,
Could you draw a quick x-ray sideview sketch of the bass clef shaped K box?
I wanted to say something about the "lowpass choke" in 3540544 and also what looks to be a similar extra pinch and chamber in your sketch below ..... In both cases this should add two orders (an extra chamber & vent set=2 orders) technically this would make it an 8th order K-cabinet with an added resonance somewhere and possibly some extra low pass filtering on the main path, however when i tried to simulate this in Akabak (on the Karlflex) adding the shelf didn't really seem to change anything, at least not that i could see, not to say that there wouldn't actually be some real change in real life, it is possible that the simulator just doesn't "get it"... On the other hand it might be possible to have a box that is technically 8th order but not effectively 8th order (because it still operates the same as a 6th order) ....... By the way, with a shelf in the rear chamber AND a shelf in the front chamber this would technically create a 10th order cabinet!! But is it effectively 10th order(?), only if two extra resonances are created or if there are sharper cutoffs, if i understand this correctly .....
I haven't experimented very much with the height of the K-aperture/front chamber, i mostly just stuck with 23" to 24" height (and driven at the end like a Karlsonator) because that is what the Karlflex called for BUT things have changed now with the addition of the Freddi-mod cavity which adds 14 inches + or - an inch depending on how you look at it making the front chamber around 37 inches in length (with a 90 degree bend in this case) and driven in an offset manner just past the 1/3rd point WHICH WORKS A HECK OF A LOT BETTER!
..... There is no reason why a person could not make the aperture/front chamber straight (with no 90 degree bend) and just have a tall tower-like cabinet at around 37" to 40" tall ..... At 80L net we could have a square footprint and outer dimensions of 38" x 13.5" x 13.5" using 1/2" ply ... The top of the K-slot could start about 14" to 16" down from the top ............If the slot started any higher than that it could potentially detune the freddi-mod cavity, and require it to be longer, and perhaps end up looking like the white K-box on the left side of your (Freddi's) posted picture...
NOTE: Regarding the Freddi-modded Karlflex: It is a beautiful synchronicity that in this situation the offset of the vent (the drive) on the front chamber using the Freddi-mod ends up being close to 1/3rd which mirrors the nearly 1/3rd driver offset of the main path! It wasn't planned this way , it just happened to work out this way ... How very "As Above, So below" spooky and esoteric .. I like it!
Freddi is a Karlson Wizard
Maybe if i crawl inside of my Frigidaire freezer(maybe the heat will be traded for bitter cold
.... hehe .... Actually , despite all of my kvetching we have had it pretty easy here this summer , the heat started late and we are about to get some relief when the monsoon rains come Freddi ,
Could you draw a quick x-ray sideview sketch of the bass clef shaped K box?
I wanted to say something about the "lowpass choke" in 3540544 and also what looks to be a similar extra pinch and chamber in your sketch below ..... In both cases this should add two orders (an extra chamber & vent set=2 orders) technically this would make it an 8th order K-cabinet with an added resonance somewhere and possibly some extra low pass filtering on the main path, however when i tried to simulate this in Akabak (on the Karlflex) adding the shelf didn't really seem to change anything, at least not that i could see, not to say that there wouldn't actually be some real change in real life, it is possible that the simulator just doesn't "get it"... On the other hand it might be possible to have a box that is technically 8th order but not effectively 8th order (because it still operates the same as a 6th order) ....... By the way, with a shelf in the rear chamber AND a shelf in the front chamber this would technically create a 10th order cabinet!! But is it effectively 10th order(?), only if two extra resonances are created or if there are sharper cutoffs, if i understand this correctly .....
I haven't experimented very much with the height of the K-aperture/front chamber, i mostly just stuck with 23" to 24" height (and driven at the end like a Karlsonator) because that is what the Karlflex called for BUT things have changed now with the addition of the Freddi-mod cavity which adds 14 inches + or - an inch depending on how you look at it making the front chamber around 37 inches in length (with a 90 degree bend in this case) and driven in an offset manner just past the 1/3rd point WHICH WORKS A HECK OF A LOT BETTER!
..... There is no reason why a person could not make the aperture/front chamber straight (with no 90 degree bend) and just have a tall tower-like cabinet at around 37" to 40" tall ..... At 80L net we could have a square footprint and outer dimensions of 38" x 13.5" x 13.5" using 1/2" ply ... The top of the K-slot could start about 14" to 16" down from the top ............If the slot started any higher than that it could potentially detune the freddi-mod cavity, and require it to be longer, and perhaps end up looking like the white K-box on the left side of your (Freddi's) posted picture... NOTE: Regarding the Freddi-modded Karlflex: It is a beautiful synchronicity that in this situation the offset of the vent (the drive) on the front chamber using the Freddi-mod ends up being close to 1/3rd which mirrors the nearly 1/3rd driver offset of the main path! It wasn't planned this way , it just happened to work out this way ... How very "As Above, So below" spooky and esoteric .. I like it!
Freddi is a Karlson Wizard
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here's a little 6.5" K based upon one of Carl's designs
plan - quite a bit of front chamber
https://lh6.googleusercontent.com/-...ABVY/Kn9Ql6AVzrY/w1040-h796-no/HAK6.5.GCF.PNG
result
I'd like to have a little K-coupler using the B&C 10fw64 and K-tube with compression - not sure how suitable the woofer would be -?
http://www.bcspeakers.com/products/lf-driver/10-0/10fw64
plan - quite a bit of front chamber
https://lh6.googleusercontent.com/-...ABVY/Kn9Ql6AVzrY/w1040-h796-no/HAK6.5.GCF.PNG
result
An externally hosted image should be here but it was not working when we last tested it.
I'd like to have a little K-coupler using the B&C 10fw64 and K-tube with compression - not sure how suitable the woofer would be -?
http://www.bcspeakers.com/products/lf-driver/10-0/10fw64
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Freddi,
Carl's design has a nice organic shape to it, did he happen to say what the benefit of that shape is? I am curious ....
I am guessing that the front chamber is taking up around or slightly more than 1/3rd of the total internal airspace? So a roughly 2:1 back/front chamber ratio?
The finished box is attractive.... The red is bold, I like it
I was just checking out that link for your B&C, very high EBP, very low QTS, low VAS, low moving mass, strong motor ...... These look like suitable specs for a midbass/midrange horn......
Do classic Karlsons typically do well with such low QTS drivers?
that is Marinus' little 6.5K above - I believe the purpose of the curved chamber is to try to get more energy out the aperture and reflections away from the cone - a full height aperture may work better
here's one of Carl's testboxes with a laminated veneer K-tube - he makes the boxes so they can be flat packed for storage
I think Karlson fare pretty well with low qts drivers - 12pe32 is in one of my K12s- its interesting to compare the little K vs my Advent - if you have a compression driver laying around, then make a K-tube for it
here's one of Carl's testboxes with a laminated veneer K-tube - he makes the boxes so they can be flat packed for storage
An externally hosted image should be here but it was not working when we last tested it.
I think Karlson fare pretty well with low qts drivers - 12pe32 is in one of my K12s- its interesting to compare the little K vs my Advent - if you have a compression driver laying around, then make a K-tube for it
An externally hosted image should be here but it was not working when we last tested it.
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Karlflex tower ideas
Freddi ,
That 12pe32 has an incredibly low QTS, how does it sound in the K12? does it seem to have enough warmth and bottom end to it?
Below is the idea that i mentioned about straightening out the Freddi-Mod and front chamber (instead of a 90 degree bend) on the Karlflex..... This is a rough sketch..... This idea makes for a much taller tower shaped cabinet .......
I suspect that the one on the far right would do a little better with low QTS drivers, but if a person wanted to make the front chamber considerably larger (without increasing the size of the cabinet's footprint) then the standard Karlflex format would be easier to modify for that purpose since it has the cabinet depth to support a larger front chamber .. (this particular mod to increase front chamber size would also shift the fundamental tuning upward)
NOTE: the concept sketches are not to scale, and i have not tried to sim the tower versions on the right yet... If someone was interested in building one of them i would go ahead and perform the simulations in Akabak and work out the details..
Freddi ,
That 12pe32 has an incredibly low QTS, how does it sound in the K12? does it seem to have enough warmth and bottom end to it?
Below is the idea that i mentioned about straightening out the Freddi-Mod and front chamber (instead of a 90 degree bend) on the Karlflex..... This is a rough sketch..... This idea makes for a much taller tower shaped cabinet .......
I suspect that the one on the far right would do a little better with low QTS drivers, but if a person wanted to make the front chamber considerably larger (without increasing the size of the cabinet's footprint) then the standard Karlflex format would be easier to modify for that purpose since it has the cabinet depth to support a larger front chamber .. (this particular mod to increase front chamber size would also shift the fundamental tuning upward)
NOTE: the concept sketches are not to scale, and i have not tried to sim the tower versions on the right yet... If someone was interested in building one of them i would go ahead and perform the simulations in Akabak and work out the details..
An externally hosted image should be here but it was not working when we last tested it.
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K12 vented are pretty much mid-bass creatures - 12pe32 on the stuff I listen to most such as earlier Johnny Cash albums, sounds very good - on that type of material. I would not miss the "deeper bass" of the Advent system (and I'm a big fan of Henry Kloss) - the slotted pipe tweeter is a great thing and one may prefer it to a CD-waveguide. A baffle to offset a weak low end could be added to a K-tube where one bolts to a compression driver,
I'm tossing around the idea of having Bill Woods' 70Hz horn built as a midbass toy but would consider a Karlflex - the little horn should work well for what it is but sims funky in hornresp offset driver - Bill's real horn according to his graphs did not behave that way
12pe32 is a nice little driver
I'm tossing around the idea of having Bill Woods' 70Hz horn built as a midbass toy but would consider a Karlflex - the little horn should work well for what it is but sims funky in hornresp offset driver - Bill's real horn according to his graphs did not behave that way
12pe32 is a nice little driver
Freddi,
We mix some Johnny Cash tracks into our playlist here at the house sometimes, although i think they are his later recordings ... Which older Johnny Cash album is your favorite? I wouldn't mind adding some old cash to our list
I just took a look at the Bill Woods' 70hz horn and that looks like a great design for a driver like your B&C 12PE32 , should have gobs of midband gain and obscene output! The Karlflex would probably not have as much output as that FLH, but would have more bandwidth...
By the way Freddi, i tried out the SounqubedHDS12 (A $99 sub driver with monstrous motor strength for a 12, and this sim was with the dual 2 ohm coils in series at 52v) in one of these 8th order boxes, and it gets us great output in a small cabinet but it seems that we sacrificed bandwidth ... Looks to be strictly subwoofer duty with no more than 40hz-100hz usable range, but very high output for just a bit over 100 liters net ..
An externally hosted image should be here but it was not working when we last tested it.
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besides the typical original Sun recording collections which include "Get Rhythm", I like the following album a lot http://www.amazon.com/Sings-Ballads-True-West-Johnny/dp/B00006GO9E
there oughta be some applications for a punchy/loud 8th order BP
there oughta be some applications for a punchy/loud 8th order BP
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