Freddi ,
Behind a slot the PA310 doesn't have enough upper-midrange presence, that was my experience with it ..... Not sure if the High-Q LPF would add enough presence in that scenario, i haven't experimented with that idea on the PA-310 yet (only on some 10" EV drivers in FLHs) .. .... Your Kappa 12a on the other hand has more of the rising response required to have potential behind a K-slot
..... I plan on digging into some Akabak scripts here to see if we can come up with a solid 60hz tuned K-slotted cabinet for you
Freddi ,
Behind a slot the PA310 doesn't have enough upper-midrange presence, that was my experience with it ..... Not sure if the High-Q LPF would add enough presence in that scenario, i haven't experimented with that idea on the PA-310 yet (only on some 10" EV drivers in FLHs) .. .... Your Kappa 12a on the other hand has more of the rising response required to have potential behind a K-slot
I plan on digging into some Akabak scripts here to see if we can come up with a solid 60hz tuned K-slotted cabinet for you
well Karlson's 1954 K12 was pretty much a 60Hz K (more like 63Hz tuned)
- the second version jumped on the holes & slots bandwagon with a distributed 6 slit vent. Under sine, that produces horrific overtones (I say distortion - Geddes said no = "modulated noise") the slit vent sounds good under most music conditions. If the K gets too big then power handling will be limited and excursion goes up. If the front chamber is too small , then perhaps coloration will get out of hand. What's one to do ?? I also have lively 15" which could be used in a higher tuned Karlflex. Did Karlson hit the absolute sweet spot with his approach?How does one raise tuning on the 115BK form? its about 53Hz with its 27sq.in. vent.. What happens as vent area is increased ?
when scaled, the constricted transflex model's tuning drops into the mid 40s - can that be raised a bit without changing the cabinet's bulk?
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How does one raise tuning on the 115BK form? its about 53Hz with its 27sq.in. vent.. What happens as vent area is increased ?
when scaled, the constricted transflex model's tuning drops into the mid 40s - can that be raised a bit without changing the cabinet's bulk?
Freddi ,
Increasing the vent's cross sectional area should raise the cabinet's tuning ....
increasing the vent area in your constricted transflex fudge model of the 115BK might take a double fudge - -do you think just opening the constricted area is good enough for hornresp? Can that front coupler be mated with a Karlflex rear section to any good effect ? Its about 1 cubic foot and a good sounding K-coupler.
- -do you think just opening the constricted area is good enough for hornresp? Can that front coupler be mated with a Karlflex rear section to any good effect ? Its about 1 cubic foot and a good sounding K-coupler.
increasing the vent area in your constricted transflex fudge model of the 115BK might take a double fudge
Freddi,
Double Fudge sounds delicious!
heheheIf you are confident that you want to go with a series tuned arrangement with K-slot then lets resurrect the ole Constricted Transflex discussion for this project, what say ye?
Necromancy? Yay or Nay?
The rear section of the Karlflex (or like that of the Karlsonator) with a fiber stuffed driver-offset can really help tame the response , and the "Freddi-mod" (at the top of the front chamber) could also be employed ..
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keeping HR running, inspit of MS
Hi there D. I run an older version of HR, running in a computer offline. Therefore, MS tampering has not been a factor for several years. As long as we can keep our computers operating, MS can go its own way and HR can survive. however, not having the latest updates may bother some people. thanks, again to you...regards, Michael
Hi MMJ,
Thanks for your kind words - they are much appreciated!
Unfortunately Hornresp is not immortal - it will only survive for as long as Microsoft chooses to support VB6 applications
Kind regards,David
Hi there D. I run an older version of HR, running in a computer offline. Therefore, MS tampering has not been a factor for several years. As long as we can keep our computers operating, MS can go its own way and HR can survive. however, not having the latest updates may bother some people. thanks, again to you...regards, Michael
It is built and tested at low level.
It is a ferocious beast. With only a few watts the thoroughly damped car rattled in ways he never heard a car rattle before. I am afraid of what will happen when he feeds this bass 3500 watts tomorrow.Tomorrow Saturday there will be a car audio meet at MDS outside Gothenburg, and the owner is going to measure and spl-test this monster.
With only a few watts outdoors with the mouth pointing away from our house it rattled our radiators inside our house 5 meters behind the bass.
I hope I can post some measurements and comparisons with simulation soon. I was way to tired yesterday.
Cheers,
Johannes
Johannes ,
3500 watts is a lot for a single 12!
Looking forward to hearing the reports and seeing the measurements and comparisons
Perion,
The mouth can be made larger which reduces air particle velocity ....... As an example look to post #916 ...You can copy the code from that post and paste it into a txt file and then place that file into your Hornresp import folder , then import it through Hornresp (go to "File" ---> "Import") ...
Still an issue
Thank you MMJ ! Yes, in non expanding "badass bandpass" 6th order boxes the problem is more prominent at the mouth but in 8th order boxes we have the same issue of high particule velocity at the transition from the small CSA section to the the larger CSA section, at least with very strong drivers ( they tend to like narrower paths ) at high power. In that case enlarging the mouth will not reduce velocity higher up in the horn. Therefore, in my opinion making the transition smooth ( tapered instead of stepped ) is important in that case. What do you guys think ? Have you ever encountered a case of dynamic compression with super planar enclosures ?
Thank you MMJ ! Yes, in non expanding "badass bandpass" 6th order boxes the problem is more prominent at the mouth but in 8th order boxes we have the same issue of high particule velocity at the transition from the small CSA section to the the larger CSA section, at least with very strong drivers ( they tend to like narrower paths ) at high power. In that case enlarging the mouth will not reduce velocity higher up in the horn. Therefore, in my opinion making the transition smooth ( tapered instead of stepped ) is important in that case. What do you guys think ? Have you ever encountered a case of dynamic compression with super planar enclosures ?
I could not attend the competition today, but my son reported that they hit 130 dB with only 65 watts measured from the amp, and with 500 watts they cracked the windshield.
With a fast growing crack in the windshield the enthusiasm for pushing closer to 145 dB was slightly subdued.
My son and the owner was mighty impressed by the sheer tactile power and the clean punchy bass.
It is a sound quality oriented build, so it was a great success.
He needs to wire the voice coils in parallel to get more power from the amp, but I guess he needs to replace his windshield before this.
Cheers,
Johannes
I could not attend the competition today, but my son reported that they hit 130 dB with only 65 watts measured from the amp, and with 500 watts they cracked the windshield.
With a fast growing crack in the windshield the enthusiasm for pushing closer to 145 dB was slightly subdued.
My son and the owner was mighty impressed by the sheer tactile power and the clean punchy bass.
It is a sound quality oriented build, so it was a great success.
He needs to wire the voice coils in parallel to get more power from the amp, but I guess he needs to replace his windshield before this.
Cheers,
Johannes
These are some amazing preliminary results Johannes
It would be a good idea to make sure that the driver is well run-in (broken-in) before increasing the power to extreme levels 
.. .
Perion,
These Paraflex cabinets can be built with the panels that make up the path placed at mild angles to provide a smooth expansion much like you would see with other folded horns
I personally tend to stick with all 90 degree angles if possible and stepped expansions just for a sake of simplicity , but with most of my more current Paraflex designs you will see multiple steps of expansion in the path , so in general the jumps in Cross Sectional Area are less extreme because there are smaller jumps and more of them
Take a look at the layouts in post #881 which have 3 steps of expansion .... As with any quarterwave resonator (compound or not) maximum pressure at the closed end is exchanged for maximum velocity at the mouth near the fundamental tuning (and of course a higher velocity demands more cross sectional area to avoid issues with turbulence, loss, and compression) ................... So because of this i can absolutely see the value in having an expanding path, but since we are dealing with such incredibly long waves it seems to me that steps in expansion should suffice (but I am going with a few steps as opposed to just one, if i can help it) ...
Perhaps someday we will get around to comparing a Paraflex cabinet based on the 3-step layout versus a Paraflex cabinet with a constant smooth expansion (same internal volume , same driver , same tuning etc) , just to see if the stepped cabinet shows signs of additional dynamic compression or losses in the real world
.. .... It would be a great experiment! 
Many updates to post here .... Need to catch up on stuff soon ..
The feedback we are getting from people about these compound loaded QW cabinets so far is extraordinary ....... We just had a couple of guys in the UK build a pair of Paraflex cabinets for their Lab12c drivers and they believe they are seeing at least 8db (as much as 10db) advantage over the old reflex cabinets that they had those same drivers in previously .. ... Not measured yet , just subjective based on how the subs are now keeping up with his high efficiency PA tops (and where he has to set the gains now compared to before) .... Still incredible nevertheless, but to be fair we have to point out that the Paraflex cabinets are considerably LARGER I will be posting their project photos and reports soon , along with many other plans and projects ..... Lots to catch up on ...
The feedback we are getting from people about these compound loaded QW cabinets so far is extraordinary ....... We just had a couple of guys in the UK build a pair of Paraflex cabinets for their Lab12c drivers and they believe they are seeing at least 8db (as much as 10db) advantage over the old reflex cabinets that they had those same drivers in previously .. ... Not measured yet , just subjective based on how the subs are now keeping up with his high efficiency PA tops (and where he has to set the gains now compared to before) .... Still incredible nevertheless, but to be fair we have to point out that the Paraflex cabinets are considerably LARGER
I will be posting their project photos and reports soon , along with many other plans and projects ..... Lots to catch up on ...Perion,
These Paraflex cabinets can be built with the panels that make up the path placed at mild angles to provide a smooth expansion much like you would see with other folded horns
I personally tend to stick with all 90 degree angles if possible and stepped expansions just for a sake of simplicity , but with most of my more current Paraflex designs you will see multiple steps of expansion in the path , so in general the jumps in Cross Sectional Area are less extreme because there are smaller jumps and more of them
As with any quarterwave resonator (compound or not) maximum pressure at the closed end is exchanged for maximum velocity at the mouth near the fundamental tuning (and of course a higher velocity demands more cross sectional area to avoid issues with turbulence, loss, and compression) ................... So because of this i can absolutely see the value in having an expanding path, but since we are dealing with such incredibly long waves it seems to me that steps in expansion should suffice (but I am going with a few steps as opposed to just one, if i can help it) ...
Perhaps someday we will get around to comparing a Paraflex cabinet based on the 3-step layout versus a Paraflex cabinet with a constant smooth expansion (same internal volume , same driver , same tuning etc) , just to see if the stepped cabinet shows signs of additional dynamic compression or losses in the real world
Thank you alot MMJ !
I could not attend the competition today, but my son reported that they hit 130 dB with only 65 watts measured from the amp, and with 500 watts they cracked the windshield.
With a fast growing crack in the windshield the enthusiasm for pushing closer to 145 dB was slightly subdued.
My son and the owner was mighty impressed by the sheer tactile power and the clean punchy bass.
It is a sound quality oriented build, so it was a great success.
He needs to wire the voice coils in parallel to get more power from the amp, but I guess he needs to replace his windshield before this.
Cheers,
Johannes
Nice! Where are the pics?