Matthew, i have been looking at Hornresp and came up with this.
Data for the Box 130 liter
FR with a low knee of 35 hz and 116 dB
X max like this
This speaker will be a bit big and will usually be pushed up against the backwall. So I was wondering if FR will close in on Ang = 1 ?
That would gain maybe 3-5 dB extra SPL?
Cheers
Data for the Box 130 liter
FR with a low knee of 35 hz and 116 dB
X max like this
This speaker will be a bit big and will usually be pushed up against the backwall. So I was wondering if FR will close in on Ang = 1 ?
That would gain maybe 3-5 dB extra SPL?
Cheers
Hi there TB46!
I haven't tried the Large Voice Coil feature yet , i need to go download the newest version of Hornresp and check that out ...
I have been following up on a few ideas that you had mentioned or included when making Karlflex sketches a while back (like using extra stuffing/lining, and the way to apertures extend etc) , i am testing things in the real world with this prototype cab as i continue to chop it up and change it around and measure and listen and measure again
, and progress is being made! 
I just wanted to say thanks again for all of the design ideas and also the work that you put into those fantastic sketches 🙂
Rumblings and ramblings
Thank you 😀
Thats just a technique some people use with HR in an attempt to emulate what the response will really look like in real life , I think it was someone here on DIYaudio that came up with it, and it is still kind of controversial ....... It was a response to the fact that people were building tapped horns based upon HR sims that showed underdamped saddle shaped responses , but when built the cabinets played fairly flat in real life (or someone who built a cabinet based upon a sim that had flat response , yet when the real cab is measured they find out that the cabinet had an overdamped hump shaped response .... )....... I have heard a few theories attempting to explain why this virtual/actual discrepancy occurs, some people blame it upon panel flex and lack of bracing, other people say it revolves around the way HR factors Le into it's calculations and they mention the fact that Le changes with frequency...... I have a good example of that with my DATS unit, i can measure a voicecoil's inductance at either 1khz or 10khz (1k is industry standard i believe) , and with my PA310 driver i get .6mh @10khz and 1.6mh @ 1khz ....
I think it is standard practice to measure SD (cone area in square centimeters) by including half the width of the surround along with the cone .... Most of the pro 15" drivers with accordion surround end up with an SD figure in the mid 800s with the majority falling in between 840 and 870 .... Occasionally i will see as low as 800 or as high as 900 but those are much less common ....
If the manufacturer doesn't give you an SD figure to work with just plug your approximated SD into HR then get your other parameters like QTS, VAS, FS as close as you can to what is published, you may find that the BL factor or MMD ends up being off the mark by a small percentage but don't sweat it, this is about as close as we can get without having someone measure the actual driver.............................................. Getting a driver measured is of course always ideal since the real parameters are often somewhat different than what is published. The sample 15LB100 that folks at "The Box" brand measured a few years ago might not be exactly what they sell today because over the years their OEM may have started using a different voicecoil former, or a different spider, a different cone treatment, or whatever , you get the idea ....
We are also all over the spectrum on our listening tastes here at the house🙂 but yes , you are correct as with most (but not all) music there is just "unrecognizable rumble" below 40hz and yes, you are right, perhaps it does add something to the mood or the ambiance of the experience but at the same time i think that most people don't realize that having a system which is flat down to 40hz (or even 45hz for that matter) can have a deep sounding tone and produce some very satisfying low notes ...
I think there is some confusion regarding this subject due to the tendency of some speaker manufacturing brands to stretch the truth for marketing purposes .... Cerwin Vega for example sells these front loaded horns with expanding path lengths of between 5 and 7 feet long and CV claims that these boxes have bass extension reaching down into the low 30s but what their marketing department intentionally fails to point out is the fact that these things generally don't sound good unless you use them in multiples of four or more .... As a single cab you get very little down at 30hz , in fact the output that you do get down at 30hz is miniscule compared to what you get at 80hz because of the outlandish rising response ... Trying to improperly use a single CV bass horn loaded with crummy driver means you end up with something that sounds like Gallagher repeatedly hitting an empty cardboard box with a baseball bat! yuck !
............ So somebody who hears such a trainwreck might think to themselves: " If that is what 30hz extension sounds like then i must need 20hz response to get the deep sound i want!" .......... 
That is an extreme example of course 😛 , but i have heard people say the same thing about the rising response on some of the BFM bass horns like the T48, which are tremendously efficient at 100hz and that is great if i am only trying to reproduce sounds in the range of 80 to 120hz🙄 but of course that is not the case so EQ or crossovers are adjusted to even things out and your "headroom" and maximum output still remain limited by your capabilities in the subbass range if you want reasonably flat response...
*end of rant*
ANYWAY, yes , shooting for a 40hz FB makes designing easier in regards to getting strong output from a small cabinet using a driver with limited xmax .... Some of the cabinets i have designed recently have 35hz tunings but generally those were for drivers like the Lab15-4 or the PA385S which are capable of more excursion .... I also recently designed an ML-Transflex tuned to 30hz for a friend in Texas , but it was for an 18" driver with high xmax rating ...
Thank you 😀
Thats just a technique some people use with HR in an attempt to emulate what the response will really look like in real life , I think it was someone here on DIYaudio that came up with it, and it is still kind of controversial ....... It was a response to the fact that people were building tapped horns based upon HR sims that showed underdamped saddle shaped responses , but when built the cabinets played fairly flat in real life (or someone who built a cabinet based upon a sim that had flat response , yet when the real cab is measured they find out that the cabinet had an overdamped hump shaped response .... )....... I have heard a few theories attempting to explain why this virtual/actual discrepancy occurs, some people blame it upon panel flex and lack of bracing, other people say it revolves around the way HR factors Le into it's calculations and they mention the fact that Le changes with frequency...... I have a good example of that with my DATS unit, i can measure a voicecoil's inductance at either 1khz or 10khz (1k is industry standard i believe) , and with my PA310 driver i get .6mh @10khz and 1.6mh @ 1khz ....
I think it is standard practice to measure SD (cone area in square centimeters) by including half the width of the surround along with the cone .... Most of the pro 15" drivers with accordion surround end up with an SD figure in the mid 800s with the majority falling in between 840 and 870 .... Occasionally i will see as low as 800 or as high as 900 but those are much less common ....
If the manufacturer doesn't give you an SD figure to work with just plug your approximated SD into HR then get your other parameters like QTS, VAS, FS as close as you can to what is published, you may find that the BL factor or MMD ends up being off the mark by a small percentage but don't sweat it, this is about as close as we can get without having someone measure the actual driver.............................................. Getting a driver measured is of course always ideal since the real parameters are often somewhat different than what is published. The sample 15LB100 that folks at "The Box" brand measured a few years ago might not be exactly what they sell today because over the years their OEM may have started using a different voicecoil former, or a different spider, a different cone treatment, or whatever , you get the idea ....
We are also all over the spectrum on our listening tastes here at the house🙂 but yes , you are correct as with most (but not all) music there is just "unrecognizable rumble" below 40hz and yes, you are right, perhaps it does add something to the mood or the ambiance of the experience but at the same time i think that most people don't realize that having a system which is flat down to 40hz (or even 45hz for that matter) can have a deep sounding tone and produce some very satisfying low notes ...
I think there is some confusion regarding this subject due to the tendency of some speaker manufacturing brands to stretch the truth for marketing purposes .... Cerwin Vega for example sells these front loaded horns with expanding path lengths of between 5 and 7 feet long and CV claims that these boxes have bass extension reaching down into the low 30s but what their marketing department intentionally fails to point out is the fact that these things generally don't sound good unless you use them in multiples of four or more .... As a single cab you get very little down at 30hz , in fact the output that you do get down at 30hz is miniscule compared to what you get at 80hz because of the outlandish rising response ... Trying to improperly use a single CV bass horn loaded with crummy driver means you end up with something that sounds like Gallagher repeatedly hitting an empty cardboard box with a baseball bat! yuck !
............ So somebody who hears such a trainwreck might think to themselves: " If that is what 30hz extension sounds like then i must need 20hz response to get the deep sound i want!" .......... That is an extreme example of course 😛 , but i have heard people say the same thing about the rising response on some of the BFM bass horns like the T48, which are tremendously efficient at 100hz and that is great if i am only trying to reproduce sounds in the range of 80 to 120hz🙄 but of course that is not the case so EQ or crossovers are adjusted to even things out and your "headroom" and maximum output still remain limited by your capabilities in the subbass range if you want reasonably flat response...
*end of rant*
ANYWAY, yes , shooting for a 40hz FB makes designing easier in regards to getting strong output from a small cabinet using a driver with limited xmax .... Some of the cabinets i have designed recently have 35hz tunings but generally those were for drivers like the Lab15-4 or the PA385S which are capable of more excursion .... I also recently designed an ML-Transflex tuned to 30hz for a friend in Texas , but it was for an 18" driver with high xmax rating ...
Last edited:
Sebastian,
That curve looks about right now 🙂
and yes, that is correct, sitting on the ground and pushed up against a wall would be quarterspace or 1pi , and yes it will show more output on the bottom end 🙂 , it is boundary gain or room gain ... The only reason i stick with halfspace on my sims is to make sure sure i am not comparing apples to oranges if you know what i mean, it just makes for fair comparisons ...
wonder what would be more fun - the little Karlflex? - or RCA-Fan's 123 liter (~160l bulk) 70Hz horn? I think hinged mouth extension might be used on the horn - would that screw-up a K? - could just have hinged side panels to make the front wider - does that have any use other than potentially creating a rattletrap?
here's an optimistic and non-offset driver sim for the horn at 1W/2pi - the offset model gives deep dips not present in the real horn
here's an optimistic and non-offset driver sim for the horn at 1W/2pi - the offset model gives deep dips not present in the real horn
GOOD NEWS!
Oh the RCA-Fan horn! I looked at those designs recently ... Very loud and kicky! Seems like your Kappa looks good in one , almost usable out to 1k 🙂
Big hinged barndoor flare panels could be interesting on a K box .... hmm ....
Freddi, I HAVE SOME GOOD NEWS! , I pulled the driver out of the prototype Karlflex a few days ago then i blocked off the vent leading to the parasitic chamber , then put the driver back in and glued on the K-aperture panels (using PL , so it is permanent now) , then i also went ahead and blocked off the parasitic chamber's vent on the front of the box as well, in other words that parasitic chamber is basically disconnected from the system........ So as of today i am finally listening to a simple 60-ish liter Karlflex!!
STILL HAS PLENTY OF BASS! It has enough to keep up with the mids even though my FB is currently tuned wayyy too low at around 33 or 34hz right now (with a closed K-slot and just a big open terminus only directly in front of the driver's cone .... Apparently the internal vent can be made a heck of a lot shorter in the final build !
I will have to go back into Akabak and recalculate this vent length ..
I have managed to get a few measurements even though my microphones phantom power supply is acting flaky today (hopefully it is not the mic itself
) ... Response still looks good (just lacks the bump centered around 68hz that was generated by the para-chamber), phase response also still looks great ...
Oh the RCA-Fan horn! I looked at those designs recently ... Very loud and kicky! Seems like your Kappa looks good in one , almost usable out to 1k 🙂
Big hinged barndoor flare panels could be interesting on a K box .... hmm ....
Freddi, I HAVE SOME GOOD NEWS! , I pulled the driver out of the prototype Karlflex a few days ago then i blocked off the vent leading to the parasitic chamber , then put the driver back in and glued on the K-aperture panels (using PL , so it is permanent now) , then i also went ahead and blocked off the parasitic chamber's vent on the front of the box as well, in other words that parasitic chamber is basically disconnected from the system........ So as of today i am finally listening to a simple 60-ish liter Karlflex!!
STILL HAS PLENTY OF BASS! It has enough to keep up with the mids even though my FB is currently tuned wayyy too low at around 33 or 34hz right now (with a closed K-slot and just a big open terminus only directly in front of the driver's cone .... Apparently the internal vent can be made a heck of a lot shorter in the final build !
I will have to go back into Akabak and recalculate this vent length ..
I have managed to get a few measurements even though my microphones phantom power supply is acting flaky today (hopefully it is not the mic itself
) ... Response still looks good (just lacks the bump centered around 68hz that was generated by the para-chamber), phase response also still looks great ...
Last edited:
that is good news on the simplified K-flex having kicky output even with low tuning - can you see a way to make the vent length adjustable without a removable back panel?
Last edited:
I would think they are professionals, so maybe they have remeasured the driver, don't you think 😛
Yes you are right. I believe very much it has something to do about how dynamic and transientwise the bass is produced. Of cause spl also play a part. For example I have some basshorn, looks like this:
Hey kids get out of my horns, are you deaf ? 😀They are wimpy 15" drivers 30 $ a pice but F.....H... they slam, even with lowcut at 40 hz. So yes, I think you can get good bass without the superlow hz.
Speaking of super cool old-timey shtuff
Great old article snippet! 16 cycles as claimed? That truly is a bold claim 😛
They definitely got that other part about "They show up well on percussive sounds" correct ...
Subjectively terms like kicky, dynamic and fast can be used to describe this sound and yet there is still plenty of support for the low notes as well which are also conveyed with detail .......... That RCA-FAN horn is even kickier and certainly louder but lacks the support for the low notes, and that is the compromise ...... The reason i knew about that particular horn is because a friend of mine was planning on building some to be used as "kick-bins" in some uber multi-way system, and they would be perfect for that application🙂...
I personally also use Front Loaded Horns as "kick bins" in one of my sound systems here at my place in Arizona , it is a four-way system sitting in my living room right now .... The kick-bins are just old CV b36a cabinets (5 foot path), I modified them to shrink the back chamber (i did it using closed-cell foam blocks) and these cabs work really well from about 80hz on out to around 240hz where the EV midhorns take over ................................ The entire system is basically made out of old cabinets that i ended up with when local nightclubs and bars discarded them (as they upgraded and updated), i gladly took whatever they were giving away and did some refurbishing so i could in turn use them to cobble together this old-school system ........ The whole project definitely took a number of years to complete (the transformer driven FrankenPiezo arrays are part of this system) and now i have something that not only works great but is loaded with novelty value as well!! 😛 hehe ...................... Too bulky to be considered portable (for small events) by today's standards in my opinion, so it just sits in our living room and gets used for music, movies, video games and house parties 🙂
The Karlflex cabs on the other hand will be our portable set😀
that is good news on the simplified K-flex having kicky output even with low tuning - can you see a way to make the vent length adjustable without a removable back panel?
Great old article snippet! 16 cycles as claimed? That truly is a bold claim 😛
They definitely got that other part about "They show up well on percussive sounds" correct ...
Subjectively terms like kicky, dynamic and fast can be used to describe this sound and yet there is still plenty of support for the low notes as well which are also conveyed with detail .......... That RCA-FAN horn is even kickier and certainly louder but lacks the support for the low notes, and that is the compromise ...... The reason i knew about that particular horn is because a friend of mine was planning on building some to be used as "kick-bins" in some uber multi-way system, and they would be perfect for that application🙂...
I personally also use Front Loaded Horns as "kick bins" in one of my sound systems here at my place in Arizona , it is a four-way system sitting in my living room right now .... The kick-bins are just old CV b36a cabinets (5 foot path), I modified them to shrink the back chamber (i did it using closed-cell foam blocks) and these cabs work really well from about 80hz on out to around 240hz where the EV midhorns take over ................................ The entire system is basically made out of old cabinets that i ended up with when local nightclubs and bars discarded them (as they upgraded and updated), i gladly took whatever they were giving away and did some refurbishing so i could in turn use them to cobble together this old-school system ........ The whole project definitely took a number of years to complete (the transformer driven FrankenPiezo arrays are part of this system) and now i have something that not only works great but is loaded with novelty value as well!! 😛 hehe ...................... Too bulky to be considered portable (for small events) by today's standards in my opinion, so it just sits in our living room and gets used for music, movies, video games and house parties 🙂
The Karlflex cabs on the other hand will be our portable set😀
Last edited:
Nice with all these cabinets for free 😛 That never happens where I'm from 🙁
I like your trick with the foam blocks. Please post some pictures of your 4-way system, love that old cool stuff.
By the way I found an interesting driver for my paperhorns that can reach to 200hz. It's an 8" and it claims to do 19500hz. HMM pretty high for such a big driver. Looks like this:
FR
Modelled in hornresp it will do 120 db at 200 hz at 20v, nice.
But maybe I will need a phase plug, or HF will cancel ??
That way I can keep the Karlflex simple. Or will I lose out to much?
I like your trick with the foam blocks. Please post some pictures of your 4-way system, love that old cool stuff.
By the way I found an interesting driver for my paperhorns that can reach to 200hz. It's an 8" and it claims to do 19500hz. HMM pretty high for such a big driver. Looks like this:
FR
Modelled in hornresp it will do 120 db at 200 hz at 20v, nice.
But maybe I will need a phase plug, or HF will cancel ??
That way I can keep the Karlflex simple. Or will I lose out to much?
Not sure how i could make that vent easily accessible for adjustment , i just plan to make it much shorter , i need to shift FB upward by 6 to 8hz..
Little people in your horns! =P
Sebastian,
I would hope that they would, i know i would if i were manufacturing these things, after all it is the responsible thing to do right? ........ MCM is usually way off the mark on published specs which is no surprise , they are notorious for that, so no shocker there, but a friend off of DIYaudio recently acquired some large B&C drivers which measured considerably different than what is published and that was a big surprise since B&C has such a great reputation in the industry and makes such excellent products ..
Crazy kids! Your too young to rave!
.....
Are those your bass horns? It looks like you have an infestation of children in your horns
Nice usage of the "v-plate" technique
Sebastian,
I would hope that they would, i know i would if i were manufacturing these things, after all it is the responsible thing to do right? ........ MCM is usually way off the mark on published specs which is no surprise , they are notorious for that, so no shocker there, but a friend off of DIYaudio recently acquired some large B&C drivers which measured considerably different than what is published and that was a big surprise since B&C has such a great reputation in the industry and makes such excellent products ..
[/QUOTE]Yes you are right. I believe very much it has something to do about how dynamic and transientwise the bass is produced. Of cause spl also play a part. For example I have some basshorn, looks like this:
View attachment 504185
They are wimpy 15" drivers 30 $ a pice but F.....H... they slam, even with lowcut at 40 hz. So yes, I think you can get good bass without the superlow hz.
Crazy kids! Your too young to rave!
.....
Are those your bass horns? It looks like you have an infestation of children in your horns
Nice usage of the "v-plate" technique
haha on the kids - better I guess than a mice infestation😀 - - I'm thinking of having my cutter do RCA-fan's 70Hz horn for a little reference item - - a Karlflex12 would be welcome as an alternative if some basic dims were posted -re: tuning if the vent sat on side cleats then perhaps it could be accessed from the cutout (?)
I know a guy who knows a guy
It is not normal here either, i was just lucky enough to know the right people and to be in the right place at the right time .... I used to help many of the bar owners and nightclub folks with their sound systems back in those days ...
Sure thing! I will post some pics in a bit 🙂
The big closed cell styrofoam blocks were being thrown out by the local "Lowes" store (a large warehouse style store for contractors and the general public and a great place to buy materials for DIY home improvements etc, do they have such places in Denmark?) ...
The foam blocks were used as some sort of packing materials in the shipments the store receives, so after they unload the trucks they don't need the styrofoam anymore, and it just gets discarded .... I think this stuff is somewhat more dense than standard styrofoam but still super light and very easy to work with .. .
Marketing claims of useful response up to nearly 20,000hz from an 8" driver is suspicious , not entirely impossible but unlikely, and above 4khz or 5khz it would be terribly "beamy" (lack of dispersion) so yes a phase plug would be needed ...... Any bandpass effects or spectral "tilt" added by the horn design will likely take away from the higher frequencies produced by that driver so unless it has a naturally rising response the "tilt" will need to be compensated for ...
.....
A Karlflex loaded with a 15LB100 driver will get you up pretty high (at least 700hz , but probably more like 1khz or 2khz) so that gives you many different options for your mid-high section 🙂
Ever consider a line array for your mids and highs? I have found some dirt-cheap drivers that perform well and can be arranged in a vertical line of four or more to get your 100db+ @1w/1m ...
It is not normal here either, i was just lucky enough to know the right people and to be in the right place at the right time .... I used to help many of the bar owners and nightclub folks with their sound systems back in those days ...
Sure thing! I will post some pics in a bit 🙂
The big closed cell styrofoam blocks were being thrown out by the local "Lowes" store (a large warehouse style store for contractors and the general public and a great place to buy materials for DIY home improvements etc, do they have such places in Denmark?) ...
The foam blocks were used as some sort of packing materials in the shipments the store receives, so after they unload the trucks they don't need the styrofoam anymore, and it just gets discarded .... I think this stuff is somewhat more dense than standard styrofoam but still super light and very easy to work with .. .
Marketing claims of useful response up to nearly 20,000hz from an 8" driver is suspicious , not entirely impossible but unlikely, and above 4khz or 5khz it would be terribly "beamy" (lack of dispersion) so yes a phase plug would be needed ...... Any bandpass effects or spectral "tilt" added by the horn design will likely take away from the higher frequencies produced by that driver so unless it has a naturally rising response the "tilt" will need to be compensated for ...
.....
A Karlflex loaded with a 15LB100 driver will get you up pretty high (at least 700hz , but probably more like 1khz or 2khz) so that gives you many different options for your mid-high section 🙂
Ever consider a line array for your mids and highs? I have found some dirt-cheap drivers that perform well and can be arranged in a vertical line of four or more to get your 100db+ @1w/1m ...
As requested
Sebastian ,
Here are some pictures of our cobbled together and refurbished 4-way living room horn system ....
You can see the 4 element transformer driven Frankenpiezo arrays mounted within the fronts of the midrange horns ... The mid horns are made by Electrovoice and contain a 10" woofer which covers about 240hz on up to 2khz , and below those you see the CV B36a cabs which are 36" x 24" x 24" with 5' path containing an 18" driver with light cone and high FS, these are actually decent from 80hz on up to around 240hz where the EV midhorn takes over .. .
The sub in the middle is a clone of an old CV design with 7' path (36" x 24" x36") and is good down to about 45hz (not 30hz as claimed, sorry CV) , the club that used this cabinet first blew the plate amplifier so it had to be bypassed, then ended up blowing out the driver, replaced it, and then they blew out the driver AGAIN .... Djs can be terribly rough on equipment , they tend to hook up things improperly and then attempt to force the equipment to do things the equipment wasn't meant to do which of course causes failures.... We ended up getting some double 18 cabs for that club and this horn cab ended up in my lap .... I loaded a reconed Peavey Low-Max 18 driver into it and it has worked ever since ..... We have thrown 1000 watts of thumpy music at this thing all night long on party nights with no problems at all, and it has generated it's share of noise complaints and visits from the local police on those nights
...
That was back during the end of our moreso wild phase in life which was only about 5 years ago.. As of late this sub has a very easy life and rarely gets played at high levels anymore ...... It has served it's purpose well enough for what i consider a "dated" 4th order design but honestly the 6th order series tuned tech discussed in these forums such as tapped horns, and Transflex cabs (including Karlflex ,Karlsonator, or a scaled up Xki etc) (with the right drivers) are capable of more performance in a smaller package ....
I just noticed that there are some cobwebs in the mouth of the sub horn , i should probably clean that😛 .... Your horns are infested with children and mine are infested with spiders ...
NOTE: cats love to use these old carpeted cabinets as scratching posts!
🤐
Sebastian ,
Here are some pictures of our cobbled together and refurbished 4-way living room horn system ....
An externally hosted image should be here but it was not working when we last tested it.
You can see the 4 element transformer driven Frankenpiezo arrays mounted within the fronts of the midrange horns ... The mid horns are made by Electrovoice and contain a 10" woofer which covers about 240hz on up to 2khz , and below those you see the CV B36a cabs which are 36" x 24" x 24" with 5' path containing an 18" driver with light cone and high FS, these are actually decent from 80hz on up to around 240hz where the EV midhorn takes over .. .
An externally hosted image should be here but it was not working when we last tested it.
The sub in the middle is a clone of an old CV design with 7' path (36" x 24" x36") and is good down to about 45hz (not 30hz as claimed, sorry CV) , the club that used this cabinet first blew the plate amplifier so it had to be bypassed, then ended up blowing out the driver, replaced it, and then they blew out the driver AGAIN .... Djs can be terribly rough on equipment , they tend to hook up things improperly and then attempt to force the equipment to do things the equipment wasn't meant to do which of course causes failures.... We ended up getting some double 18 cabs for that club and this horn cab ended up in my lap .... I loaded a reconed Peavey Low-Max 18 driver into it and it has worked ever since ..... We have thrown 1000 watts of thumpy music at this thing all night long on party nights with no problems at all, and it has generated it's share of noise complaints and visits from the local police on those nights
...That was back during the end of our moreso wild phase in life which was only about 5 years ago.. As of late this sub has a very easy life and rarely gets played at high levels anymore ...... It has served it's purpose well enough for what i consider a "dated" 4th order design but honestly the 6th order series tuned tech discussed in these forums such as tapped horns, and Transflex cabs (including Karlflex ,Karlsonator, or a scaled up Xki etc) (with the right drivers) are capable of more performance in a smaller package ....
I just noticed that there are some cobwebs in the mouth of the sub horn , i should probably clean that😛 .... Your horns are infested with children and mine are infested with spiders ...
NOTE: cats love to use these old carpeted cabinets as scratching posts!
🤐
Last edited:
Sketch and current prototype measurement for Freddi
Freddi ,
Here is a concept for the revamped simple Karlflex, this will definitely get us a higher tuning ..... It is meant to have a very narrow K-slot or a lack of K-slot and just a large mouth open in front of the driver's cone (which is how i am currently running the prototype and it seems to produce the best bottom end with this undersized front chamber) ... I will fix up one of my Akabak scripts to emulate what you see in the sketch to verify that the offset and tuning is correct etc ....
Offset stub (s1) section is 4" across internal, and the internal height of the Freddi-mod cavity and main vent are both 2.5" each ... Distance between top of baffle and the back of the front panel (defining the front chamber) is 3.5" ..
and here is a measurement of the prototype as it is right now ... . I suspect i might be getting a little bit of room gain here because this is an undersized cabinet for such a low tuning, i expected the bottom end to be a few more decibels down from this based upon sims , but hey i am not complaining! 😀 ...... This is with the Dayton mic which i think is sadly giving up the ghost little by little , it only works half the time as if i dropped it or something but i don't recall dropping it or getting it wet or anything *shrug*, i tried a few different phantom supplies and the mic still seems intermittent regardless of what supply i use on it ..... Luckily i have a backup mic i can use until i replace the Dayton ....
The dip at 300hz will hopefully fill in to some degree when we get the FB shifted up .... That lump in response that you see centered around 210hz is the upper odd harmonic resonances (the 5th perhaps) which will shift upwards when the fundamental is made higher therefore helping to fill in that dip..
Freddi ,
Here is a concept for the revamped simple Karlflex, this will definitely get us a higher tuning ..... It is meant to have a very narrow K-slot or a lack of K-slot and just a large mouth open in front of the driver's cone (which is how i am currently running the prototype and it seems to produce the best bottom end with this undersized front chamber) ... I will fix up one of my Akabak scripts to emulate what you see in the sketch to verify that the offset and tuning is correct etc ....
Offset stub (s1) section is 4" across internal, and the internal height of the Freddi-mod cavity and main vent are both 2.5" each ... Distance between top of baffle and the back of the front panel (defining the front chamber) is 3.5" ..
An externally hosted image should be here but it was not working when we last tested it.
and here is a measurement of the prototype as it is right now ... . I suspect i might be getting a little bit of room gain here because this is an undersized cabinet for such a low tuning, i expected the bottom end to be a few more decibels down from this based upon sims , but hey i am not complaining! 😀 ...... This is with the Dayton mic which i think is sadly giving up the ghost little by little , it only works half the time as if i dropped it or something but i don't recall dropping it or getting it wet or anything *shrug*, i tried a few different phantom supplies and the mic still seems intermittent regardless of what supply i use on it ..... Luckily i have a backup mic i can use until i replace the Dayton ....
An externally hosted image should be here but it was not working when we last tested it.
The dip at 300hz will hopefully fill in to some degree when we get the FB shifted up .... That lump in response that you see centered around 210hz is the upper odd harmonic resonances (the 5th perhaps) which will shift upwards when the fundamental is made higher therefore helping to fill in that dip..
great details - hopefully you can get a bit more backwave/vent fill around 300 - is the offset stub's distance to the bottom of the cabinet also exactly 4"?
I'm surprised by PA-310-8's on-axis high frequency extension in the Karlflex prototype.
are the dimensions given external? - if so are they for 1/2" panels?
I'm surprised by PA-310-8's on-axis high frequency extension in the Karlflex prototype.
are the dimensions given external? - if so are they for 1/2" panels?
"but a friend off of DIYaudio recently acquired some large B&C drivers which measured considerably different than what is published and that was a big surprise since B&C has such a great reputation in the industry and makes such excellent products .. "
Driver equivalency check:
(Qts^2) times Vas should be within ±10% or better.
Fs/Qts should be within ±10% or better.
That will take about 30 seconds, then you can do a Hornresp or WinISD design if you want a crosscheck.
Driver equivalency check:
(Qts^2) times Vas should be within ±10% or better.
Fs/Qts should be within ±10% or better.
That will take about 30 seconds, then you can do a Hornresp or WinISD design if you want a crosscheck.
K-hump? hmmm..... Needs a more marketable name =P
Correct , 4" between the internal face of the bottom panel and the bottom of the S1 panel or at least that is how i sketched it , after running the numbers in Akabak i might find out that an inch or two may need to be trimmed off of the bottom of that S1 panel to get the offset dialed-in just right for smooth response around the third harmonic.
Right , it looks pretty good up to around 5khz on axis, but as soon as you move off-axis it becomes apparent that the PA-310 starts to get get beamy and lose dispersion above 2khz ..... So i think that this system would be good with the PA310 low passed at 2khz and then a good high frequency driver with a sensitivity of between 96db to 100db @1w/1m would need to take over at 2khz ...
At first i was using one of my 2k Frankenpiezos (very similar to and based upon what Brian Steele discovered a few years ago by combining GRS and Goldwood 1016 components) .... The plain Frankenpiezo 1016 by itself wasn't quite loud enough to keep up with the Karlflex, it was falling at least 3db short maybe more , so then i decided to use one of my transformer networks to drive the Frankenpiezo and bingo! Now the highs were perhaps a few decibels hot so i lowered the swamping resistor value from 400 ohms to 200 ohms and now it sounds about right 🙂
If i were to go with something other than my Frankens i might be tempted by something like this (if they will actually handle enough power):
Tymphany H25TG05-08 1" Titanium Dome Tweeter with Waveguide 8 Ohm
Freddi, your slit K-tube might also be a good solution if it gets fairly flat ..
Yessir , that is correct .... The dimensions in black at the bottom are external using 1/2 inch ply panels ........
Bracing will be the standard bifurcation style holed bracing like i used in the prototype .... The final sketch set will include bracing examples and also stuffing/lining depiction ...
The mouth shape that i have ended up with really cannot be called a K-slot necessarily because it isn't really shaped like a slot, more like a K-radius or K-hump hehe , but in it's defense it works better than any other shape i have tried so far ...... It is time to rip the cardboard, duct tape and clamps off of the front of this thing so i can glue on a proper panel and post a decent looking picture for you guys 🙂
Correct , 4" between the internal face of the bottom panel and the bottom of the S1 panel or at least that is how i sketched it , after running the numbers in Akabak i might find out that an inch or two may need to be trimmed off of the bottom of that S1 panel to get the offset dialed-in just right for smooth response around the third harmonic.
Right , it looks pretty good up to around 5khz on axis, but as soon as you move off-axis it becomes apparent that the PA-310 starts to get get beamy and lose dispersion above 2khz ..... So i think that this system would be good with the PA310 low passed at 2khz and then a good high frequency driver with a sensitivity of between 96db to 100db @1w/1m would need to take over at 2khz ...
At first i was using one of my 2k Frankenpiezos (very similar to and based upon what Brian Steele discovered a few years ago by combining GRS and Goldwood 1016 components) .... The plain Frankenpiezo 1016 by itself wasn't quite loud enough to keep up with the Karlflex, it was falling at least 3db short maybe more , so then i decided to use one of my transformer networks to drive the Frankenpiezo and bingo! Now the highs were perhaps a few decibels hot so i lowered the swamping resistor value from 400 ohms to 200 ohms and now it sounds about right 🙂
If i were to go with something other than my Frankens i might be tempted by something like this (if they will actually handle enough power):
Tymphany H25TG05-08 1" Titanium Dome Tweeter with Waveguide 8 Ohm
Freddi, your slit K-tube might also be a good solution if it gets fairly flat ..
Yessir , that is correct .... The dimensions in black at the bottom are external using 1/2 inch ply panels ........
Bracing will be the standard bifurcation style holed bracing like i used in the prototype .... The final sketch set will include bracing examples and also stuffing/lining depiction ...
The mouth shape that i have ended up with really cannot be called a K-slot necessarily because it isn't really shaped like a slot, more like a K-radius or K-hump
hehe , but in it's defense it works better than any other shape i have tried so far ...... It is time to rip the cardboard, duct tape and clamps off of the front of this thing so i can glue on a proper panel and post a decent looking picture for you guys 🙂
a K-tube with something like a P-Audio BM440 with subjectively keep up with a 12pe32 in a Karlson 12 and also with 2-2035H in a JBL 4638. - - on the driver equivalency, I've got Nirvana Super8s' whose fs and qts have crept up from the upper 40's and 0.26 to 73Hz and 0.34 - something has stiffened in their suspension
does the 18.25" depth include a 1/2" thick aperture plate?
how long would you guess for the vent? - if I get one built, the aperture will probably look more K-like ;^)
does the 18.25" depth include a 1/2" thick aperture plate?
how long would you guess for the vent? - if I get one built, the aperture will probably look more K-like ;^)
Last edited: