Freddi-Mod cavity locations
GENTLEMAN !
Since the idea was brought up recently by Schlager, Tb46, and Freddi i decided to try some experiments in Akabak using my generic simple Karlflex script by moving the Freddi-Mod cavity (stub) from the top of the box to the bottom of the box, and then combinations of both top and bottom at the same time using various cavity dimensions (adjusting height and length) ...
After mucking around with it for a while i have come to the the conclusion that a single Freddi-Mod cavity (stub) located at the bottom of the box is not very effective all by itself .... The stub is more effective if located at the end of the interchamber vent at the top of the box as has been used in the prototype and also as Freddi suggested a long time ago in an old K-cab sketch ... HOWEVER using the Freddi-Mod on the bottom of the cab in conjunction with Freddi-mod cavity stubs on top of the box seems to work really well !! ........................................................... So in other words, a Freddi-mod on the bottom all by itself is not that great, but one or two Freddi-mods on top of the cab along with one on the bottom does the trick!
GENTLEMAN !
Since the idea was brought up recently by Schlager, Tb46, and Freddi i decided to try some experiments in Akabak using my generic simple Karlflex script by moving the Freddi-Mod cavity (stub) from the top of the box to the bottom of the box, and then combinations of both top and bottom at the same time using various cavity dimensions (adjusting height and length) ...
After mucking around with it for a while i have come to the the conclusion that a single Freddi-Mod cavity (stub) located at the bottom of the box is not very effective all by itself .... The stub is more effective if located at the end of the interchamber vent at the top of the box as has been used in the prototype and also as Freddi suggested a long time ago in an old K-cab sketch ... HOWEVER using the Freddi-Mod on the bottom of the cab in conjunction with Freddi-mod cavity stubs on top of the box seems to work really well !! ........................................................... So in other words, a Freddi-mod on the bottom all by itself is not that great, but one or two Freddi-mods on top of the cab along with one on the bottom does the trick!
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Yes, i am propositioning you
TB46 ,
I really love the way your drawings look .... What would it take to get you to draw the sketch from post #1611 in your style? I can send you a few Frankenpiezo 1016s along with the step-up transformer and crossover networks that go with them I was actually just getting ready to order more transformers from Parts Express ...
TB46 ,
I really love the way your drawings look .... What would it take to get you to draw the sketch from post #1611 in your style? I can send you a few Frankenpiezo 1016s along with the step-up transformer and crossover networks that go with them
I was actually just getting ready to order more transformers from Parts Express ...
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18" driver on sale
By the way guys if anyone is in the market for an 18" driver Parts Express currently has a screaming deal on this PRV 18SW2000 on sale for $170
shipped for free.... Some of these Brazilian drivers can be very good .... The only vital parameter that was missing from PRV's list for this driver was the voicecoil inductance measurement, so i just sent a message off to Parts Express asking them to measure one of those 18SW2000s and get back to me with the "Le", specifically at 1khz ...
By the way guys if anyone is in the market for an 18" driver Parts Express currently has a screaming deal on this PRV 18SW2000 on sale for $170
shipped for free.... Some of these Brazilian drivers can be very good .... The only vital parameter that was missing from PRV's list for this driver was the voicecoil inductance measurement, so i just sent a message off to Parts Express asking them to measure one of those 18SW2000s and get back to me with the "Le", specifically at 1khz ...Hi MMJ,
I happen to like the sketch you have in Post #1611, it conveys all the necessary information.
For me it's not a matter of incentive or compensation but a matter of time. I'll probably will give it a try using your blue "Internal Dimensions", and 1/2"nom.(.469") material, but it may take a while.
I'm also "mucking" around in AkAbak (for freddi, Post #1188 etc.), and it is very slow going for me. The more detail you want the longer it seems to take? Have you had a chance of connecting a stub @ S2 (on the back side of the driver), this is where Tom Danley is connecting his ducts in the one example that was mentioned earlier (DTS-20)? Actually, he is connecting four stubs there (two ea. through a common coupler). I wonder if this applies here?
Back to the "real" work.
Regards,
I happen to like the sketch you have in Post #1611, it conveys all the necessary information.
For me it's not a matter of incentive or compensation but a matter of time. I'll probably will give it a try using your blue "Internal Dimensions", and 1/2"nom.(.469") material, but it may take a while.
I'm also "mucking" around in AkAbak (for freddi, Post #1188 etc.), and it is very slow going for me. The more detail you want the longer it seems to take?
Have you had a chance of connecting a stub @ S2 (on the back side of the driver), this is where Tom Danley is connecting his ducts in the one example that was mentioned earlier (DTS-20)? Actually, he is connecting four stubs there (two ea. through a common coupler). I wonder if this applies here?Back to the "real" work.
Regards,
HOORAY !
I am glad that you like it!
That would be fantastic!!!! and If you ever want a set of FrankenPiezos with transformers the offer still stands
I originally had 1/2" ply in mind when creating the drawings ....
Yeah, if you go with a great amount of detail (as in breaking your cabinet down into 50 different components) your script will also end up excessively large and complicated ... There is a point of diminishing returns because you just end up with more parts to manage and the potential for error increases , so i just try to keep mine as simple if i can , but there are some efforts (like modeling a K-aperture and slot) that require complexity ... Luckily for me the Aperture style "E" (from #1611) is relatively simple ...
About stubs connecting to S2 , it is basically exactly what we have in the Karlflex , the S1 section acts as a stub and also an extension to the path length .... It is the same method as offsetting your driver 1/3rd down the path in a TL or QWP , the S1 section (or the 1/3 length section) acts as a stub to suppress the third harmonic and smooth response while also contributing to the total path length ......... One third of the path length equates to the 3rd harmonic ......
We could absolutely split up the volume of the S1 section to create different path lengths (very similar to the idea of stacking Freddi-mod stubs with staggered tunings) ...
However adding and stacking more Freddi-mod cavities at the top of the cabinet (connecting to the end of the interchamber vent) is an idea that appeals to me because the cabinet's performance will improve with the added front-chamber volume.... The front chamber is key to the performance of these designs and even with a single Freddi-mod we are still not quite achieving the classic 2:1 (back:front) volume ratio............ Dual Freddi-mod stubs stacked at the top of the cabinet should be getting closer to the 2:1 back:front chamber volume ratio, but i am basically stuck with a single in my "simple Karlflex" design version in order to avoid exceeding the 24" height (staying at this height or below conserves ply material) ...
I am glad that you like it!
That would be fantastic!!!! and If you ever want a set of FrankenPiezos with transformers the offer still stands
I originally had 1/2" ply in mind when creating the drawings ....
I'm also "mucking" around in AkAbak (for freddi, Post #1188 etc.), and it is very slow going for me. The more detail you want the longer it seems to take?
Back to the "real" work.
Regards,
Yeah, if you go with a great amount of detail (as in breaking your cabinet down into 50 different components) your script will also end up excessively large and complicated ... There is a point of diminishing returns because you just end up with more parts to manage and the potential for error increases , so i just try to keep mine as simple if i can , but there are some efforts (like modeling a K-aperture and slot) that require complexity ... Luckily for me the Aperture style "E" (from #1611) is relatively simple ...
About stubs connecting to S2 , it is basically exactly what we have in the Karlflex , the S1 section acts as a stub and also an extension to the path length .... It is the same method as offsetting your driver 1/3rd down the path in a TL or QWP , the S1 section (or the 1/3 length section) acts as a stub to suppress the third harmonic and smooth response while also contributing to the total path length ......... One third of the path length equates to the 3rd harmonic ......
We could absolutely split up the volume of the S1 section to create different path lengths (very similar to the idea of stacking Freddi-mod stubs with staggered tunings) ...
However adding and stacking more Freddi-mod cavities at the top of the cabinet (connecting to the end of the interchamber vent) is an idea that appeals to me because the cabinet's performance will improve with the added front-chamber volume.... The front chamber is key to the performance of these designs and even with a single Freddi-mod we are still not quite achieving the classic 2:1 (back:front) volume ratio............ Dual Freddi-mod stubs stacked at the top of the cabinet should be getting closer to the 2:1 back:front chamber volume ratio, but i am basically stuck with a single in my "simple Karlflex" design version in order to avoid exceeding the 24" height (staying at this height or below conserves ply material) ...
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KARLFLEX VIDEO
HAPPY HALLOWEEN EVERYONE!
I made this video earlier today featuring the Karlflex and various things around my house as we listen to music during the tour .... I am just glad to find a camera with a built in microphone that didn't overload & distort too much when subjected to loud music.
https://youtu.be/krvtPAdgVnw
HAPPY HALLOWEEN EVERYONE!
I made this video earlier today featuring the Karlflex and various things around my house as we listen to music during the tour .... I am just glad to find a camera with a built in microphone that didn't overload & distort too much when subjected to loud music.
https://youtu.be/krvtPAdgVnw
HAPPY HALLOWEEN EVERYONE!
I made this video earlier today featuring the Karlflex and various things around my house as we listen to music during the tour .... I am just glad to find a camera with a built in microphone that didn't overload & distort too much when subjected to loud music.
https://youtu.be/krvtPAdgVnw
Very, very cool - thank you.
I am glad that you liked it Beau ! I don't think the sound was conveyed perfectly (i think it might be starting to compress the audio as i enter the living room) but i tried a few different cameras and this one seemed to handle the higher SPLs better than the others that we tried ...
I appreciate your drawings greatly
TB46 ,
This is awesome! You work so fast!
I can also see that you have the Fu-Manchu or Horseshoe style Aperture which works for the wider boxes Very cool ..
Thank you for doing this Sir .....
I noticed that you added the optional panel .......... The prototype box tuned so darn low to begin with i have to wonder if the official Karlflex will also tune lower than simmed , so i intentionally aimed high with it..... The optional panel (duct extension) may result in a tuning as low as 30hz FB! .... The prototype loaded with 12" driver (and aperture style E) ended up with an FB of 34hz (without the optional panel) , so i ended up making a few holes in the interchamber vent with a hole saw which effectively trims the interchamber vent down to about 5" of length and now i have a measured FB of roughly 38.5hz .... I may pull the driver out again to make a few more holes in the Interchamber vent to see if i can hit my target of 40hz tuning (which is more ideal for this light midwoofer)
....
I am glad that you liked the video, it was fun to put together....
If i ever have the time to improve my video editing skills i may produce a build-video or video tutorial or some such thing for the Karlflex.....
I also have a friend here in town that programs and operates a large CNC router table at a local shop, he has offered to make Russian Birch flatpacks for me in the past (and he did for my DC-TL tower project, and the panels were perfect), i will check in with him and see what he is up to....... He might be willing to sell and ship flatpacks to folks! (would be a great solution for people who are interested in building these cabs but don't have the power tools)...
Hi MMJ,
Cool video.
Here is a first try at a drawing of your enclosure from Post #1611 (I still think your sketch is all that needed).
Regards,
TB46 ,
This is awesome! You work so fast!
I can also see that you have the Fu-Manchu or Horseshoe style Aperture which works for the wider boxes
Very cool ..Thank you for doing this Sir .....
I noticed that you added the optional panel .......... The prototype box tuned so darn low to begin with i have to wonder if the official Karlflex will also tune lower than simmed , so i intentionally aimed high with it..... The optional panel (duct extension) may result in a tuning as low as 30hz FB! .... The prototype loaded with 12" driver (and aperture style E) ended up with an FB of 34hz (without the optional panel) , so i ended up making a few holes in the interchamber vent with a hole saw which effectively trims the interchamber vent down to about 5" of length and now i have a measured FB of roughly 38.5hz .... I may pull the driver out again to make a few more holes in the Interchamber vent to see if i can hit my target of 40hz tuning (which is more ideal for this light midwoofer)
....I am glad that you liked the video, it was fun to put together
.... If i ever have the time to improve my video editing skills i may produce a build-video or video tutorial or some such thing for the Karlflex.....
I also have a friend here in town that programs and operates a large CNC router table at a local shop, he has offered to make Russian Birch flatpacks for me in the past (and he did for my DC-TL tower project, and the panels were perfect), i will check in with him and see what he is up to....... He might be willing to sell and ship flatpacks to folks! (would be a great solution for people who are interested in building these cabs but don't have the power tools)...
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Hi Fred I.
I have the highest regard for your opinions on sound. You are both a measurement guy and you seem think the end result is more important than current audio fashion. I've noticed over the years that your interests lean more towards impact and hit rather than low bass extension. How would you categorize this new K-design? Is it a hit box or a low bass extender in your opinion?
I ask because I'm now waffling about either a Tapped Horn or a K-Flex. I'm using Altec model 19's now and would like to get an efficient bottom end set up because as happy as I am with 40Hz for casual music listening, it doesn't work long term without the bottom end.
I have the highest regard for your opinions on sound. You are both a measurement guy and you seem think the end result is more important than current audio fashion. I've noticed over the years that your interests lean more towards impact and hit rather than low bass extension. How would you categorize this new K-design? Is it a hit box or a low bass extender in your opinion?
I ask because I'm now waffling about either a Tapped Horn or a K-Flex. I'm using Altec model 19's now and would like to get an efficient bottom end set up because as happy as I am with 40Hz for casual music listening, it doesn't work long term without the bottom end.
- without one in my hands, I cant say - hopefully there's adequate "hit" in all of the designs presented by MMJ and TB46 - MMJ should be able to say for his case of PA310 and the Frankenpiezo - if one just has "hit" and no low bass extension, then one must either add a woofer/sub, be relegated to music with little bass content - or go without "deep bass - I'm having an ~90Hz midbass horn built so may have to listen to acoustic era recordings - bass got pretty strong by the late 1920s with early electric recording.
- I'm having an ~90Hz midbass horn built so may have to listen to acoustic era recordings - bass got pretty strong by the late 1920s with early electric recording.Hi freddi,
I'm still working in AkAbak for the one from Post #1188, etc.. I hope to find a little time to play around w/ ducts/stubs @ the top and @ the bottom and so on. The basic enclosure looks promising, it has the characteristics of a T-TQWT w/ a Karlson aperture. I may have to fiddle w/ the aperture to find the optimum size. So it's a back and forth between ducts/stubs/aperture, but I'm still hopefull. Just letting you know I haven't given up yet.
Regards,
I'm still working in AkAbak for the one from Post #1188, etc.. I hope to find a little time to play around w/ ducts/stubs @ the top and @ the bottom and so on. The basic enclosure looks promising, it has the characteristics of a T-TQWT w/ a Karlson aperture. I may have to fiddle w/ the aperture to find the optimum size. So it's a back and forth between ducts/stubs/aperture, but I'm still hopefull. Just letting you know I haven't given up yet.
Regards,
hi tb46 - are you seeing pretty good correlation between Akabak and hornresp? - (I've a lotta faith in McBean )
MMJ and tb46 - are taller KF variants possible - to cut front to back depth?
I've got an old Eminence/Dayton 295-070 woofer which worked pretty well in a simple pipe- it would be fun to have something with less bulk
https://www.youtube.com/watch?v=UJTctkDPKpE
)MMJ and tb46 - are taller KF variants possible - to cut front to back depth?
I've got an old Eminence/Dayton 295-070 woofer which worked pretty well in a simple pipe- it would be fun to have something with less bulk
https://www.youtube.com/watch?v=UJTctkDPKpE
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Karflex and Tapped Horn
Zelgal ,
Maybe i can help describe it.... Based upon the way my prototype sounds i would say that it has a good mixture of both impact and extension although with this light PA310 12" driver i am currently using it is best tuned as a 40hz cabinet... If you wanted more extension and a deeper tuning more along the lines of 35hz or even 33hz i would build the Karflex 100L or 120L version and load it with the Lab15-4 or the Dayton PA385S-8 .........
(if being ultimately compact is an absolute necessity you could even go with an Alpine SWS12D in a 33hz tuned 60L Karlflex which is a tiny box but won't be likely to have the same impact as using one of the 15" pro drivers listed above in the wider cab)
You mentioned a Tapped Horn as another alternative so i am assuming that you would not need the Karlflex to reach into the upper midrange correct?
A Karlflex will have a nice rich tone with those drivers balanced with impact , and will be considerably more compact than a Tapped Horn (but sacrifices a small amount of efficiency due to the cabinet size difference).
Zelgal ,
Maybe i can help describe it.... Based upon the way my prototype sounds i would say that it has a good mixture of both impact and extension although with this light PA310 12" driver i am currently using it is best tuned as a 40hz cabinet... If you wanted more extension and a deeper tuning more along the lines of 35hz or even 33hz i would build the Karflex 100L or 120L version and load it with the Lab15-4 or the Dayton PA385S-8 .........
(if being ultimately compact is an absolute necessity you could even go with an Alpine SWS12D in a 33hz tuned 60L Karlflex which is a tiny box but won't be likely to have the same impact as using one of the 15" pro drivers listed above in the wider cab)
You mentioned a Tapped Horn as another alternative so i am assuming that you would not need the Karlflex to reach into the upper midrange correct?
A Karlflex will have a nice rich tone with those drivers balanced with impact , and will be considerably more compact than a Tapped Horn (but sacrifices a small amount of efficiency due to the cabinet size difference).
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It is ALIVE!
TB46 ,
Once again AWESOME WORK!
Thank you so much for this
I am going to send you a private message so be sure to check your email when you can
TB46 ,
Once again AWESOME WORK!
Thank you so much for this
I am going to send you a private message so be sure to check your email when you can
or - "StubbyK" (does anyone remember Stubby Kaye?https://www.youtube.com/watch?v=_TfcJ82FAhw )