Very nice!
Tb,
Your sim looks like a great 120db 30hz tuned box, and the drawings are excellent as your drawings always are
To make this into a 35hz tuned box all that has to be done is to flip the Karlson Aperture upside down It shortens the main path length and adds parallel tuned action , you end up with about 123db output , a few more volts of power handling and a knee at 35hz..
I like your idea of countersinking the drivers so there is no risk of the frame's raised rim choking the aperture, and yes, bracing would be a highly recommended.
Tb,
Your sim looks like a great 120db 30hz tuned box, and the drawings are excellent as your drawings always are
To make this into a 35hz tuned box all that has to be done is to flip the Karlson Aperture upside down
It shortens the main path length and adds parallel tuned action , you end up with about 123db output , a few more volts of power handling and a knee at 35hz..I like your idea of countersinking the drivers so there is no risk of the frame's raised rim choking the aperture, and yes, bracing would be a highly recommended.
Chris661 ,
Freddi said it best with "six of one vs half dozen of the other" if we are talking about similar sized cabinets with the same tuning.... However this Karflex does have some amount of quarter wave loading and it is also a 6th order alignment (a reflex is 4th order) so it wouldnt suprise me at all if this box has an edge over a reflex when built and measured, meaning an advantage in regards to either cone control or output (or both!) if all goes well ...
Take for example the "Cubo", it is a rather compact design if i remember correctly , it is also 6th order and had significantly better output than a reflex ..... The Cubo wasn't quarterwave though, so i fully expect this Karlflex box to at least match (if not beat) the output from a Cubo (if same size and same FB) but with better upper bandwidth!
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I am onboard!
I plan on building a few of these to finish off my mini-pa that is already half built (just need subs) .... For the longest time i was utilizing my friends woodshop when he lived down the street but he recently moved to Vegas
so i have been buying up some basic powertools and bits and pieces of woodworking gear here and there, i had my eye on a table-saw i spotted at a pawn shop earlier today, it was selling for peanuts so i think i might pick that up early next week, then i will be ready to build two Karlflex cabinets
.....I already have a few of these small class-d amps to drive the subs ..... Freddi convinced me to try out these Dayton PA-310s so i will order those and i will put them in the 40hz tuned Karlflex cabs made out of birch ply or maybe Arauco ply if it looks good enough, then when finished i will get response measurements and impedance measurements to post here ... I will probably try some different experimental apertures until i find something optimal ...
With that said, if anyone else gives these designs a try i think that would be fully awesome , i just hope that they will post on here with results and impressions .....
I am really glad that we have all taken the time to explore the various aspects of these designs and virtually develop something that looks fantastic and very practical ... All of the big brains here on DIYaudio are an incredible resource!
I plan on building a few of these to finish off my mini-pa that is already half built (just need subs) .... For the longest time i was utilizing my friends woodshop when he lived down the street but he recently moved to Vegas
so i have been buying up some basic powertools and bits and pieces of woodworking gear here and there, i had my eye on a table-saw i spotted at a pawn shop earlier today, it was selling for peanuts so i think i might pick that up early next week, then i will be ready to build two Karlflex cabinets .....I already have a few of these small class-d amps to drive the subs ..... Freddi convinced me to try out these Dayton PA-310s so i will order those and i will put them in the 40hz tuned Karlflex cabs made out of birch ply or maybe Arauco ply if it looks good enough, then when finished i will get response measurements and impedance measurements to post here ... I will probably try some different experimental apertures until i find something optimal ... With that said, if anyone else gives these designs a try i think that would be fully awesome , i just hope that they will post on here with results and impressions .....
I am really glad that we have all taken the time to explore the various aspects of these designs and virtually develop something that looks fantastic and very practical ... All of the big brains here on DIYaudio are an incredible resource!
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Hi MMJ,
It's hard to tell w/ Patrick Bateman what he is talking about at a given time. His mind seems to be a few steps ahead of his communication output. The T/S came from this TH thread, Post #2:
http://www.diyaudio.com/forums/subwoofers/230405-300-th-50-knockoff.html
The thread gets a little convoluted at times, but, as always in P.B.s threads, there is a lot of interesting thinking and information.
Alpine provides a very nice application guide w/ T/S parameters and drawings, and you are correct P.B.'s values are a little different, so they may be measured. The underhung voice coil results in the lower Le, it may not be necessary to double it for a simulation, but I don't know.
I like the response that this enclosure is giving w/ a low end corner of about 30Hz. If you don't want to go that low, you may want to take another look @ tapped horns, for ~ 1ft^3 more you should get ~ 5dB more output in the range from 50-110Hz (same @ 40Hz). The other advantage is the larger duct cross-section @ the mouth, and because you can push the resonance point up higher (e.g.: 40Hz) this will give you a displacement null there, and a reduced main peak in the passband. So many choices.
Looking forward to what you come up with.
Regards,
It's hard to tell w/ Patrick Bateman what he is talking about at a given time. His mind seems to be a few steps ahead of his communication output. The T/S came from this TH thread, Post #2:
http://www.diyaudio.com/forums/subwoofers/230405-300-th-50-knockoff.html
The thread gets a little convoluted at times, but, as always in P.B.s threads, there is a lot of interesting thinking and information.
Alpine provides a very nice application guide w/ T/S parameters and drawings, and you are correct P.B.'s values are a little different, so they may be measured. The underhung voice coil results in the lower Le, it may not be necessary to double it for a simulation, but I don't know.
I like the response that this enclosure is giving w/ a low end corner of about 30Hz. If you don't want to go that low, you may want to take another look @ tapped horns, for ~ 1ft^3 more you should get ~ 5dB more output in the range from 50-110Hz (same @ 40Hz). The other advantage is the larger duct cross-section @ the mouth, and because you can push the resonance point up higher (e.g.: 40Hz) this will give you a displacement null there, and a reduced main peak in the passband. So many choices.
Looking forward to what you come up with.
Regards,
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Hi MMJ,
It's hard to tell w/ Patrick Bateman what he is talking about at a given time. His mind seems to be a few steps ahead of his communication output. The T/S came from this TH thread, Post #2:
http://www.diyaudio.com/forums/subwoofers/230405-300-th-50-knockoff.html
The thread gets a little convoluted at times, but, as always in P.B.s threads, there is a lot of interesting thinking and information.
Alpine provides a very nice application guide w/ T/S parameters and drawings, and you are correct P.B.'s values are a little different, so they may be measured. The underhung voice coil results in the lower Le, it may not be necessary to double it for a simulation, but I don't know.
I like the response that this enclosure is giving w/ a low end corner of about 30Hz. If you don't want to go that low, you may want to take another look @ tapped horns, for ~ 1ft^3 more you should get ~ 5dB more output in the range from 50-110Hz (same @ 40Hz). The other advantage is the larger duct cross-section @ the mouth, and because you can push the resonance point up higher (e.g.: 40Hz) this will give you a displacement null there, and a reduced main peak in the passband. So many choices.
Looking forward to what you come up with.
Regards,
TB,
Ok, cool
, I don't want to assume too much but yes, it is probably safe for us to say that those must be his (or someone's) measured T/S parameters ... Its great to see that they are so close to what is published, and it says something about the quality of these Alpine drivers ...These Alpine drivers certainly do look magnificent in a a Tapped Horn but the cabinets are so much larger and more complicated to build as well .... So yeah , compromises, always more compromises to choose from .. .
As far as cross sectional area at the mouth is concerned: it is an issue with these ML cabinets if you are using uber power with uber drivers in a tiny ML cabinet, there is definitely a point of diminishing returns and that is their limitation (mainly due to air particle velocity sims) .... These cabinets are really going to be geared towards drivers that cost half (or less) than the uber drivers, and the cabinets are also synchronously half the size of a similarly tuned TH , so in the end it all works out
.... For example: Instead of a 120 liter TH with a 200 dollar driver you can make two 60 liter Karlflex cabinets with a 100 dollar driver in each, the builds are simpler, you spent the same amount of money, and the performance meets or exceeds the TH and the system is more portable ... I am working out the details on what each cab is capable of , and it looks like it will be based upon power levels as guidelines ... So far it looks like 500w max for the 60L cab , and 750w for the 90L cab ...... I will post more about it here in a bit after i double check everything to confirm ...
Chris,
I can scale up the 60 liter box to 90 liters or 100 liters and sim your 15" Beyma
Do you have measured T/S parameters for that driver or would you like me to just use the published specs?
Let me know
Hey MMJ, I haven't been able to measure them, so the published specs will have to do. I suspect they'll be close.
Chris
Phivates ,
The one i spotted at the pawn shop was just a cheap Ryobi, but it was buried behind some other stuff so i couldn't get a really good look at it and they were getting ready to close at the time, so i will get back over there in the next few days to inspect it more closely ...
I have this wonderful old heavy desk sitting in the middle of my covered back porch area right now and i was thinking a benchtop saw would be perfect because i could just bolt it down to the desk and that would make a very solid platform ...
Chris ,
Ok , i will try the published parameters, and yep , since the manufacturer is reputable the figures will likely be very close ... The reason i asked is because when i was searching the web for parameters the other day i found two different sets of published figures for that particular driver, the biggest discrepancy was with the QMS , my guess would be that one set of specs was for an older version ..... Hopefully you have the one with higher QMS ...
In the 90 or 100 liter cab you will be limited to about 750 to 800 watts , but that works out just about right since your driver will also be bound by it's linear XMAX figure at those power levels .... The extra electrical power handling just means less thermal power compression for you
Here are the high QMS figures i found, at this link http://www.beyma.com/getpdf.php?pid=15P1200Nd/N
That is a fantastic QMS figure
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Those are the parameters I've been using.
I must say, these drivers are very very good - I'd recommend them for any sub or midbass use - I'm currently running them up to 1kHz to meet a DH1a a side. Hit them with a NU6000DSP and they just take it. Cone excursion can get to 40mm p/p and they still sound fairly clean. The suspension puts the stops on going up to 50mm, though.
Only problem for midrange use is the 1.6kHz breakup node requires some notching. I went all-out and did a notch plus LR4 crossover. No hint of midrange nastiness inherent of 15" two-ways, just an incredibly clean dynamic sound.
Interested to see what you come up with - I've a 2nd pair of these drivers just lying around...
Chris
I must say, these drivers are very very good - I'd recommend them for any sub or midbass use - I'm currently running them up to 1kHz to meet a DH1a a side. Hit them with a NU6000DSP and they just take it. Cone excursion can get to 40mm p/p and they still sound fairly clean. The suspension puts the stops on going up to 50mm, though.
Only problem for midrange use is the 1.6kHz breakup node requires some notching. I went all-out and did a notch plus LR4 crossover. No hint of midrange nastiness inherent of 15" two-ways, just an incredibly clean dynamic sound.
Interested to see what you come up with - I've a 2nd pair of these drivers just lying around...
Chris
Sounds like a fun little system , With those monstrous EV compression drivers you are able to move your crossover point low enough to avoid most of the beaming issues or off-axis losses in the upper midrange ... Dispersion should be decent
I recently had the pleasure of getting to tinker around with some old EV DH2A drivers on some HR60 fiberglass CD horns..They had a massive "tilt" in the response of course but once you compensate for that, Holy Goats! They have a big sound to them
A table saw conversation belongs in a different forum but I'll just say that as a retired carpenter with friends who are missing fingers that the recent trend of putting large blades into tools with tiny tops is WRONG. You need space in front of the blade. I'd tell you to just get a readily available Rockwell/Delta off CL except for the wrong tilt (unless you're a leftie) so here, again, size matters, along with two handfuls of other factors. Oh and thanks for the lively thread.
FredM
FredM
details details
I just wanted to let you guys know that i went over a few details on this Karlflex design again, and the particle velocity looks good with the cabinet version made for a single 12... Also the two cheap fosgate 10s from ApexJr in a 25" cab has a reasonable velocity figure, and the particle velocity is also just fine for the 15" drivers that i have simmed in the 90 liter Karlflex cabinets, so no problems there at all ...
UNFORTUNATELY the two Alpine SWS 10s in the 25" tall Karflex looks like it might have some particle velocity issues when driven at full power ......... Somehow i missed this detail when simming it earlier, in fact i recall that the 2x SWS 10 combo had particle velocity in the safe range when initially simulated so perhaps i need to backtrack and figure out what was different about those earlier Karlflex sims i was using ....
It is crummy to have to say it but two 10s with 15mm xmax (each) at 1000 watts (for both) is really pushing our luck with this tiny cabinet and it's vent sizing .... I would hate to see someone build that particular configuration just to have port compression or chuffing at full power, of course just because the drivers handle 1000 watts it doesn't mean you have to necessarily slam them with 1000 watts .... In Palsa's situation where he would be driving the box with 500w he should be perfectly alright, the box would sound clean, and the drivers would have a very long life.... Very reliable...
The power limitations are no big deal really and i will explain why i say that:
Keep in mind that these are tiny boxes and they can host affordable drivers so for example two 60 liter Karlflex cabs loaded with inexpensive woofers can easily compete with (or exceed) a 120 liter cabinet with a driver that is twice as expensive .... So this all works out, with the benefits of the Karlflex being an incredibly simple build, and smaller cabinets in multiples are more portable than a big bulky box making the multi-Karlflex option a very practical and elegant alternative to Tapped Horns and Front Loaded Horns , RLHs etc ...
So this is how it all seems to be working out, here are some approximate but safe guidelines:
Also, The Air particle velocity simulates as a peak very near FB, so that peak can be smoothed over a bit with the use of some stuffing at the S1 end (closed end) of the path, however adding too much stuffing can cause losses of efficiency at FB so practice moderation because overstuffing would likely be counterproductive ...
*end of rant*
Will post various ideas for apertures in a bit..
I just wanted to let you guys know that i went over a few details on this Karlflex design again, and the particle velocity looks good with the cabinet version made for a single 12... Also the two cheap fosgate 10s from ApexJr in a 25" cab has a reasonable velocity figure, and the particle velocity is also just fine for the 15" drivers that i have simmed in the 90 liter Karlflex cabinets, so no problems there at all ...
UNFORTUNATELY the two Alpine SWS 10s in the 25" tall Karflex looks like it might have some particle velocity issues when driven at full power ......... Somehow i missed this detail when simming it earlier, in fact i recall that the 2x SWS 10 combo had particle velocity in the safe range when initially simulated so perhaps i need to backtrack and figure out what was different about those earlier Karlflex sims i was using ....
It is crummy to have to say it but two 10s with 15mm xmax (each) at 1000 watts (for both) is really pushing our luck with this tiny cabinet and it's vent sizing .... I would hate to see someone build that particular configuration just to have port compression or chuffing at full power, of course just because the drivers handle 1000 watts it doesn't mean you have to necessarily slam them with 1000 watts .... In Palsa's situation where he would be driving the box with 500w he should be perfectly alright, the box would sound clean, and the drivers would have a very long life.... Very reliable...
The power limitations are no big deal really and i will explain why i say that:
Keep in mind that these are tiny boxes and they can host affordable drivers so for example two 60 liter Karlflex cabs loaded with inexpensive woofers can easily compete with (or exceed) a 120 liter cabinet with a driver that is twice as expensive .... So this all works out, with the benefits of the Karlflex being an incredibly simple build, and smaller cabinets in multiples are more portable than a big bulky box making the multi-Karlflex option a very practical and elegant alternative to Tapped Horns and Front Loaded Horns , RLHs etc ...
So this is how it all seems to be working out, here are some approximate but safe guidelines:
- A 60 liter 35hz Karlflex cabinet is a 500 watt box .. Can host a 12" woofer with up to 15mm xmax and handle 500 watts .... Or it can host two 10" woofers with 10mm xmax and handle 500 watts ...
- A 90 liter 35hz Karlflex cabinet is a 750 watt box , and can host a 15" driver with 15mm xmax , or 4x8" inch drivers at 750 watts ...... The 100 liter cabinet should handle approximately 800 to 850 watts .......
- I haven't worked it out in detail yet but the Karlflex scaled up for an 18" woofer should handle considerably more power (so far the power handling tracks the net-size scaling of the box perfectly with this layout), an estimation at this point would be in the 1400-1500 watt range..
Also, The Air particle velocity simulates as a peak very near FB, so that peak can be smoothed over a bit with the use of some stuffing at the S1 end (closed end) of the path, however adding too much stuffing can cause losses of efficiency at FB so practice moderation because overstuffing would likely be counterproductive ...
- Final thought for this post: A height of at least 25" is of course necessary for a dual 10" driver setup, but for a single 12" or 15" it might be possible to trim off a few vertical inches with this new fold (in exchange for a little extra width) since we have an abundance of path length with this new yet more nostalgic cone-facing-forward arrangment .... We have more than enough path length with this fold, so much in fact that (at 24" H) the tuning of the box will be around 40hz without any aperture panel being added at all !!! Very little additional loading (via the aperture) is required to shift the FB down, so i am thinking that if our FB target is 35hz in some cases and 40hz in other cases reducing the box height by a few inches to shorten the path length might actually make this box easier to work with when trying out various custom Apertures (less chance of overshooting the target FB by going too low) .......
*end of rant*
Will post various ideas for apertures in a bit..
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Good information , thank you
Phivates ,
I think the Ryobi is a 10" , and yeah the top is small on it ...
I will take a look at my local craigslist for a Delta or Rockwell right now ....
I AM left handed !
and I am enjoying the lively thread too !
Phivates ,
I think the Ryobi is a 10" , and yeah the top is small on it ...
I will take a look at my local craigslist for a Delta or Rockwell right now ....
I AM left handed !
and I am enjoying the lively thread too !
APERTURE OPTIONS AND IDEAS, not perfectly drawn but you get the idea
There are many different ways to arrange the aperture on the Karlflex , some will extend path and some will add parallel loading (which is great for heavier drivers that need improved midbass output), some will create a mixture of both series and parallel loading .... Some will have more bandwidth and some will have less ..... These could all be considered "tapped" to some extent , because even in the Parallel alignment's case there is a shared mouth/terminus/Aperture where a short path and the main path converge before exiting the cabinet ...
Keep in mind that the FB is right around 40hz with no panel at all on the front of this 24" Cone-forward Karlflex, so in order to get down to a 35hz FB (or lower) there has to be some amount of extension to the main path which can be provided by the front panel , but it doesn't take much ... All aperture options depicted in the rough drawing (with the exception of option 2) add some amount of path length to the main path .... The amount of shift in FB will depend on how large you make the aperture (or the two apertures in some cases) , and (or also) where you place the aperture as with option 3...
I am sure there are many other ways to arrange an aperture, these are just a few off the top of my head ... Would be fun to have someone make a variety of apertures and measure the response of each one ... I will probably do some amount of this experimentation when i build the Karlflex boxes for the PA-310
There are many different ways to arrange the aperture on the Karlflex , some will extend path and some will add parallel loading (which is great for heavier drivers that need improved midbass output), some will create a mixture of both series and parallel loading .... Some will have more bandwidth and some will have less ..... These could all be considered "tapped" to some extent , because even in the Parallel alignment's case there is a shared mouth/terminus/Aperture where a short path and the main path converge before exiting the cabinet ...
Keep in mind that the FB is right around 40hz with no panel at all on the front of this 24" Cone-forward Karlflex, so in order to get down to a 35hz FB (or lower) there has to be some amount of extension to the main path which can be provided by the front panel , but it doesn't take much ... All aperture options depicted in the rough drawing (with the exception of option 2) add some amount of path length to the main path .... The amount of shift in FB will depend on how large you make the aperture (or the two apertures in some cases) , and (or also) where you place the aperture as with option 3...
I am sure there are many other ways to arrange an aperture, these are just a few off the top of my head ... Would be fun to have someone make a variety of apertures and measure the response of each one ... I will probably do some amount of this experimentation when i build the Karlflex boxes for the PA-310
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I'd be cautious about inviting wheezing - - a roundover on the inside edge of the aperture with rasp/file/sandpaper or router would help. In a regular Karlson setup, the baffle is angled back so there's greater cross-sectional area behind the narrow-upper portion of the slot.
Ahhhh yes , good suggestion
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