4CF per Eminence recommendation might be good - although less could work. I ran 12lta open baffle with a cheap 21" woofer plus tweeter.. Also had 12lta stuffed into an Aristocrat and have run them in Karlson K12 (kinda llike that combo - it played Danley's Harley recording pretty well - - an AN10 in reflex would be jumping out of the gap trying to do the same. K12 are tuned ~62Hz so that's part of the power handling. I dropped a 12lta a couple of months ago - about a 3.5 foot drop where the back of the frame hit something - did not bend the frame but now the coil seems to rub
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Ah yes. open baffle...back in the lost years when I was too cheap to buy more wood, didn't know what I was doing...the seemingly only thing I knew was the "acoustic short circuit", or "doublet operation".
--------------------------------------------------------------------------Rick.........
--------------------------------------------------------------------------Rick.........
K12 sounds like it could have some promise... I need to do more reading so I can understand how the enclosure works.
Part of the allure of the bbbib design was good output even at something like 25 hz....
I wish i could listen to them all side by side!
Open baffle.. now thats a whole 'nother animal! I'd have to hear it in person to believe it!
Every new project is another mission... ha!
Part of the allure of the bbbib design was good output even at something like 25 hz....
I wish i could listen to them all side by side!
Open baffle.. now thats a whole 'nother animal! I'd have to hear it in person to believe it!
Every new project is another mission... ha!
Scott - fair point! Maybe worth an experiment before i build any enclosures... I'm just doubting its going to have the full sound I'm looking for.. though i could see (hear?) it being amazing for acoustic stuff.
I was hoping not to have to rely on crossovers too much... just roll in the tweeter up high where the full range rolls off like 8-10k.
I was hoping not to have to rely on crossovers too much... just roll in the tweeter up high where the full range rolls off like 8-10k.
K12 would probably have a useful limit of about 70Hz - K15 a half octave lower. The rear chamber volume and overall tuning (~like a series bandpass box) vs parameters set the low end. I like Kappa12a in K12 size with a K-tube/compression driver tweeter and would add a modest subwoofer. The Karlsonator 12 will go down probably as low as K15 and is tuned per plans to ~37Hz vs about 45Hz for K15. Adding a helper tweeter, if on top, pushes it pretty far from the woofer. It would be interesting to run 12lta in K15. (K15 - the original Karlson, was finished in the summer of 1951 - made its debut at the 1952 hotel New Yorker show) XRK971 has an elaborate akaback model for K15 type - I think its sims are somewhat optimistic on the low end - X's Karlsonator sim seems to work pretty well.
a tqwt about 4 or so cubic feet might be another option - whether better than reflex = ?
a higher source impedance amp such as SET with little or no global NFB would tend to give more "bass" open baffle (in the Z peak region) than common solid state amp. A series resistor can be put between a solid state amp and speaker - raises Q plus forms a variable voltage divider where the resonance frequency is attenuated less than the lower impedance regions
a tqwt about 4 or so cubic feet might be another option - whether better than reflex = ?
a higher source impedance amp such as SET with little or no global NFB would tend to give more "bass" open baffle (in the Z peak region) than common solid state amp. A series resistor can be put between a solid state amp and speaker - raises Q plus forms a variable voltage divider where the resonance frequency is attenuated less than the lower impedance regions
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My experience with really big FRs is limited to the 12LTA in Em-Kens. To get somewhat decent mid-top it sactifices at the bottom. There is a range of tuning in the Em-Ken thou — if you have lots of room gain you can tune it lower for deeper bass. Daniel is borrowing our Em-Kens and has subwoofers (2 with 2xSDX10) and supertweeters (the dipole Heils).
I believe the sweet spot for fidelity in FRs is 4-5” drivers (ie Mark Audio Alpair7.x/10.x, Fostex FF165wk). That size tends to have better mid/top and capable of greater DDR/detail. The larger ones go at least as low, but sacrifice efficiency to do so If you are playing really loud in a big room they might not cut it.
A compromise might be phase plugged Visaton B200s. Better fidelity than than the 12LTA but a much higher price and a “box” for them is a big OB or fairly big box — not that the 12LTA doesn’t need a biggish box.
Note that magnet size alone is not relevant without considering the entire magnetic circuit, As a generalization more magnet typically gives more efficiency, lower Qt, and less bass capability.
dave
I believe the sweet spot for fidelity in FRs is 4-5” drivers (ie Mark Audio Alpair7.x/10.x, Fostex FF165wk). That size tends to have better mid/top and capable of greater DDR/detail. The larger ones go at least as low, but sacrifice efficiency to do so If you are playing really loud in a big room they might not cut it.
A compromise might be phase plugged Visaton B200s. Better fidelity than than the 12LTA but a much higher price and a “box” for them is a big OB or fairly big box — not that the 12LTA doesn’t need a biggish box.
Note that magnet size alone is not relevant without considering the entire magnetic circuit, As a generalization more magnet typically gives more efficiency, lower Qt, and less bass capability.
dave
Freddi - I see, had not realized that karlsonator and karlson were not the same. They are certainly neat enclosures, especially the acoustic lensing. Karlsonator sounds more my speed if its tuned to 37hz. Is there any merit to mounting the tweeter behind the front panels directly in front of the woofer, and get the same dispersion for the highs?
Dave, the em-ken is another design i was i interested in. I'd like to keep this a budget build, so unfortunately fancy/expensive drivers are out. I'm still trying to wrap my head around what a 5" driver cranked up with some classic rock playing would sound like... doesn't seem that a cone that size would play well at 50-60hz while cranking the amp to 11. So you're stuck turning down the bass to cut distortion, or back to adding helper woofers, crossovers, etc.
On a side note, the drivers you treat w/ enabl and phase plugs look amazing... No doubt they sound much better too!
Dave, the em-ken is another design i was i interested in. I'd like to keep this a budget build, so unfortunately fancy/expensive drivers are out. I'm still trying to wrap my head around what a 5" driver cranked up with some classic rock playing would sound like... doesn't seem that a cone that size would play well at 50-60hz while cranking the amp to 11. So you're stuck turning down the bass to cut distortion, or back to adding helper woofers, crossovers, etc.
On a side note, the drivers you treat w/ enabl and phase plugs look amazing... No doubt they sound much better too!
if your tweeter is small enough, then it can be mounted on a bracket, across the 12" speaker, in pseudo coax fashion. On top, a tweeter will generally still blend pretty well. A K-tube can be used "inside" the front chamber where it will fit but I'm not sure what driver makes a good inexpensive K-tube helper tweeter.
here's a "near copy" of the 1960's Karlson X15 - my builder accidentally raised the driver cutout about 7/8 of an inch. The K-tube shown is a clone of one x15 tube ~1.874" ID - I've had Beta12cx (close in parameters to 12lta) in this cabinet - of course it didn't go low but had a scary amount of "hit" on a Japanese drum CD - I thought the cone would break but only moved about 1/4" peak to peak
"this" is a good way to do 2- way Karlson speakers. A one inch ID pipe, 5.3" long with half ellipse slot makes a good K-tube for a compression driver. If the compression driver just fired through a hole in the upper speaker baffle, there would be excessive reflections, and energy storage. The tip of the K-tube is usually ~ flush with the front aperture
"GregB" came up with the "Karlsonator" variant a few years back
X15 copy 27.75"H x 19.375" W x 14" D - the original Karlson X15s used a CTS 15 inch woofer with Qts ~0.28, Fs ~41Hz
- chamber volumes are roughly 2 cubic foot rear - 1 cubic foot front. For 12LTA, those volumes could be proportioned more
like a regular K12
here's a "near copy" of the 1960's Karlson X15 - my builder accidentally raised the driver cutout about 7/8 of an inch. The K-tube shown is a clone of one x15 tube ~1.874" ID - I've had Beta12cx (close in parameters to 12lta) in this cabinet - of course it didn't go low but had a scary amount of "hit" on a Japanese drum CD - I thought the cone would break but only moved about 1/4" peak to peak
"this" is a good way to do 2- way Karlson speakers. A one inch ID pipe, 5.3" long with half ellipse slot makes a good K-tube for a compression driver. If the compression driver just fired through a hole in the upper speaker baffle, there would be excessive reflections, and energy storage. The tip of the K-tube is usually ~ flush with the front aperture
"GregB" came up with the "Karlsonator" variant a few years back
X15 copy 27.75"H x 19.375" W x 14" D - the original Karlson X15s used a CTS 15 inch woofer with Qts ~0.28, Fs ~41Hz
- chamber volumes are roughly 2 cubic foot rear - 1 cubic foot front. For 12LTA, those volumes could be proportioned more
like a regular K12
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I don't know about 11, but 9 is likely doable. We surprised even Mark Fenlon with what A10p would do in an FHXL.
dave
Yeah, but you see, these speakers go to 11.
Sorry, that's Spinal Tap of course.
It occurs to me that I've had lots of various "high end" computer speakers (with the 2 satellites and a small sub) over the last 15 years, and that these are essentially "FAST" systems. Many of them sounded pretty good at reasonable listening levels. But none went low enough to catch the bottom end of actual music (what, maybe 40hz or so?), and none of them can rock and fill the house with good reasonably clean sound like my dear old much maligned fisher ds-826s. They actually sound pretty decent cranked up to "11" (though one out to quantify what dB "11" is!). Thus, it would seem that wattage, driver size, and enclosure size matter.
I was looking at the FH and FHXL at one point, but was just concerned they wouldn't sound "big enough". Seems silly to say, but if I'm going to build a new set of speakers, they better blow the fishers out of the water in all respects!
Freddi, thanks for the explanation on the tweeters in the Karlson
Sorry, that's Spinal Tap of course.
It occurs to me that I've had lots of various "high end" computer speakers (with the 2 satellites and a small sub) over the last 15 years, and that these are essentially "FAST" systems. Many of them sounded pretty good at reasonable listening levels. But none went low enough to catch the bottom end of actual music (what, maybe 40hz or so?), and none of them can rock and fill the house with good reasonably clean sound like my dear old much maligned fisher ds-826s. They actually sound pretty decent cranked up to "11" (though one out to quantify what dB "11" is!). Thus, it would seem that wattage, driver size, and enclosure size matter.
I was looking at the FH and FHXL at one point, but was just concerned they wouldn't sound "big enough". Seems silly to say, but if I'm going to build a new set of speakers, they better blow the fishers out of the water in all respects!
Freddi, thanks for the explanation on the tweeters in the Karlson
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"...and phase plugs look amazing...no doubt they sound better too!"
According to the experimentation & measuring of this thread I mentioned, the removal of the dust-cover helped some, adding a phase-plug worsened a 2.5Khz. 'hotspot'...even applying some absorbent inside the pole piece hole didn't help...the discussion withered away when "he" mentioned reapplying the dust cap with some absorbent felt on the concave inside of the dust cap...
--------------------------------------------------------------------Rick..........
One of my mentores uses a pile of felt to make phase plugs for his woofers.
The dustcap opens up the space above the polepeice into an open ended resonator, and the felt kills residual oil can resonances.
Whizzer cone drivers in particular seem to benefit from phase plugs.
dave
Tapped?! You sure? Pretty sure it's not, though relocate the driver and it's a TH, which means it's limited to 2-2.5 octaves depending on the driver.
GM
Re: phase plugs, i seem to recall the fellow in that thread using a felt sock over a wood phase plug... seems like a felt stack would funtion similarly, thpugh neither looks as pretty as a polished wood plug. ;-)
Greg, pretty sure you and scottmoose were the principle designers of the bbbib, so you'd know better than i... but granted it was 10 years ago! The rear output of the 12lta was thru the TH (exiting thru the top of enclosure), front was direct radiated.
Greg, pretty sure you and scottmoose were the principle designers of the bbbib, so you'd know better than i... but granted it was 10 years ago! The rear output of the 12lta was thru the TH (exiting thru the top of enclosure), front was direct radiated.
The BIB was the work of the sadly missed Terry Cain, but GM and Dr, Lindgren were 2 that took up the banner and did huge amounts of work on them. Godzilla also needs kudos for help promoting them. I even added my bit to the pool.
dave
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