One of the 80 litre sims Jeff did looks promising, probably needs to be a bit bigger.
Freddi, my miniOnkn designs are not Onkens per-se, they only borrow the sandwhich vents on the sides.
dave
In too small a box the 12lta is bass light... after playing them in 2.5cf cabs i realized right away there was not enough bass. Accepting a drivers limitations is part of the process. I hope ob suits them... i've got the wood cut... maybe this weekend i'll put them together for a listen. I will compare them to the boxes they are in now and sit them atop the H-frames.
with Vbr=(Vas*fs*qts)/fc (~2.2 cubic foot for 12LTA assuming low Z drive) as a very rough starting point, the existing "X15" size Karlson coupler might work with 12LTA and a new coupler may be better - treble could be augmented with a K-tube internally or on top. my X15 copy did pretty well subjectively with Beta 12CX which is close in spec - it could play the odaiko loud enough to make me jump with about 1/8" peak to peak cone movement. It must have hit 120dB. A good K-tube to make is using one-inch pvc and a half-ellipse slot ~5.3" long with a 1/8" starting gap - an unslotted stub can be added to make it go somewhat lower and also easier to mount within the regular Karlson type as the tip of the waveguide should reach the wings plane.
be cool to eventually see your cab Dave.
IIRC 12LTA has ~ 0.080" overhang (?) but a fairly large xmax spec based on distortion. 12CX might have ~3mm overhang - does 12LTA go into compression faster?
been a lot of years since I ran Beta 12CX in a X15 copy (X15 was Karlson's commercial speaker of 1965 sporting a mini-coupler for the tweeter - later going to a slotted pipe and concurrent with his open-end waveguide patent)
too bad Eminence doesn't offer a 54oz magnet version of 12LT- that would kick up the transients and in some cases make the box requirement smaller.
be cool to eventually see your cab Dave.
IIRC 12LTA has ~ 0.080" overhang (?) but a fairly large xmax spec based on distortion. 12CX might have ~3mm overhang - does 12LTA go into compression faster?
been a lot of years since I ran Beta 12CX in a X15 copy (X15 was Karlson's commercial speaker of 1965 sporting a mini-coupler for the tweeter - later going to a slotted pipe and concurrent with his open-end waveguide patent)
An externally hosted image should be here but it was not working when we last tested it.
too bad Eminence doesn't offer a 54oz magnet version of 12LT- that would kick up the transients and in some cases make the box requirement smaller.
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Another potential option? First I read this and then I found this. I was dubious about the usability of piezos and I guess rightly so, but if that article's correct then perhaps that tweeter would also serve. One fun advantage is that it does not need any crossover components! Then again, if it operates from 6k up, there will be some overlap.
My understanding is that no-xo-ing a piezo works, but won't really get the best of it. I don't have any direct experience with it, though.
It would be neat to see a write up of someone walking through the various bits of info floating around regarding proper piezo use and evaluating the results. I've seen a lot more "you should" than "I have"...
It would be neat to see a write up of someone walking through the various bits of info floating around regarding proper piezo use and evaluating the results. I've seen a lot more "you should" than "I have"...
I have to say I've been eating this thread up. For some time the 12LTA has looked good to me. This cinches it. Since my amp wants a 4 ohm load I thought 2 per channel with this tweeter between them
http://www.creativesound.ca/pdf/LAR1.pdf
after reading the experiences here maybe I could go cheaper on the tweeter.
I have also been considering an impedance correction circuit to make things easier on my amp. Any thoughts?
no box/ Open Baffle Thanks, Evan
http://www.creativesound.ca/pdf/LAR1.pdf
after reading the experiences here maybe I could go cheaper on the tweeter.
I have also been considering an impedance correction circuit to make things easier on my amp. Any thoughts?
no box/ Open Baffle Thanks, Evan
I have the smaller version of that tweeter. A great tweeter, but not efficient enuff for this application.
dave
dave
I have one of those here -- working on the data sheet. Looks to be very interesting. Goes way lower than you need, but if you are doing an MTM laybe low enuff.
dave
wont there be time alignment or phase issues with simply placing a tweeter inside the mouth of the 12LTA?
I figured that one could use a piece of PVC pipe or some material to position the tweeter at the correct location for proper time alignment and phase...But the trial and error process of cutting different lengths of tube (perhaps millimeter by millimeter?) might be quite laborious. I wouldn't know!
As to the tweeter alignment, why couldn't you use the FM trick?
You would need a partner, an FM tuner that will pick out the noise between channels, and an amp. Simply vary the position of the tweeter until the " noise " sounds in phase....
Can't the Beta 12 LTA's bottom end extension be improved with a bit larger box volume? I seem to recall doing some sim's when this thread started, that showed with proper venting the driver would give an F3 down in the low '30s with like 5.5 Cu ft. ( I know that's Hyoooge )....Can't locate the sim's now🙁
my 2 C.
John
You would need a partner, an FM tuner that will pick out the noise between channels, and an amp. Simply vary the position of the tweeter until the " noise " sounds in phase....
Can't the Beta 12 LTA's bottom end extension be improved with a bit larger box volume? I seem to recall doing some sim's when this thread started, that showed with proper venting the driver would give an F3 down in the low '30s with like 5.5 Cu ft. ( I know that's Hyoooge )....Can't locate the sim's now🙁
my 2 C.
John
>>> Can't the Beta 12 LTA's bottom end extension be improved with a bit larger box volume?
Yup, it needs a big box. I went with a smaller box atop H-frames. I love them!
Yup, it needs a big box. I went with a smaller box atop H-frames. I love them!
>>> Hi. Did you already try them on OB ?
Tomorrow i plan to sand and cut but don't expect to have things ready for listening until the glue dries. You will see pics maybe next week of what i did (i made an easel like structure... very simple, stable and cheap to build). I have high hopes for this project... We'll see... hear... how it all sounds.
Zilla
Tomorrow i plan to sand and cut but don't expect to have things ready for listening until the glue dries. You will see pics maybe next week of what i did (i made an easel like structure... very simple, stable and cheap to build). I have high hopes for this project... We'll see... hear... how it all sounds.
Zilla
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