I've been working on an OB Beta 12LTA over Alpha 15 H frames. I know, that's not full range, but thought you full rangers might like this as well.
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I finished the tweeter pods that mount to the pole piece on the 12LTA. Thanks go to Ron Brady over at the fullrangedriver forum for the idea. The Lanzar DCT's are available on ebay for $15 shipped. They have a supposed 96dB SPL. I'm currently using a 4.3 uF Solen cap that I had on hand. Ron recommends 4 uF high quality cap.
I used three 1/4" x 1/4" round neo magnets to secure the pod to the pole piece. It's strong enough to hold it in place. And, of course easliy removed if needed. I initially tried a big flat washer, but it won't work.
The bottom of the 2" diameter 1-3/4" long PVC is a piece of 1/8" thick garolite. The bottom is fastened to the PVC with JB weld. The magnets are also fastened to the garolite with JB weld from the inside. The most important part is to make sure the magnet poles are installed correctly before gluing them in. Sanded the pipe and shot some Krylon Fusion satin black.
I used the flat surface mount base from the Lanzar kit (there's 3 different mounts - surface, angled, flush). The base is also fastened to the top of the PVC with, you guessed it, JB weld - hey I like it. Using the base allows you to remove the tweeter easily.
Here's some pics...
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I finished the tweeter pods that mount to the pole piece on the 12LTA. Thanks go to Ron Brady over at the fullrangedriver forum for the idea. The Lanzar DCT's are available on ebay for $15 shipped. They have a supposed 96dB SPL. I'm currently using a 4.3 uF Solen cap that I had on hand. Ron recommends 4 uF high quality cap.
I used three 1/4" x 1/4" round neo magnets to secure the pod to the pole piece. It's strong enough to hold it in place. And, of course easliy removed if needed. I initially tried a big flat washer, but it won't work.
The bottom of the 2" diameter 1-3/4" long PVC is a piece of 1/8" thick garolite. The bottom is fastened to the PVC with JB weld. The magnets are also fastened to the garolite with JB weld from the inside. The most important part is to make sure the magnet poles are installed correctly before gluing them in. Sanded the pipe and shot some Krylon Fusion satin black.
I used the flat surface mount base from the Lanzar kit (there's 3 different mounts - surface, angled, flush). The base is also fastened to the top of the PVC with, you guessed it, JB weld - hey I like it. Using the base allows you to remove the tweeter easily.
Here's some pics...
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I did a couple of web searches several months ago, when considering my own Beta 12 LTA project.
At the time, I was able to find a small number of Automotive tweeters like the Lanzar ( which was one of them ). My own minimum requirement called for very high efficiency, and preferably a fabric dome.
I'll see if I can find my notes, and post the other choices I found.
My recollection was that they were all inexpensive enough to pick up all of them to try. I planned to use a bit of wooden doweling as my mount ( closet rod ). One of the reasons I backed off the proposed project was fear of ruining a $60 driver trying to drill through the pole piece to run the tweeter wires. I second the request to see the magnet, and would love details on how you did the deed, if you drilled the pole bit of the driver...Blow by blow if you please...
My own were to go into a cabinet inspired by Thuras/Onken resistive vent much like the Emken, only different in that the vents would have surrounded the driver on the front face of the baffle.
Let me see if I can find those notes.
I'll be following this thread with interest....
John
BTW, Kudo's on the nice looking work, kec. How do they sound???
At the time, I was able to find a small number of Automotive tweeters like the Lanzar ( which was one of them ). My own minimum requirement called for very high efficiency, and preferably a fabric dome.
I'll see if I can find my notes, and post the other choices I found.
My recollection was that they were all inexpensive enough to pick up all of them to try. I planned to use a bit of wooden doweling as my mount ( closet rod ). One of the reasons I backed off the proposed project was fear of ruining a $60 driver trying to drill through the pole piece to run the tweeter wires. I second the request to see the magnet, and would love details on how you did the deed, if you drilled the pole bit of the driver...Blow by blow if you please...
My own were to go into a cabinet inspired by Thuras/Onken resistive vent much like the Emken, only different in that the vents would have surrounded the driver on the front face of the baffle.
Let me see if I can find those notes.
I'll be following this thread with interest....
John
BTW, Kudo's on the nice looking work, kec. How do they sound???
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I found my notes, and could even decipher the intent of the design! Still!!
Here's the order I recorded them in, I didn't record the effficiency/ dome material/ Etc. though.
Lanzar DCT
Power Acoustik NB 1,2,or 4
Absolute TW-800
Boss TW-18
Boss TW-20
Hitron HS-200
As I said previously, I can't recall much else about the idea, other than high enough efficiency to mate with the Beta 12 LTA, and my own preference for fabric dome's over metalic. Though as a rule I prefer horns to domes. To each his own...
I can't vouch for the quality of any of these, and would have to defer to someone who's actually used/heard them as to SQ, and suitability. I was just chasing an idea to see where it went at the time. I only list these here to possibly help someone else who may have the guts to take a brand new driver and poke holes in it!
John
Here's the order I recorded them in, I didn't record the effficiency/ dome material/ Etc. though.
Lanzar DCT
Power Acoustik NB 1,2,or 4
Absolute TW-800
Boss TW-18
Boss TW-20
Hitron HS-200
As I said previously, I can't recall much else about the idea, other than high enough efficiency to mate with the Beta 12 LTA, and my own preference for fabric dome's over metalic. Though as a rule I prefer horns to domes. To each his own...
I can't vouch for the quality of any of these, and would have to defer to someone who's actually used/heard them as to SQ, and suitability. I was just chasing an idea to see where it went at the time. I only list these here to possibly help someone else who may have the guts to take a brand new driver and poke holes in it!
John
Yup, a dremel is part of the program on these... very doable as the bezel and frame are all plastic. The plan is to spon some wood with a cavity where the FT17 plugs into one end and the other end is bolted thru the pole vent. I have the bits to prototype onr with PVC pipe which is conveinently of the right diameters.
dave
dave
Isn't the Eminence Beta-12-CX coaxial close enough to use in the same cabinet with some minor tweaking? It's the same price, and it's all set up to add the 1" compression driver of your choice. It just seems like a lot less work.
Eminence Beta-12CX
Eminence Beta-12LTA
Beta 12-CX coaxial
Fs 47
Vas 5.7 Cu ft
Qms 6.69
Qts .48
Qes .51
XMax 3.0 mm
Beta 12-LTA
Fs 45
Vas 4.8 Cu ft
Qms 6.44
Qts .51
Qes .55
XMax 3.2 mm
Eminence Beta-12CX
Eminence Beta-12LTA
Beta 12-CX coaxial
Fs 47
Vas 5.7 Cu ft
Qms 6.69
Qts .48
Qes .51
XMax 3.0 mm
Beta 12-LTA
Fs 45
Vas 4.8 Cu ft
Qms 6.44
Qts .51
Qes .55
XMax 3.2 mm
Maybe. Do they sound similar? You wouldn't have a phase plug on the CX though. Maybe it's not needed on the CX? I dunno.
I listened to them for a few hours yesterday. I really like them. The detail they add to the 12LTA is amazing and blends in quite nicely. I like this concept since the removal of the dust cap removes most of the nasty 6dB 5K-7K peak and adds a phase plug and super tweeter all at the same time. Again, thanks for this idea goes to Ron Brady.
More info about this is here: if phase plug 12lta, still need that notch ckt ? (Page 1) / FullRangeDriver Forum / Fullrangedriver Forum
Without knowing more about the 12LTA and its requirements as far as helper-tweeters, I think you should know that the FT17H might not be as good as the spec sheet states. It rolls-off very early and most regular tweeters will out-supertweet it IMO.
Blue trace = wide open response (28µF cap)
Red trace = 1µF cap
Green trace = 0.47µF cap
An externally hosted image should be here but it was not working when we last tested it.
IIRC, the highest point at 7kHz on the blue trace was about ~rated sensitivity, so ~100dB, which means that at ~15kHz, it's only 90dB and falling. I'm not the only one to have noticed this and it's a bit disapointing. It still sounds nice with the corrected response as a "ghosted" super-tweeter, but that was with drivers of mine less sensitive than 12LTA.
Anyone else have data on this?
IG
Interesting, I thought this driver was dropped some years ago and why Adire stopped offering their HE12, but all things considered, this is the way I would go even though it drops like a rock above ~15 kHz, though some extreme HF piezos ringed around it and capped off around 60 kHz should work fine for adding some top end 'air'.
IIRC, one of Adire's tweaks was to damp the CD's front chamber with 4/0? steel wool. Maybe Kevin/DIYCable will share Adire's mods now that it's no longer available.
Right, the CX wants a little larger cab tuned a little lower, so at most, a little in room 'critical' damping of the vent or extra internal damping may be required.
GM
Thanks for posting the plots IG81. They coincide with my ears.
Interesting point Rev. Billy Bob. For me, I'd choose the 12lta because of it's extended range provided by the whizzer. This way I can easily add tweeters using simple caps (and coils if I want a steeper slope due to too much overlap between drivers). The 12lta is a wide range driver that can be enhanced on top. It's not perfect but it's easier to enhance the top than building a crossover lower down in frequency IMHO. Many disagree, but it's my listening room and I like keeping things simple, effective and enjoyable... even if on paper it's not exactly right (which I don't think exists).
Zilla
Interesting point Rev. Billy Bob. For me, I'd choose the 12lta because of it's extended range provided by the whizzer. This way I can easily add tweeters using simple caps (and coils if I want a steeper slope due to too much overlap between drivers). The 12lta is a wide range driver that can be enhanced on top. It's not perfect but it's easier to enhance the top than building a crossover lower down in frequency IMHO. Many disagree, but it's my listening room and I like keeping things simple, effective and enjoyable... even if on paper it's not exactly right (which I don't think exists).
Zilla
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