I am listening to open baffle Beta 12lta in my parents living room thru old (1990s) Cary el34 tube amp/pre and find them so relaxing. It's a big, lush sound that fills the room. This is a larger room than they were in a month ago. The vocals and harmonies are great (not perfect... a touch forward) and supporting instruments just float... i'm listening to Amiee Mann. One day soon i will hook up the Dayton T-amp i have (the $99 one) and see how much of this magic is attributable to the tubes. The 'tone' is fabulous!
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JRKO, I like the phase plugs you have put in your Beta 12LTA. I haven't had a chance to go through the entire thread yet, but thought I would mention this to you.
I'm just getting back into the 'diy' universe again after walking away from the frustrations of not being able to get my hexagon enclosure project to work satisfactorily for me. So now that I am back and tackling the project again, I'm trying to play 'catch-up' on things.
I've read several of Thorsten's articles on tweaking the Beta 12LTA, and am interested in later coming up with a good 12" driver setup. Unfortunately the 12" driver is just a hair too big for substituting the BOFUR in my project. I didn't make the six sides wide enough to come up with a vertical cabinet large enough to have it fit down on top and accommodate the threaded metal shafts/metal outer rods needed to support the sound diffraction lenses. So I'll have to reserve a good 12" full range driver for a later project, once I am able to finish the original project.
Does anyone have smooth measurements recorded for this driver, and have it tweaked about as far as it can go? I'm still reminded of the Hammer Dynamics Super 12, and John Wyckoff's modifications to the 12".
Anyway, I'll try to catch up on this thread and read this thread as it continues on.
I'm just getting back into the 'diy' universe again after walking away from the frustrations of not being able to get my hexagon enclosure project to work satisfactorily for me. So now that I am back and tackling the project again, I'm trying to play 'catch-up' on things.
I've read several of Thorsten's articles on tweaking the Beta 12LTA, and am interested in later coming up with a good 12" driver setup. Unfortunately the 12" driver is just a hair too big for substituting the BOFUR in my project. I didn't make the six sides wide enough to come up with a vertical cabinet large enough to have it fit down on top and accommodate the threaded metal shafts/metal outer rods needed to support the sound diffraction lenses. So I'll have to reserve a good 12" full range driver for a later project, once I am able to finish the original project.
Does anyone have smooth measurements recorded for this driver, and have it tweaked about as far as it can go? I'm still reminded of the Hammer Dynamics Super 12, and John Wyckoff's modifications to the 12".
Anyway, I'll try to catch up on this thread and read this thread as it continues on.
Let me ask a question: Once you cut away all the junk in the center,
whats difference between Beta12-LTA and Beta12-CX at same price?
As the TS parameters appear nearly identical...
It seems to me you save yourself the effort of cutting off the Whizzer,
and you get a dustcap that breathes... Is it all about the phase plug?
Where you to put a dome there, is that dual purpose as a phase plug?
Was thinking more along the lines of adding whizzer based upon LTA
to the CX, so as to raise electrical crossover frequency out of the vocal
region.
whats difference between Beta12-LTA and Beta12-CX at same price?
As the TS parameters appear nearly identical...
It seems to me you save yourself the effort of cutting off the Whizzer,
and you get a dustcap that breathes... Is it all about the phase plug?
Where you to put a dome there, is that dual purpose as a phase plug?
Was thinking more along the lines of adding whizzer based upon LTA
to the CX, so as to raise electrical crossover frequency out of the vocal
region.
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I believe there is some difference in the response curve of the two. But from what I can tell, the real difference is that the LTA is designed to be a one piece driver, with a solid cap, while the CX is set up for a screw on high compression driver to be mounted on the back of the driver. Hence the 'breathing dust cap'. Here is what I mean.
I wonder just how good these are when coupled together? I know that Celestion CDX1-1731 has been recommended here on the forum. Seems to be a good price right here.
page 10 "From listening I do know that I don't like the cupped sound and removing the whizzer did get rid of it."
I had the same problem with my pioneer b20. It added a saxy-ness honk (or cupped sound) to things that drove me nuts. I had dust cap and whizzer but added cotton batten between cone and whizzer. It has something to do with the whizzer and it improved when I trimmed a bit of it off (like 1/8th), but then I needed full 12db boost on the 10 band equalizer at 16khz versus 6db boost neede to my ears b4 trimming.
I don't notice people complain of this on other drivers.
Maybe it is caused by a large whizzer compared to the cone's size.
Norman
I had the same problem with my pioneer b20. It added a saxy-ness honk (or cupped sound) to things that drove me nuts. I had dust cap and whizzer but added cotton batten between cone and whizzer. It has something to do with the whizzer and it improved when I trimmed a bit of it off (like 1/8th), but then I needed full 12db boost on the 10 band equalizer at 16khz versus 6db boost neede to my ears b4 trimming.
I don't notice people complain of this on other drivers.
Maybe it is caused by a large whizzer compared to the cone's size.
Norman
I will soon join the 12LTA wagon, have high hopes for them.
What is the max diameter for the phase plug, 48mm-49mm?
Has anyone tested aluminum phase plug and what it does to the driver's inductance, impedance and HF response? Or using copper ring (massive copper washer for ex.) on bottom of a wooden phase plug, which would also act as a shorting ring and could in theory reduce the inductance a bit and possibly even reduce THD. This might require the phase plug to be attached with a screw through the magnet's rear went though.
What is the max diameter for the phase plug, 48mm-49mm?
Has anyone tested aluminum phase plug and what it does to the driver's inductance, impedance and HF response? Or using copper ring (massive copper washer for ex.) on bottom of a wooden phase plug, which would also act as a shorting ring and could in theory reduce the inductance a bit and possibly even reduce THD. This might require the phase plug to be attached with a screw through the magnet's rear went though.
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Can work in K15 cabinet
I think the 12LTA can work well in a Karlson K15 cabinet (1954 with 30.5 sq in vent). This is a simulation in AkAbak at 3 meters away with 1 watt input power. Super efficient driver - too loud for most listening applications inside a house.
I think the 12LTA can work well in a Karlson K15 cabinet (1954 with 30.5 sq in vent). This is a simulation in AkAbak at 3 meters away with 1 watt input power. Super efficient driver - too loud for most listening applications inside a house.
Attachments
12LTA has a weak motor & 0.08" overhang so imo not as subjectively dynamic in a K12 as 80 and 109oz magnet Eminence coax but would be appropriate for K15 to maximize its potential. 12LTA in the 6-slit vent K12 did do well on Danley's Harley bike track vs AN10 in a reflex where the Nirvana lost all cone control. A Karlson between K15 and k12 size should work. A K-tube helper or something like Selenium's ST324 would work. 1 Maybe I'll add a Nuke 6000 to my amplifier collection :^) 1KW if decent quality on the low watts would allow for pretty good drum transients. Would a K with rear chamber = (qts*fs*vas)/50 be about right for 12LTA?
Can't figure why ST324 availability suddenly dried up and blew away.
Was a great tweeter with great dispersion, and absurdly inexpensive.
Clone of JBL, but now that JBL owns Selenium, whats the problem???
Slots can touch off high order modes in a waveguide, but only when
there are opposing walls to support those modes. Slot on a flat face'd
180 degree waveguide very simply evades the entire issue...
Its about an inch from ring radiator to slot mouth, there's probably
a dip or peak associated with that length, but I could never hear it...
Beta12LTA has a different dispersion pattern than ST324, unless you
put it in a Karlson, then its no problem... A great match to continue
the dispersion pattern of a Karlson.
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For Beta12LTA, this tweeter might be another reasonable match.
http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-1028
4ohms, but if you can work around that, or Siamese 2 in series....
Was a great tweeter with great dispersion, and absurdly inexpensive.
Clone of JBL, but now that JBL owns Selenium, whats the problem???
Slots can touch off high order modes in a waveguide, but only when
there are opposing walls to support those modes. Slot on a flat face'd
180 degree waveguide very simply evades the entire issue...
Its about an inch from ring radiator to slot mouth, there's probably
a dip or peak associated with that length, but I could never hear it...
Beta12LTA has a different dispersion pattern than ST324, unless you
put it in a Karlson, then its no problem... A great match to continue
the dispersion pattern of a Karlson.
------
For Beta12LTA, this tweeter might be another reasonable match.
http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-1028
4ohms, but if you can work around that, or Siamese 2 in series....
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Freddi, you should put in something K15 size with sideways shelf and Kukoo
Klock upper chamber. I don't think the clock actually needs complex curves
as I've drawn, just angles or simple rounds... Same K15 volume, same K15
vent area... Removable bottom may not be critical for tool access on a 12"
in such a big cabinet, but makes sense when sideways shelves act as brace.
Klock upper chamber. I don't think the clock actually needs complex curves
as I've drawn, just angles or simple rounds... Same K15 volume, same K15
vent area... Removable bottom may not be critical for tool access on a 12"
in such a big cabinet, but makes sense when sideways shelves act as brace.
My phase plugs are 44mm dia & 70 in total length as recommended by Dave of P10, forum member JKRO very kindly got me a pair made. I seem to remember that the parallel section should be 30mm in length.
The 12LTA is a beast of a driver for its price, I've had mine running for 12 months in P10's EmKen enclosures and am pleased with them (Enclosure's good as well)
The LTA needs a fair bit of running in, mine were used as gaming monitors in free air for a few months and had test tones played through them, but only after giving them a good thrashing - quite a few in reality - in the cabinets did they start to sound more relaxed.
Mine have their whizzer's pluffed and have added thick felt to the insides of the basket legs to reduce reflections.
After reading some where on this forum that phase plugs might be better off being made of a 'sound absorbing' material, I made a 'craft felt' sock that slips over the plugs. This has tamed their shoutie-ness a bit more and imaging has improved.
JKRO likes the addition of a Fostex FT17H tweeter, I have these bit some thing about the sound when crossed with a simple 2.2uf cap don't sit well with my ears (maybe I'm too close to the speakers) so I use a pair of 25mm soft domes cannibalised from a pair of Wharfdale Diamond speakers.
Not the last word in HiFi, but defo good bang for £/$.
Thanks! How much is there clearance on the sides with 44mm diameter plug?
I was looking at these 48mm diameter aluminum knobs and thinking maybe they used as the shorting rings...: 2pcs 48x22mm Solid Aluminum Volume Amplifier Test Knob | eBay
Alu knob against the pole piece, phase plug glued on the alu knob and the whole deal attached in place from the magnet's vent (preferably with a non-ferrous material bolt, aluminum, brass etc. would be good). I think one should sand off the anodizing layer (because it does not conduct) and then some more if needed. By attaching the plug to a hand drill and turning the hell out of it agains fine water sanding paper this would be quite easy.
Not the most expensive thing to try. What do you guys think?
Damn some rosewood, walnut, ebony etc. phase plug would look nice. Or on the other hand some lighter colored wood like maple tree. Finishing the plug with shellac might affect the sound a little as the plug is in constantly vibrating place. Also the chosen wood might affect the outcome.
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Hi Legis,
Voice coil OD is 50.8mm, so maybe 48 - 49 id.
A professional musician friend called round early evening and commented strait away that the 12lta 'sounds a damn sight smoother, what crazy thing have you done now?'
I sat him in the hot seat and let him listen to a song, when it ended I pulled one felt sock off and hit play again..... then handed him the felt sock.
'Amazing!'
£20 phase plugs with 10p's worth of felt wrapped round em.
Don't let me put you going mad with ideas.... but some times the real simple stuff works better and costs less hair pulling.
Accept that these are inexpensive PA wide-ish range drivers, accept their limitations and enjoy
ps - go easy with the loud dial, with 97db/1w sensitivity one can go from 0 - deaf in only a few seconds. I SimRace, one neighbour commented that it sounded like there was a motor race going on round the village...... told her that it was me and my monster speakers, driving a Ferrari F458 GT3 sim car while wearing my old motorcycle helmet and earplugs
She lives over 300ft away
Voice coil OD is 50.8mm, so maybe 48 - 49 id.
A professional musician friend called round early evening and commented strait away that the 12lta 'sounds a damn sight smoother, what crazy thing have you done now?'
I sat him in the hot seat and let him listen to a song, when it ended I pulled one felt sock off and hit play again..... then handed him the felt sock.
'Amazing!'
£20 phase plugs with 10p's worth of felt wrapped round em.
Don't let me put you going mad with ideas.... but some times the real simple stuff works better and costs less hair pulling.
Accept that these are inexpensive PA wide-ish range drivers, accept their limitations and enjoy
ps - go easy with the loud dial, with 97db/1w sensitivity one can go from 0 - deaf in only a few seconds. I SimRace, one neighbour commented that it sounded like there was a motor race going on round the village...... told her that it was me and my monster speakers, driving a Ferrari F458 GT3 sim car while wearing my old motorcycle helmet and earplugs
She lives over 300ft away
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