Another alternative in an adjacent/current thread:
http://www.audioheritage.org/vbullet...l=1#post430265
Another alternative in an adjacent/current thread:
http://www.audioheritage.org/vbullet...l=1#post430265
If you have no experience then get a professional technician to do it like our Edgewound at Upland loudspeaker repairs. It’s not as simple as it might seem and to do the job properly requires cleaning out the magnetic gap and careful centering of the diaphragm with test equipment.
The Radian diaphragms are designed to be a drop in replacement for the Jbl diaphragms. The motional impedance curve a similar so it should work in with the crossover okay. There may be some response variations however so expect to hear some subtle differences.
On my do to list is to measure a radian diaphragm and work out any crossover tweaks required for the popular legacy systems.
https://m.facebook.com/UplandLoudspeaker/about
http://www.audioheritage.org/vbullet...ression-Driver
Seems like I will just need some masking tape to clean out the gap where the voice coil goes in and a Oscillator for a curtain frequency to make sure there is no buzzing? correct? If there is buzzing just slightly tap on the diaphragm surround mount til buzzing stops? Correct?
You need a reasonable signal voltage which l don’t recall off hand and sweep oscillator and a power amp. Ideally an oscilloscope to evaluate the sine wave. Also ear muffs.
One slip of the screw driver and it’s game over.
If l were you l would ask Edgewound to do it.
IF dead set on DIY, here's some old man ranting for you:
You may also need to open up the holes slightly on the diaphragm 'frame' and/or put a -slight- bevel/relief on the outside of the frame where it meets the top plate... to allow for more -minor- adjustments (ONLY if needed).
Tech Manual calls for 2.83v input 550-1.2KHz, but is slim on details like... is that RMS, peak, peak-to-peak and with the driver 'loaded' (horn attached) or hanging in the breeze (on the low end of the frequency range in particular). I'd keep it below 2v p-p regardless, working your way up from much less.
Do you have a way to measure this? A -normal- Digital voltmeter will not likely give you a good reading at higher audio frequencies (often calibrated for 60Hz). An oscilloscope would be good...using it properly, better. Along with hearing protection (as has been noted), and tolerant family/neighbors.
Hearing the distortion of a voice-coil barely touching does take some experience (other times it's quite obvious). Then there's the phase plug to diaphragm spacing... probably other things I'm not thinking of.
All that said, sometimes you get lucky (or are ok with it being non-optimum). Have a way to measure on-horn frequency response later?
Mostly, if the process does not go so well and something is damaged, you have ZERO remedy, but maybe gained some experience.
It may sound like I'm leaning toward a recommendation of leaving it to the pros (as most should)... but if you have the time, interest, and can afford to make a few mistakes, have at it!
(is there an emoji for getting off of a soapbox?)
Good plan
Ken's a good guy. Hope it all comes together.
Absolutely
The whole job is only as good as your drivers so it’s worth getting them right.
Ok fellas, I'm back to report I got both my 2245H reconed and my 2420H horns repaired with new Radian Diaphragms by Ken @ Upland. Ken did a great job on both and now I can get back to my JBL 4345 build.
That’s great news
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