From Email that I got today:
“….. I see that you are considering trying the metal diaphragm again in your S2s. I am using the metal diaphram for the moment (it is all that i have), but have the terrible ringing problem, especially on female vocals. Sounds like the diaphragm is hitting something and the voice just rings for a moment... How are you going to get rid of this if you use the metal again, or are you just going to use for the fundamental channel?? “
There are 4 reasons why the S2 drivers have “terrible ringing”.
1) Dirt in gap. It could be fixed by cleaning the gap.
2) Improper centering of cone when the cones rib the walls of the gap. (Or the dirt in the gap). It could be fixed by re-centering the diaphragm. Be advised that it might be trickier with specific S2 drivers then with others.
3) Natural ringing of the metal diaphragms. The Vitavox older metal suspended diaphragm had own quite brutal top, I have written about it a lot in past. However, I would not characterize it as “terrible ringing” but rather as very minor mechanical distortions. I have also to testify that I have witnessed my metal diaphragms sound very clean, so this subject is under investigations: amplification, electricity, roll off and so on… A plastic suspension cone has no such effect but it has other problems (response, secondary resonance, etc…)
4) The faulty cones. Do not forget that the metal suspended diaphragms are over 50 year old and many of them worked not in greenhouse-like home environment driven by a low power SET but in movies theaters, driven by >100W PP crap, in many instanced with pentodes output.. The S2 is 10W driver and they were severely stressed on the fields. The aluminum cones have a have tendency to develop internal crack when they over-stressed – you do not see it but it’s there. That crack has own “terrible ringing” effect. This problem made Altec in past to move from fully aluminum cones on this 802 driver to the symphonic (plastic) suspension on their 808A drivers. Still, with proper amplification the full Altec’s aluminum do sound much more interesting, though can not handle a lot of power….Rgs, Romy the caT
"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche