Ryan Gimpert
From:
Detroit, Michigan, USA
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Posted 16 May 2018 5:26 am |
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Looking for something that can give me good head room.
JBL D, E, or K12...Altec...EV....will also consider the right Eminence model.
Let me know! |
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Jim Dickinson
From:
Washington, USA
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Posted 16 May 2018 12:45 pm
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You can always use a speaker with a higher ohm voice coil, like a 16 ohm, it won't hurt the amp and power transfer loss will be minimal.
There is a lot of misinformation about what is the real impedance of speakers. You can tell by the DC resistance of the coils, simply take a good ohm-meter and measure across the terminals.
A 8 ohm driver measures 6.5ohms, 6.2-6.8 variation
A 12ohm driver ought to measure 9-10 ohms.
A 16 ohm driver 12-13 ohms.
Many musical instrument drivers measure lower than above, for years 5.5 ohms was their 8 ohm target, done to draw more current and appear louder than they ought to. If you could find a 16 ohm MI driver, you are probably right on, they will usually measure 10.5 ohms. Eminene NEO's are all too low, their 8 ohm drivers are 4.6-5.5 ohms.
What diameter are you looking for, I can rebuild you an ALTEC 418 15" or if I can find a frame, a 417 12" model. I have a source of good used 418 magnets, they use the same one. I won't do it until I get our magnetizer which is in transit from California. Most alnico MI magnets, ALTEC JBL's, Trusonic's, etc, need to be recharged, former hard Rock and Roll use flattened them, they recharge just fine. Ceramic, or feritte magnets don't tend to discharge. I have a proper source of the rest of the parts. We ought to have the magnetizing beast here and functioning sometime in late June, it weighs 18oo pounds needs 3 phase power. Other than that ask any questions you like. Be careful of reconner's they usually use whatever parts they can find, which usually are not right, and only a very few can recharge your speaker.
I do know Eminence will make you a custom Voice coil impedance, but their 16 units ought to be right on a real 12 ohms, with 10.5 ohm DC resistance. |
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