In Reply to: Sam, I would like to try that posted by spkrman57 on January 17, 2003 at 13:35:51:
is safe at LR levels, especially since the altecs can cross as low as 500 or 800Hz. 2nd order. Remember, a 12dB pad means only 1/16 the available power can get to the voice coil.
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So, nominal values for 16 ohms series xover at 1.6kHz. are 1.6mH and 6.21uF, again not written in stone. Minimize the DCR of the coil. Try to get your pad values so the total Z in that portion of the series circuit is 16 ohms.
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Weems suggested multiplying the L by 1.25 and the C by 0.83 for maximum flat response from each driver (2.0mH/5.15uF). Using the raw values I mentioned above provides the flattest Z back to the amp, obviously hooked to 16ohm taps for tubers.
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Since PE has no 14ga. 1.6mh coils, using 1.8 or 2.0mH, and playing with the cap value (between 5 and 6uF) will be needed. For those small partial values, throw on a dayton film/foil bypass of 0.22uF across the main cap. Under $40 in parts, plus your pad resistors.
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I found the sound "quicker" using the series xover, but with the dual 15's I figured running out to 1.6kHz. was too high. Using a single 2226J is perfect, and the series coil should be plenty of attenuation for the woofer. Wayne suggested 1.4mH I believe for "pseudo-BW" as in the 4 Pi Pro's...this circuit is very close.
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Some guys have run the altecs down to 500 and 800 with just a single cap, at moderate volumes. So taking it up 2X higher than normal, and crossing it 1st order is "safe". At least under 100dB:) And the simplicity of a single cap feeding the HF. Try it, you will like it... Sam
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I'm tempted to pull the 2035's from my quasi-4 Pi Pro's and install 2226J's, with altec HF drivers on the H290's, and follow my own advice:) nope, too hard to pull those damn port tubes loose from the rtv and retune:(
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