I have recently built a 50w tube amplifier and I am thinking of building the Theater 4 PI. Could you send me a copy of the plans.
Thank you for the very nice article on crossover design and speaker motors on your site.
Just a quick note on tube amp. output impedance. Many of the small SE 2a3 and 300b amps do not use feedback. This causes the output Z to be quite high( Often in the 2 to 4 ohm range. ) Also sometimes even large tube amps without feedback like the Mesa Baron at about 100watts have a high output Z. The Baron is 4 ohms or greater. This much output Z has serious effects on damping. It also acts as a voltage devider so that the voltage at the speaker terminals varies with changes in speaker impedance. This can result in peaks of several DB at the typical crossover related Z peak.
Got to go.
Thanks
Brian