An adjustment has been made make correct for the imbalance in sensitivity between the woofer and the tweeter. I have used the SPICE circuit analysis program to calculate electrical response curves for an 8 or 16 Ohm Hiraga circuit with corresponding constant resistance loads. Hiraga Crossover Electric Response Curves Calculated with the SPICE Circuit Analysis Program: For a 16 ohm version one would double the inductor, resistor, and L-pad values and halve the capacitor values. Here is the crossover circuit for the 8 ohm Hiraga circuit, with an L-pad added tor control of tweeter output. The circuit is second order, crossing over at 580 Hz, with a notch filter creating a dip of about 4 dB at about 3500 Hz, which can compensate for excessive sensitivity of the tweeter horn in the middle of its band, and can diminish harshness in this range that sometimes plagues recorded music, particularly on massed strings and massed vocals. The circuit also provides a rising high end above 10 kHz which helps the tweeters out at the top end where they roll off around 12 kHz.
#ALTEC LANSING ATP3 CIRCUIT BOARD FULL#
I liked the result, finding the frequency response provided by the circuit to provide a nice full midbass which adds to the loveliness of these speakers. I obtained the circuit from the Jon Stronczer article, and decided to try the crossover circuit on my Altec Lansing A7 loudspeakers. The Hiraga crossover circuit of interest was designed by Jean Hiraga for use with a pair of Altec Lansing A5 loudspeakers he famously showed in his Paris salon.