So I just simulated this using XSim and resistors for the drivers.
If the impedance magnitude is correct, and driver resonance is a good reason why it would not be, the two woofers in parallel without the switch being thrown go down to about 1.5 Ohms at 42 Hz.
Hopefully this is actually where the driver resonance is, because otherwise it's horrific. The few actual impedance curves I've seen of Infinity speakers from the era have been horrible too.
If the impedance magnitude is correct, and driver resonance is a good reason why it would not be, the two woofers in parallel without the switch being thrown go down to about 1.5 Ohms at 42 Hz.
Hopefully this is actually where the driver resonance is, because otherwise it's horrific. The few actual impedance curves I've seen of Infinity speakers from the era have been horrible too.