Subwoofer/monoblock connection

IF your amps are not differential amps, your connects are as Miller states.

Yeah, if the amps are balanced (differential) you cannot simply wire + to + and - to -. The REL method is one sub to each amp, using whatever connection method you wish. (I use bananas with spade speaker connections) If balanced, simply leave the negative lead disconnected. If there is hum, ground this lead to a chassis ground. Some amps, such as Pass, provide a ground post for just such a connection. If you still have hum you will most likely have to use the low level inputs from a pre-out or Sub-out on your preamp. IF your amps are not differential amps, your connects are as Miller states.

Put these two together and it means all you have to do is connect +/- to +/-.

Caution!!! Some amplifier (bridged amplifier and some class D amplifier) are not safe to connect to subwoofer via high level (speaker level) +/- to +/- connection.

What monoblock amps that you like to connect to the high level inputs on a pair of subwoofers?

Any way you like. I use spades. This leaves the banana connector free. For a while I twisted bare wire and stuffed it in the banana hole. You could also twist bare wire around the bare part of the spade connector. Really. Does. Not. Matter.

Thank you for the response.  I should have phrased my question more precisely.  Since the amps only have one set of binding posts, how would I connect both the sub cable and speaker cable?

All subs, regardless of how they are labeled, are mono. Additionally, with any sub that takes high level inputs the first thing in the circuit is a 20k to 50k ohm resistor. This is necessary to drop amplifier voltage down to the same as a line level input. This also means that connecting a sub this way presents a negligible load on the amp.

Put these two together and it means all you have to do is connect +/- to +/-. Which channel won't matter, because it is mono. It won't even matter if one amp is connected to one sub, or all of them, the load is too miniscule to matter. You can even sometimes run from one amp to one sub, and then from that sub to the next. Really, any way you do it is fine.