You absolutely need the specs from the amps and all the monitor speakers. Also note that mix 'n match of different speakers can be problematic. Even when the speaker impedances match, one speaker model can be more efficient (i.e. louder at working distance) than another. A matter of trying it out.

Formula to calculate combined impedance: Zc = 1 / ( 1/Z1 + 1/Z2 + 1/Z3 + …)
You don't want to be lower than the lowest impedance the amps can handle.

You should be able to, just don't ever connect 3 in a row.

It does depend on the amp ratings and speaker ratings so check them out.

Typically, an amp will allow a 4 ohm load without issues. Most typical speakers are rated 8 ohms, so when you daisy chain two of them together, the load on the amp becomes 4 ohms, which as said most amplifiers can handle. But you have to watch, some speakers are 6 ohms, so two daisy chained gives 3 ohms which may be unsafe for the amp. Some amps say they will handle a 2 ohm load, but I honestly would not recommend putting that kind of load on an amp, they just say that so they can say it's a 2000 watt amp (at 2ohms) instead of the reality which is something 500 watts at 8 ohms, the number 2000 helps sell more amps.

A stereo amp has two separate amplifiers so for all intents and purposes, what you do with one side of the amp has no real effect on the other side (as far as I know) when set to stereo (as opposed to bridged or parallel amp setting)

Steve

Yes, an amp specified as 2000W into 2 Ohms can only do 500W into 8 Ohms.

P = V^2 / Z so with max 2000W into 2 Ohms the max output voltage is 63 Volts. With that voltage you can only get 500W into an 8 Ohm speaker.

An amp with a 2 Ohms load spec should be able to handle it too. It will get a lot hotter though!

I was hired this summer to run sound for a church just for one day when their sound guy was on vacation. He had 4 speakers daisy chained together coming from one channel of the amplifier, the other side of the amplifier wasn't even being used LOL. So, in that case we had four 8 ohm speakers which together create a 2 ohm load (math check?), so technically the amp they were using was capable (I think. . .maybe), but I'm sure it got hot, and if they just set the amp to parallel mode they could have used both sides and still just used one aux mix, but I didn't want to confuse anybody so I left it the way it was and just let the folks know about the issue (probably right over their heads though), made it through the gig at least hehe.

I have read that an amplifier provides better damping the higher the ohm load is compared to the amp load capability, so an amp capable of a 2 ohm load which has an 8 ohm load on it will have better control of the woofer. Damping is the ability of the amp to bring the speaker back to rest when the input signal stops, making for tighter sounding bass. For that reason I tend not to daisy chain any of my speakers these day (always looking for sound nirvana and every little bit helps)

Steve

Yes, low end can become an issue with max load, especially when the speaker cables are, eeh, marginal. 2000W into 2 Ohms that's over 30 Amps! Even with short runs speaker cabling becomes a serious part of the equation. Only 1 Ohm cable resistance and up to 30% of the amp's output power will be dissipated in the cables, with a preference for LF power!