Sub-Amp Wiring Question - Damping Factor Vs. Power Vs. Bridged/Stereo Mode

You can run Mcintosh valve amps in series or parallel. Normally one after the other they can't handle low impedance. Paralleled they can half the impedance, to 2 ohms. They sound like crap, but you can do it and that is what Mcintosh recomends..

Using a 4 ohm tap on a SS will give you the highest output with the least amount of dampening and cone control. The lower the impedance the higher the distortion and much lower if any dampening. IF they are using a passive XO only ONE type offers any dampening at all. 6db first order, BUT I guarantee when the impedance goes HIGH the speakers will go out of phase. 

Plate amps and Active XOs DON'T.. 

As I said 8 ohms offers better cone control and can offer a lower octave without a strain. It's a sub it dosn't need watts it just needs controlled movement. Nothing else to compete with so to speak.. WHY a million watts?

I could do it with 100 watt plate amps with cone control.. BUT 1000 watts will blow stuff up if it's not controlled some how.. Just saying.. :-)

Two Dayton amps and 4 subs has allowed me to run them every which way, and so they have been tried at 4, 8 and 16 ohms. Technically at 4 ohms the amps have a lot more power and so should play a lot louder. In practice it hardly matters because no matter which way I run there is plenty of bass. At 4 ohms the bass is warmer and fuller. At 16 tight and articulate. 8 is in between but closer to 16 than 4. So I run mine at 8.

Currently, I am using 2 ohm wiring and one channel of the amp.

Why not utilize both channel of your amp as @holmz suggested?

You can wire each voice coil to a separate channel of your amplifier, and each amp channel will see a 4 ohm load and be able to provide up to about 750 watts (if the amp can double up power if load halved).

It's a sub it dosn't need watts it just needs controlled movement. Nothing else to compete with so to speak.. WHY a million watts?

It’s a 10” sub that has an efficiency of 82.7 dB and it’s in a sealed box. Plus I like to be able to turn it up sometimes to hit somewhat realistic volume levels on bass heavy tracks. I have everything working against me from a power standpoint, haha. I need massive wattage to make this work. And it does work. Some of the best bass I’ve ever heard has come out of this sub with proper DSP implementation. After moving to a new house and running into power issues from my utility, I kind of had to start from scratch. I even tried large sealed lead acid batteries with large capacitors and DC amplifiers. Fortunately I was able to get the utility to track down and fix one of the power supply problems so now I’m back to using an AC power amp and am currently trying to optimize it. 

I use 12K Behringers on 91% efficient speakers @ 8 ohms. BUT I have a TON of overhead. I see the price doubled too. I use to get 3 for 1200.00 Great deals..
I'll tell you something else, they are dead quiet. They have fans, I disconnect 2 and put one on a toggle.. LOL Never even get warm, without a fan..6 years old now. They run 12 8" drivers or 4 18" HE drivers right up a flag pole.

82.7 mercy!!! 90-91% efficient is what I run. 82.7 you would need a welding machine to pump it out.

Start there 83% efficient is a tosser for me. Get a better driver, FIRST. 375 watts at 8 ohms on any of my systems will run you right out of the room. 110-115db. I can turn it all the way up to 100% 700 watts per sub (close) and hit 125 db, I can bump the gain, quit a bit. That is under 35% gain . High power class Ds and High efficiency speakers will get really loud, IF that is what you like. Direct coupled great dampening, otherwise VERY little.

Have a half way safe New year and the other half, don't be unsafe. BUT if you're gonna do something with the stereo while you're drunk, please take a video.. 

Half Safe, ALL the way HAPPY NEW YEAR.... Video Please.. :-)