Ok heres how it works out...
Each voice coil is 4 ohms. you are using amplifiers that are 2 ohm stable in stereo..which means the lowest impedance you should bridge to either amp is 4ohms. Connecting a 4ohm load to a stereo amplifer bridged to both channels..is running the amplifier at 2 ohms..so technically..this setup if using both amps this way will be two-2ohm setups.
As far as if there will be more distortion with a 2ohm vs a 4ohm vs an 8ohm has to do with the particular amplifiers specs. Heres some examples I pulled off manufacturors websites. The first is an alpine amp I am actually installing in a 2007 saleen extreme mustang this week with 2 JL 10W7's ..along with a boatload of other goodies..I will post pics when it is completed.
Alpine PDX-1.1000
RMS Power (at 14.4V THD+N,20Hz-200Hz)
Per channel into 2 ohms : 1000W x 1 (<=1%THD+N)
Per channel into 4 ohms : 1000W x 1 (<=1%THD+N)
Notice the THD as WELL as the power output does not change despite the ohms load.
Ok another amp....
Alpine PDX-2.150
RMS Power (at 14.4V THD+N,20Hz-20kHz)
Per channel into 2 ohms : 150W x 2 (¡Ü1%THD+N)
Per channel into 4 ohms : 150W x 2 (¡Ü1%THD+N)
Brigded 4 ohms: 300W x 1 (¡Ü1% THD+N)
Notice with this alpine amp that the THD never changes nor does the power..it is 150 X 2 in stereo..or 300w X 1 when bridged @ 4ohms (this is how your amps will be running). Note this amp is 2ohm stable....but it only shows specs bridged into 4ohms...that's because as I stated before the 2ohm rating on a 2 channel amp is per channel..the amp is technically running at 2ohms when a 4ohm load is bridged to it. Ok next amp...
Boss BL1000
Max power: 500W x 2, 2 ohms
RMS power: 210W x 2, 4 ohms
Bridged power: 1000W x 1
THD: 0.01%
OK..notice the difference in the way the specs are done. With Alpine it is not that they are underrated..that would be really poor marketing and self defeating. The key is that alpine amps are rated honestly and at usable power levels.
This Boss 1000w amp is maybe 400w RMS at best going down hill with the wind at it's back. They claim the THD rating is at RMS levels so I guess we have to believe that. next...
Sony XM-D9001GTR
mono subwoofer amplifier
550 watts RMS x 1 at 4 ohms
900 watts RMS x 1 at 2 ohms
2-ohm stable
Here'a a Sony mono amp.....notice they give no THD specs..oh well. Now..the RMS ratings for this amp are not too bad..but notice when the load is cut in half..the power does not double.
So whats it all about? We see one amp that the power stays the same regardless....one amp that doubles when the ohms load is halved..and one that is rated 200 watts less then double when the load is halved. This is your answer..lol Hope it doesn't add even more confusion.
Now..for my opinion on using both those amps to one DVC sub...I don't think it is worth the extra work..but if you have time try it out. The deal is this. Running each of those amp at 2ohms (bridging then each to a 4ohm voice coil) will allow each amp to operate at it's highest power level..assuming the power level goes up when bridged...by how much? As you see it depends on the particular amplifiers specs.
Which will sound better?? I don't know 100% so no harm in trying other then it sounding like total doggy doo after the install.
Now..if You follow my advice and just install the Alpine,,,,since that amp can not handle a 2ohm load bridged to it (which would technically be running the amp at 1ohm..no good) we need to series the coils for a final load of 8ohms. When we bridge that to the amplifier it will technically be running at 4ohms. So you may have less output vs. the 2 amps..but it won't hurt anything..as a matter of fact at 4ohms that amp will be running cooler. If that amp loses half it's power at 4ohm you will be running 80watts to it..not bad...if not 160w. But either way it is honest RMS power and I would assume a cleaner signal. Using both amps I would think the Boss would reach distortion levels much sooner if trying to match the alpines output.
I don't know what effect that will have since i have never tried this myself....has anyone else? post results. But I can't imagine feeding each coil of a DVC a different sine wave (although how different I can not predict) with any great results. In other words it may sound like ass..but can't hurt too much to try it..maybe I am wrong, you decide.
Custom Audio
Lynbrook NY
ASE/MECP master certified