Is there a way to convert between the 2 rating so I can compare subs better.

Subtract 3 db from the 2.83 volt/m rating and it equals 1w/m. Im about 95% sure

Nope, The rating will differ with different loads.

The output in watts with a 2.83V is going to differ with the resistance of the coil. With 1w/1m, it's always a single watt. When comparing a 8 ohm driver to a 4 ohm driver, the 4 ohm driver will get twice the power due to the lower resistance.

2.83 volts at 4 ohms will give you about 2 watts.

2.83 volts at 8 ohms will give you about 1 watt.

The 2.82 volt rating will make less efficient drivers at a lower load seem to be much more efficient when they are not.

As for an easy way to convert them, I cannot answer that question but I am sure some more knowledable people will have a bit more insight on that.

To calculate 1W/1M SPL = 112+10*LOG((9.64*10^(-10)*FS^3*VAS)/QES)

Vas = Liters

To calculate 1W/1M SPL = 112+10*LOG((9.64*10^(-10)*FS^3*VAS)/QES)

Vas = Liters

There's the answer you were looking for!

Thanks Bromo

Wow thats got me wondering about my Mach5 IXL 12"...I'm sure that driver is an exception, it will be quite good right?

An easy way to figure it out is subract 3db for a 2.83V rating every time you halve impedance from 8 ohms...

So, if it is a 4 ohm sub, subtract 3db, a 2 ohm sub 6db, etc.... This is just a rough way to get the numbers, but it is usually pretty close.

An example is-

Sub X is rated at 90db 2.83V/1M. It has dual 4 ohm coils and the sensitivity is rated with the coils in parrellel (2 ohms). This sub is roughly 84db 1W/1M.