some guy was telling me that all subs run in a mono state is this true?

 

it's not the subs that run in mono, its the amp.

 

well - yeah - they do run monoral - bass is like unidirectional

 

No, low bass is omnidirectional.

Any single speaker is mono. It takes two speakers with separate left and right signals to be stereo.

 

It's a bit tricky with subs. You can get a sub with dual voice coils and wire right and left separately to each coil. All this does is provide a convenient way to mix the left and right down into a mono source (without ever really mixing the electrical signals). Now, you could have two subs, with one fed from the left and one fed from the right. For most music, you probably couldn't tell the difference between this and a system where just a mono (mixed) signal is sent to both subs.

 

Feeding two different signals into the voice coils would be a bad idea. They would be fighting each other on the same sub and something would break. If you are going to wire the voice coils to separate channels, then you need to supply a mono signal to those amp channels.