I play an RVS amp with Roland and Moog synth, the rest of my band plays too loud so I need more volume (you know guitar players ). Well this has a speaker output, will this help or should I just add a second amp? Does anyone have one of these? Any help is good help.
Thanks

The extra speaker can only safe be used for an extra speaker cabinet.
This will give you some extra but most likely not enough.
I don't know the rvs amp but to have enough in a band situation you need for keyboards a lot more watts as the guitars!

This is by the way often not only caused by the guitars but very often by drummers..
Because the drums are too loud guitars have to go louder too.

I use 2 x 300 watt for my keyboards, while our guitar amps are only 50 en 60 watt.
(only the base uses 150 watt)
This can give you an idea what you need.

The alternative is go through the PA if you have one and use a monitor for yourselve.
(you have those hotspot's on a stand which work great as well)

Fred