Hello all,
I'm new to the forum. I have a Roland RD170 and a Yamaha sequencer. Also, a set of Behringer b2031a's. Do I need a small mixer to hook the RD170 and the sequencer to the monitors? What do I need to know about balanced and unbalanced connections?
Thanks

In your set-up it will have little effect.
Using balanced cables and connectors will reduce interference to the audio especially on long cable runs.

A mixer might be useful, do you intend to expand on the system, if so get a mixer with a few extra inputs than you need - for future expansion.