Most USB and 1394 Audio Interfaces use 1/4" TRS Outputs.
The answer to your question is yes, you need a 1/4" Cables, however a dual cable would not allow you to spread your Monitors far enough apart, you'd have to pull the dual cable apart. You're better off purchasing two individual TRS 1/4" cables of the appropriate length that will be the distance from your interface to your monitors. In most cases 2M or 3M is adequate.