First: What is a direct box and why is it used:
A direct box or (DI) is used when you need to send an unbalanced signal; most commonly bass, electric acoustic guitars or keyboards direct to your mixing board. Typically these instruments have unbalanced ¼” outputs. On a typical stage the Drums and guitar amps will use microphones to carry their sound to the front of the house mix while the aforementioned instruments will most likely run direct to the mixer. Without a DI you would be running hi impedance instrument cables to the mixer and that can present problems. Of these problems these three are the most common:
#1. These unbalanced cables can pick up unwanted noise and inference, also the longer the cable run, the more likely this becomes. A good direct box eliminates the “hum” or noise by balancing the signal.
#2 . Because a Di takes a ¼” unbalanced cable (and signal) and it converts it to a balanced signal via 3-pin connector Microphone cable and carries your signal to the mixer, you should use a DI if your cable is longer than 20 feet; the low-z balanced mic cable will carry your signal extremely far without degradation.
#3. Most DI’S offer pad and loop features –the pad feature helps make sure you sound isn’t distorting because it’s too loud before it ever even gets plugged in to the mixer (not all mixers start at the same volume) , and the loop helps you monitor yourself directly on stage or duplicate the signal for things like recording, or amplifying in yet another location!
So, in short most direct boxes allow you to: Avoid unwanted noise, send a nice strong signal far away, avoid that signal clipping when it gets there, and duplicate that signal so that it can be in two places at once! They are a tool every musician should have in their gig survival kit.
See the Modtone
See the Radial