Mono, stereo or multichannel - which DI is best? It depends upon your point of view.
If audience members are sitting right in front of the left PA loudspeaker, they will be unable to hear what is coming out of the right PA loudspeaker. Will they benefit from stereo?
Stereo may sound great in the practice room or be invigorating on stage, but in most live venues, it is rarely enjoyed by all. The advantage that a stereo DI brings is capturing the stereo sample without having to reprogram the synth.
And if you do decide to have a stereo rig on stage, a stereo DI allows the house engineer to mix both channels and pan them stereo (if beneficial).
A stereo DI is often used at the output of a keyboard mixer. Here’s why: on a stage, all of the microphones go to a mic splitter before the signal is sent to the house mix position.
Mic splitters are designed to handle mic levels, typically around -50 dB. A keyboard produces a -10 dB signal while a mixer can produce +4 dB or more.
A look at one reason why a passive DI can be a better choice for electronic keyboards. Courtesy of Radial Engineering.
This excessive level will cause the mic splitter to overload. The pad on a direct box lowers the output so that it matches that of a microphone and protects the mic splitter from being overloaded by the mixer.
Multichannel direct boxes bring forth the added advantage of independent control over each instrument.
Here’s the deal: when you mix the sound so that it is comfortable on stage, it may in fact not be ideal for front of house.
In other words, you may find that you need extra jam to hear your piano on stage, and have the string synth pushed back in the mix.
But in the arena, the piano-to-string volume ratio may not sit well with the rest of the band. What happens? The keyboard mix gets pushed back.
When you have the luxury of sending independent keyboard signals to front of house, the mix engineer is allowed to orchestrate.
With more control, the engineer can decide how much piano fits and if the strings are too loud, can simply back them off.
Who would have ever thought that a DI would have so many twists and turns, especially after being around for 40 years!
Peter Janis is president of Radial Engineering. In 1982, he was hired by CBS Fender as new product director for what would eventually become Fender Canada, and spent time at the ARP factory in Massachusetts learning to program the advanced Chroma polyphonic synthesizers. He met Harold Rhodes and spent several years servicing Rhodes pianos before they were eventually discontinued, and during that time, also added the Akai product range to the Fender sales portfolio and developed many of the Akai’s early samples.