|For years, guitarists and s ound engineers have been trying to find a way to capture the sound coming from the amplifier without the challenges of using a microphone. Although getting a great sound with a mic can be accomplished, it usually takes a lot of time and careful mic placement. This can take hours and even days to get just right.But in a live situation, this is simply impossible due to time restrictions and available space on stage.So for years, a ‘compromise’ has been achieved by placing a mic directly on the speaker cone.Now if you stop and think about it, the sound of a guitar changes depending on where you are standing. This is particularly acute with guitar amps with two speakers or more. Why? Because the ‘phase relationship’ between the speakers and your ears changes depending on where you stand. This is due to different frequencies cancelling each other out causing nodes, an effect commonly known as ‘comb filtering’. To avoid comb filtering the mic is placed right on the speaker. This way only the sound from one driver gets into the mic.
Now if you take the time to listen to the guitar tone that is produced two inches from the speaker, you will find that the sound is really not that pleasing. Furthermore, moving the mic ever so slightly can have a dramatic effect on the tone. (ex: capturing the sound from the middle of the speaker sounds very different from the edge.) But we do it this way because it is quick and is pretty much the best compromise we have been able to find so far…
But what sound engineers really want is a way to capture the sound from the amplifier that is consistent night after night. This has become all the more prevalent since the advent of in-ear monitors as guitarists are no longer listening to their amps; they are hearing the guitar and amp through a microphone, mixing console and ear buds. All of a sudden, they are beginning to realize that the tone is nowhere near as good as what they were able to achieve in the studio. This has augmented the need for a simple audio interface. We call it the Radial JDX.
|The Radial JDX Reactor is designed to ‘capture’ the signal from the complete amplifier by connecting in between the head and the speaker cabinet.
This is very different from the direct feed coming from a guitar amp. A direct feed from an amplifier is completely void of any interaction with the speaker cabinet which as any guitarist will attest, plays an integral role in the amp’s tone. In fact, the amplifier’s ability to control the speaker – known as the damping factor – produces effects such as ‘sag’ and the counter-EMF (electro-magnetic field) also causes the amp’s output stage to constantly react as the level, impedance and load changes. It is the relationship between all of these factors that produces the sound. By capturing the reactive effect, the JDX comes closer to the original tone than any other guitarinterface ever.
Once connected, the signal is transformer isolated. The transformer works double duty by both providing a reactive electro-magnetic interface with the amp and speaker while also isolating the JDX to help eliminate ground loops. Then the JDX processes the signal with via a unique class-A buffering circuit plus a series of filters to recreate the typical response curve from a 12” guitar speaker cabinet. The signal is then electronically balanced to match a microphone level and sent along the audio path with the other mics and direct boxes to the console.