For decades, audio mastering engineers have relied on harmonic analysis and denoising algorithms, among other highly sophisticated signal processing techniques, in order to separate the stationary noise component from the tonal component of a sound, but since it has always involved a considerable amount of processing, it was never something that could be done in real-time… until now.
Fission, the very first in Eventide’s “Structural Effects” plugin line, uses a patented algorithm that will split audio in a fraction of the time it takes with ordinary processing tools, separating harmonic content from the transient noise of a signal and processing the two components independently through seven tonal effects and six transient effects including compression, dynamics, EQ, signal gate, tremolo, phaser, reverb, pitch shifting, chorus and delay effects, all of which I will discuss in further detail later.
Even though I’ve placed emphasis on “real-time” processing, you must also understand that latency can be an issue here, except for use with live instruments in musical situations that don’t necessarily need to sync up with your DAW. But if you’re going to process drums and percussive material in real-time, you can expect upwards of 50ms of latency, which is quite forgivable as far as I’m concerned, taking into account that this is new technology that will likely become much faster in the foreseeable future.
As a mastering plugin, Fission is perfect for reshaping and re-tuning drums, which is obviously going to be its most practical use, although you can also create “bowed” sounds by completely removing the transient noise of any sound that has a distinct tonal body, such a guitar, eliminating the need for a volume pedal or any volume swell plugins. Another really cool aspect of this type of noise removal is that you can play fast phrases, still maintaining that “bowed” dynamic without having to worry about transients slipping through the cracks. It might sound like a volume swell, but nothing is being “swelled” at all.
It all starts in the “Structural Split” controls section, with a “Source Type” horizontal slider / menu with over a dozen Source Type tunings, a “Focus” slider adjusting the “sonic energy” toward either the transient or the tonal audio channel, a “Smoothing” control acting as a sort of attack & decay envelope adjusting the transition (in time and frequency) between the transient and the tonal audio channels, a “Trans Decay” knob for even further adjustment of the decay of transients and especially useful as a virtual auto-swell control, a simple “On/Off” button that basically switches the Structural Split algorithm on and off, and a “Waveform View” with a dual display of both the transient and the tonal audio streams, illustrating the time, frequency and signal magnitude, which really helps you visualize the whole process.
Other than the “Modulation” button for random voice chorusing of the delay tap within the Tonal Delay, both the Tonal and Transient Delay modules are identical, each with three modes: “Off” in milliseconds (indicated by a clock symbol), “Manual” tempo sync (indicated by an un-fastened padlock symbol) and “Session” tempo sync in accordance with your host tempo (indicated by a fastened padlock symbol). In addition to the “Time” control are also controls for “Feedback”, independent “Lowcut” / “Highcut” filters (both of which are in the feedback path), a “Mix” control and a “Warp” button that (when switched on) simulates analog tape echo type glide between delay times, which is really fun with lots of feedback.
I was especially impressed by the Transient Tap Delay, which has similar tempo sync controls, but also has a few surprises, such as a “Taper” control that (depending on the position of the bipolar knob) will either fade taps in or out, a “Spread” control that distributes each individual tap along an exponential / logarithmic curve, forcing the taps either toward the beginning or end of the delay length, and up to thirty-two taps, each one panned slightly apart to create a sense of depth.
The Transient Phaser has similar time controls, an LFO / Envelope button that determines whether the phaser is controlled by an LFO or by an envelope driven by the Transient Effects section input, a control that determines the number of allpass stages, a “Feedback” control, a control that determines the “Base” frequency from which the modulation sweeps from, and a simple “Depth” control that will determine how far up the frequency domain the modulation sweeps.
Now, you might be wondering why there’s no phaser included in the Tonal Effects section, or why there’s no chorus included in the Transient Effects section. While I think a phaser can be useful as a tonal effect, I can see why the phaser is only included as a transient effect since it doesn’t require musical information to do what a phaser does; on the flipside, I can see why there is no chorus in the Transient Effects section since a chorus effect is more noticeable with musical information, so it makes perfect sense actually.
The Tonal Chorus effect is somewhat self-explanatory, with controls for LFO speed, depth, mix and a bipolar knob for low / high-shelf filtering, but the multi-voice aspect of this chorus springs to life with the “Size” knob, which will effectively spread out the chorused voices, and the randomized modulation really helps to make this a velvety, “swirly” chorus effect that I really enjoy.
Both the Tonal and Transient Reverb modules might appear similar, but they are actually very different. The Transient Reverb has a much higher echo density since sudden transients are more noticeable than tonal reflections. The Transient Reverb has independent “Low Damp” / “High Damp” filtering whereas the Tonal Reverb has only one “Damp” filter attenuating high frequencies. Another notable difference in the Tonal Reverb is the “Shape” parameter, adjusting the perceived distance between the source and the reflective surface…and if you reverberate only the tonal audio channel, you will avoid those “grainy” artifacts produced by most reverb plugins that process everything you feed them.
One of the most useful effects so far is the Transient Gate + EQ, which is perfect for reshaping transients and breathing life into percussive sounds. The “Gate Thresh” knob ranges from zero to -100 decibels, and the remaining controls for a 3-band overdrive-able EQ let you color the transient signal however you like. I prefer to set the gate threshold to about -64 dB and really crank the “High Gain” to create bright, pillowy transients that make kick drums pop and snare drums sizzle just beautifully.
You might be a little confused by the appearance of the Transient Dynamics effect, which has all the same basic controls as the Tonal Compressor, but I assure you there’s a lot more going on here than just basic compression. With the “Ratio” knob below 1:1 (center position) the effect functions as an expander / gate, but if the Ratio is set higher than 1:1, the effect functions as a compressor / limiter, with basic attack and release controls and a “Make-Up” (post compression / limiting or EQ / gating) control with up to twenty-four decibels of gain, which is quite a bit of juice.
I don’t really need to flesh out the Tonal Compressor and Tonal EQ controls since they pretty much perform the same basic functions I’ve described in the last two transient effects. Moving right along…
The Tonal Tremolo has a built-in envelope which can be used to modulate the LFO depth and/or rate in combination with the LFO signal, with a bipolar envelope sensitivity control that will determine the overall strength and direction of the envelope’s output signal; negative values output an inverse envelope effect. The “Spread” knob basically pushes both LFOs (on the left and right stereo channels) out of phase. The remaining controls are more or less self-explanatory. The “Rate” knob is almost exactly the same as the “Time” knob in the delay modules, except that the LFO rate is measured in hertz instead of milliseconds when not in tempo sync mode. There are five basic LFO waveforms: sine, saw up, saw down, triangle and square. It’s actually one of the most feature-rich effects on-board.
The Tonal Pitch shifter effect has three voices, each with bipolar tuning controls (+/- 1 octave), two of which have on/off switches. A “Fine Tune” knob will attenuate the pitch of all three voices, and a built-in bypassable tuning meter is ideal for tuning drums and transposing harmonies. I do wish we could fine tune decimated semitone values, especially for use with unisoned voicings, but I’m very happy with everything we get within the Tonal Pitch shifter and Fission as a whole.
As far as transient processing goes, I don’t think anything compares to what Fission has on offer. It can process drums, percussion, and all kinds of instruments in ways that totally redefine the source material and open up a whole new world of possibilities, not just for mix engineers, but also for modern film and game composers, sound designers and recording artists of all genres.
I’ve heard some people complain that there aren’t enough effects, and I couldn’t disagree more. I would, however, like to be able to mix the effects in creative ways, but that might involve a considerable overhaul to Fission’s framework. Also, there are noticeable artifacts produced by the splitting process, but I assure you, they aren’t very noticeable until you solo the transient channel; in fact, I can see myself making all sorts of experimental sounds that way! That being said, I’m really excited about the sound design possibilities here, and I’m looking forward to using Fission in several of my own projects.
More info: Fission ($179)
Eventide Fission Review
As far as transient processing goes, we don’t think anything compares to what Fission has on offer. It can process drums, percussion, and all sorts of other instruments in ways that totally redefine the source material and open up a whole new world of possibilities.