As with all Analog Code plugins, the TwinTube plugin is modeled after an SPL analog hardware processor. In this case the TwinTube processor of SPLs RackPack modular system has been the paragon.
Our programmers did a great job in creating a very good sounding tube simulation. The special qualities of the analog TwinTube are in enhancing in fact nearly any signal with the classic analog sound attributes. Now we can fully transfer those amazing results to the digital domain. And where could the warm, transparent and smooth sound of analog tube and coil filtering make more sense than in DAW productions?
The TwinTube plug-in is the first combination of two essential tube effects in a single processor, that is, saturation effects along with harmonics processing. Both stages work separately from each other and are based on individual processing stages. The effects can therefore not only be applied both individually or separately, but also in common. Harmonics processing can be applied to four different fundamental tone frequency bands to improve presence and clarity without raising signal levels significantly. The saturation control can be compared to the sound effects of tape saturation to add warmth and achieve more density with virtually any kind of sound source.
In the original analog design, the saturation effects are generated through the tube being pushed to and beyond its normal operating limits. In contrast to semiconductors, a tube thus pushed to such levels does not clip from a certain level, approaching more gradually its level limits and thereby producing its typical tonal result, which in audio signal processing can have such often profitable aural effects.
On one hand (and depending on the amount applied), from subtle to extensive harmonic distortion and on the other hand, a compaction of the sonic event, that is, a limiting effect that exhibits a pleasant, rounded or soft sound. Acoustically and also in its range of applications this can be compared very well with tape saturation effects. Harmonic distortion and limiting are the generally known, “classic” tube effects, which are today cornerstones of sound processing.
But other less known and potentially important effects are a tube’s ability for improving presence and spatial qualities through its processing of specific regions of the overtone series. In the analog original of the TwinTube Processor, a special circuit comes into play for overtone/harmonic processing that involves coil filtering working in conjunction with the tube. The control reacts dynamically to the audio signal and a resultant tonal quality is the alignment of level relationships in the overtone spectrum. Such overtone “enrichment” does not operate on the generator principle of exciters (wherein distortion is added to the original signal). The TwinTube harmonics control effects rather a more equalized overtone structure resulting in a sound which in effect appears much more in the foreground, but without doing so through extreme level changes. Thus, for example, a voice appears immediate apart from the overall mixture, “sitting” clearly outlined in the mix’s foreground.