Direct-X VST plug-ins
License : 12
- Tone-Param Fs2.
- Tone-Shelf Fs2.
- Spectro SculpturA.
Real Time F.I.R.
All the plugins supplied with the SculpturA pack are based on an F.I.R-type filter (finite impulse response) designed in 1999 by Vincent Burel. This new kind of F.I.R filter, emulating passive electronic filtering units, is the first and only one in the world to work in realtime without any processing latency. As a consequence, these plugins can be used in exactly the same way as other - traditional - plugins, without the need to specify a particular buffer size or use any delay compensation feature.
What does F.I.R mean !?
F.I.R stands for "Finite Impulse Response" (whereas I.I.R stands for "Infinite Impulse Response"). This characteristic determines the type of algorithm that is used (in a mathematical meaning), as well as the filter's behaviour (technical specifications). F.I.R-type digital-audio filters can be compared to the passive filters we would find among analog electronic components, whereas I.I.R-type filters are more generally used to simulate active filters, that is to say the kind of filters needing an additional source of power (OP Amps, etc...).
F.I.R : What for !?
The main differences between a F.I.R filter and an I.I.R filter (at least, for the characteristics that may be of interest for us) focus on their resonance and response time. An I.I.R filter needs two steps to work : it starts resonating to detect the required frequency and then maintains this resonance at the required level. This process takes time. A standard parametric EQ (therefore, I.I.R type), in order to achieve +12 dB at a given frequency, will need at least 4 periods of the signal to start resonating and therefore get to the nominal level (required level). An F.I.R-type filter will reach its nominal level over the first period.
No resonance !
The advantage of non-resonant filters (this is the case with F.I.R filters) is that they fully respect sound integrity. Indeed, if there is no resonance, there is less artefact and the filter generates very few residual oscillations. Mathematically, F.I.R filters have no predictive and no recursive section (re-injection), which allows us to consider them more unbiased, because they use the available material only, and nothing else.
F.I.R. for Mastering.
Thanks to these characteristics, F.I.R EQs are well suited for mastering where what has to be achieved is maximum sound neutrality and transparency. Where traditional EQs tend to exaggerate or swamp basses, turn trebles into an aggressive bell sound and modify the texture of vocals when cutting mid-frequencies, F.I.R filters will let you equalize signals without affecting these subjective elements. F.I.R EQs only increase or lower the level of a signal which is already there, nothing more.
From a fully technical point of view, VB-Audio's F.I.R EQs do not follow the traditional diagrams of standard filters. Moreover, one will notice possible distortions between the nominal values (required ones) and the actually measured values. This characteristic is part of the analog-filtering simulation aspect of these EQs and some inaccuracies and weirdnesses represent one of the secrets giving these EQs astonishing musical qualities.