SPL Iron V2 Two-Channel Tube Mastering Compressor (Black/Silver) - Manual (Page 5)

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Introduction Introduction
Operating Principles of a Compressor
The basic operating principles of a compressor/limiter can be easily explained.
The level of an audio signal is reduced according to the specified Attack time and Ratio
whenever it exceeds a given threshold. This reduction ceases when the Release time
elapses, while the compressed signal is amplified with the Make-Up Gain.
Compressors basically differ from each other in the technology used. This technology –
tubes, opto, FET, or VCA – is what gives a compressor its particular character. Some units
sound soft and silky, some sound pounding, while some others make sound fatter, and
there are those that make sound clearer, harder or more percussive. The trick resides in
how the unit is technically designed, in the signature of the maker. Different compressors
with the exact same settings might work and sound completely different. They provide
different sounds for different applications and music styles.
Nowadays, the compressor has become a key element when it comes to provide dynam-
ics and punch to any production. The number of compressors available is huge and it‘s
easy to succumb to the promises made by software emulations and analog recreations of
vintage gear as the perfect solution. Unfortunately, many of these emulations and recre-
ations differ quite a bit form their original counterparts. You must simply accept that the
components used today, like the transformers, tubes and all other passive elements, are
different to the ones originally used and that they can‘t be digitally emulated. No soft-
ware (DSP-emulated compressors) or hardware replica will ever be able to sound like the
original.
An authentic sound can only be achieved with the original unit.
IRON Mastering Compressor
The IRON mastering compressor is not a copy of a classic unit, but rather an original con-
cept in itself. Our goal was to conceive a compressor that provided a pleasant, melod-
ic-sounding, transparent compression, inspired on the vintage compressors of the radio
era. And we wanted it to be versatile enough to adapt perfectly to the needs of modern
mastering studios. Thus, the Iron combines not only the sonic virtues of legendary vin-
tage tube compressors with the advantages of the High Dynamic 120V operating voltage
in a single unit. It also sets a new benchmark in terms of tube compressor technology,
with the innovative implementation of a parallel dual-tube circuit. Thanks to the espe-
cially conceived Mu-Metal iron transformers, the signal of each channel is split across
two different twin-triode tubes. The combination of the different response curves of both
tubes results in a transparent and musically pleasant compression. Additionally, peak
signals of the control voltage are limited by a feed-forward resistive opto-isolator. Thus,
the output signal remains lively even with a high gain reduction. The compression is only
noticeable with extreme settings.
But mastering is not the only domain where the IRON sets new standards. It can also be
used to process individual instruments, like vocals, bass, guitar, strings, etc. The IRON is
also an excellent option for subgroups.