Audified Announces U73b Compressor Plug-in

Effect Emulates Vintage German Broadcast Processor
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BOSKOVICE, CZECH REPUBLIC: multimedia software and hardware development specialist Audified is proud to announce availability of the U73b Compressor effect plug-in for Mac (AAX, AudioUnit, VST2, VST3) and PC (AAX, VST2, VST3) — an authentic emulation of the unique-sounding Sixties-vintage German broadcast compressor/limiter hardware predecessor with which its shares its name.

Working with the NWDR (Nordwestdeutscher Rundfunk) — responsible for public broadcasting in the German states of Hamburg, Lower-Saxony, Schleswig-Holstein, and North Rhine-Westphalia from September 22, 1945 to December 31, 1955, Telefunken developed the U73, an all-tube, three-stage push/push variable mu design (with a theoretical compression ratio of 100:1), during a three-year period, born out of a need to conform to the high standards set by the IRT (Institut für Rundfunktechnik) — the primary research institute for German-speaking public broadcasting organisations — while seeking a suitable solution for handling full-frequency response FM (Frequency Modulation) radio broadcasts. By building the U73 into a Danner double-cassette module chassis like its U76 sibling, the two Telefunken designs shared significant circuitry and components, though the U73 went on to become the fastest tube compressor ever built, thanks to its forward-triggered side-chain feature. Fully finalised, the design was licensed to TAB (Tonographie Apparatebau) in Wuppertal-Elberfeld, West Germany (as was), who manufactured this, the last tube compressor in the Telefunken/IRT grey series for almost 30 years, finally discontinuing it in 1980. Nevertheless, its premier price and fixed setup effectively ensured that U73s only made it outside of Germany for one specific (non-broadcast) application — as a final mastering compressor for vinyl-cutting lathes, mostly with an automatic release trigger. TAB even ended up making several versions of the U73 for Telefunken, the most well known being the U73b, used for producing audio recordings mostly, thanks to an added ability to change compression level, as well as external release time control and internal attack time control. Consequently, almost all records recorded and cut in Europe between 1960 and 1980 were mastered through a stereo pair.

While modelling the U73b circuitry as it was originally designed, Audified — as evidenced by U73b Compressor’s gorgeous GUI — has helpfully seen fit to add an IN(put) and OUT(put) gain, both before and after the modelled compression circuit to aid adjusting compression in a more modern manner fit for truly 21st Century workflow. Which is why the U73b Compressor plug-in has helpfully also been boosted with a VU (Volume Unit) meter and selectable side-chaining.

The effect of this unique plug-in is audible from the moment it is ‘switched on’ — just like its namesake hardware predecessor. Its upper-positioned knob acts as a compressor/limiter switch, switching between Kompr (compressor), Durchschalt (bypass), and Begr (limiter) modes. The compressor mode has a lower threshold setting and a gently rising ratio; reversely, the limiter mode provides a higher threshold setting with higher ratio, but still with smoothsounding, soft-knee compression. The lower-positioned knob sets the release time; the first three positions provide fixed release times, while the three red-coloured positions provide adjustable program content-dependent release time options. Outside the authentic-looking onscreen reproduction of the original U73b front panel, SIDECHAIN selects the signal source for controlling gain reduction.

U73b Compressor is perfect for mastering purposes, but also lends itself beautifully to mixing drums, bass, guitar, vocals, and voiceovers. Vintage-sounding compressed/limited recordings are perfectly possible in this day and age with U73b Compressor, that’s for sure! Try before you buy with a downloadable demo.

U73b Compressor is available to purchase (as an iLok dongle-protected plug-in) for $149.00 USD directly from Audified’s online shop here:

Watch well-known Czech Republic producer and musician Boris Carloff’s informative introductory U73b Compressor video here:

About Audified (

Audified is the premier brand of privately-owned Boskovice-based DISK Multimedia, s.r.o. in the Czech Republic, created to develop specialised audio applications, as well as handling the company’s high-end hardware product portfolio. Pioneering the development of audio applications for live (realtime) performance, as well as developing the first audio effects plug-ins for Apple’s Mac OS X, the company created some of the first plug-ins for PowerCore, TC Electronic’s hardware-accelerated DSP platform, prompting the Danish developer’s then-PR Manager Thomas Valter to comment, “Our two companies have been working closely together on various projects, and we are very satisfied with the products that have been a result of our cooperation.” Consequently, the company returned to its host application and audio effects developmental roots in 2007 by branding itself with the Audiffex appellation to resourcefully reflect that directional change. Credentials apart, Audiffex and sister brand Audified are not just for-profit businesses, however; their parental company clearly cares about the future of audio software/hardware development, developing partnerships with both Janacek Academy of Music and Performing Arts (JAMU) in Brno, Czech Republic — realising a research project to bring modern audio engineering technologies to music education, and also Brno University of Technology, one of the Czech Republic’s leading research and teaching institutions — working with the Faculty of Electrical Engineering and Communication Technologies on scientific projects. Participating in organising entry exams and teaching at these highlyrespected higher education establishments has helped establish the first specialised studies of audio engineering in the Czech Republic.