Access Music has released a public beta version of OS 4.5 for the entire Virus TI series of synthesizers. TIOS 4.5 brings several new types of chorus effect to the Virus TI series, ranging from faithful models of renowned vintage chorus and tremolo effects, to the brand new Hyper Chorus. It also adds a authentic rotary speaker simulation and several new mod matrix sources have been implemented.

Vintage Chorus
The Vintage Chorus is an emulation of the 70's chorus technology based on a technique known as bucket brigades, which can be considered a predecessor of today's digital sampling technology. The Vintage Chorus covers not only the exact sound of the famous Chorus Ensemble but also many other derivatives of that era which were based on the same basic circuitry, most notably that of the built-in chorus of the Juno 60.

Hyper Chorus
The Hyper Chorus is a six-voice chorus with up to three delay lines each for the left and right side. Despite this, it is staggeringly simple to use, as it is usually only necessary to adjust only the Depth parameter to achieve a huge and warm sound.

Air Chorus
The Air Chorus is a subtle kind of chorus, as it doesn't mix the direct sound to the processed signal. Instead, it modulates the pitch of the left and right side of the signal independently from each other. The resulting chorus sound happens in the air between both speakers, where both signals add together.

Rotary Speaker
The Rotary Speaker chorus type is an faithful recreation of the sound made by the legendary Leslie speaker. Best known for the wonderful effect it has on the sound of the Hammond organ. The Leslie speaker modulates the sound by rotating both the bass speaker drum and the tweeter horn inside a cabinet - but, crucially, they are rotated at different speeds from each other. The result is a complex example of the Doppler effect, and the way it affects the sound is magical. It's basically like a vibrato, tremolo and chorus in one. The Leslie speaker also works surprisingly well with both electric and acoustic pianos - the result is a very distinctive sound, instantly recognisable from many iconic recordings.

New Mod Source: Analog Key
Many of us have owned a vintage analog synth at some time or another, and most of those that have will be only too aware of their tendency to become increasingly unpredictable in their behaviour. Unstable tuning and inconsistent key-tracking are just two typical symptoms of this. The funny thing is, these characterful in- stabilities can be just as inspiring as they are infuriating - it is often these little quirks that help a sound stand out in the mix. In TIOS 4.5, Access Music have provided a way to introduce some of these quirks into the Virus TI, by way of the Analog Key modulation sources. The idea is to deliberately skew the key tracking in such a way as to create inconsistency across the keyboard, but in a repeatable way. So, by this method, you can make it so that certain keys are always off pitch by a certain amount, or are duller or brighter than the keys on either side, for instance.

The public beta version of OS4.5 is available for download now. The download is free for existing Virus TI users.