bringing mojo back – volume 2

ThrillseekerVBL is an emulation of a vintage broadcast limiter design that follows the classic Variable-Mu design principles from the early 1950s. These tube-based devices were initially used to prevent audio overloads in broadcast transmission by managing sudden level changes in the audio signal. From today’s perspective, and compared to digital dynamic processors, they appear to be rather slow and can be considered more of a gain structure leveler. However, they still shine when it comes to gain riding in a very musical way – they’ve written warmth and mojo all over it.

ThrillseekerVBL is a modded version that not only features basic gain control, but also gives detailed access to both compression behavior and the characteristic of tube circuit saturation effects. Used in subtle doses, this provides the analog magic we so often miss when working in the digital domain while overdriving the circuit achieves much more drastic musical textures as a creative effect.

ThrillseekerVBL offers an incredibly authentic audio transformer simulation that models not only the typical low-frequency harmonic distortion, but also all the frequency- and load-dependent subtleties that occur in a transformer-coupled tube circuit and that contribute to the typical mojo we know and love from the analog classics.

new in version 2

Conceptually, the mkII version has been refined in that the peak limiting itself is no longer the main task but versatile and musically expressive gain control as well as a thrilling saturation experience. The saturation is now an integral part of the compression and is perfectly suited for processing transient-rich material. Both compression and saturation can be individually activated and controlled.

The circuit-related frequency loss in the highs has been almost eliminated and the brilliance control – originally intended just for compensation – can now also perform exciter-like tasks. The bias control has been extended to shape the harmonic spectrum in much greater detail by allowing the contribution of second order harmonics as well as the adjustment of the saturation behavior in the transient area of the signals. The transformer circuit has also been technically revised not only to resolve all the subtleties realistically but also to reproduce an overall tighter sound image.

ThrillseekerVBL has become a real tonebox, able to reproduce a wide range of tonalities. It provides access to the attack and release behavior and all compression controls can also affect the saturation of the signal, even when the compression function is turned off. This allows specific textures of signal saturation to be realized. As with the good old outboard devices, the desired sound colorations can be achieved just by controlling the working range. And if too much of a good thing is used, the DRY/WET control simply shifts down a gear.

To further improve the user experience some additional UI elements have been added giving more visual feedback. Although oversampling has been added, the actual cpu load was significantly reduced thanks to efficient algorithms and assembler code optimizations.

ThrillseekerVBL mkII will be released October 14th for Windows VST in 32 and 64bit as freeware.

released: ThrillseekerVBL – Vintage Broadcast Limiter

Bringing mojo back – Thrillseeker VBL is an emulation of a “vintage broadcast limiter” following the classic Variable-Mu design principles from the early 1950′s. They were used to prevent audio overshoots by managing sudden signals changes. From today’s perspective, and compared to brickwall limiters, they are rather slow and should be seen as more of a gain structure leveler, but they still are shining when it comes to perform gain riding in a very musical fashion – they have warmth and mojo written all over.

Thrillseeker VBL is a “modded” version, which not only has the classic gain reduction controls but also grants detailed access to the amount and appearance of harmonic tube amplifier distortion occurring in the analog tube circuit. Applied in subtle doses, this dials in that analog magic we often miss when working in the digital domain, but you can also overdrive the circuit to have more obvious but still musical sounding harmonic distortion (and according side-effects) for use as a creative effect.

On top, Thrillseeker VBL offers an incredibly authentic audio transformer simulation which not only models the typical low-end harmonic distortion but also all the frequency and load dependent subtleties occurring in a transformer coupled tube circuit, and which add up to that typical mojo we know from the analog classics. This would not have been possible with plain waveshaping techniques but has been realized with my innovative Stateful Saturation approach, making it possible to model circuits having a (short) sort of memory.

ThrillseekerVBL is a freeware VST audio plug-in for Windows x32 and you can download a copy in the Downloads section.

Related Links

• modeling the distortion in Thrillseeker VBL

VBL – final teaser & release info

ThrillseekerVBL will be released 1st of July 2013 as a freeware VST audio plug-in for Windows x32.

ThrillseekerLA 1.0.1 update available

Changelog for Release 1.0.1

• Stronger 2nd and 3rd harmonics added in the interstage
• Link algorithm revised and simplified
• SC lowcut filter revised

The update is available in the downloads section.

 

what I’m currently working on – Vol. 7

Updates, basically. I’m still struggling with a preFIX update due to some technical issues I just can’t get, errrm, fixed (some VST hosts still do not respond to reported delay changes). Well, lets see how many month or years this will gonna take to work around or maybe then those hosts are just obsolete 😉 At least, I’m pretty much sure that we will see two other updates here during Q2: First, there will be a smaller update for the BaxterEQ where small  is indeed the proper wording because it’s mainly about an additional but just smaller GUI version.

quote of the day

IMHO, its not about randomness (noise) in components at all. Its about the (very short) memory some circuits can deploy, depending on the overall load of the system. The shortcoming of the component modelling approach is still that the whole modeled system is deterministic (which is not). – bootsy

towards stateful saturation – very first audio shots

Around a year ago or so I’ve already started to look into a couple of stateful non-linear models which could be more suitable for a musical and convincing digital saturation experience. To make it even more harder, they should avoid the usual drawbacks such as huge latency or insane cpu consumption – if ever possible of course.

Meanwhile, my journey into the non-linear DSP land has made an important stopover with a first prototype implementation for such an approach, yielding a DSP core for musical harmonic distortion generation based on a stateful model. This opens the door for quite a number of interesting applications such as harmonic exciters or devices which needs convincing amp models whether thats a compressor output stage or even part of a guitar amplifier effect.

towards stateful saturation

the static waveshaper y = tanh(x)

Still today, most developers are sticking to static waveshaping algorithms when it comes down to digital saturation implementations. This wasn’t very convincing to me from the very beginning and in fact it was one of the motivations why I’ve started my own audio effect developments – to come a little bit closer to what I thought what saturation and non-linearity in general is all about.

And so the Rescue audio plug-in was born in summer 2007 and was already an approach to relate audio transient events to the signal saturation itself. Not that much later TesslaSE appeared which was a different exercise leaning towards a frequency dependent non-linearity implementation coupled in a feedback structure. I still really love this plug-in and how it sounds and prefer it over much more sophisticated designs even today in quite some cases. Following, the pre-amp stage in BootEQmkII then focused on “transformer style” low-end weirdness and did feature oversampling on the non-linear sections of the device. A really great combination with the EQ – smooth and very musical sounding. The TesslaPRO thingy sums up all this and puts it into one neat little device with an easy to use “few knob” interface. Don’t let you fool by this simplistic (but so beautiful) design: It already features everything which makes a saturator to stand out from the crowd today: transient awareness, frequency dependency, dedicated low-end treatments. Sound-wise this results in a way smoother saturation experience and a better stereo imaging en passant.

With FerricTDS not only the notion of  subtle frequency dependent compression got extended to a core saturator algorithm. Since revision 1.5 I’ve ditched the oversampling based core and included a version which premiered the notion of memory into the non-linearity which transforms it from a stateless into a stateful algorithm. One could basically see this as a system which reacts different on the very same actual input signal depending on the recent history of events (on a very microscopical level). The input stage algorithms which I’ve included in NastyVCS and NastyDLA (both are actually the same) are a cpu and feature wise stripped down version of that to have the basic sound of it already as an option when mixing the tracks and its according fx.

Quite recently, I’ve started to look into implicit stateful models where memory is not applied from the outside of the algorithm but the algorithm itself contains a sort of memory. As an example, I’ve implemented a stateful version of the well-known tanh() function so that it is aware of recently occurred events but provides the very same harmonic structure compared to the original. Given some analyzer plots it even shows the very same transfer curve but in fact it does not limit strictly anymore but allows some minor overshots of some peak signals. Interestingly, the sound appears a little bit brighter (without letting you see that through the analyzer plot) and the low-end appears not to be that hard “brickwalled” but a little bit smoother. Lets be assured that I’m going to follow this path and then lets see where this will lead to in 2011.