The TesslaSE Remake

There were so many requests to revive the old and rusty TesslaSE which I’ve once moved already into the legacy folder. In this article I’m going to talk a little bit about the history of the plugin and its upcoming remake.

The original TesslaSE audio plugin was one of my first DSP designs aiming at a convincing analog signal path emulation and it was created already 15 years ago! In its release info it stated to “model pleasant sounding ‘electric effects’ coming from transformer coupled tube circuits in a digital controlled fashion” which basically refers to adding harmonic content and some subtle saturation as well as spatial effects to the incoming audio. In contrast to static waveshaping approaches quite common to that time, those effects were already inherently frequency dependent and managed within a mid/side matrix underneath.

(Later on, this approach emerged into a true stateful saturation framework capable of modeling not only memoryless circuits and the TesslaPro version took advantage of audio transient management as well.)

This design was also utilized to supress unwanted aliasing artifacts since flawless oversampling was still computational expensive to that time. And offering zero latency on top, TesslaSE always had a clear focus on being applied over the entire mixing stage, providing all those analog signal path subtleties here and there. All later revisions also sticked to the very same concept.

With the 2021 remake, TesslaSE mkII won’t change that as well but just polishing whats already there. The internal gainstaging has been reworked so that everything appears gain compensated to the outside and is dead-easy to operate within a slick, modernized user interface. Also the transformer/tube cicuit modeling got some updates now to appear more detailed and vibrant, while all non-linear algorithms got oversampled for additional aliasing supression.

On my very own, I really enjoy the elegant sound of the update now!

TesslaSE mkII will be released by end of November for PC/VST under a freeware license.

working ITB at higher sampling rates

Recently, I’ve moved from 44.1kHz up to 96kHz sampling rate for my current production. I would have loved to do this step earlier but it wasn’t possible with the older DAW generation in my case. With the newer stuff I was easily able to run a 44.1kHz based production with tons of headroom (resource wise – talking about CPU plus memory and disk space) and so I switched to 96kHz SR and still there is some room left.

I know there is a lot of confusion and misinformation floating around about this topic and so this small article is about to give some theoretical insights from a developer perspective as well as some hands-on tips for all those who are considering at what SR actually to work at. The title already suggests working ITB (In The Box) and I’ll exclude SR topics related to recording, AD/DA converters or other external digital devices. [Read more…]

ThrillseekerLA – the short story behind

The Oscar credit for the most addictive GUI artwork goes to Patrick once again.

There are actually two stories behind the ThrillseekerLA venture: One being the creation of a cutting edge compressor design for the digital domain while the other one is about taking a huge leap forward on my journey towards stateful saturation. [Read more…]

the Dynacord VRS-23 analog delay

(click images to enlarge)

The VRS-23 was a quite successful BBD delay in the 80’s and some thousands of units were sold during that time. It’s a mono-in / stereo-out device and capable of delay times up to around 400ms. Providing also very short timings and a modulation option makes it capable of creating chorus and flanger type of effects as well. There were different revisions available and shown here is a later one with the white faceplate. [Read more…]

the Ibanez AD202 analog delay

The so-called bucked-brigade device (BBD) delay line generator is a somehow quirky and really unique technical design. Such  devices are built upon analog components entirely, but being discrete in time they are halfway digital. Their analog input voltage samples are stored and moved through a line of capacitors one step after another and hence the name comes from analogy with the term bucket brigade: a line of people passing buckets full of water. [Read more…]

the side effects of intermodulation in audio processors

typical IM distortion in a digital compressor

The general and most obvious effect of intermodulation components in audio signals is distortion of course – hence the concept of “intermodulation distortion” (aka “IM distortion” or simply “IMD”). IM distortion and harmonic distortion are two pairs of shoes and must be defined individually as already shown in the short essay about “myth and facts about aliasing” but more on this later on.

The existence of intermodulation components can affect the performance of an audio production in various ways. In the best case, IMD components are a desired artistic effect e. g. to obtain heavily crushed audio effect signals but in the worst and rather common case, they are one of the contributing factors which deteriorate the overall audio quality and might ruin a production. [Read more…]

myths and facts about aliasing

A recent trend in the audio producer scene seems to be to judge an audio effect plug-in just by analyzing the harmonic spectrum, which is usually done by throwing a static sine-wave right into the plug-in and then look at the output with a FFT spectrum analyzer afterwards. In this article I’m going to talk about what this method is capable of and where its limitations and problems lie and that aliasing gets confused with a lot of other phenomenons quite often. I’m also clearly showing that this method alone is not sufficient enough to judge an audio plug-in’s quality in a blackbox situation.

a spectrum plot showing noise, harmonic distortion and aliasing

a harmonic spectrum plot showing quantization noise, harmonic distortion and aliasing effects

[Read more…]

the magic is where the transient happens

Transients and so on

This article could have been an esoteric one but then it would probably be titled as “the magic is where the change happens” or something like that. Don’t worry, this is just about some findings and myth on audio transient processing and it’s, errm, reincarnation in the upcoming TesslaPRO VST audio plug-in. [Read more…]