ThrillseekerXTC mkII released

ThrillseekerXTC – bringing mojo back

ThrillseekerXTC mkII is a psychoacoustic audio exciter based on a parallel dynamic equalizer circuit. It takes our hearing sensitivity into account especially regarding the perception of audio transients, tonality and loudness.

The mkII version now introduces:
• Plugin operating level calibration for better gainstaging and output volume compensated processing.
• A reworked DRIVE/MOJO stage featuring full bandwidth signal saturation and a strong
focus on perceived depth and dimension. It provides all those subtle qualities we typically associate with the high-end analog outboard gear.
• Special attention has been taken to the mid frequency range by introducing signal compression which improves mid-range coherence and presence.
• Relevant parts of the plugin are running at higher internal sampling frequencies to minimize aliasing artifacts.

Available for Windows VST in 32 and 64bit as freeware. Download your copy here.

What I like about the Behringer 2600

What I really like about the Behringer 2600 is that it’s not just a plain copy but introduces some real useful improvements over the original concept. Most important to me is the 19″ form factor which not only reduces the originals size and fits in the rack but also remains big enough to enjoy a great user experience while cabling and tweaking things. And they got rid of those speakers! Instead it offers 2 filter revisions to choose from, two of the oscillator sections are now fully featured, the LFO is part of the main chassis now and new additional timing options for the envelopes has been added as well.

On the other hand, the Behringer 2600 sticks to CV gate voltages following original levels which limits full integration in todays modular world quite a bit. However, this is currently not a big deal to me. I only wish they would have made a true analog delay instead of the spring reverb (emulation). Offering audio in, the device also doubles as an excellent analog effect unit which seems to be a little bit underrated in this regard. Given it’s pricepoint, this feature is already something to consider if one is just looking for an outboard analog filter box or an alternative for something like a MS-20.

The ARP 2600 turns 50

And if time allows, watch this awesome documentary about the history and story behind ARP:

Getting the most out of the SPL Tube Vitalizer

In this article I’m going to share some analysis insights but also proposing an easy to follow 3-step approach for finding the sweet spot while processing any kind of material with this device.

Preparing for winter season: room heating with style

So, having now a Tube Vitalizer here on my desk (at least for some time), I was surprised about the lack of usable online reviews and background information. One just finds the usual YT quality stuff which might be entertaining in the best case but also spreads misinformation ever so often. To save those influencers honor it must be said that the Vitalizer concept is really not that easy to grasp and its quirky user experience makes it not easier. The manual itself is a mixed bag since it contains some useful hints and graphs on the one hand but lots of marketing blurb obscuring things on the other. Time to clean up the mess a little bit.

What it actually does

While easily slotted into the “audio exciter” bucket, some more words are needed to describe what it actually does. Technically speaking, the Vitalizer is basically a parallel dynamic equalizer with an actual EQ curve behaviour which aims to mimic equal loudness contours as specified in ISO226. Rather simplified, it can be seen as a high and low frequency shelving EQ to dial in a basic “smile” EQ curve but one which takes hearing related (psychoacoustic) loudness effects into account. It does this also by generating curves differently based on signal levels, hence the term “dynamic EQ”. And wait, it also adds harmonic content galore.

Taming the beast

To obtain an equal loudness contour the main equalizers center frequency must be properly set depending on the tonal balance of the actual source material. This center frequency can be dialed in somewhere between 1k and 20kHz by adjusting the Hi-Mid Freq knob which defines a cross-over point: while frequencies below that point gets attenuated, the higher frequencies gets boosted. However, this attenuation is already a signal level dependent effect. Opposed to that, the LF EQ itself (which actually is not a shelving but a bell type curve) has a fixed frequency tuned to 50Hz and just the desired boost amount needs to be dialed in. The LF curve characteristic can be further altered (Bass soft/tight) which basically thickens or thins out the below 100Hz area. Finally, this EQ path can be compressed now with the Bass Comp option.

A typical EQ curve created by the Vitalizer

On top of the main EQ path, the Tube Vitalizer offers an additional HF boost and compression option which both can be dialed in to complement the LF behaviour in a very similar fashion but in the high frequency department. Internally, both are in a parallel configuration and mixed back into a dry signal path. The according Process Level knob can be seen as a kind of dry/wet option but only for main the EQ part. The upper HF part is mixed back in separately by the Intensity dial.

Gain-Staging is key

For the EQ section as a whole, the Drive knob is the ticket for proper gain-staging. If compression can be dialed in properly for both compressors (as indicated by the blue flashing lights) input gain is in the right ballpark. One might expect to hear actual compression going on but it appears to be a rather gentle leveling effect.

Gain-staging for the output stage has to be concerned separately which might become an issue if the tube stage is activated and operates in shunt limiting mode. Now you have to take care about proper input levels since the Attenuators for both output channels are operating after the limiter and not beforehand.

Tube stage limiting: input (red) vs output (blue)

Which directly leads us to the additional harmonic content created by this device. First of all, there is always additional harmonic content created by this device, no matter what. One might expect the device to not show any such content with the solid state output stage but it actually does. The tube output stage just increases that content but signal level dependent of course and 2nd order harmonics are always part of that content. A serious additional amount of harmonics gets added as soon as the HF filter gets engaged by dialing in Intensity (and LC Filter mode activated!) but this sounds always very smooth and natural in the top end, surprisingly.

Delicious content

Also impressive is the low noisefloor for both output stage modes, tube and solid state. The first one introduces pretty strong channel crosstalk, though.

Workflow – Finding the sweet spot in 3 easy steps

Initial condition:

  • Drive, Bass, Bass Comp and Intensity set to 0
  • Device is properly gain-staged

1. Set Process to 5 and now find the best fit for Hi-Mid Freq for the given source material. For already mixed 2bus stuff you can narrow it down to 2-3kHz most likely.

2. Dial in Bass (either left or right depending on source and taste) and some compression accordingly.

3. Only then dial in some further HF content via Intensity and some compression accordingly. Adjust HF Freq so it basically fits the source/taste.

Workflow – Tweaking just one knob

My good old buddy Bootsy told me this trick which works surprisingly well.

Initial condition:

  • Left most position: Bass
  • Right most position: Bass Comp, High Comp, High Freq
  • 12-o-clock position: Drive, Intensity
  • Hi-Mid-Freq set to 2.5kHz

Now, just dial in some (few) Process Level to taste.

He also recommends to drive the input to some extend (VU hitting the red zone) using the Tube stage in limiter mode while always engaging LC Filter mode for HF.

FerricTDS mkII released

FerricTDS mkII – the updated award winning Tape Dynamics Simulator

New in version 2:

  • Introducing operating level calibration for better gainstaging and output volume compensated processing
  • Metering ballistics revised and aligned accordingly
  • Updated tape compression algorithms increasing punch, adding 2nd order harmonic processing, less IMD
  • Updated limiter algorithm featuring ADC style converter clipping
  • All non-linearities are running at higher sampling frequencies internally
  • Adding a sophisticated analog signal path emulation

Available for Windows VST in 32 and 64bit as freeware. Download your copy here.

What loudspeakers and audio transformers do have in common

Or: WTF is “group delay”?

Imagine a group of people visiting an exhibition having a guided tour. One might expect that the group reaches the exhibitions exit as a whole but in reality there might be a part of that group just lagging behind a little bit actually (e.g. just taking their time).

Speaking in terms of frequency response within audio systems now, this sort of delay is refered to as “group delay”, measured in seconds. And if parts of the frequency range do not reach a listeners ear within the very same time this group delay is being refered to as not being constant anymore.

A flat frequency response does not tell anything about this phenomena and group delay must always be measured separately. Just for reference, delays above 1-4ms (depending on the actual frequency) can actually be perceived by human hearing.

This always turned out to be a real issue in loudspeaker design in general because certain audio events can not perceived as a single event in time anymore but are spread across a certain window of time. The root cause for this anomaly typically lies in electrical components like frequency splitters, amplifiers or filter circuits in general but also physical loudspeaker construction patterns like bass reflex ports or transmission line designs.

Especially the latter ones actually do change the group delay for the lower frequency department very prominently which can be seen as a design flaw but on the other hand lots of hifi enthusiast actually do like this low end behaviour which is able to deliver a very round and full bass experience even within a quite small speaker design. In such cases, one can measure more than 20ms group delay within the frequency content below 100Hz and I’ve seen plots from real designs featuring 70ms at 40Hz which is huge.

Such speaker designs should be avoided in mixing or mastering situation where precision and accuracy is required. It’s also one of the reasons why we can still find single driver speaker designs as primary or additional monitoring options in the studios around the world. They have a constant group delay by design and do not mess around with some frequency parts while just leaving some others intact.

As mentioned before, also several analog circuit designs are able to distort the constant group delay and we can see very typical low end group delay shifts within audio transformer coupled circuit designs. Interestingly, even mastering engineers are utilizing such devices – whether to be found in a compressor, EQ or tape machine – in their analog mastering chain.

64bit plugin rollout started, announcing mkII plugin versions

The very first 64bit plugin versions are out now, starting with the plugins from the public beta test earlier this summer: epicVerb, BaxterEQ, preFIX, NastyDLAmkII, NastyVCS and DensityMkIII. All versions have been carefully revised, are backwards compatible and some includes bugfixes and improvements as well. VST3 versions are not (yet) included due to stability issues. For further release notes and downloads please refer to the download page.

The remaining VoS plugins are planned to be (re-) released one-by-one until end of this year. Most likely, they will reappear as mkII versions 🙂 First one will be FerricTDS mkII which is already in the finishing process and to be released early September.

stay tuned!

The renaissance of the Baxandall EQs

Already in 1950, Peter Baxandall designed an analog tone correction circuit which found its way into some million consumer audio devices later on. Today, it is simply referred to as a Baxandall EQ.

What the f*ck is a Baxandall EQ?

Beside its appearance in numerous guitar amplifiers and effects, it made a very prominent reincarnation in the pro audio gear world in 2010 with the Dangerous Music Bax EQ. The concept shines with its very broad curves and gentle slopes which are all about transparancy and so it came to no surprise that this made it into lots of mastering rigs right away.

And it also had a reason that already in 2011 I did an authentic 1:1 emulation of the very same curves within the Baxter EQ plugin but just adding a dual channel M/S layout to better fit the mastering duties. For maximum accuracy and transparancy it already featured oversampling and double-precision filter calculations to that time and it is still one of my personal all time favourite EQs.

BaxterEQ

During the last 10 years quite a number of devices emerged each showing its very own interpretation of the Baxandall EQ whether thats in hard or software and this was highly anticipated especially in the mastering domain.

A highly deserved revival aka renaissance.

When comparing units be aware that the frequency labeling is not standardized and different frequencies might be declared while giving you same/similar curves. More plots and infos can be found here (german language).

Lets talk about mixing levels (again)

Some years ago we had lots of discussions about proper mixing levels in the digital domain – with mixed (sic!) results, IIRC. Meanwhile, more and more influencers are claiming that targeting -18dBFS with a VU meter readout is the “digital audio sweet spot” and the way forward in terms of plugin gain staging. In practise that would imply mixing digital peak levels at around 0dBFS again but maybe I’ve missed something during my absence in recent years. So, to what mixing levels are you up to in your DAW today?

[CLOSED] VoS plugins 64bit public beta 1

Update 07/16/21: The beta has been closed. Stay tuned for upcoming info and releases. For the time being, the beta package remains available in the download section. Thanks to all here for contributing!!!

Until around mid July you can grab here the VoS plugin 64bit public beta package. Included are epicVerb, BaxterEQ, preFIX, NastyDLAmkII, NastyVCS and DensityMkIII in both 32 and 64 bit, VST 2 and 3 for Windows PC.

Please be careful using them since they are beta. They might crash, generate loud noises and things like that. Also do not use them in real productions since parameters and settings might change until release and break compatibility.

To report issues just create a comment right to this post and please include detailed information about the issue, which plugin is actually affected and in which host and version.