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Voxengo Transmodder VST HELP

Voxengo Transmodder VST Screenshot


Preset management
Knob control
Transient analyzer
Dynamic filter
Mode buttons
Graphical display
Troubleshooting tips and additional information


Transmodder is a transient-driven filtering system in PC VST plug-in format. Transmodder could also be called a transient modification system, since it allows the user to modify the audio material by means of dynamic filtering--in accordance with the transient content of the signal--delivering spectacular sonic pronunciation and definition.

The core element of Transmodder is the transient analyzer which processes narrow- or broad-band signals and detects all rising-level transients such as snare drum, bass drum, high hat hits, vocal sibilants and other types of transients. In the course of detection, the transient analyzer generates an envelope signal which replicates the transient structure of the signal being analyzed. This also includes the detection of differences between sharp and soft transients, which generate high and low envelope levels, respectively.

Transmodder features five dynamic filters. Each can be controlled by envelope signals generated by up to two transient analyzers. The good thing about the filters used in Transmodder is that they work in a bypass mode when the envelope stays at zero, causing no coloration to take place. This is especially useful in mastering applications where processing transparency is usually desirable.

The most evident purpose of this plug-in is to make the bass and high frequency content stand out in the mix or make it less noticable. This effect is very different from what a compressor/expander does because Transmodder 'sees' transients only. So, if there is a cymbal sound, only its very beginning will be 'seen' by Transmodder: the cymbal sound's body will be left unchanged. Moreover, transient detection does not depend on the absolute incoming sound level, which is why in Transmodder there is no such parameter as 'processing threshold'.

Transmodder is a useful mastering-stage plug-in. Since it is not extremely CPU consumptive, it can be used in track insert slots, too. Transmodder can work extremely well with drums, guitars and bass. One of the most remarkable thing in this 'transient' processing is, in most cases, it adds punch and brightness without severely affecting the overall perceived frequency balance.

Transmodder features:

  • Four transient analyzers
  • Five dynamic filters
  • Real-time spectrum analyzer
  • Transient detection meters
  • Mid/side channel processing
  • Narrow band sweeping
  • High quality mode
  • Factory presets
  • "A-to-B" comparisons
  • Mono-to-Stereo, Stereo-to-Stereo processing
  • All sample rates supported
  • 64-bit internal precision
  • Native assembler DSP code

  • Preset management

    Top buttons

    You can use the "Preset..." menu button to perform basic FXP/FXB preset/bank management tasks. The "Set as default" menu option of the "Presets..." menu allows you to assign the currently loaded program to the default preset program. This default program will be loaded whenever you enable a new instance of the plug-in or reset the current program. You can use the "Reset default" option to restore the default factory preset.

    By pressing the "A|B" button, you can exchange the current and shadow (or, alternatively, "A" and "B") programs. The "Copy" button copies the current program to a shadow one.

    Since only a single shadow program is used for the whole program bank, you can use "A|B" button to copy programs. To do so, you first need to switch to a program you want to copy and press the "Copy" button. Next, switch to a program where you want to put the first program and press the "A|B" button.

    The "Reset" button can be used to reset the current program. All parameters will return to their default states.

    Knob control

    Knob control

    To change a knob control's value, drag it with the left mouse button and move it up or down. For finer adjustment, press the right mouse button while dragging. Double-clicking on the knob with the left mouse button will return the knob to its default position.

    Transient analyzer

    Transient analyzer

    In this picture you can see knobs and switches which adjust the transient analyzer's behavior.

    In short, the transient analyzer detect transients in the given spectral range and generates an envelope signal in the absolute range 0 to 1 (this is visible on the meter: full blue is 1, full black is 0). This envelope can then be connected to the filter's gain setting. E.g., when the envelope is at 1, the filter runs at its specified Range setting. When the envelope is at 0, the filter makes no adjustments to the signal. If the envelope is at 0.5, the filter will use half its Range setting, etc.

    Mode switch disables the analyzer or selects the frequency band this analyzer should process. Broad means broad-band processing. Please note that broad-band processing may not sound precise, and in some cases may even generate unpleasant artifacts. BPass means single band processing, in which only a given spectral band is being analyzed. This mode is the most precise and most useful one: with its help, it is possible to precisely detect transients in particular spectral parts (The BPass2 and BPass3 modes are "wider" versions of the BPass mode). LPass - lower part of the spectrum, HPass - higher part of the spectrum.

    CnFreq parameter adjusts the center frequency for low-, high- and band-pass filters.

    Chnl switch selects which actual or derivative signal channel should be analyzed. Max - analyzer processes the maximum of the two stereo channels. Avg - average of the two stereo channels is processed. Mid - middle signal of the stereo pair is used. Side - side signal of the stereo pair is used. Please note that the side channel for a mono signal is zero.

    Env.Cmp (envelope compression) switch selects the envelope compression strength. As mentioned in the introduction, the analyzer generates envelopes of varying levels depending on the original transient power. Envelope compression allows compression of the detected levels to reduce the absolute level difference in the envelope signal. Such compression can be used to reduce or increase the swing of the dynamic filters.

    Scale parameter scales the envelope signal (and saturates it so that it never exceeds 1). The Scale parameter is useful in making transients more apparent.

    Time adjusts the minimal interval between the transients. For higher frequencies, the time should be smaller, for lower frequencies it should be higher. Otherwise, transient detection may become smeared and may generate 'warbling' artifacts.

    Sense parameter adjusts the sensitivity of the analyzer: e.g. when the sensitivity is higher, the analyzer will detect almost all level changes. When the sensitivity is low, only high-power 'stable' transients will be detected.

    Listen switch can be enabled to monitor the signal the analyzer processes.

    Overlay switch can be enabled to overlay the envelope signal on the original signal. The envelope signal is translated into a 440 Hz sine wave. Please note that you can tune the peak power of the sine wave on the help screen.

    You can use the following tuning sequence:

  • Choose an appropriate Mode and CnFreq. BPass mode is appropriate for most situations.
  • Choose a Chnl (Channel) the analyzer should process.
  • Depending on the CnFreq, an appropriate Time parameter should be used. The Overlay switch can be engaged on this step: if you hear a 'buzzy' sound, then the Time should be increased.
  • Sense should be set up. Actually, it is better to tune Time and Sense controls together.
  • As a final step, both the Env.Cmp and Scale parameters should be selected. For higher Env.Cmp values, Scale can be left minimal. For lower Env.Cmp values, Scale can be increased.
  • Tuning the filters is a much easier task and should be done after the analyzer is set up. As a final step, the Scale parameter of the analyzer can be additionally fine-tuned.

    NOTE: If tuning the analyzer is a hard task for you, then simply engage the global "Auto" mode. This mode is less precise but it can provide some usable settings quicker.

    Dynamic filter

    Dynamic filter

    This is a dynamic filter's control panel. The top-left knob controls the filter's frequency. The bottom-left knob controls the filter's bandwidth.

    Range is the maximum gain a filter can reach when the transient is detected.

    Two "TA" selectors above allow you to attach transient envelopes of up to two analyzers to this dynamic filter. The transient envelope controls a filter's gain setting. Enable the Link switch to link the CnFreq parameter of the analyzer to a filter's frequency setting. This way you can modify the analyzer's frequency in sync to the filter's frequency adjustments.

    You may use the +1 option in any TA selector to feed the filter with a constant +1 envelope signal: this means filter will be running at full power all the time. Please note this option overrides second TA selection - so there is no meaning in selecting an actual transient analyzer together with the +1 option.

    The Decay parameter adjusts the decay time of the filter. Since in most cases, the transient envelope generates very short transient 'bursts,' it can be desirable to prolong their effect on the filter.

    The button with the "L & R" label printed on it selects the audio channel this filter is applied to.

    The "S" switch enables the "solo" mode for the designated filter. The "M" switch mutes the filter. Please note that soloing does not work in the same way as in the multi-band processing plug-ins. I.e., you would not hear a band-pass filtering effect.

    Mode buttons

    Mode buttons

    The "TA Mode" switch selects between manual and automatic analyzer tuning. In the automatic mode Time, Sense and Scale parameters will be automatically chosen according to the CnFreq and Mode values of the transient analyzer.

    The "High/Normal Quality" button is used to switch between the normal and the high-quality processing modes. The high-quality processing mode internally uses a two-times higher sample rate, performing 2x oversampling. The high quality mode uses about three times more CPU resources. The "Auto" quality mode disables oversampling in the normal real-time plug-in operation and turns oversampling on during the offline audio bouncing. Please note that the "Auto" mode may not work properly in all hosts (if the host does not report back when it enters the offline processing mode).

    Graphical display

    Graphical display

    This is the part of the graphical display screen which can be seen by pressing the Graph button. This screen helps a lot in both finding the appropriate frequencies for the analyzer and tuning the filters, since it features a real-time FFT spectrum analyzer (shown in light blue).

    The "Block" selector specifies the block size of the spectrum analyzer. The larger the block size, the larger the resolution in the lower frequency range, but the lower the time coherence in the higher frequency end. The "Speed" selector specifies the speed (averaging coefficient) of the spectrum analyzer. The slower the speed, the higher the latency of the spectrum analyzer. The "Slope" selector (which is defined in dB per octave) allows you to adjust the spectrum analyzer display slope towards higher frequencies. This can be useful because higher frequencies are usually weaker than lower frequencies, and thus tuning them can be a difficult task. By choosing an appropriate slope setting, you can compensate for this behavior and make the spectrum plot more convenient and meaningful.

    This picture also shows control points, which can be dragged with the left mouse button to adjust the dynamic filter's Range and Frequency (you may additionally hold the SHIFT key to enable more precise movements). Double-clicking on a control point returns it to the 0 dB Range position. You can hold the CTRL key while dragging a point to enable its Range adjust only. Holding the ALT key while dragging a point adjusts its frequency only. A control point's position fully corresponds to the state of the dynamic filter in accordance with the number displayed on it.

    If several points are selected and you double-click any of the selected points, all selected points will be reset to 0 dB. While dragging a control point, you can adjust the filter's bandwidth by additionally holding the right mouse button.

    Pointing to a control point with the mouse cursor will cause it to be encircled with the green circle, and the corresponding filter's frequency response curve will become green. The orange curve on the picture above shows the summary frequency response of all active filters. The curve shown in dark red is an estimation of the effective frequency response all filters have for the moment.

    You can also edit groups of control points by selecting them. Just start dragging the control surface. In response to your dragging, a box will appear showing the selection area. All control points that enter this area become selected. Later you can move a group of selected points (encircled with a dashed line) like you are working with a single point. To add points to the current selection, you have to press the SHIFT key before starting to drag the control surface. To deselect the currently selected points, simply click the control surface anywhere.

    On the graphical screen you may also see vertical lines of varying colors. Horizontal position and color of these lines correspond to the CnFreq parameter of the according transient analyzer. You may move these lines to adjust CnFreq parameters of transient analyzers.

    You can engage the Narrow band sweeping function by clicking the left mouse button on the control surface while holding the CTRL key. This function allows you to listen in a sweepable manner to a selectable narrow band in order to detect various sonic artifacts.


    Pressing this button will display the plug-in's info screen. This screen shows copyright and registration information, and contains the "Help" button which opens the bundled HTML help file you are reading now.

    This screen also contains the following global setting: a global setting is one that affects all plug-in instances in all audio host applications.

    The "Overlay Level" selector specifies the peak volume of the the envelope signal when it is being overlaid as a sine wave on the original input signal.

    Troubleshooting tips and additional information

    What is a transient?

    A transient can be described as a quick volume change (bass drum, high hat). If the volume stays constant (like a synth pad or bass sustain), no transients can be detected. There are two types of transients: rising- and falling-level transients. Transmodder detects rising-level transients only.

    Can I use Transmodder for de-essing?

    Transmodder should not be generally used as a de-esser. However, it can be successfully used as a treble smoothing process.

    I am a little confused by the two frequency adjustments. The frequency adjustment on the 4 transient analyzers selects the area where you wish to modify the transients. Then there is a frequency adjustment on each of the 5 filters.

    Transient analyzers do no change the sound - they only "catch" the transients. These transients can then be used to drive any of these 5 filters.

    Does the analyzer react to the rate of change of the audio, i.e. NOT to an absolute level?

    Peaks are detected regardless of the absolute signal volume: what is important is the instantaneous level difference (the "Sense" parameter affects the level difference sensitivity) in the given time-frame (specified by the Time parameter). Then the "Scale" parameter scales (amplifies) the resulting transient envelope.

    Something seems funny when I try to use the Overlay to tune the TA - the Overlay tone seems spurious and obviously not useful. Any time the audio engine is on and Overlay is selected, after about 30sec or so I hear something that sounds like a geiger counter. The meter shows activity - but nothing is playing.

    Since Transmodder's transient analyzer is indifferent to the signal level it may detect something if it's only a dithering noise.

    What is the exact Q or Bandwidth (the "narrowness" of the filter) when using the "listen" mode?

    What you hear in the Listen mode depends on the Mode of the transient analyzer. BPass is steep (Q 1.70), BPass2 is less steep, BPass3 is two times less steep as BPass.

    Is Transmodder similar to some competing transient-designing plug-ins?

    In some cases, transient-shaping plug-ins can reshape attack, sustain and release stages of the sound, but this is probably out of the reach of Transmodder. In the case of Transmodder, transient moments can only be amplified or attenuated. However, it is possible to perform advanced tricks by using two filters together (one with the negative and the other with the positive gain, and varying decays). Both filters should be driven by the same transient analyzer. Although such approaches may look complex, they can give further control over transients.

    Transmodder looks like a complex plug-in. Can you help?

    Indeed, it is a pretty 'complex' plug-in. Not that it is scientifically complex, but you would need to understand sonic spectrum and dynamics concepts to be able to tune it precisely.

    You can also try this: enable the Graph mode and set the spectrum update speed to 128. This way you will see an instant spectrum content. Visually analyze which spectral parts go up and down most often and with the greatest span. These areas are the most dynamic ones, and they have the highest number of transients. Knowing these areas, you can adjust the analyzer to detect these transients.

    The next step is to tune the filters. The logic is simple: if a transient exists, make some part of the spectrum stronger according to it, or maybe weaker--depending on your preference. This allows you to amplify bass, bass drum or high hat hits. Some mixes may have too 'sharply' outstanding high hats or vocal syllables - you can tune the filter to reduce them, thus making the whole mix sound much smoother. It is also possible to do spectral demasking this way - e.g., make the 1 kHz range lower in volume when high- or low-frequency transients are detected.

    It is also a good idea to check out the factory presets for some quick treatment examples.

    What "Env.Cmp" is for?

    Envelope compression allows you to compress detector's dynamics. This way you can apply equally-powerful filter adjustments to transients of varying intensity.

    Does the analyzer react to the rate of change of the audio, ie NOT to an absolute level?

    Peaks are detected irregardless of the absolute signal volume: what is most important is the level difference. Large Sense values allow Transmodder to detect small level differences (e.g. 0.5 dB) while smaller values force it to detect strong level differences (like 3 dB) in the given timeframe (specified by the Time parameter). (These 'dB' figures are only comparative examples - in action, the actual figures can be different).

    Is Transmodder is an enhancer kind of plugin?

    Transmodder is not of this type for sure, but it can be configured to 'enhance' the higher frequencies.

    Happy Musicmaking!

    Copyright © 2004-2008 Aleksey Vaneev

    VST is a trademark of Steinberg Media Technologies GmbH.
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    Plug-in uses PNG library by Gustavo Huffenbacher Daud