More Than a TLA-100A

THis SUMMIT COMPRESSOR IS A CLASSIC, but we felt that there are a couple of features that could really bring this unit into the 21st century. So we decided to add an extra panel below the unit. If you don’t care about fancy features, just disregard that panel and the TLA-100A will work just as the original unit.

Low Cut

It is always handy to have the ability to filter out the lowest frequencies so that the compressor doesn’t react on them. Here you also have the possibility to choose whether you want to put the low cut on the entire signal (just as if you would have had a Low Cut inserted before the TLA-100 plug-in) or put on just the detector part of the compressor (a.k.a. “sidechain filtering”).

Parallel Inject = Parallel Compression

Parallel compression, ie. mixing a compressed signal together with the original signal, is a standard practice today. So instead of using several mix buses to achieve this we added a knob.

Saturation = Headroom = Mix Level Adjust

It’s always difficult to choose what level the virtual 0 VU should correspond to in the digital world. Some people use drum loops that peak at 0 dBFS, while others use material recorded at -24 dBFS. That’s why we added the Saturation control. With that control you can tune the headroom and the amount of saturation from the tube output stage in the compressor. Without it, you would have to use the Gain control to set the desired amount of distortion and compensate for that loss or increase in volume with a separate volume control. The Saturation does all that. In one knob.

 

User Interface

The user interface consists of two panels, the upper panel, containting the original TLA-100A knobs and switches, and the lower panel that offers extra functionality.

Upper Panel

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  1. Attack, Release, Meter select
  2. Gain (output volume)
  3. Reduction/Output meter
  4. Gain reduction
  5. Sidechain

Attack: A three position switch with FAST, MEDIUM and SLOW settings, which corresponds to the time it takes the compressor to respond to the input signal.

Release: Controls the time it takes the compressor to return to unity again. A three position switch with FAST, MEDIUM and SLOW settings. The release time is also effected by the program material. The slower the release time setting, the more the program material determines the release time.

Meter Select: Allows monitoring the output level (OUTPUT) or the amount of gain reduction taking place (REDUCTION).

Gain: Output volume. Unity gain is at “25”. The value display in the lower menu bar will show 0.0 dB.

Gain Reduction: Sets the amount of gain reduction and the operating point where gain reduction begins. The higher the gain reduction, the higher the ratio becomes. Works almost like a threshold control.

Sidechain: If you have an external sidechain present, switch to ext to use the external sidechain as target signal for the compressor. Use when you want a signal to duck under the external signal (for instance ducking strings under a bass drum, or music under a voice over).

Lower Panel

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  1. Low cut (frequency)
  2. Low cut selector
  3. Saturation saturation LED
  4. Parallel inject

Low Cut: Adds a low cut filter on either the detector or the input. From OFF to 600 Hz. OFF disables the low cut functionality.

Low Cut Selector: Select if the low cut filter should affect the input: like a normal low cut filter placed before the TLA-100A, or just the detector so that low frequencies doesn’t trigger the compressor.

Saturation: Sets the amount of headroom in the unit. If you need more distortion, turn up this knob. Distortion can sometimes be very useful together with slower attack times when you get loud transients. Use the Saturation knob to limit the transients.

Saturation LED: Indicates distortion at the output. You will get the best result if the saturation is used sparingly on percussive sounds, like a drum bus. Let it take care of occasional peaks, and do not run it too hot.

Parallel Inject: Adds the un-affected dry signal to the compressed (WET) signal. If you are using the compressor to shape the sound instead of compressing the volume (a rather normal use case these days), it is often useful to blend some of the original signal with the compressed track. An overcompressed drum track has few transients, which will make it sound dull and without energy, but if you blend some of the original transients into that track you’ll get the energy back while maintaining the overcompressed sound.

 

Block Diagram

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The drawing above illustrates the functionality of the plug-in. Green lines illustrate the main signal path and red labels the parameters.

The Low Cut parameters switch between either the detector low cut filter or the input filter.

Only one of the low cut filters is active at a time or both bypassed (by setting the Low Cut frequency parameter to OFF).

 

Mono and Stereo Operation

The Summit Audio TLA-100A plug-in can operate in both stereo and mono modes. In stereo mode the plugin will work as the real unit in “stereo link” mode. This means that both channels will get the same amount of gain reduction (which will preserve your stereo image). How the different modes (stereo, mono and mono-tostereo) are selected depends on your host software.

 

Extended Features

A whole range of added control can be accessed with Extended Features. Please see the separate "Extended Features" manual for more information.

 

Credits

Oscar Öberg – Modeling
Niklas Odelholm – Extra features and testing
Torsten Gatu – Framework programming
Arvid Rosén – Framework programming
Ulf Ekelöf – 3D rendering