TBProAudio Impress2 Compressor Plugin User Manual

: June 13, 2024
: TBProAudio

Table of Contents

Introduction
Features
Design
Minimum System Requirements
How to use
Plugin Controls
Demo mode versus Registered Mode
Plugin activation
Conclusion
References
Read User Manual Online (PDF format)
Download This Manual (PDF format)

Impress2
Manual

Introduction

Welcome to Impress, a wideband stereo compressor including side-chain and various prefilter options. The goal of the design was to cover a broad range of compression applications in today’s mixing and mastering situations with strong focus on low aliasing. So, Impress could be used to shape subtle a snare sound, glue different tracks on instrument bus and even do complex tasks like design or voice over’s. All Impress parameters are easy to read and control. Additionally Impress gives visual feedback to make musical decisions right.

Features

Impress offers following features:

zero latency click-free 64-bit internal processing
low aliasing compressor design
“real” oversampling, up to 8x
stereo/left/right/mid/side processing
external side-chain
main signal multiband filter, up to 192 dB/Oct (Lackwits-Riley design)
detector signal pre filter, up to 192 dB/Oct
2 compressor modes: classic and clean (low aliasing)
3 gain stage modes: modern, vintage and vintage clean
2 level detection modes: peak, RMS and RMS with BS.1770 pre-filter
short/long attack/ release times
Look Ahead
low aliasing soft knee
Gain reduction limit
dry/wet
peak/RMS measurement
flexible signal monitoring
preset management
easy to use GUI
large and accurate live meters
gain transfer graph
time response graph
GUI scale

Design

Diagram below shows the basic structure of Impress:

Compressor: The compressor part has two inputs (Main and Detector) and one output (Out): the main signal is the audio stream to be processed by the compressor, the detector signal is the signal for the level detection. In most applications both signals are the same, for side-chain effects separate signals are used.
Beside the classic “to go” design Impress offers a clean, low aliasing design with two envelope follower. The gain stage could run in “vintage” mode with a thermal noise emulation. The “knee” function is optimized for low aliasing operation.
Multiband Filter: The main signal could run through a multiband filter stage. The signal is split into three frequency bands, the mid band feeds the compressor, the output of the compressor is mixed with the low and high band again. The multiband filter is based on the Lackwits-Riley design (up to 192 dB/Oct steepness), which prevents any phase shifts.
Filter: The detector signal could also run through a filter stage .
Detector Input: The detector signal path could use either channel 1+2 or channel 3+4/sidechain.
Monitoring: Signals through Impress can be individually monitored in order to control the effect of each signal stage (M).

Minimum System Requirements

Windows 7, OpenGL 2 GFX card
Mac OS X 10.11, Metal GFX card
SSE2 CPU
Win: 32/64 Bit VST, 32/64 Bit VST3, 32/64 Bit AAX
OS X: 64 Bit VST, 64 Bit VST3, 64 Bit AU, 64 Bit AAX
Tested with: Cocos Reaper, Steinberg Cubase/Unendow/Wave lab 6+, FL Studio 12+, PT2018+, Reason 9.5+, Studio One, Ableton Live
For latest information please visit www.tbproaudio.de

How to use

Impress is designed to reset all internal measurements if significant parameter changes are made. This keeps all displays updated.
Impress uses various graphical elements to control the parameters of the plugin:
Value button:
Mouse click and drag up/down changes value of the parameter.
Mouse double click opens value input box.
Mouse ctrl click resets value.
Mouse-wheel increments/decrements value

Button:
Mouse click enables/disables function, small red LED means “on/enabled”
Popup menu button:
Mouse click opens popup menu.
Slider:
Mouse click and drag up/down changes value of the parameter.
Mouse double click opens value input box.
Mouse ctrl click resets value.
Mouse-wheel increments/decrements value

Plugin Controls

6.1 Presets
Preset menu loads and saves user presets. Presets stored to %localappdata%/Impress for Windows or /Users/xxx/Library/Application Support/Impress for Mac OSX are imported as user presets. Prev and next button step trough all presets.
6.2 Main
6.2.1 Monitor
This control selects plugin audio output (please refer to 3, monitoring). Following signals could be routed to output:

original main signal
main signal, filtered by multiband filter
output of compressor, not mixed with low/high band of multiband filter
original detector signal
detector signal, filtered
final output signal of Impress plugin

6.2.2 Oversampling
Main and detector signal could be oversampled up to 8 times. As Impress uses highest quality up/down-sampling algorithms for low aliasing operation significantly more CPU resources are used.

6.3 Main Signal Stage
Before the main signal goes into the compressor, the full stereo signal or parts of it (e.g. left or mid signal) could be selected. after the compressor stage the unprocessed part (e.g. right or side signal) is added.
Then the signal could be sent through 3 multi band filter, only the mid band is then treated by the compressor. After the compressor stage the low and high band are mixed to the compressed signal. As the design of the multiband filter is based on Lackwits-Riley the absence of phase shifts is guaranteed. Placing several instances of Impress in series gives a flexible multiband compressor.

ChanSel (Channel Selector): stereo (default), left, right, mid+side, mid, side
MB (Multiband): off, on (red light)
LC (LowCut): sets the lower limit of mid band, 1 – 22049Hz
HC (HighCut): sets the higher limit of mid band, 1 – 22049Hz
Slope: sets filter steepness, 24dB/Oct – 192dB/Oct, in 24dB/Oct steps
6.4 Detector Selector
This control selects which plugin input is routed to the detector signal stage.
Channel 1+2 of the plugin are always routed to the main signal stage.
Channel 1+2 could also be routed to detector signal stage (normal operation). Or channel 3+4/Side-chain could be used as detector signal. In this mode the level detection of the compressor is controlled by a different signal then the main signal (side-chain effects)

Det Input (Detector input): Main (channel 1+2), SC (channel 3+4/side-chain)
6.5 Detector Signal Stage
Before the signal form channel 1+2 or 3+4/side-chain is routed to the detector input of the compressor parts of the signal can be selected. Additionally the signal can be filtered in order to let the level detector focus on a specific part for the spectrum.

ChanSel (Channel Selector): stereo (default), left, right, mid+side, mid, side
Flt (Filter): off, on (red light)
LC (Low Cut): sets the lower limit of the filter, 1 – 22049Hz
HC (High Cut): sets the higher limit of the filter, 1 – 22049Hz
Slope: sets filter steepness, 24dB/Oct – 192dB/Oct, in 24dB/Oct steps
6.6 Compressor
The compressor module is a soft knee variable-ratio processor with maximum compression becomes a limiter.
6.6.1 Compressor Type
Classic: Classic digital compressor design with well known gain follower
Clean: Low aliasing design, gain follower and double level envelope follower
6.6.2 Level Detector
Peak: Classic peak level detector
RMS: Signal level is calculated from RMS value
6.6.3 RMS Window
Selectable RMS window size in ms, 0 – 3000ms, in 0,1ms steps
6.6.4 Threshold
Calibrated in dBs. If detector level is below threshold level, compression starts to act. Click and drag handle to adjust the threshold level, additionally press ctrl key to fine tune. Shift click resets to default value. Double click on the threshold value below opens input window. -60dB – +12dB in 0.1dB steps
6.6.5 GainStage Type
Modern: Classic digital gain stage design
Vintage: Analog gain stage with thermal noise emulation
Vintage C: Analog gain stage, without thermal noise emulation
6.6.6 Ratio
This controls the compression ratio in the region above threshold, 1 – info (limiter), in 0.1 steps
6.6.7 Knee
Adjustable low aliasing soft knee, knee starts -x dB below threshold and ends +x dB above, 0 – 24dB, in 1dB steps
6.6.8 Attack
Calibrated in ms, adjusts attack time of the compressor from 0 – 1000 ms in 0.001ms steps Envelope is shown in the response graph on the right side
6.6.9 Hold
Calibrated in ms, adjusts hold time of the compressor from 0 – 2000 ms in 0.001ms steps Parameter is only used in compressor type “classic”.
6.6.10 Release
Calibrated in ms, adjusts release time of the compressor from 0 – 5.000 ms in, in 0.001ms steps.
If clean compressor mode is selected release time also effects hold times of double level envelope follower
Current Envelope is shown in the response graph on the right side
6.6.10.1 Auto Release
Release time is calculated program dependent, 125dB/s
6.6.11 Makeup Gain
Adjust the output level of the compressor in dB, -24dB – +24dB, in 0.1dB steps
6.6.11.1 Auto Makeup Gain (AMG)
If switched on makeup gain is calculated ratio dependent
6.6.11.2 Set Makeup Gain
Sets makeup gain so that output level reaches 0dBFS. Hold shift key to reach -0.1dBFS
6.6.12 Dry/Wet
This control mixes the dry signal with the wet (compressed) signal, 0 (dry) – 100 (wet)
6.6.13 Look Ahead
Main/Detector signal is “pre-delayed” in order to let compression start “earlier”, 0 ms – 3000 ms, in 0.001ms steps
6.6.14 Max Gr
Limit maximum gain reduction. This is very useful for vocal compression, just to avoid over compression.
-96 – 0dB, in 0.1dB steps
6.7 Meter

Meters for main signal (Inp), detector signal (Det), output (Out) and gain reduction (GR).
LED signal meter range is from -60dBFS to +12dBFS, in 3dB steps.
LED gain reduction meter is from -60dB to 0dB, in 3dB steps.
Value below meters show maximum value.
If signal clips (above 0dBFS) top LED lights red.
Click on the meter resets max. values and heat-maps in the scope display.
6.8 Scope
6.8.1 Gain Transfer Graph

This display show the current gain transfer curve (white line), current threshold value (blue line), maximum main signal level (red area) and current main signal level (light red area).
Additionally heat-maps of main signal (top) and output signal (right) are shown
6.8.2 Impulse Response Graph
This display shows current response graph of the compressor (in ms).
6.8.3 Plugin info menu
This control opens the plugin info menu. It provides more information about the plugin, online version check opens the manual and online change-log.

Demo mode versus Registered Mode

In demo mode (without activation) the plug-in mutes audio every 90 seconds for a short period. This could be circumvented by clicking on the “TBPro Audio” logo within 90 seconds.

Plugin activation

The plugins needs to be registered/activated to remove demo restrictions. Please go to www.tb-proaudio.de to purchase the activation key. After purchase you will receive an email from TBPro Audio with either the (zipped) activation key file or the activation key in text form. Go to the plugin menu->Activate plugin. Please follow the steps described here: https://www.tbproaudio.de/support/productactivation. After successful activation the key symbol shown in the GUI appears in golden colour.