ST596 Harmonics Processor User Manual
The ST596 is an Analog Harmonics Processor dedicated to professional music producers and studio engineers. It generates and extracts harmonics from the source signal. The harmonics can be added back to the source signal enhancing the source signal. The effect can be subtle or more dramatic depending on the controls setup. The ST596 can be used with various types of instruments, vocals, and for mastering the mixed track.
Please remember! The ST596 is analog hardware and it has limits. The DRY signal path can be overdriven and it will clip if the signal level is higher than 20dBu. It is not recommended to pass a high signal level. Please refer to the procedure below, get familiar with the ST596 before proceeding with bold and creative experiments…
The ST596 is professional studio equipment. The user should read and learn the basics of audio engineering before the use of any studio equipment.
Improper use or lack of basic knowledge will result in unwanted results or might be a cause of damage to your studio equipment.
The architecture and signal flow
Before the use of the ST596 please refer to the simplified signal flow diagram below.
The source signal is passed in parallel between the Analog Modeling circuit, which is responsible for generating and extracting the harmonics, and the Dry control. Both signals can be blended together to achieve the desired effect. The tape emulation circuit is after summing the DRY and WET signal and affects the sum of both signals.
The TAPE MIX knob controls the amount of tape effect added to the signal.
- The Drive knob controls the amount of harmonics produced by the Analog Modeling circuit. Only the harmonics are added to the source signal.
- The Wet knob sets the level of harmonics added to the source signal.
- The Dry knob controls the level of the source signal and the total output level when the ST596 is engaged.
- The Tape Mix knob allows the blending between the signal processed by the Tape Analog Emulator and the signal from the previous stages.
- The HFC switch cuts off the high frequencies to remove the air harmonics content. This feature helps with vocals and other HF-rich signals. It can be used also in a creative way.
- The LFS switch blocks the LF content passed to the Analog Modeling circuit, preventing the lows from being overdriven. This feature helps with LF-rich signals such as drums, bass guitar, bass synths, and bass tracks.
- The Tape-In switch engages the Tape Emulator circuit.
- The Process switch works as the bypass switch.
How to use ST596
The ST596 is easy to use even for less experienced users. It is recommended to follow the procedure below to get familiar with ST596.
- Make sure that input and output are connected to correct sockets on the back of the 500 rack
- Switch OFF all custom routing features in your 500 rack
- Set DRIVE knob to a minimum – max left
- Set the DRY knob to the maximum and the WET knob to the minimum
- Set the TAPE MIX knob to the max left
- Reduce the level from the DAW to -12dBu
- Press the PROCESS Switch – LED ON
- Play the 1kHz test signal or 1kHz track and confirm that the signal pass from input to output – the IN/OUT levels should be equal
- Set the WET to 50% and increase the DRIVE level – the harmonics should become audible
- Change the level of the WET signal and the DRIVE amount to achieve the desired effect
- Use the DRY and WET knob to control the overall output level from ST596
- Press the TAPE IN Switch – LED ON
- Turn the TAPE MIX knob right to achieve the TAPE saturation effect.
Important. The amount of harmonics generated by the ST596 is depended on the signal level sent to the unit. If the signal level is too high the DRIVE knob may lose the ability of the linear control of the harmonics content. It is recommended not to excide the 0dBu level.
The optimal input level is -10dBu.
The LFS and HFC functions
The LFS (Low-Frequency Safe) function blocks the LF content of the source material from being passed to the harmonics generator. This is useful if the source signal is rich in lows and removes the rumbling effect. LFS can be used in a creative way. For example, if you wish to add the edge to your kick drum or bass guitar without losing the dynamics on the LF spectrum of the recording. Please note that the LFS may increase the overall peak level of the output signal for LF-rich sources.
The HFC (High-Frequency Cut) is a low pass filter that reduces the level of highs above 12kHz. The HFC is placed after the DRY and WET signal sum and before the tape emulator. It can be used to reduce the HF harmonics and “round-up” the tone.
The Analog Tape Emulator
The Analog Tape Emulator allows adding the tape-like saturation and the glue to the music material. The circuit generates the harmonics and adds compression similar to the tape recorder. If driven harder the tape emulator will compress or even limit the signal. Some output level reduction may occur if the input signal level is high. This is the normal behavior of the circuit and it can be used in a creative way. The TAPE MIX knob allows controlling the amount of the tape effect added to the output signal. The plots below present the compression curve and the THD curve of the tape emulator.
Please study the plots below which will help you to get better results with ST596 Tape Emulator. The LFREZ jumper enables the LF frequency bump of the Tape Simulator.