Electro-Harmonix Stereo Talking Machine

Need help?

Do you have a question about the Electro-Harmonix Stereo Talking Machine and is the answer not in the manual?

Summary

Special Features of the Stereo Talking Machine

QUICK START GUIDE

Setup Instructions

Guides users through connecting cables and powering on the Stereo Talking Machine for initial use.

Preset and Manual Settings

Explains how to select presets and configure manual settings using knobs and footswitches.

Sweep Level LEDs Explanation

Details the function of the Sweep Level LEDs, indicating filter positions during operation.

PRIMARY KNOB FUNCTIONS

Blend Control

Adjusts the wet/dry balance of the effect output, mixing processed and dry signals.

Voice Type Selection

Selects one of nine distinct filter types or 'voices' for the sound.

Attack Knob Function

Controls the rise time, or speed, of the filter sweep from rest to maximum position.

Decay Knob Function

Manages the fall time, or speed, of the filter sweep from maximum to rest position.

Sensitivity Knob Function

Adjusts filter response to playing dynamics and reverses sweep direction (polarity).

PRIMARY SWITCH FUNCTIONS

Presets Encoder Functionality

Manages preset selection, saving, and toggling auxiliary functions on/off.

Bypass Footswitch and LED

Toggles the unit between effect mode and bypass mode; LED indicates active mode.

Preset Footswitch and LED

Loads selected presets and enters auxiliary knob edit mode for advanced adjustments.

AUXILIARY SWITCH FUNCTIONS

Auxiliary Functions Toggle

Enables/disables auxiliary functions like Fuzz, LFO, and Volume Control via the PRESETS knob.

Auxiliary Edit Footswitch

Allows editing of auxiliary function parameters by holding the PRESET footswitch.

AUXILIARY KNOB FUNCTIONS

Volume (Blend Knob) Control

Adjusts the overall output volume of the Stereo Talking Machine.

Fuzz Tone (Voice Knob) Control

Modifies the treble or high frequency response of the fuzz effect.

Fuzz Gain (Attack Knob) Control

Determines the amount of distortion or fuzz applied to the signal.

LFO Rate (Decay Knob) Control

Sets the speed or rate of LFO modulation applied to the filter sweep.

LFO Depth;Shape (Sensitivity Knob) Control

Controls the amount and type (triangle/sawtooth) of LFO modulation.

I;O CONNECTIONS

Input and Output Jack Usage

Details how to connect instruments, amplifiers, and external effects via various jacks.

Expression Pedal and Control Voltage Input

Explains the use of an expression pedal for manual filter control.

POWER SPECIFICATIONS

Power Requirements and Adapter

Specifies the voltage, current, and plug type for the AC adapter, and current draw.

TECHNICAL SPECIFICATIONS

Audio and Impedance Details

Lists sample rate, bit resolution, and input/output jack impedance values.

PRESETS MANAGEMENT

Preset Save Procedure

Step-by-step guide to saving custom sound settings to one of the nine programmable presets.

Preset Load Procedure

Instructions for loading saved presets using the footswitch or knob combination.

Preset Unload Procedure

How to revert to current knob settings from a loaded preset.

Factory Preset Restore Procedure

Method to reset all presets back to their original factory settings.

The Electro-Harmonix Stereo Talking Machine (STM) is a vocal formant filter designed to transform guitar sounds into growling, gurgling, and snarling textures. This highly customizable envelope-controlled digital vowel filter utilizes multiple moving filters to achieve its unique sonic effects.

Function Description

The core function of the STM is to apply vocal formant filtering to an input signal, typically a guitar. It achieves this by sweeping between two distinct filter settings, mimicking the way a human mouth moves to form various vowel sounds. The device offers nine selectable voices: seven human vowel filter combinations, a classic wah-wah filter, and the legendary dual-band filter of the EHX Bassballs. These voices can be swept in either a forward or reverse direction, effectively doubling the available sound options.

Beyond its primary vocal filtering, the STM incorporates several auxiliary functions that expand its sonic capabilities. These include a programmable distortion (Fuzz) to add grit and growl, an internal Low-Frequency Oscillator (LFO) for automatic filter modulation, and a volume control for overall output adjustment. An effects loop side-chain allows for the integration of external effects pedals between the STM's preamp and filter sections, preserving the instrument's original dynamics.

The STM operates in both mono and stereo configurations. In stereo mode, certain voice types (WAH, BB, AH-OO, AH, OW-EE) produce a pan sweep synchronized with the filters, creating a dynamic stereo image. Other voice types (EE, EE-ER, AH-I, I-A) shift the filters differently for each output, resulting in a wide and lush sound field.

Usage Features

The STM is designed for intuitive operation with a combination of knobs, footswitches, and LEDs.

Quick Start Guide:

To begin using the STM, connect your instrument to the INPUT jack and an amplifier to the MONO/L output. Power the unit with the included AC adapter. Activate the effect by pressing the BYPASS footswitch until the STATUS LED lights up.

Preset Settings:

The STM features nine fully programmable presets, allowing users to save and recall their favorite sound creations. Factory presets are pre-loaded to showcase the STM's sonic range and can be overwritten. Presets capture the settings of all five black knobs and the auxiliary functions.

Loading Presets: Presets can be loaded by repeatedly pressing and releasing the PRESET footswitch to cycle through them, or by turning the PRESETS knob to select a number and then pressing the PRESET footswitch. The PRESET LED will light solid to indicate a loaded preset, and a corresponding LED in the ladder will blink to show the recalled VOICE mode.
Saving Presets: To save a preset, create your desired sound, turn the PRESETS knob to the desired preset number, and then press and hold the PRESETS knob for 3 seconds until the LED ladder blinks.
Unloading Presets: To unload a preset and revert to current knob settings, turn the PRESETS knob clockwise until no LEDs in the LED ladder are lit.
Factory Reset: To restore factory presets, press and hold both the PRESETS knob and the PRESET footswitch while applying power, continuing to hold until the LED ladder blinks rapidly.

Manual Settings:

For manual control, set the BLEND, VOICE, ATTACK, and DECAY knobs to their full clockwise positions, and SENSITIVITY to 1 o'clock. Ensure the PRESET LED and auxiliary function LED are off. Play your instrument and adjust the SENSITIVITY knob until the Sweep Level LEDs light up completely after each note. The ATTACK and DECAY knobs control the filter sweep speed. The VOICE knob selects different voicings or filter types.

Primary Knob Functions:

BLEND: Controls the wet/dry mix of the effect. Minimum (counter-clockwise) is 100% dry, maximum (clockwise) is 100% wet.
VOICE Type: Selects one of the nine filter types. Turning the knob changes the filter type, indicated by a brief blink of the corresponding LED. The STM does not blend between voices; the knob acts as a switch.
ATTACK: Varies the rise time of the filter sweep. Counter-clockwise provides the fastest rise (8 mS), while clockwise provides the slowest (1200 mS).
DECAY: Varies the fall time of the filter sweep. Counter-clockwise provides the fastest fall (8 mS), while clockwise provides the slowest (1300 mS).
SENSITIVITY (w/ voice polarity): Controls the input volume required to trigger the filter sweep, affecting the STM's responsiveness to dynamics. A center detent signifies the off position for no envelope response, useful when using an expression pedal. Turning the knob clockwise from the center detent sweeps filters in the forward direction (e.g., OW->EE), while counter-clockwise sweeps in the reverse direction (e.g., EE->OW).

Footswitches and LEDs:

BYPASS Footswitch & LED: Toggles between Effect mode and buffered Bypass mode. The red LED lights when in Effect mode.
PRESET Footswitch & LED: Loads selected presets. Also used to enter auxiliary knob edit mode by pressing and holding. The PRESET LED lights solid when a preset is loaded.

Sweep Level LEDs:

Two orange LEDs under the PRESETS knob visually indicate the filter's position. When both are unlit, filters are at their rest position. When both are lit, filters are at their maximum position. These LEDs sweep on and off, mirroring the audible filter sweep.

Auxiliary Switch Functions:

The STM's auxiliary functions include Fuzz, LFO Filter Modulation, and Volume Control. These can be used independently or in combination and are saved with presets.

AUXILIARY TOGGLE Encoder (PRESETS Encoder) and AUX STATUS LED: Press and release the white PRESETS knob to toggle auxiliary functions on or off. The leftmost orange LED illuminates when auxiliary functions are on.
AUXILIARY EDIT Footswitch (Preset Footswitch): Hold down the PRESET footswitch to adjust auxiliary parameters. While held, the black knobs control their auxiliary functions. Turn the desired knobs to change parameters; the leftmost orange LED will blink. Release the footswitch to exit edit mode; knobs return to primary functions.

Auxiliary Knob Functions:

VOLUME (BLEND knob): Adjusts the overall output volume.
FUZZ TONE (VOICE knob): Increases treble/high frequency response of the fuzz. Requires FUZZ GAIN to be active.
FUZZ GAIN (ATTACK knob): Controls the amount of distortion. Full counter-clockwise bypasses the fuzz section.
LFO RATE (DECAY knob): Controls the speed of LFO modulation. Requires LFO DEPTH/SHAPE to be active.
LFO DEPTH/SHAPE (SENSITIVITY knob): Sets the amount of triangle (counter-clockwise) or sawtooth (clockwise) wave modulation. The center detent is off.

I/O Connections:

INPUT: Connect your instrument or other effects pedal here.
SEND / RETURN: An effects loop for integrating external pedals. SEND connects to the external effect's input, RETURN to its output.
MONO/L and R OUTPUTS: MONO/L is for single output or primary amp. R is for stereo output to a secondary amp.
EXP PEDAL: Connect an expression pedal for manual filter control, similar to a wah pedal. The SENSITIVITY knob should be set to 12 o'clock to disable envelope response when using an expression pedal. The toe/heel positions can be swapped by moving the SENSITIVITY knob slightly into the negative range.

Maintenance Features

The Electro-Harmonix Stereo Talking Machine is designed for reliable operation.

Power Supply: Use the supplied Electro-Harmonix 9.6DC-200 power supply (9.6 Volts DC 200mA / Center Negative). Using the wrong adapter may damage the unit and void the warranty. The STM does not take batteries.
Preset Management: The STM's nine programmable presets allow users to save their customized settings. These settings are retained even after power is disconnected, ensuring that preferred sounds are readily available. The manual suggests using a dry erase marker to label the white painted blocks corresponding to each preset number, facilitating easy recall and organization of custom sounds.
Warranty: Electro-Harmonix provides a one-year warranty covering defects in materials or workmanship for original purchasers from authorized retailers. For service, customers are advised to contact EHX Customer Service to obtain a Return Authorization Number (RA#) and include a written description of the problem, contact information, and a copy of the purchase receipt.
FCC Compliance: The device complies with FCC rules for Class B digital devices, designed to provide reasonable protection against harmful interference in residential installations. Users experiencing interference are advised to reorient/relocate the receiving antenna, increase separation between equipment and receiver, connect the equipment to a different circuit, or consult a dealer/technician. Unauthorized modifications could void the user's authority to operate the equipment.