Synthesis Technology E520 Hyperion Eurorack Stereo Effects Processor (Silver)

The E520 Hyperion is a mono/stereo in, stereo out effects module. It is 48HP wide, 35mm deep and uses less than 230ma of +12V and less than 50ma of -12V.

Powered by a 480MHz ARM Cortex M7 CPU, the E520 has 64MB on on-board SDRAM for recording up to 6min of stereo audio at 48KHz sample rate. The LCD screen and optical encoder navigation uses the same 'shallow' menu scheme of our E352 and E370 modules, with the addition of 4 'soft keys' for selecting options without having to leave the main page.

The E520 uses a premium audio path not usually found in Eurorack. Crystal Semi CODECs, TI OPA-series op amps (in the audio sections) are used along with low-noise, dedicated LDO voltage regulators for a clean, full soundstage. Audio conversion uses 48KHz sample rate, 24bit resolution with a line or synth level setting.

The Input and Output gains can be independently set for Line or Modular levels. This allows direct interfacing to DAWs/audio interfaces without a mixer or VCA stage. It also makes interfacing from your old keyboard synths/drum machines into your modular gear quck and easy.

The E520 is designed to fit into a 4ms 48HP powered PODX Desktop case.

Currently, there are 26 different algorithms included with the E520, and more can be added in the future as internal memory allows. Each algorithm can have up to 4 PARAMETERS under voltage control. The initial value of a PARAMETER is set by a panel knob, and then external CVs of up to +-5V at 10KHz can be applied. In addition, most algorithms employ feedback which can be modulated by external CVs as well. Typical PARAMETERs are delay time, LFO speeds, pitch shift amount and many others.

The row of 'soft keys' are usually 1-3 for algorithm selections (such as range of Delay Time) while the 4th is a BYPASS function. Some algorithms use the TAP TEMPO button for tapping in Delay Time, LFO Speed or similar functions. Other algorithms repurpose the TAP TEMPO as a 'FREEZE' or 'HOLD' function. The SYNC IN jack can be used like the TAP TEMPO functions, but driven by a clock or Gate signal.

The E520 has a unique 'dual chained mono' mode, where either:

different algorithms cam be placed on Left and Right channels (for example Shimmer on Left and the Voder filter on Right). This can be thought of as 2 Mono Ins, and 2 Mono Outs.

2 algorithms can be 'chained' , where the Left algorithm internally feds the Right algorithm. This is a Mono In, Stereo Out signal chain (both Left Out and Right Out can be used).

Chaining of stereo effects is not possible due to limitations of internal memory and the DSP speed required to maintain the 48KHz sample rate.

Algorithms in the E520 fall into 3 catagories:

Time Domain Effects - delay, chorus, phase shifting/flanging, frequency shifting and others.

Frequency Domain (Spectral) Effects - Our unique Spectral Crusher, vocoder, time-stretching and others.

Utility - frequency and level measurements

TIME-DOMAIN EFFECTS

Stereo Pattern Delay

The Stereo Pattern Delay is a stereo tapped delay line with CV-controlled tap patterns. Each channel (left / right) has its own separate delay line with two sets of taps: Primary and Secondary. The patterns are chosen from a set ov 64 and the length of the patterns can be adjusted via buttons. Mixing between Primary and Secondary, filtering and feedback all allow control over the complexity and dynamics of the output. Tap Tempo or external clocks can be used to set the base time rate and a selectable multiply/divide ratio can scale the rate.

Stereo Flanging Delay

The Stereo Flanger Delay is short delay which allows smooth control of the delay line length over intervals of 0-100ms which makes it particularly useful for Flanging and Karplus-Strong effects. This is a true stereo effect in that there are separate delay lines for Left and Right channels but they can be processed identically. The unique feature of this algorithm is the inclusion of an 8-stage allpass diffuser at the input with control over mix and length which can be used to thicken up the sound prior to flanging. Additional features are that the delay control can be done either in linear time or exponential frequency, and that the output can be set into flanger mode which makes comb-filter sounds easier to achieve.

Stereo Chorus

The Stereo Chorus is multi-tap chorus with selectable number phases and an integrated LFO with variable frequency and depth. It is a true stereo effect: the Left and Right channels are completely independent but can be processed with identical parameters. Variable feedback is available as well as selectable LFO waveform and optional phase offset between the Left and Right channels.

Resampling Mini Delay

This effect is based on the E580 Resampling Mini Delay and encompasses or extends all of its functions. Stereo inputs are mixed down to a single channel, resampled (the sampling rate may be reduced by a variable amount through a band-limited interpolation process), pass through a delay line with a fixed and variable tap, and are then resampled to two separate outputs. Separate L/R feedback controls allow fine adjustment of recirculation on both the fixed and variable delay. Three mode settings emulate various classical delay characteristics.

Stereo Clean Delay

The Stereo Clean Delay is a non-resampling delay (the sampling rate is constant throughout the processing) which always runs at the full 48kHz rate and introduces no interpolation artifacts into the signal while the delay length is stable. This is a true stereo effect in that there are separate delay lines for Left and Right channels but they are processed identically (same delay length, same filtering, etc.). A switchable resonant 4th-order lowpass filter is available in the feedback path if desired. Ping-pong feedback between the two channels may be enabled.

Stereo Resampling Delay

The Stereo Resampling Delay is resampling delay which allows control of both the delay line length (for granular cross-fade effects) as well as sample rate (for smooth delay changes and FM effects). This is a true stereo effect in that there are separate resamplers and delay lines for Left and Right channels but they are processed identically (same delay length, same filtering, etc.). A switchable resonant 4th-order lowpass filter is available in the feedback path if desired. Ping-pong feedback between the two channels may be enabled.

Prime Dual Tap Delay

The Prime Dual Tap Delay is an emulation of the Lexicon Prime Time T93 rack-mount delay. It is a resampling delay which allows control of both the delay line length (for granular cross-fade effects) as well as sample rate (for smooth delay changes and FM effects). As the original, this is a mono effect in that there is one delay line whose input is an equal mix of Left and Right channels and separate output taps for Left and Right channels with independent delay lengths that are selectable from a pre-determined set which includes delays that have relatively prime ratios. Controllable 4th-order lowpass filters are available in the feedback path if desired. Buffer lengths well beyond that of the original Prime Time effect are available and the two outputs may be mixed down to mono if desired.

Stereo Reversing Delay

The Stereo Reversing Delay is reversing and resampling delay which allows control of both the delay line length (for granular cross-fade effects) as well as sample rate (for smooth delay changes and FM effects). This is a true stereo effect in that there are separate resamplers and delay lines for Left and Right channels but they are processed identically (same delay length, same filtering, etc.). A switchable resonant 4th-order lowpass filter is available in the feedback path if desired. The unique features are that this delay can be run forward or backwards and it can be frozen to keep playing the current delay contents without changing.

Deflector Shield

The Deflector Shield is a recreation of the original E560 Deflector Shield module. It is a monophonic effect similar to the original Bode frequency shift which applies a variable frequency offset to any input signal. As the original, there are three distinct operating modes, as well as a unique carrier morphing feature that provides unusual output harmonics. Although the input is mono, there are two outputs which allows simultaneous up/down shift as well as true quadrature outputs. Variable feedback is available as well as linear or exponential frequency CV response.

Stereo Frequency Shifter

The Stereo Frequency Shifter is similar to the Deflector Shield but is a true stereo effect, the Left and Right channels are completely independent but are processed with identical parameters. Similar frequency shifts, carrier morphing and modes are available but the output modes are limited to variations of Up and Down shifting. Variable feedback is available as well as linear or exponential frequency CV response.

Stereo 24-stage Phaser

The Stereo Phaser is an all-pass phaser with selectable number (6, 8, 18, or 24) of all-pass stages and an integrated LFO with variable frequency and depth. It is a true stereo effect: the Left and Right channels are completely independent but are processed with identical parameters. Variable feedback is available as well as selectable LFO waveform and optional phase offset between the Left and Right channels.

Stereo Pitch Shifter

The Stereo Pitch Shifter is a granular pitch shifter with +/-2 octave range, variable grain size and chaos offset. It is a true stereo effect: the Left and Right channels are completely independent but are processed with identical parameters. Variable feedback is available as well as selectable shift quantization to an equally tempered scale.

Stereo Shimmer Reverb

The Stereo Shimmer Reverb is a reverb combined with a granular pitch shifter in the feedback path that can be used to introduce a variety of ambient, soaring textures. It is a true stereo effect: the Left and Right channels are processed independently but share the same reverb loop so that sounds in one channel will reverberate in the other, but from a different part of the process so that stereo imaging does not collapse.

Variable feedback is available as well as selectable shift amounts to allow for a wide range of moods, dark, chaotic and ethereal. Infinite mode is controlled via the Tap Tempo input and preserves the sound in the reverb by disabling inputs, filters and internal attenuation, extending its duration for hours.

Stereo Looper

The Stereo Looper is a time-domain looper with resampling that provides up to 5.8 minutes of looping duration at the full sample rate and approx 45min at the lowest rate. It provides the usual feature set of recording, overdubbing and playback.

SPECTRAL EFFECTS

Spectral effects are processed in the frequency domain using the Fast Fourier Transform. All spectral effects in the E520 use a 1024 point complex FFT to provide two 512 point real transforms at a rate of 2.7ms which provides a good compromise between time and frequency resolution, while allowing full stereo processing for most effects. Frequency resolution is 512 bins of 48Hz each.

Voder Speech Filter Bank

The Voder is a set of 15 stereo 2nd order bandpass filters spaced to mimic human vowel sounds. It is based on a 1939 Bell Labs 'technology demonstartor'. It is a true stereo effect: the Left and Right channels are completely independent but can be processed with identical parameters. In addition to selecting the specific vowel sound there is also control over pitch, width and resonance, lag and morphing. A random sample/hold allows stepping through the sounds at a rate determined by the Tap Tempo input.

Spectral Crusher

The Spectral Crusher is a multi-effect which provides a number of unique ways to manipulate sound in the frequency domain. Six different algorithms are available, each of which crushes audio in a different way.

Spectral Time Machine

The Spectral Time Machine is a combination of a looper, pitch shifter and time stretcher. A large (5.8 minute) memory records and loops sounds which can be played back continuously or looped with variable speed and pitch. Due to the processing overhead this is a mono effect. Left and Right channels are mixed 50/50 prior to input. Output has pseudo-stereo at some settings of the Phase Blur control.

Spectral Delay + Pitch Shifter

The Spectral Delay + Pitch is a stereo effect with independent delay and pitch shift applied to the Left and Right channels. Pitch shift quantization to equal tempered half tone intervals is available independently on each channel and a fixed value phase blur may be applied to both channels simultaneously.

Spectral Delay

The Spectral Delay is a stereo effect which delays each spectral bin by different amounts. Similar to the NI Spektral Delay plug-in, everal modes are provided to vary the bin delays in different ways. Left and Right channels have independently controlled delay parameters.

Variable-Band Spectral Vocoder

The Spectral Vocoder is a mono effect which superimposes the amplitude response of one signal (the Modulator, in the Left channel) upon another signal (the Carrier, in the Right channel) which can (among other things) be used to create talking instrument when speech is used as the Modulator signal. Various amplitude and frequency manipulations are provided to improve or distort the intelligibility of the resulting sounds, including gain adjustments, compression, enhanced sibilance (S sounds) and frequency resolution reduction.

Spretral DroneMaker

The Spectral Drone is a stereo effect which is patterned on the Michael Norris Spectral Dronemaker plugin. It takes any audio as input, samples the sounds at controllable intervals and interpolates between the samples.

Four CV input parameters are supported but their function varies depending on the operating mode so see below for details:

Length: This varies from 0.01 second to 10 seconds and controls the nominal length of the sampling interval. Shorter lengths track the incoming sound more accurately, longer lengths lead to slowly changing sounds.

Phase Blur: This controls the amount of phase blur added to the output. At full CCW no blur is added, while at full CW the maximum is added. Increasing blur will change from wavy to bubbly to glassy sounding output.

Left/Right Pitch: A variable amount of pitch shift can be added to the left channel audio prior to the sampling process. Range is -1200 cents to +1200 cents and is nonlinear to provide more fine tuning for small shifts.