electrix filterfactory & warpfactory

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Published in SOS October 1999: Close window

ELECTRIXFILTERFACTORY

379 &WARPFACTORY

349

prosSolid, attractive

packaging.Good control

ergonomics, with real-time MIDI operation.

Interesting andmusically useful

sounds.

cons

Electrix Filterfactory & Warpfactory

Filter & VocoderReviews : Processor

ELECTRIX FILTERFACTORY FILTER &WARPFACTORY VOCODER

Can these new digital interpretations of classicanalogue filters and vocoders really offer somethingnew? Paul Whitefinds out...

The new Electrix digital signal processors attracted a lot ofattention at their launch, not least because of their striking retrodesign and their abundance of real-time controls. The first twounits in the range are the FilterFactory and the WarpFactory,

conceived to appeal to both studio users and DJs, anddesigned for real-time, hands-on operation. However, MIDI functionality has been added so that absolutelyall the front-panel knobs and switches (other than the WarpFactory's mic gain) transmit real-time controllerinformation. If recorded into a MIDI sequencer, this data may be played back into the unit to recreate theoriginal performance. The more adventurous may want to edit the data within a sequencer, or even createcompletely new control data.

Constructionally, both units share the same 2U format, but instead of the usual folded-steel rack case theyhave cast-metal casings, with an angled bottom and rubber feet for convenient desktop use. They may alsobe rackmounted. Power comes directly from the mains via an EC connector on the back panel, so there are

no wall-warts to break or lose; other connections (including MIDI In, Out and Thru) are also on the backpanel, along with a rotary switch for MIDI channel selection, and the mains switch.

To return to the front panels, the knobs and buttons of both units are suitably large, for ease of use in a livesituation, and the buttons are surrounded by illuminated rings to indicate their status. This is rather morefun than the usual single LED!

FilterFactory

First out of its flightcase-style cardboard box is the FilterFactory, a stereo filter designed to produce thedistinctive resonant effect characteristic of analogue synthesizers. To make the device DJ-friendly, phonoinputs (switchable between line and record-deck cartridge) are provided in addition to balanced line-levelinput jacks. The outputs are on both phonos and balanced jacks, and there's a footswitch jack for live use.

A switch connected to the latter acts as a bypass; either a normally open or normally closed momentary-action type may be used, as the type is recognised when the unit is powered up.

In addition to MIDI for real-time control-data transfer, there are two 1V-per-octave CV inputs that may be

used to control the FilterFactory's left and right filter frequencies from a suitable analogue synth. As I nolonger have an analogue synth with CV outs I couldn't test this facility.

The FilterFactory is stereo throughout, the signal path comprising an adjustable

distortion section followed by the filter block. The Buzz control sets the amount ofdistortion to be applied, while the Trim control allows the user to adjust the finallevel of the distorted signal before it hits the filter. An Engage switch takes thedistortion in or out, and there's another, larger, switch (dubbed Momentary) thatmay be tapped to add this effect rhythmically in real time. If Buzz is disengaged,the Momentary button brings in the effect for as long as it's held down; if Buzz isengaged, pressing the Momentary button bypasses the effect. Trim determines

the relative levels of the clean and distorted sounds, so if you turn the distortedsound level right down, tapping the Trim button creates gating effects - or youcould turn up the overdrive level and add distorted accents.

Moving on to the filter section, this is a 2-pole, 12dB/octave resonant design (alldigital), though both channels can be cascaded in 4-pole mono mode to provide a24dB/octave filter, at the expense of stereo operation. The filter frequency isadjustable from 20Hz to 20kHz with variable resonance (yes, it will self-oscillate at

Sound On Sound : Est. 1985


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No input level controlsor proper level

metering.Filter has no MIDIenvelope-trigger

facility.

summaryFun, freaky and

affordable.

Really Warped...

maximum resonance!) and a choice of four filter modes: low-pass, high-pass,band-pass and notch. A single button steps through the modes, and four statusLEDs show which mode is currently active. The same type of Engage andMomentary 'bypass' buttons are used here as in the Buzz section, and in this

case, the Momentary button also resets the FilterFactory's LFO (Low FrequencyOscillator) to the beginning of its cycle, so you always get the same effect whenhitting it.

The filter frequency may be modulated by a choice of four repetitive waveforms, arandom sample-and-hold style wave, or the envelope of the input. In addition,MIDI note and CV control of frequency are possible. The repetitive waveforms are

based on forward and reverse ramps, triangle and square waves, but there's also an interesting SingleShot mode. When Single Shot is active, the Momentary button triggers a sweep envelope based on

whichever waveform is selected; the Rate control then controls envelope speed. This works in tandem withthe Division button, so that, on triggering, the current waveform will repeat between one and six times, asselected.

In normal free-running mode, the modulation rate is generally controlled by the Speed knob, though there'salso a Tap Tempo button for quickly setting up tempo-related effects in real time. Alternatively, the LFOswill sync to MIDI clock, and the Division button also works with MIDI clock to multiply the tempo up or downover the range 1:4 to 6:1. If you make a manual rate adjustment after the MIDI clock has started running,the tempo will revert to follow the manual adjustments.

As it's also possible to tune filter frequency directly from MIDI note data or from a CV input, you can turnthe filter up into self-resonance and then play the resulting pitched sound from a keyboard. However, thedesigners have not included the facility to make MIDI notes trigger the filter envelope, for conventionalsynth sweep sounds. You can use the input signal itself as a modulation source, but unless the original

envelope is very clearly defined the outcome is less predictable than with a MIDI trigger.

The final control is the Effects Mix knob, which sets the balance between dry and effected sound. Thesection which hosts this knob also incorporates status LEDs for MIDI and Power, as well as indicators ofinput and output activity. Other than these activity LEDs, there's no level metering on the unit at all.

Every knob and button sends out MIDI data when operated, as mentioned earlier, but it's also possible totransmit a dump of the entire unit's status - to a MIDI sequencer, for example - by pressing and holding theBypass button at the right of the front panel. This is particularly useful, as the Electrix units don't have patchmemories. All you need to do is record the dump of controller information during the count-in bar or barsbefore a song starts, and all the FilterFactory start settings used for that song will be saved.

Filter Tips

The FilterFactory is very straightforward to use, though I found the lack of metering worrying andoccasionally, at high resonance settings, I got the sound to break up even though the input or output level

LEDs were not signalling that anything was wrong. There are also no input or output level controls, soideally you need to be able to set your levels at source. Obviously you can't do this if you plug a recorddeck directly into the unit.

The filter section is impressively analogue-sounding, with a keen edge to its resonant sweeps and plenty offullness at the bass end. It gets quite vicious in the 4-pole mode, but is still quite controllable as long as you

don't get too heavy-handed with the resonance control. All the filter modes sound strong, including thenotch filter, which may be used to create phaser-type sounds.

Heard in isolation, the distortion section is a little rough, but played through the filter it's exactly right for

grunging things up without obscuring their character completely. Of course, it's the real-time control aspectof the FilterFactory that really brings it to life, and the control layout makes it possible to be very

spontaneous. I particularly like the Momentary buttons and tap-tempo feature, and the Single Shot mode isalso surprisingly effective when used to trigger multiple cycles of modulation. If you need 'shoot from thehip' filter effects or rhythmic filter/gating/distortion effects, this little box delivers with style.

WarpFactory

The WarpFactory follows the same styling and general format as its filter counterpart, though it also sportsa mic input to allow it to be used live without a mixer or separate mic amp - because essentially theWarpFactory is a digital vocoder optimised for voice mangling.

Like any vocoder, it has two inputs: one for the sound being mangled (Source) and another for the sounddoing the mangling (Formant). For those unfamiliar with vocoders, the frequency spectrum of the Formantsignal is imposed on the Source signal, creating a dynamic filter effect that can make instruments or soundeffects 'talk'. To up the stakes, the WarpFactory also features a formant shifter (which presumably remapsthe vocoding filters) with a range from -12 cents to +18 cents relative to the pitch of the Formant input.

The back of the case reveals

the same MIDI and I/O setas the FilterFactory, with the


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I tried a number of musical source sounds with the WarpFactory and found the usualstrings and harmonically rich synth pads were best for emulating classic analoguevocoder effects. However, I got a surprisingly good result by using a recording of

SMPTE timecode as a source, modulated by a voice, with the low Band setting. I cansee the 'waste nothing' techno brigade really going for that one!

addition of a Formant inputjack and an XLR labelledMic Bypass. The latterprovides a Thru connection

from the mic input on thefront panel, enabling the mic to be connected to a mixer as well as to the WarpFactory.

The front panel is divided into three main sections, the first of which is Formant Input. Here there's a

variable-gain mic amp with XLR input, basic 3-LED level metering, and a Select button that scrolls aroundMic, Line (Ess On), Line (Ess Off), and Auto. The Ess On setting is designed to help vocals remain clearafter processing, while the other setting is used for instruments. I suspect that Ess On routes vocal

fricatives (sibilant 'S' and 'T' sounds) directly to the output, though no technical explanation is given. TheAuto setting vocodes the Source input with itself, so any peaks and dips in the frequency response are

exaggerated.

Next is the Formant Warp section, whose controls include:

Band, which optimises performance for low- or high-frequency sounds, with the lower setting designedfor use with drums, bass instruments, and so on. Once again, no explanation of exactly how this works isgiven, but it's my guess that it changes the frequencies of the vocoder filter bands.

Gender, which moves the formant of the soundfeeding the Formant input (usually a voice) up ordown without changing the musical pitch.

Q and Order, which affect the Q (bandwidth) andresolution of the digital filters. Playing with thesebrings about some very noticeable timbral changes:

as Q is advanced, the sound quality becomes more

resonant, as you'd expect, but it also seems moregranular and electronic. Order reduces theintelligibility of the voice and rounds the sound outmore, so for clearer enunciation lower settings are best.

Noise Mix, for adding noise into the Source signal path, which can help make vocal effects moreintelligible, not to mention more hissy and menacing.

Formant Freeze, which allows the filter shape to be frozen at any instant in time, for static filtering.

An oscillator is also included, to allow users to generate the familiar budget sci-fi robot voice effect. Thisis variable from 92Hz to 241Hz, or it may be switched off. As in the case of the FilterFactory, all thecontrols output and receive MIDI controller data, so sequencer automation of any function is possible,and a MIDI dump of the current settings can be made.

In the Output section you'll find a Mix control, but this mixes only between the Source input and the treatedsignal. It isn't possible to mix any of the Formant input directly into the output to improve intelligibility,unless you use an external mixer. The Source Kill button, however, is quite useful. When this is switched

on there is no audio output from the WarpFactory unless both inputs are present, while if it is switched offthe Source signal will continue to sound even if the Formant input stops.

Go To Warp

Achieving all the classic vocoder effects with the WarpFactory is easy and, because fricative 'S' and 'T'

sounds seem to be routed directly through to the output when the mic input is selected (just as they were inthe better analogue vocoders), speech intelligibility is reasonably good. There may also be a degree ofcompression on the Formant input, as the processed signal level is reasonably even compared to someother vocoders I've tried. It also seems as though there's some sort of gate in the Formant input, becausewhen the user is not speaking into it, low-level sounds don't accidentally trigger the output. This works well

enough, but it can truncate your spoken input if you let the level drop too much.

Having control over voice formants makes it possible to change vocal timbres more radically than you canwith a traditional vocoder, and for quick and dirty sci-fi voices the internal sawtooth oscillator does away

with the need for a source input. Similarly, the noise input is great for creating sinister metallic voices - this

unit could create suitable monster voices for at least three series of Doctor Whowithout repeating itself!(Perhaps now the BBC will reconsider the fate of the good Doctor?) Switching the Band control from high tolow also produces a new set of sounds concentrating on the lower harmonics rather than the upper-midrange. This produces more monster voices, certainly, but it is also a powerful way of processing drumsounds or bass instruments.

Factory Favourites

Both of these units work really well, producing musically interesting sounds and being very intuitive to workwith. When they're abused, the sound becomes 'digital' and grainy, but that's often all to the good! The real-time control aspect is the key to the success of these boxes, and the inclusion of MIDI means that they're

just as useful in the studio as they are on stage. My main concerns are the lack of level controls and the

inadequacy of the level metering, but providing you have control over your source signal levels, thisshouldn't be too serious a problem. I'm also disappointed that no MIDI envelope triggering is featured on

the FilterFactory, even though MIDI note-to-filter frequency control is catered for.


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Published in SOS October 1999

Making music should be fun, and these little boxes from Electrix certainly help to make it exactly that. Thenumber of controllable parameters may seem small, but the range of sounds that can be achieved is widerthan you might imagine, especially from the WarpFactory. I have a feeling we'll be hearing a lot more fromElectrix in the near future.

information

FilterFactory 379;WarpFactory 349. Pricesinclude VAT.

SCV London+44 (0)171 923 1892.

+44 (0)171 241 3644.Click here to email

www.scvlondon.co.uk

electrix filterfactory & warpfactory

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