What's in a name? In the case of Antares Filter, not nearly enough to thoroughly describe the variety of effects this DSP plug-in can deliver. From the control panel alone it's clear that a lot is going on here (see Fig. 1). However, the panel's complexity belies the ease with which Filter can be learned and used. For sound shaping from the simple to the bizarre, Filter is well worth investigating.
Filter is a four-stage processor; as its name implies, each stage contains a filter. Each stage also has a tempo-synced feedback-delay line you can place before or after the filter. Furthermore, Filter's four stages can be configured in any of six arrangements: parallel, serial, and four combination routings. Add four LFOs, four envelope generators, two 48-step Rhythm Generators, a full modulation matrix, and an envelope follower, and you have plenty to play with.
Filter is available in VST and RTAS formats for Mac and Windows, in MAS format for the Mac, and in DirectX format for the PC. The plug-in supports both Mac OS 9 and OS X, and an Audio Units version is planned for future release. The package includes a CD containing all versions as well as a printed manual (which is also provided in PDF format). Filter uses challenge-and-response authorization, which can be carried out instantly online or within several days by e-mail or fax. Filter will run unauthorized for a ten-day grace period.
Although Filter will run on any system capable of running a compatible host program, four stages of filtering and delay can eat up a significant amount of processing power. To run more than one instance, you'll want a fast computer. When I ran four instances of the VST version in several hosts on a dual-processor Mac G5/2 GHz, the hosts' CPU meters registered about 35 percent.
Each filter can take on any of five shapes: lowpass, highpass, bandpass, notch (often called band reject), and flat. Flat simply lets you use the stage's delay line without filtering. Each filter's slope can be set to 12, 24, 36, or 48 dB-per-octave (also referred to as 2-, 4-, 6-, and 8-pole). With four multimode filters, a flexible signal path, and a little thought, you can create just about any filtering configuration you want. The thought involves analyzing how the filters will interact.
When you place two filters in series, only the frequencies that pass through both filters will be heard. When you place two filters in parallel, all the frequencies that pass through either filter will be heard. For example, if you place highpass and lowpass filters in series and set the cutoff frequency of the highpass filter below that of the lowpass filter, the frequencies between the two cutoffs will pass through. That gives you a bandpass filter, with the advantage that you can change the width of the band. If you place the same filters in parallel with the highpass cutoff above the lowpass cutoff, the frequencies between the cutoffs will be filtered out. That gives you a notch filter, and again you control the notch width. Place the parallel (notch) filters after the series (bandpass) filters, which is one of Filter's routing options, apply a little modulation, and you'll have a notch sweeping through an expanding and contracting band. Web Clip 1 illustrates that effect.
Filter makes arranging the filters as easy as possible by providing an interactive display showing the active filters' response curves in bright, semitransparent colors. You can bring any filter to the top by clicking its corresponding button beside the display or by clicking any uncovered portion of its curve within the display. You can then change its frequency and resonance by dragging vertical and horizontal lines that appear in the display.
As I mentioned, by setting the filter types to Flat, you can use the delay lines by themselves. And just as filter routing affects the outcome, so does the routing of the delays. With the delays arranged in parallel, Filter becomes a standard four-tap feedback-delay line. If you arrange the delays in series and increase the feedback, Filter will produce cascading echoes as later delays in the series generate echoes of the echoes generated by earlier delays.
When the delay times are very short (below roughly 30 ms) and the feedback is set high, the delay lines act like resonators. In that configuration, the delay time controls the resonator pitch and the feedback controls the decay time. Resonators are especially effective with drums, turning ordinary drum sounds into tuned percussion.
Of course, multibank filters and multitap delays are not hard to come by. Along with Filter's modulation options, however, the interaction of the filters and delays provide the most unusual results. Web Clip 2 is a percussion loop created from a single kick-drum hit processed using two Filter presets that combine delay and filtering with Filter's Function and Rhythm Generators.
Filter's four Function Generators each combine an LFO and an envelope generator. Although a Function Generator can display only one or the other at a time, they can be used simultaneously. The LFOs offer ten waveforms: sine, triangle, ramp up, ramp down, square, short pulse, long pulse, and three varieties of random — hold, slew, and ramp. Random ramp is an unusual and very useful construct that produces a ramp down from a different starting level on each cycle. It would be nice to have full control of pulse width, but the three choices provided are adequate for most tasks.
You can sync the LFOs to the host's tempo, in which case their rates are set in note values ranging from a 32nd note to 16 quarter notes. Triplets and dotted notes are also provided. When an LFO is not synced to tempo, its rate can be set in either Hertz or beats per minute. When using bpm, the LFO cycle length is a quarter note at the chosen tempo.
Filter's envelope generators are quite flexible. They offer delay, attack, decay, sustain, and release stages and can be triggered by either of the two Rhythm Generators or by MIDI. When controlled by MIDI, the envelopes can be either triggered, with a fixed sustain time set by the Hold control, or gated. You can set all envelope time parameters either directly in milliseconds or as a percentage relative to the Rhythm Generator's step size.
The Rhythm Generators are 48-step gate sequencers. Both run on the same clock and must have the same step size. Separate clocks and step sizes would be better, but at least you can set the number of steps for each independently. Like the LFOs, the clock can be free running or synced to tempo.
You can use the Rhythm Generators either to trigger the envelopes or as modulation sources. In the latter case, any step that is turned on sends the maximum value and any that is turned off sends the minimum. The two-value limit is mitigated somewhat by the modulation amount controls, which themselves can be modulation targets. That capability allows you to create pseudo-step-sequences, in which the step values are set by, for example, an LFO controlling modulation amount.
Filter also has an Envelope Follower that generates a control value based on the level of the incoming audio. Its Attack and Decay controls allow you to set how rapidly it reacts to changes in level. The Envelope Follower has many uses, the most familiar of which is the auto-wah effect produced when it is used to modulate a bandpass filter's frequency.
Filter's modulation routing is controlled by a 12-row modulation matrix (see Fig. 2). Its 39 mod sources include the LFOs, envelopes, Rhythm Generators, and Envelope Follower, as well as MIDI Note, Velocity, Mod Wheel, After-touch, Volume, and Pan. Each MIDI source can be routed separately from four different MIDI channels. Destinations include all filter, delay, LFO, and envelope parameters as well as the modulation amount for the top four modulation routings.
Filter ships with more than 100 factory presets divided into five categories roughly indicating their intended use: Beats, Effects, Instruments, Pad, and Spectral. You can get a good idea how Filter works just by exploring the presets. The manual is excellent and even the presets are fully documented.
Filter is an excellent piece of DSP software. Its filters are capable of everything from subtle coloring to modulated, resonant, slicing up of the frequency spectrum. You can use the delays as resonators, for reverblike echo effects, and as multitaps. The modulators are plentiful and offer some clever twists. The price might appear a bit high for a filter-and-delay plug-in, but it's justified by Filter's versatility and high sound quality.
Len Sassois an associate editor ofEM. He can be contacted through his Web site atwww.swiftkick.com.
Minimum System Requirements
Antares Filter 1.0
MAC: Mac OS 9 or OS X 10.2; compatible host
PC: Windows 98 or XP; compatible host
Filter 1.0 (Mac/Win)
FEATURES4.5EASE OF USE4.0DOCUMENTATION5.0VALUE4.0RATING PRODUCTS FROM 1 TO 5
PROS: Sounds great. CPU efficient. Very flexible modulation matrix. Six signal-path configurations. Excellent documentation.
CONS: Crowded control panel is sometimes hard to read. Rhythm Generator functionality is limited.