Synth Pack Pro (Mac/Win)
Hydra features three oscillators that can be arranged in three different phase-modulation routings. A multimode filter, along with chorus and bass-boosting effects, round out the signal path.
Synth Pack Pro ($139) is a bundle of three of Synapse Audio's synthesizer plug-ins (also available separately). Hydra ($99) is a 3-oscillator subtractive synth featuring three phase-modulation signal-routing models. Scorpion ($59) is a classic subtractive synth, and Plucked String ($49) uses physical modeling to emulate different stringed instruments, with emphasis on guitar and bass.
All three synths are provided in VSTi format for the Mac and PC, and in DXi format for the PC. I used each in a variety of Mac and PC hosts, including VST-AU converted versions in Logic Pro 7. The only host-related problem I encountered was not getting audio from Scorpion in Live 4.
Hydra uses different phase-modulation signal routings to produce sounds similar to FM synths. Two of Hydra's oscillators offer a selection of 39 waveforms, whereas the third, which is used solely as a modulator, is limited to a sine wave.
With the first signal-routing model, Oscillator 3 phase-modulates Oscillator 2, which is then ring-modulated with Oscillator 1. That's well suited for gong and for tuned percussion sounds that have more sparse frequency spectra than FM usually produces.
The second routing is a cascade: Oscillator 3 phase-modulates Oscillator 2, which, in turn, phase-modulates Oscillator 1. That piles sidebands on top of sidebands to produce thick inharmonic spectra suitable for chaotic, noise-based percussion and instrument-attack sounds.
In the third routing, Oscillators 2 and 3 are mixed and then routed to modulate Oscillator 1. Oscillators 2 and 3 have their own decay-sustain amplitude envelopes and modulation-amount controls, allowing you to crossfade between modulators. That makes it excellent for bright, clangorous sounds like bells and mallet instruments; the designers missed an opportunity, however, by not offering delay and attack stages on at least one of the modulating-oscillator envelopes.
Hydra's signal path ends in a multimode filter followed by chorus and bass-enhancer effects. An LFO and routers for MIDI Velocity, Aftertouch, and Modulation Wheel are provided for modulation. A unique Pitch Up, Pitch Down system uses separate delay-decay-release envelopes to bend the pitch up and down. Finally, Single, Dual, and Unison performance modes allow one, two, or all Hydra voices to be allocated to each note. Dual mode, which introduces a random detuning and pan offset between the voices, thickens the sound without usurping all voices.
One of Hydra's greatest charms is that you can change a preset's signal-routing model to produce a completely different sound. That works well with a large number of the 150 factory presets.
That Stinging Sensation
Scorpion's two oscillators offer only a sawtooth waveform, but Oscillator 2 has variable phase, can be inverted, and can be forced to reverse direction at each Oscillator 1 cycle (similar to traditional hard sync). Those options allow you to produce a variety of waveforms, and the oscillators can be ring-modulated as well.
The oscillators are followed by a resonant lowpass filter, which in turn feeds an effects chain consisting of reverb, chorus, delay, and a filtered waveshaper. Although Scorpion has a decidedly nonvintage effects chain and is programmed somewhat differently from a vintage synth, it is fully capable of classic-synth sounds, as its 100 factory presets attest.
Lots of Pluck
Plucked String starts with five physical-modeled string emulations, and adds fine control of timbre, elasticity, and plucking strength. The sound generator is followed by a lowpass filter with a Damp control that affects the filter's slope (the rate at which the highs are rolled off). Consistent with the plucked-string model, there is no filter envelope, the output envelope is ADR, and there is a delayed LFO for adding vibrato.
Plucked String has multivoicing modes similar to Hydra's; Single, Double, and Triple modes assign one, two, and three voices to each note. Even in Triple mode, you can still play eight simultaneous notes if you've set ployphony to its maximum of 24 notes. Plucked String is obviously designed to do one job, and it does it very well.
My one complaint with all three synths is that you must retrigger notes to hear settings changes, but that's a small issue. They all sound good, are stable, and are not CPU hogs (see Web Clip 1). Considering the wide variety of sounds this trio can produce, Synth Pack Pro is a bargain at the price. You can download save-disabled (but otherwise fully functional) demos from the Synapse Audio Web site.
Overall Rating (1 through 5): 3.5
Synapse Audio Software