Free Alpha 3

Summary
A solid subtractive synth that provides a base line against which other free synth plugins should be measured. The plugin has a good sound and a flexible feature set. Pros: 30 waveforms and four per voice. Modulation routing matrix. It's free. Cons: Only one LFO. 8-voice polyphony.
Scores
Features:	Fair
User Interface:	Fair
Sound:	Good
Value:	Fair
Overall:	Fair
TestTone
Reviewed on:	November 22, 2007
Reviewed with:	Logic Pro 8 -
This review used the free version of the product. TestTone and its reviewers do not accept payment from developers in exchange for a review. Please see our full Review policy.

Review of Free Alpha 3

LinPlug's Free Alpha 3 is the free version of LinPlug's commercial Alpha 3 synth plugin. Free versions of fee plugins are often just teasers, stripped of essential functionality and barely usable on their own. This isn't the case here. While Free Alpha 3 does have fewer features than its Alpha 3 big brother, the plugin remains a solid subtractive synth. And if you like it, Alpha 3 adds more features for a modest fee.

Features & Interface

Free Alpha 3's audio path runs left-to-right through its user interface. Oscillator controls are on the left, filter and amp controls are in the middle, and modulation controls are on the right.

Oscillators

Free Alpha 3 has two oscillators, each playing a choice of two waveforms, labeled "A" and "B", for a total of four waveforms playing per voice. Menus select among 30 variations of classic waveforms:

Sine	Spectra2	VintSaw2
Triangle	Spectra3	VintSaw3
Sawtooth	Spectra4	SawBass1
Square1	RichSaw1	SawBass2
Square2	RichSaw2	SawBass3
Square3	RichSaw3	SawBass4
Organ1	RichSaw4	SawBass5
Organ2	SawSpec1	SawBass6
Organ3	SawSpec2	SawBass7
Spectra1	VintSaw1	SawBass8

The "Sine", "Triangle", and "Sawtooth" waveforms are standard fare. "Square1" is a clean square wave while "Square2" and "Square3" are rougher. The 17 different sawtooth waves vary in shape and harmonics, and several simulate classic analog sawtooths. The three organ waveforms are good organ starting points, and the "Spectra1" through "Spectra4" waveforms are simply interesting without being any shape in particular.

The waveform set offers good source material for creating classic sounds. Waveform variations allow a preset to use, for instance, "RichSaw1" through "RichSaw4" on the "A" and "B" waveform choices for two oscillators to create a richer sound than that possible if the same waveform were used repeatedly.

Each oscillator's "A" and "B" waveforms also include a transpose setting labeled 2', 4', 8', 16', or 32'. The labels are a reference to organ pipe lengths. The longer the pipe, the deeper the pitch, so the 32' choice here pitches an oscillator very low. 16' is an octave higher, and so on up to 2' for the highest pitch.

The "A bal B" knob for each oscillator adjusts the balance between the "A" and "B" waveforms. A common technique used by many of the plugin's presets assigns the "A" waveform to an 8' pitch, and the "B" waveform to a deeper 16' or 32'. This adds deep bass to any note and is similar to the sub-oscillator feature of other synth plugins.

The "detune" knob spreads out the tuning of the two oscillators, and the "1 mix 2" knob adjusts the oscillator mix.

Filter

The mixed oscillator output runs through a filter controlled by a center bank of knobs. Four buttons here select among four filter types: a 12 dB/octave low-pass filter, a 24 dB/octave low-pass filter, a 12 dB/octave band-pass filter, or a 12 dB/octave high-pass filter. The 12 dB/octave filters are pretty standard, but the steeper slope of the 24 dB/octave filter is like that found in old analog synth gear. This is an essential feature if you're after that classic analog sound.

Knobs above the filter buttons adjust the filter cutoff frequency and resonance, while those below adjust a filter envelope. "Att", "Dec", "Sust", and "Rel" knobs adjust the ADSR envelope's attack, decay, sustain, and release. The "Fade" knob sets the slope of the envelope's sustain stage to cause it to gradually rise or fall while a note is held. The "Depth" knob varies the impact of the envelope on the filter. At positive depth settings, the filter modulates the cutoff frequency upwards, while negative settings lower the cutoff frequency.

Amplifier

The plugin's amp is controlled by a bank of knobs to the right of the filter. Two knobs at the top adjust the plugin's volume and keyboard velocity sensitivity, while the knobs below adjust an ADSR volume envelope.

Chorus

A built-in chorus effect thickens the sound and adds a little movement. Controls for the effect vary the length of a delay at the heart of the chorus, and the speed of a dedicated LFO to modulate the delay time. A mix knob adjusts the amount of chorusing applied to the plugin's output.

Modulation

Modulation is an essential feature in any subtractive synth. Without it, sounds are flat, unchanging, and artificial sounding. Free Alpha 3 delivers with lots of modulation abilities.

Beyond the filter and amplifier envelopes, the plugin adds a tempo sync-able LFO with a variable attack time to slowly ramp it up at the start of a note. Six LFO waveforms are available: sine, triangle, sawtooth, square, noise, and sample-and-hold. The latter two both create a random series of values, but the noise waveform smoothes them out while the sample-and-hold waveform jumps abruptly from one value to the next. Both random waveforms are useful for creating sci-fi R2-D2-like computer beeps or unpredictably changing filter shifts.

The blue panel in the upper right shows a modulation matrix that configures up to seven modulation sources, what they modulate, and how strongly. Modulation sources include the LFO, the filter and amplifier envelopes, the keyboard note played, keyboard velocity, aftertouch, and the pitch wheel, mod wheel, breath controller, foot controller, expression controller, and arbitrary controllers 16, 17, 18, and 19. A special "constant" modulation source sends a fixed value and provides the equivalent of another knob to adjust the synth's sound.

Modulation destinations for these sources include the pitch, volume, and waveform symmetry of both oscillators, master pitch and volume, the filter's cutoff frequency and resonance, and the LFO's speed. For each source and destination pair, the modulation strength can be set and even inverted so that as the source goes up, the destination goes down. Three special destinations modulate the modulation strength of the first three lines in the matrix. These can be used to cause one modulator to modulate another, such as using an envelope to modulate the LFO's speed. The same modulation source can be used multiple times, and the same destination can be modulated by multiple sources.

Other controls

The remaining controls include adjustable portamento (labeled "Glide"), a preset menu, and buttons to load and save presets to files. An "ECS" button ("Easy Controller Setup") helps configure the synth's features to respond to specific MIDI controllers. And a "Gen" button generates random patch settings.

Clicking on the "LinPlug" name flips the plugin around to display its rear panel. While there are no controls here, the rear panel shows the plugin's version number, copyright notice, and credits.

Presets & Programming

The plugin comes with 64 presets and there are more available for download on the Internet. The presets include several nice synth basses, analog pads, and swirly textures. My favorites include "Symetry pad BT" for a big deep pad with lots of modulation, "Siddhartha BT" for a gentle, resonant swirly texture, and "Funksyncer (mw+vel) BT" for a brash in-your-face lead.

The presets provide useful starting points, but the plugin's clear user interface makes it easy to create your own sounds. For a classic analog sound, set the "A" and "B" waveforms for the two oscillators to a selection of different sawtooths at 8' and 16' pitches, detune a little, turn up the chorus, use the 24 dB/octave slope low-pass filter, and adjust the cutoff frequency and resonance. For a mellower sound, set the "A" and "B" waveforms to sine waves at 2', 4', 8', and 16' pitches, turn off detuning, turn up the chorus, and use the LFO to gently modulate the first oscillator's symmetry. Using slow envelopes to modulate the filter, resonance, and LFO speed adds gentle movement and texture to any sound.

When downloading presets from the Internet, note that presets for the Alpha 3, AlphaCM, and AlphaKeys won't load into Free Alpha 3. Those plugins have a few more features that make their presets incompatible. However, presets for Free Alpha 3 can load in to Alpha 3, et al.

Sound Check

Smooth, predictable filters are a desirable feature in any synth. To check a filter's frequency response I usually set the plugin to a white noise source, then use a spectrum analyzer to plot the response. Free Alpha 3 doesn't have a white noise source, but its Alpha 3 big brother does. The filters for both plugins are the same, so the plots below show Alpha 3's filter frequency response at a 1 kHz cutoff setting with no resonance for each of the four filter types.

12 dB/octave low-pass filter	24 dB/octave low-pass filter
12 dB/octave band-pass filter	12 dB/octave high-pass filter

There are no surprises here, which is good. The filters are smooth and do what they should. Unlike many synth plugins, the filter slopes are as advertised: 12 dB/octave and 24 dB/octave. This is important because the steeper slope of a 24 dB/octave low-pass filter is a characteristic of vintage analog synth gear and an essential feature for plugins like this one that aim at recreating classic sounds.

Commentary

The plugin is smooth and easy to use, and the sound is full and clear. CPU use is low, even with lots of modulation. During testing I encountered no problems at all. Free Alpha 3 is a stable polished product.

Compared with other free synth plugins, Free Alpha 3 is a solid performer. It has a wider range of waveforms, better filters, a better sound, more modulation options, and a smoother user interface than most free plugins. It's available for the Mac and PC as an Audio Units or VST plugin, and it's a good addition to any plugin collection.

Review Scores

Features: fair

The plugin provides a solid core feature set for subtractive synthesis. It has a good selection of waveforms and its ability to play back any four of them at once gives it a rich sound. Its modulation matrix provides a lot of flexibility for adding movement for pads and textures. While the plugin's features stand out among free synth plugins, commercial plugins usually offer more LFOs, more envelopes, more effects, and more sound manipulation features, such as ring modulation and frequency modulation. LinPlug's own commercial plugins offer many of these features and are worth a look.

User interface: fair

The user interface is well laid out, well labeled, and easy to use.

Sound: good

The plugin's sound is rich and full. The 24 dB/octave low-pass filter is useful for recreating vintage analog synth sounds, and the chorus thickens the sound and adds movement.

Value: fair

The plugin is free.

Overall: fair

LinPlug's Free Alpha 3 is a solid, well thought out subtractive synth plugin that defines a base line against which other synth plugins should be measured. It has a better sound and more features than most free synths and many synths included with today's DAWs. There are fancier synth plugins that offer more bells and whistles, including other synths from LinPlug, but Free Alpha 3 provides a good core feature set for creating a wide range of classic synth sounds.

Alternatives

LinPlug's AlphaCM, distributed with each copy of Computer Music Magazine, is the same plugin with the addition of ring modulation. LinPlug's AlphaKEYS, distributed by KEYS Magazine, is the same plugin again with the addition of two more LFOs. LinPlug's Alpha 3 is the full-featured commercial version of the plugin that adds ring modulation, a noise generator, filter drive and frequency modulation, and two more LFOs.

Another good free plugin is Green Oak's Crystal 2, which has three oscillators per voice, six LFOs, six envelopes, four delay effects, and a modulation matrix similar to that in Free Alpha 3. As the name implies, the plugin's sound is crystalline and very digital.

On the PC, Ourafilmes' inexpensive SB-1 has a feature set similar to Free Alpha 3, with the addition of distortion, a gritty Moog-like 24 dB/octave low-pass filter, and a chopper/gater effect.

Further reading

For more information about LinPlug's Free Alpha 3:

• Free Alpha at KVRaudio.com. A brief description and user reviews.
• Alpha 3 Specification at LinPlug.com. A feature chart that compares the commercial Alpha 3 with its free brethren, including Free Alpha 3, AlphaCM, and AlphaKeys.

For more information about LinPlug's Alpha 3 big brother:

• Alpha at KVRaudio.com. A brief description and user reviews.
• LinPlug Alpha 3 at MusicRadar.com. Computer Music Magazine's review.