Retro AS-1 includes an application called Keyboard, which allows users to play any sound from their QWERTY keyboard and contains a graphical representation of a piano keyboard. This makes selecting a sound easy in that you don't have to have any other MIDI application or musical keyboard running with the program. To control the virtual synth engine another program named Editor allows you to control all of a sound's parameters. Once you've tweaked a sound or created one from scratch, it's a simple matter to save it in its own bank. Another benefit to using a virtual software synth rather than a hardware synth is the ability to have an unlimited amount of programs saved in memory rather than 128 or so "user slots," as most hardware synths have. In the MIDI processor application you can create splits, layers and arpeggiator files. You can also create setups, which are similar to combinations (or multis) on other hardware synths.

Once you've created a Program it needs to be stored in a Bank. A Program Bank is essentially a folder with like-minded programs stored in them. Retro AS-1 ships with a large variety of Banks that include strings, pads, leads, basses, classic keyboards and synths, percussion, techno and efx. There's a total of 19 Program Banks that ship on the CD-ROM, with more than 50 programs in each bank.

Editor components
As I mentioned, a sound program is created with the Retro AS-1 Editor. There are four main screens in the Editor: Main, Modulation, Effects and Global. The Main editor page has three oscillator sections and two filter sections. You can also decide whether or not an oscillator's pitch is controlled by MIDI note commands. Each oscillator has controls for wave type (sawtooth, sine, etc.), fine tune, random and frequency modulation amount, in addition to volume control. Within the two filters are controls for the type of filter (one pole, four-pole resonant, etc.), cutoff frequency, spread, CM amount, resonance and overdrive. You also have control over what is filtered—oscillators, other filters or ring modulator. The ring modulator can be applied to any of the oscillators, filters or external inputs.

The Modulation section controls the routings of your envelopes, LFOs to pitch, cutoff filters to oscillators, etc. You can also apply various envelopes and triggers for modulation. In addition, you have delay parameters, source and destinations, such as volume.

Within the Effects section you have two insert effects and two global effects. The insert effects include chorus, reverb, flange, overdrive and many more. You can control delay settings independently, feedback, speed, depth and wet/dry mix. The global effects are delay, reflection and reverb. You can also control send level, type (sparse, diffuse, random and reverse), predelay, brightness and length.

Within the Global screen you choose trigger (polyphonic, legato last, low or high or external audio), MIDI channel, number of voices, transposition, portamento on/off and type, panning and overall volume. Once you've tweaked a sound, you're asked whether you would like to save the sound and put it into a bank.

The MIDI processor allows you to create splits, layers, arpeggiators, and other performance controls. The Mode window allows you to select between single, split or layered timbres. You can create a split that has one program from a completely different bank and MIDI channel on the lower half of the keyboard than the upper half. You can also control arpeggiation via MIDI sync as well as the direction of the arpeggiation, whether it's a chord or played, and tempo.

Retro also contains a Mixer application, which is an onscreen, 16-channel MIDI mixer. Each channel of the console interface contains controls for banks and programs, two effects sends, panning, mute, solo and volume faders with LED to indicate MIDI volume. In addition to these individual channel strips, there's a master output section that includes master faders, the ability to lock the left/right faders into stereo mode, mute, solo and two global effects processors with send controls, which include LEDs.

In addition to all of the above, Retro AS-1 has a Status window that allows you to view CPU usage and polyphony. This can be a great aid in figuring out the right balance between quality sound and your computer system's capabilities.

The bottom line
I really enjoyed using this program. The software has been written in a way that allows novice users an easy introduction into analog synthesis via the pre-programmed sounds. At the same time more advanced users will appreciate the ability to dive into all the various parameters that can be tweaked and controlled in realtime via MIDI. BitHeadz has actually created a product that far exceeds what it is trying to emulate. Even if you had an inexhaustible budget for the aforementioned keyboards, you still would not be able to control their parameters via MIDI. Another factor to consider is the older analog keyboards were capable of coming up with a limited palette of sounds, not millions of permutations as Retro AS-1 is capable of. Considering all this software does at a cost of less than $300, I would highly recommend it to any Mac musician.

Rob Albertson is a composer and musician and the owner of Rare Air Studios Inc., a full-service audio production and post-production recording studio based in Atlanta, Ga. He can be reached at rareair@mindspring.com.

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