BitHeadz Unity DS-1 Software Sampler and Retro AS-1 Software Synthesizer

BitHeadz's Unity DS-1 and Retro AS 1 put an analog hardware sampler and analog synthesizer, respectively, as software onto Windows or Macintosh platforms, and allow them to integrate with packages like Digital Performer, Digidesign ProTools, Emagic Logic, and Steinberg Cubase. Using both BitHeadz packages in the studios at Waikato University in various configurations and versions and under various models of Macintosh for some time has afforded a sense of their practical implementation. The motivation for initially using these packages was the cost when compared to buying further hardware modules.

The packages assume a traditional way of thinking about sound generation, in contrast to more flexible contemporary software packages. It is then most fitting to judge the DS-1 and AS-1 in comparison to hardware units.

It is impossible in a review of this length to give a full evaluation of all the possible configurations on all platforms, or to give a full appraisal of every aspect of the software packages. Recent reviews on both programs in various incarnation and combinations can be accessed through the Bitheadz Web site. Based on this, most reports of the software are very positive. This reflects my experience, with the caveat of my having access to the latest Macintosh machines, sound cards, and extensive RAM upgrades. Without these, experiences may vary, according to accounts on the review page of the Web site.

The comments made here refer to current and previous versions of the Macintosh editions, used mainly in combination packages specified. [Editor's Note: Bitheadz is now packaging the AS-1 and DS-1 together as Unity Session, for Macintosh platforms only, including OS X. Unity Session also includes Osmosis, a software sample converter, as well as a large collection of samples, synthesizer pre-sets, and physical models.] Both programs are quick to install and are relatively simple to integrate with ProTools and Digital Performer, assuming familiarity with the MIDI and audio drivers in the respective packages. Early problems with patch list integration in Digital Performer have been overcome, and the packages are compatible with FreeMIDI, PC300, OMS, and CoreMIDI. MAS, VST, RTAS, DirectConnect, and ReWire protocols are all supported. Depending on the computer processing power, the stand-alone Unity DS 1 will support up to 256 possible stereo voices; Retro AS-1 supports 128-voice polyphony. Both ensure a true phased-locked stereo signal path throughout.

A brief outline of the current specifications from BitHeadz is first worth noting. Both packages have two assignable stereo filters per voice and 13 filter types, including 4-pole resonant low-pass, high-pass, band-pass, all-pass, notch, and state-variable. Multiple inputs allow parallel and/or serial filtering, and there are per-filter cut-off, resonance, cut-off modulation source/amount, and overdrive controls.

The DS-1 package comes with one GB of samples, and allows these to be played from RAM or streamed from the disk within environments such as ProTools. It can play 24-bit Sound Designer II, AIFF, CD-Audio, DLS, SoundFont 2.0, SampleCell II, and WAVE files. Multi-samples allow up to 128 samples per MIDI note, selectable via velocity or controller cross-switching, and there is control of sample volume, tune, pan, sample start, FX send, envelope, and mute grouping. Sampling allows selectable interpolation (Linear, Quadratic, Lagrange, or none), and a built-in sample editor includes a stereo record function with level controls. Signal-processing functions include normalize, gain, fade, reverse, cross-fade loop, equalization, and so forth.

Only computer processor power limits DS-1 modulations and routings, and most parameters are available as a modulation source and/or destination. There are six-stage envelope modulators (delay, attack, decay, sustain, sustain decay, release), selectable linear or exponential curves for envelopes, and six low frequency...