BitHeadz Retro AS-1
Software synthesizer for Macintosh and WindowsBy Steve Gregory
December 1, 1998
Introduction
Over the past several years, our expectations as to what a synthesizer should be capable of have risen dramatically. Synthesizers are now expected to not only produce clean crisp bells, full strings, and luscious pads, but due to the explosion of interest in analog sounds, searing leads and the ever ubiquitous dulcet tones of the TB-303. Traditional methods of sound generation, such as PCM synthesis, just don't cut it for some of the dynamic analog sounds. The only options for the 303 junky were to shell out anywhere up to $1300 for a real 303, buy one of the 500 different brands of 303 clones (all of which purported to sound like the "real" thing), or break into a studio and steal a real 303. This was of course until ReBirth came along. A small company called Propellerheads single-handedly managed to drop the second hand prices of real 303's by at least a third simply by producing a piece of software that sounded exactly like the real thing. Now it seems as if another company is onto the same idea in a more general sense. This time a small Californian group called BitHeadz has produced a piece of software called Retro AS-1. It is a physically modeled, multi-timbral analog-style synthesizer for the Power Macintosh, and has extremely impressive specifications. It is capable of up to 32-note polyphony (depending on the computer system), responds on 16 channels, ships with 1000 patches, and has an impressive architecture with extensive routing possibilities with easy point and click programming. Is it possible that this software can take the place of more traditional analogs?
Installation
The software comes in the form of an archive on CD ROM and a single slip of paper indicating how to install the product. Once installed, a 150 page manual is available in Adobe Acrobat format. It would have been nice to have a "real" manual, but this is definitely a trend that many software companies are following. Installation went without a hitch, although I did notice that the software had apparently installed perfectly when I entered the wrong password. Not cause for too much excitement however, it was just an untruthful dialog box. The archive unpacks to create a directory of 1000 patches, a directory of synthesizer control utilities, a synth editor, midi processor, and various other goodies. The synthesizer itself resides as an engine and objects library in your extensions folder. It also comes with a control panel for allocating resources and optimizing the synthesizer. BitHeadz has obviously gone to great trouble in order make this synth work with all setups. OMS names and FreeMIDI names are provided for all patches, and the synth is easily detected in the OMS setup.
Using the Thing
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| The Retro AS-1 main editing page allows quick access to the oscillator and filter controls. (Click for a close-up) |
Analog synths have always tended to provide easy access to all major programming functions; the controls for oscillators, filters, LFOs, envelopes, and so on are all generally one per function. Digital synths have tended not to do that, utilizing "soft keys" where each button's function changes context depending on what page is displayed in the LCD. It is an important point. Once we move into replicating real systems in software, it's very easy to get caught creating user interfaces that simply replicate an existing physical equivalent -- does twisting a knob really make sense when you are doing it with a mouse on a computer screen for instance?
BitHeadz have obviously thought through a lot of these issues, and have created a user interface that makes programming the synth easy without having to learn a whole new system. Most of the parameters are either drop-down lists or sliders, which makes the tedious effort of doing everything with a mouse much easier. Creating patches is all done from the Editor that comes with supplied on the CD. There are four windows (each accessed via tabs at the top). The main page accesses the three oscillators and two filters and also features a configuration window where the current combination of filters and oscillators can be viewed. The next page handles all the modulation routings, another one is for effects, and there is a final global settings window. I found this setup very easy to get used to, and within 10 minutes of firing up the software, I was producing patches without looking at the manual. BitHeadz also provides a utility that lets you click on a virtual piano keyboard if you don't have a MIDI keyboard available.
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The software ships with a number of other utilities as well. These include a virtual mixing console which allows you to select the patch, volume, pan setting, and effects on a per-channel basis. BitHeadz has provided a massive library of sounds, and these are accessible by category (conveniently done with directories) from the mixing console itself. Personally I was a little disappointed with the patch set that was provided -- it's always a bad thing in my mind to call a patch "Super Jupiter" if it doesn't really sound like one. Likewise, the provided 303 patches didn't really grab me as being particularly realistic (using that as it seems to be the "grand piano" that all new analogs these days are tested by). In my opinion the sounds are definitely better than the kind found in the vintage expansion board for the JV-1080/2080 for example, but not as good as what you could get out of something such as a Nord Lead. That said, I should say that I would have been completely happy to have got *no* sounds with this synthesizer. The architecture is powerful enough that the synth is capable of producing some really great sounds, and I'm sure that most users will want to buy it with the intention of creating a lot of their own sounds anyway. It's like not wanting an ARP 2600 because it doesn't ship with a good piano sound.
Architecture
Oscillators:Each patch can have up to three oscillators. In the first release, the only available waveforms for the oscillators were Sine, Saw, Square, White Noise, and Triangle. BitHeadz has already released several free updates which added Sine Squared, Glottal, Pink Noise, and Red Noise waveforms. Each oscillator also has coarse and fine tuning settings (with random tuning settings for "analog instability"). Sawtooth, Glottal, and square waveforms can be further modified with the symmetry slider. A value of 100 on a sawtooth wave produces a triangle wave, and a value of 100 on the square wave produces a pulse. Symmetry is also available as a possible modulation destination so that LFO could control it. I particularly enjoyed the FM capabilities of the software. AS-1 allows any of the oscillators, including the input and output stages of the filters to be selected as the frequency modulator. Not only does this allow for some great sounding bells and metallic tones, but also some wonderfully weird sound effects caused by creating feedback loops.
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| The available routing topologies. The two filters can also be arranged in series. In addition to the two insert effects displayed, there can be up to two global effects, like delay and reverb. |
Filters:
There are two filters available per patch, and the user is free to choose from 13 different types. The routing configurations allow for any or all oscillators to be sent through the filters, and outputs from one filter can go straight into another one for up to 48 dB of rolloff. The current filter types that shipped in version 1.0 for review included a 6dB single pole low pass (non resonant), a 12dB low pass (non resonant), a 24dB 4 pole low pass resonant filter, and four various kinds of 12dB resonant "state variable" filters. BitHeadz delivered on their promise of more filter types with the 1.10 update which offers six new types: a 1 pole high pass, 2 pole high pass, 4 pole high pass (resonant), and three all pass resonant filters. There are some extra modulation parameters available for filters other than the usual cutoff and resonance however. The multi-pole filters allow access to a "spread" parameter which varies the cutoff frequencies within the multiple poles of the filter itself, and the three low pass filters allow access to an extra filter cutoff modulation slider, where the modulation source can once again be any one of the oscillators or ins/outs of the filters. Finally each filter can be overdriven to really grunge up that sound. Believe me, there are hours of enjoyment to be had here. One thing to remember is that the more components are added to the patch, the more work the CPU has to do. This definitely becomes a factor once you decide to start trying to recreate your favorite Jean Michel Jarre track.
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So now that you have a multiple oscillator frequency modulated noise beast belching away happily through a 48dB filter stage, you may decide it's time for a touch of low frequency oscillation. The software has one window for all modulation, and handles it quite effectively. Routings are displayed in a listbox in the left-hand side of the window, and can be added or deleted easily with buttons below it. Clicking any of the routings pops up the settings below for both source, destination, and amount in a drop down listbox from where they can be changed. This is a great way to provide quick access to a mass of modulation routings without making a mess of the screen with multiple interface elements. On the right hand side of the screen is a similar listbox with a list of modulators. Clicking on the pitch envelope pops up sliders beneath for Attack, Decay, Sustain Level, Sustain Decay, and Release for example. You can also edit the envelopes graphically. It's possible to create more modulators, so there is nothing (short of running out of CPU power) to stop you from creating 10 different LFOs all running at different speeds and with different waveform shapes. That is definitely not something available on most ordinary synthesizers! You can even create random modulators triggered by different events, such as the release of a MIDI pedal. I was unhappy, however, with the way in which global controllers have been implemented. The global controllers are set in the master control panel, but there are only four controllers to choose from. The available controllers are modulation wheel, breath control, foot pedal, and expression. This made it impossible for me to do something relatively simple such as assign the pitch bend wheel to control cutoff -- something many people may wish to do who own Roland keyboards with an on/off modulation lever. Please, please add more modulation input options in the next version! While on the subject of controllers and modulation, virtually all of the useful sliders you are likely to love to twiddle respond to non registered midi parameter messages though. This means that any MIDI fader box worth its salt could function as a hardware controller (if a poor unfortunate soul somewhere can be coerced to make up a patch).
Effects:
While there are only a few different kinds of effects, the architecture does allow for two insert effects per patch and then two global overall effects. Once again, having insert effects on every patch when used in a multi-timbral setup is probably something most Macs are not going to take too kindly to. I had a few quibbles with the effects of the 1.0 release. For a product aimed very much at the dance market, it would be great to see delays measured in bpm rather than milliseconds, or at least able to sync to MIDI clock. A recent update now allows for effect delay times, LFO's, and arpeggiator to all be synced to MIDI clock. It would also be nice to have the effects modulatable themselves in some way, so that at least the reverb depth could be assigned to a global controller. That aside, the architecture is extremely powerful.
Using Multi-Timbrally
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| The Retro AS-1 Control Panel (found only in the Mac version.) |
In order to do a real test, I decided to fire up my copy of Logic Audio 3 and use Retro AS-1 multi-timbrally as a sound module. The manual does note that running other software in the background will affect the performance of the synthesizer, but unless you can afford the expense of dedicating a machine to it, this is the situation most users will find themselves in. Things tended to go fairly well for the first three or four tracks, but after that I had very audible dropped notes. Opening up the retro control panel revealed that the synthesizer defaults to a maximum of 8 voice polyphony. After a quick reboot to test the new settings with 32 voices, things were definitely better. The strain of running a big sequencer in the background definitely made performance very sluggish -- especially once I turned on the AS-1's built-in effects. This was with a 180Mhz Mac 7300 (604e processor) with 128mb memory -- not something I would have considered a slow or underspecced computer. After choosing simpler patches requiring less processing the situation was somewhat better. Obviously computers are getting faster, however real-time audio DSP puts a strain on pretty much any of today's processors. BitHeadz has provided a few ways to maximize performance, and include a whole section in the manual on this subject. Every user's experience is likely to be different in this area. The control panel is the best place to start. It is also possible to set the sample rate that the AS-1 will render sounds in, the buffer length, and the maximum percentage of the CPU to be utilized by the engine (between 10 and 60). Switching off oscillators and filters that are not needed in the patches also helps things a lot. BitHeadz provides a mini sequencer of their own -- the "MIDI processor" utility. This is definitely one way to create arpeggiations and simple parts without having to use up processor cycles by running a full blown sequencer. For many users this may in fact be sufficient, especially if you intend to create sounds, write them out as audio files (8-, 16-, or 24-bit), and read them back into your audio sequencer (yes it does that too). The MIDI processor functions a little like a cut down version of Roland's RPS (real-time phrase sequencer) available on synths like the JP-8000. Basically, sequences can be assigned to keys on your MIDI keyboard and triggered every time they are hit. These can be everything from arpeggios, to percussive chord parts or repeating riffs.
Updates
BitHeadz has been quite active in adding new features and enhancements to Retro AS-1. In the last five or size months, five separate updates have been issued (which can all be downloaded for free), providing some significant changes aside from the usual bug fixes and tweaks. A very incomplete list of update features include the addition more LFO waveforms, more filter types, support for Digidesign direct I/O where individual MIDI channels can be routed to different physical audio outputs, and support for Digisystem INIT 3.3. One update also included a program cleaner application that will remove unused modulators, modulation routings, and other things that save some CPU processing. Just drag and drop your programs on the cleaner and you're done. Very handy. It's very comforting to see the company actively improving the product with regular free updates.
Conclusion
After all is said and done, how does the thing actually sound? Well, it sounds like an analog synth that's for sure. I wouldn't go as far as saying that it recreates all the sounds of the classic analog synths, although it does do better than a lot of so called vintage and analog ROM cards and modules I've heard. The programmability and routing possibilities make it a great sound creation tool, and I'd just love to be able to feed in audio files instead of oscillators and use the thing is a sound effects box. I certainly won't be throwing out my analog synth collection just yet, but what I will be doing is using the Retro AS-1 to provide a bunch of additional parts that I couldn't have done with my monophonic analogs. I have a few complaints with the lack of real-time controllers and the number of applications you need to fire up in order to control all aspects of the synth, but that aside it's a very major step forward for computer based synthesis. It is my belief that the next huge area of development in high tech music will be alternative controllers for synthesizers such as AS-1. Now that our computers are fast enough to act as sound sources in themselves, we need to have new MIDI units covered in sliders, knobs and buttons to free us from the mouse. Retro AS-1 is only the first version of a software based synth, but clearly displays a new direction for sound creation. With many more enhancements in store, I look forward to finding out what the brains at BitHeadz are thinking of next.
For more information on Retro AS-1, visit BitHeadz' web site at www.bitheadz.com. There you will find additional sounds, demo versions for both Mac and Windows, and the user's manual.