The Darkstar is an eight note polyphonic multitimbral synthesiser with 2 Oscillators, 2 Envelope generators, 2 LFOs and 1 filter with 3 types. It also incorparates a centre mounted joystick which controls an oscillator 1+2 mixer and ring modulation effect but which can be switched to control the filter cut-off and resonance, this is a novel element which was a major attraction to me.

The 2 oscillators share the same set of controls. You select which one you are editing by toggling a long red button underneath the oscillator control knobs. The waveforms are independently adjustable between a 'Sawtooth' and 'Rising', at least so it says the manual. The small labels on either side of the waveform knob look like a sawup and a square. The morphing between them is smooth and harmonically they are different but still complementary for the most part. there could be a wider range of selection available for the Oscillator's waveforms, or even for just one of them, this would significantly expand the potential for sound creation. Oscillator 2 is variable in pitch relative to oscillator 1, the options are 0,5,7,12,16,17,19 and 24 semitones of offset. This is adjustable using the same knob as the waveform when shift is selected (a helpful shift light flashes). Pitch Mod is also independently adjustable for each oscillator, as is Pulse Width, Pulse Width Modulation and tuning (+/- 2 semitones).

Oscillator two is a bit different from oscillator one. The oscillator type can be changed between:

Two independent envelopes share the same control bank in the top right corner of the module. These are standard ADSR types. The velocity sensitivity of each envelope is also adjustable when the top right shift is active. A row of indicator LEDs is used to show which value (0-7) is assigned to the envelope being edited. A value of zero means that different velocity values have no effect, a value of 7 will introduce a big change between high and low velocitys. Since the envelopes can be used on filters and for modulating parameters like Pulse Width Modulation changing the sensitivity can be very useful for controlling the dynamics of a part.

The two LFOs are also independent of each other with 3 controls for both. LFO rate (SPEED) can be controlled via midi clock by activating shift and rolling the speed button, The choices are OFF (in which case the speed is adjusted manually), 1/8 beats, 1/6 beats, 1/4 beats, 1/3 beats, 1/2 beats, 2/3 beats, 3/4 beats, 1 beat, 2 beats, 3 beats, 1 bar, 1.5 bars, 2 bars, 3 bars and 4 bars. It is possible to assign different midi syncs to the LFOs, for example 1/8 beat for LFO1 and 1/4 beat for LFO2. The next knob along is the Delay, this introduces a preset delay before the LFO starts oscillating, so you can have an attack stage of a patch unmodulated. The LFO waveshapes available are: Ramp, Tri, Square, Sine, Pulse, Sample and Random. Sample is presumably a sample and hold type of modulation and it's a good one. The shape of the selected LFO is displayed using LEDs beneath the knobs. A Synchronisation setting in the LFO menu lets you choose whether or not the LFOs will start from the beginning of the waveform when a note is played.

The Filter (only 1 unfortunately) is possibly where the grunt is lacking. It's not lacking in control, it is lacking in basic fatness and drive. it's so subtle that it's quite hard to get the settings right, sometimes there's just not much going on despite massive fiddling. This is where setting the joystick up to control the filter is useful, do this in the 'filter' menu by changing 'cont' from 'pot' to 'joy'. Basically the filter is either a Low pass, Band pass or High pass 12dB filter. The resonance can be modulated and the amount of modulation from the source can be set. useful LEDs indicate which modulation source is being used (either LFO or either envelope). The third control is ENV MOD. The manual leaves me somewhat confused about this, but it sets the amount of that the filter frequency is 'opened by the audio modulation'. I take this to mean the output of the part, which seems to lead to a paradox, since the output surely changes when the value of this knob is altered. In anycase I find this knob quite annoying and set it to 0. This knob shares LFO2 modulation (presumably to frequency although again the manual doesn't say even though it overstates the obvious in most other sections.)

Tucked away above the envelope section is the part output section. These share the knobs with the envelopes. There's Level, Panning, Tremelo and Portamento. How exciting.

The Darkstar can play 8 notes from any of 5 different parts at once. A part is basically a patch and all five are stored as part of one preset. You can set each part to respond to different midi notes (so you can have different sounds on the same keyboard) and transpose the key (so consecutive octaves can play different sounds in the same key). BUT you have to decide, for each part what it's polyphony is and stick to it, unless you can manually jump about between the menus and juggle the numbers, which always have to add up to eight. As far as I know you can't change this over midi. This isn't hugely constraining, since you can still have a polyphony of 4 on two parts or a polyphony of 2 on 4 parts (so notes can overlap on each part). The parts can be set to respond to different midi channels and pitch bend range can be changed. All these parameters are controlled using the awful menus (see below).<

This clever multitimbral function invokes demons of it's own. I had no idea how to banish these until I realised the nature of the beast. I was increasingly distressed when editing sounds on the Darkstar because no matter what I did there was always this bass hum on the sound which I couldn't edit out, but didn't seem to present on the presets. When I learned more about the multitimbral set up everything became clear. When I originally got my Darkstar I went through and set up the user presets (all 16 of them) so that the parts within the multis were split so that the polyphony was shared amongst the first two or three. When you do this a sound (the default sound I believe) is active on each part with a polyphony assigned to it. Unfortunately, I wasn't so clever when it came to setting the midi channel, which was still channel 1 for each part of each preset. You may have realised yourself what the problem was by now. Each time I triggered a note on the sound I was editing I was also triggering a default sound on the second part of the multi, which I could also hear. The problem has since been solved by setting a different midi channel for the second part of a troublesome multi. More fool me, but I reckon this isn't too hard a mistake to make. The really silly thing about it is that when you press the 'audition' button it plays the sound from the other part in the multi aswell if it's set to the same midi channel. I think it should only preview the sound your editing, since, if you're playing two parts at once on purpose it would require changing the midi channels of one of the parts and possibly setting up a new midi channel on your sequencer if you want to listen to just one sound to edit it.

The menus are a bit of a problem. Take for example the oscillator. Most of the controls are in the oscillator section, but Pulse Width Modulation, Pitch Modulation, Oscillator sync and Osc2 type are controlled using the four d-pad nav buttons when the Oscillator menu button on the bottom is selected. The 4 digit LCD display then shows you a truncated description of what you're altering. Similarly, there are many small trivial functions which are controlled from the other seven 'PROG' buttons, which double up as the bank and program select keys. The one on the right is the most interesting, labelled 'modulation'. This lets you change the magnitude of the effect that the mod wheel and after touch have over the modulations specified in the PITCH MOD and FILTER MOD settings.

As with any system where knobs are shared this can mean that the value the knob is pointing to is nothing like the actual value in use, but it is easy to mentally note the value of the knob before you move it and then move it back after shift is released, without affectng the shifted value. Generally the secondary functions of knobs are chosen to be ones which are not often adjusted. Of course you could always set up a midi hardware controller that controls the secondary functions so that all the knobs show the correct values. In this case a large controller would be needed because there are two oscillator, envelopes and LFOs, so perhaps as many as 24 knobs would be needed. There are already quite a few knobs and there would be an absolute forest of them if there was one per function, so to keep it as affordable as possible they have opted to share almost every knob with other functions.

Another reason might be that there are 2 or 3 products developed by Red Sound which also have the same size and shaped case as the Darkstar (the Federation Pro and the Darkstar Vocoder as well as any future configurations). Some might say that working to a pre-determined front panel arrangement is a design constriction that has some negative implications. I find that DarkStar quite easy to use now I've learned, but learning some of the proceedures (like the one for saving a patch in a different bank, which is very complicated and can go wrong if maximum care is not taken) was not so straight forward as it might have been with a more intuitive layout for some of the fancier options. Having said that though, the general layout of the Darkstar is well organised.

If we didn't have this case though, we might not get the joystick. This is one of the things that attracted me to this synth. It controls a ring mod effect and a mixer between the two oscillators. So, you can have just OSC1, with no ring mod, just OSC2 ring modulated (presumably by OSC1). Or any combination in between (eg. 25% OSC1, 75% OSC2 half ringmodded by the opposing OSC). As mentioned, you can also use the joystick to control the filter Cutoff and Res. It would have been nice though, if they had found a way to use the joystick to control more things on the synth, or even assign the different axes to external midi controller numbers. A missed opportunity if you ask me.