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Chroma Polaris

Programmable Polysynth with Sequencer

CBS-Fender's 'budget' polysynth retails at £1700. Mick Jones finds out if it can hold its head above the competition.


Over a year after its announcement, the poor man's Chroma is now in full production. But is the autumn of 1984 the right climate for an '83 design?


According to a certain authoritative encyclopaedia, Polaris is situated an estimated 1086 light years away from Earth. And judging by the time it's taken for CBS-Fender's latest synth project to get off the ground, you can almost believe it.

The review sample - the only one in the country, no less - arrived without the preset sounds, sequences and instruction manual with which all production models will be supplied. If and when the time comes at which you feel like parting with the requisite £1700, your Polaris should come with 132 preset voices and 12 factory sequences courtesy of Chroma endorsee Herbie Hancock. The machine will then require only a mains lead and a pair of headphones in order to provide a complete self-demonstration.

The locations for all those voices are stored in an area called 'Bank Select/Program Select', located to the extreme right of the Polaris' front panel. There are blue-shaded alphanumeric touch-pads with associated red LEDs (A-J & 1-12) which I found a bit awkward mechanically. However, voice selection needs only a letter and a number while sequences are labelled with a number only, which is some consolation. This zone also doubles as a master control section for a variety of other functions from save and load for cassette (both voice programs and sequences can be saved either singly or together) to organisation of sync and metronome or MIDI channels, plus memory check, diagnostics, location swapping and many more. Next-door, a cluster of 14 touch-pads (and LEDs) nestle around a single slider in an area called 'Assignable Control'. There are various performance parameters which can be called up one at a time and set by the slider before moving on to the next until performance controls are set to your satisfaction for each individual voice. If I reel off all 14 functions here, this article will rapidly degenerate into a shopping list, but suffice to say that it includes pedal controls and volume (input stage, I assume) on the left-hand side, and LFO mod, pitch-bend and vibrato to the right.

Specification



The layout of sound-generating controls on this six-voice, two VCOs per voice poly is fairly conventional, but examination of the two oscillators provides at least one interesting feature. At first glance, the option of a triangle wave appears to have been left out, but in fact the Polaris allows the effect of modulating between rising and falling ramps ('Saws' on the panel) in the same way many synth players are used to adjusting pulse waves. At the mid-point of travel on the pulse-width slider it is usual to find a square wave, and in the same way, you'll find your triangle wave in the middle of travel when the slider is controlling 'saws'. Pulse width modulation can be switched between sweep (LFO) or envelope, and each oscillator can be transposed up or down by any interval over the whole keyboard.

VCO1 has a facility for ring modulation, while VCO2 differs in sporting a 'sync' option which locks the pitch of the two oscillators in unison. The LFO (Sweep) can be sine or square wave, while the low-pass filter has a touch-pad for switching in noise or, alternatively, can itself be set into oscillation, as it can on most of today's synth designs. It's worth mentioning that the envelope for the filter is in five stages, as 'sustain decay' has been added immediately before release, while sustain itself has been omitted from the volume envelope to leave the user with a three-stage ADR section. The ability to switch velocity sensing into either envelope (or both) is very useful indeed. In fact this and the ring mod, which added an exciting edge to some otherwise fairly ordinary sounds, have to rate as my two favourite features on the synth. My least favourite feature has to be the complexity involved with actually switching an oscillator off: first you need to select pulse-wave, then set width to maximum or minimum, set PWM at centre, and then, well if you've no vibrato in that voice you'll be OK, but if you have, you may need to go to the 'assignable control' section and cancel that as well. The operation is as painful as the description.

Anyway, to the left of the master volume (and tune) slider is a section marked KYBD, which allows you to split the keyboard at whichever note suits your purpose best or to link two voices together in 'unison'. At this point your six-note polyphony is reduced to three, but the good news is that key assignment is so versatile and effective that the public at large will probably never know: I can't see this being used as an advertising gimmick on a machine in this projected price range, but check it out for yourself - some of the possible 'linked' voices are truly excellent.

The remaining panel feature is the sequencer, which is a simple real-time unit with Stop, Record and Play touch-pads together with an option to move forward or back one beat at a time, though there are no editing facilities in the sense of provision for correcting playing mistakes.

If any of you can remember far enough back to conjure up an image of the Chroma Polaris as it was being advertised a year or more ago, you might not find exactly what you expect when production samples finally appear in the shops. The cheerful ARP orange of the prototype has been replaced by subdued shades of blue, but then again, beauty is only a coat of paint or two deep: in the eye of this beholder, the long spell under wraps seems to have chrysalised - rather than crystalised - Polaris' cosmetic appearance.



"There is no aftertouch facility such as that provided on the DX7, but with velocity sensing as good as this, I really don't think you'd miss it."



Sounds



There are some rather good points about the new Polaris, however, the first and most important of which has to be the return of rich old analogue sounds.

You should find it fairly straightforward to compile strings, brass, and the usual harpsichord and clav variations, and the ultimate sonic range is broad, encompassing hard drum sounds, and 'woody' marimbas, not to mention extensive possibilities in the silly noise department. The voices stored in memory when I switched the test sample on were a somewhat motley selection, doubtless the result of twiddling by un-deserving reviewers (like myself), though at least one previous experimenter really knew what he was doing: even on first brief scrutiny, there was more than enough available to whet the appetite for the factory presets, when they eventually appear.

Polaris employs a somewhat curious system of sharing memory between voices and sequences. Thus, with all preset locations occupied you have 700 notes to spread over your 12 sequences, but with all presets erased to the default setting, you get a total of 1500 notes, almost enough to make the unit worth consideration as a master sequencer, in the studio at least, if not on stage. As mentioned earlier, there are no editing functions for correcting mistakes, but at least you're able to chain and loop. Don't forget that if your sequence is the type that uses only two or three notes at a time, then the notes remaining will be at your disposal to play along with 'live' on the keyboard with the voice of your own choosing, though there are no facilities for overdubbing.

There is no aftertouch facility such as that provided on the DX7, but with velocity sensing as good as this, I really don't think you'd miss it. Being able to route the sensing via filter envelope, volume envelope or indeed both gives a degree of control which made me rather reluctant to switch the machine off at all.

The Transpose feature is also all it could be, since you can move both oscillators over the whole keyboard independently of each other. This provides more octaves in total range than I could comfortably compute, as well as any key-change or interval spacing your heart may desire. A further point worth mentioning is the 'assignable control' section, as changes in performance parameters affect all voices. It's only rarely that two different voices require identical depth and speed of vibrato, and these elements may well require constant attention and updating during live performance. The Polaris allows you to program depth and level for a wide range of pedals such as glide and sustain, as well as the usual pitch-bend, LFO modulation, and vibrato. One parameter in this section that takes us off at a slight tangent is the 'detune' facility, which replaces the more commonly-fitted onboard chorus. It's the old horses for courses syndrome really, I suppose, but I don't see this as a drastic omission since most players with £1700 to spend will already have decided on (and acquired) a favourite chorus device. On the other hand, the lack of a stereo output was a little bit disappointing.

Interfacing



As far as I know, no other analogue polysynth comes equipped with quite such a wide range of interface facilities. There's CBS' own Chroma and MIDI In, Out and Thru as well as Sync In and Out sockets for use with a drum machine or tape, and finally a five-pin DIN to make life easy saving to and loading from cassette. For once, a keyboard interface section that makes a serious attempt to be friendly with the rest of the world. CBS are not the most enthusiastic advocates of the MIDI concept, so all credit to them for at least conceding the point. The sync facility is alleged to be adjustable for a wide range of clock rates to allow compatibility with just about anything on the market, and although I couldn't persuade my Drumatix to tap along, I don't think you'll have too many problems once you have the benefit of a user manual. The machine that arrived on my doorstep had no mains lead, never mind a manual!



"The cheerful ARP orange of the prototype has been replaced by subdued shades of blue, but then again, beauty is only a coat of paint or two deep."


The debit side of this (p)review has to be handled with kid gloves, as the pre-production model I was lucky enough to get my hands on did have one or two little idiosyncracies that I'm sure won't appear on the production models when they hit the shops. I can't imagine that the followup to the Chroma could be released on the market receiving MIDI an octave higher than normal, and with an abrupt cutoff on release of any length, instead of the usual natural fade. The problem facing the unfortunate (p)reviewer is to decide, or guess, which shortcomings will have been eliminated for distribution and which are straightforward weaknesses in the system itself.

One small niggle from my own point of view was that with such excellent scope for interfacing already present on the Polaris, the job has been left unfinished with the omission of old-fashioned CV and Gate connectors. A certain well-known Chroma demonstrator made the valid point that a line has to be drawn somewhere, and that with so many digital-to-analogue converters available, the problem could be easily overcome. It must also be pointed out that CBS are far from being alone in conveniently forgetting this humble device, but I still wonder whether Polaris' designers have missed an opportunity to tie up digital and analogue equipment for the extra cost to purchasers of only a few leads, thus further endearing the unit to keyboardists who possess much-loved but now almost unusable monosynths brooding in the bottom drawer, awaiting just such a new lease of life.

I detected a little unevenness on the slider for the 'Assignable' section, particularly when setting pitch-bend depths: another case for quality control that I would hope to see cured in time. Something that caused me greater concern was a similar but more tangible problem with the performance levers. The usual pitch-bend and LFO modulation are provided on sprung levers that return snappily to centre when you let go, the depth and/or speed of effect being programmed from the 'Assign' section. So far so good, but I was disappointed to discover that only a very small percentage of travel was actually effective on either function so that, in a sense, the controls' action has more in common with that of a switch than a lever. Then there's the problem of distinct interval changes occurring whenever you attempt to move over an interval much wider than a tone: I found it impossible to get a slow, smooth manual glide. It's true that, like touch-sensitivity, performance wheels, joysticks and the like can never be all things to all players but my personal assessment is that from a player's point of view, these are by far the weakest link in the Polaris chain.

Functions



The synth comes equipped with an enormous range of dual function buttons offering all sorts of routing possibilities, but in amongst all this ergonomic cleverness, I can't help thinking the designers have fallen into their own trap. The vast array of available options is undoubtedly useful to have, but the layout of upper and lower functions on the 'Bank Program select' offers no help to the uninitiated whatsoever (though voices and sequences are simplicity itself to locate and store). I fear that a good deal more flipping through the user manual than most of us are used to may be necessary before all the functions become anything approaching second nature to use. I pined for an LCD a la Yamaha DX7, on even a diagram like the one on the JX3P, just for a hint or two. I can tell you that 'Memory Store' converts the 'Assignable' section into a crude barograph that gives a rough idea of how much memory has been used to date, but I can't detail how to go about setting Sync In and Out to a specific rate or condition, or indeed 101 other things.

The Polaris behaved beautifully as obedient MIDI slave, but nothing software buff Jethro Hill or I could do would induce it to take on the role of master. Hill loaded a program into a Commodore 64 that detects any hint of output from the relevant MIDI socket (as well as muttering something malevolent about oscilloscopes that I couldn't quite make out), but drew a complete blank. He gave me a quick and convincing demonstration of the bug-free condition of his program, and after much discussion we came to the firm and unavoidable conclusion that a manual would have helped...

Conclusions



Trying to assess a programmable poly-synth without any of its factory presets - especially when there are going to be 132 of them - is a bit like trying to road test a Ferrari Daytona without road wheels. You can map out a few personal comments on aesthetics or available facilities, look at the finish of the paintwork, and maybe even rev the engine up a bit, but at best, a fair proportion of your judgement is likely to be speculative.

What can't be disputed is that at its current asking price, the Polaris is facing some pretty stiff competition from a number of rival keyboards that cost an important bit less. And as it stands at the time of writing, it's riddled with unfortunate details - like unfriendly levers and pushbuttons and a grossly over-complicated control section - that undermine what is a potentially excellent concept. Mind you, the 16-bit Intel microprocessor that lurks beneath Polaris' neat exterior is something of an intellectual giant, so if some user-friendly software for popular (in Britain!) home computers were to become available, all my reservations about the control panel's awkwardness would be firmly brushed to one side.

Personally, I really enjoyed having a Polaris in the house for a few days, despite the numerous operational headaches it caused me. Its basic sound is good enough for it to succeed as a performance instrument, and I only hope its manufacturers don't sacrifice quality control in a misguided endeavour to push it into dealers' showrooms as soon as possible. The Polaris is probably the make-or-break instrument for CBS' keyboard division, so they've got to get it absolutely right. Because £1700 is a lot of money to pay for a polysynth that isn't.

Further information from: CBS-Fender, (Contact Details).


Also featuring gear in this article



Previous Article in this issue

Newsdesk

Next article in this issue

Emulator II


Electronics & Music Maker - Copyright: Music Maker Publications (UK), Future Publishing.

 

Electronics & Music Maker - Nov 1984

Gear in this article:

Synthesizer > Rhodes > Chroma Polaris


Gear Tags:

Analog Synth
Polysynth

Review by Mick Jones

Previous article in this issue:

> Newsdesk

Next article in this issue:

> Emulator II


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