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Yamaha CS6X

Yamaha CS6X

The CS6x has more features than any previous Yamaha Control Synth, with plenty of polyphony, real‑time controllers, onboard effects, and basic sampling. You can even fit PLG expansion cards, giving you access not only to fresh sounds, but also other forms of synthesis.

As we ride out of the grotty old 20th century and into the shiny new 21st, we're not all living in elevated Jetsons pod houses and driving to work in Futurama air cars, but the world has broken out in the colour of sci‑fi, silver. Glittering millennium‑silver merchandise adorns the shops, and it's becoming increasingly possible to equip the studio to match — at least, until we all get a bit fed up of silver.

Yamaha embraced the idea of the silver synth in their last Control Synthesizer, the CS2x, and are sticking with it for the latest in the family, the CS6x and its rackmounting sibling, the CS6R. The £1299 CS6x inhabits the middle ground between value instruments such as the £599 CS2x and do‑it‑all workstations such as Korg's Triton and Yamaha's EX5, which approach the £2000 mark. Its specification is very worthy: 61‑key aftertouch‑sensitive keyboard, 64‑note polyphony, 16‑part multitimbrality, effects, arpeggiator, MIDI‑file playback capability, basic sampling, computer interface, an audio input which can access the synth's effects (see the 'Need Input' box), and the capacity to accept up to two optional internal boards from six available (see the 'Expanding Universe' box). You might see shades of Roland's JV‑series instruments in this last feature, but Yamaha go further, in that four of the boards offer different synthesis systems to the CS6x owner, rather than simply providing new waveforms.

SmartMedia cards (a 4Mb card is supplied) are used for storing extra sounds, and samples can be created with the 'Phrase Clip' sampler. This is not ideal, but the synth ships with a utility called Card Filer, which allows such data to be swapped between card and computer. Connectivity is pretty good: the usual stereo audio output is augmented by two individual outs, and there are four sockets for foot controllers, plus a breath‑controller socket. Other features include pitch‑bend and modulation wheels, plus a ribbon controller and a set of real‑time control knobs, which can be used for quick sound editing.

Like its predecessors, the CS1x and CS2x, the 6x is aimed at producing chart and club material, while also being a general‑purpose instrument in disguise — it does a particularly good job for the dance‑inclined, but don't write it off if dance isn't your cup of designer energy drink. Its 384‑Voice sound memory features numerous more widely applicable Voices alongside the snappy, spacey, synthy ones, and because it's completely programmable there's much scope for customisation. Similarly, though the CS6x's real‑time control knobs are obviously what the dance market wants, everybody likes physical controls, whatever their musical direction.

Anatomy Of A Voice

Yamaha's tried‑and‑tested AWM2 Sample & Synthesis system is used to generate the CS6x's sounds. This method has been discussed in various past reviews, so we'll be brief here.

A single CS6x Voice — or patch — is made up of between one and four 'Elements', each of which consists of a waveform chosen from 479 on board. Each Element can be passed through a synthesis system comprising resonant filter, Envelope Generators for amplitude, filter and pitch, and a Low Frequency Oscillator. Drum Voices are slightly different, collecting up to 73 individual waveforms (assigned to MIDI note numbers) in a kit. Each drum waveform can access all the CS6x's synthesis parameters. Effects are chosen as part of a Voice, but the two insert effects can, usefully, be enabled per‑Element. Each Element also has an EQ section.

An instrument aimed at the dance market could stand or fall on the quality of its filter. The CS6x's multi‑mode device is apparently a new design developed specifically for the instrument, and Yamaha are rightly proud of it — it's warm and rich or squelchy and biting whenever it needs to be, and offers a dizzying range of variations. Low‑pass, high‑pass, band‑pass and band‑reject types are all available, with LP, HP and BP coming in several flavours and 'digital' or 'analogue'‑style variations. The low‑pass filter type is particularly well‑specified, being available in 1‑pole (6dB/octave), 2‑pole (12dB/octave), 3‑pole (18dB/octave) or 4‑pole (24‑dB/octave) versions.

Another factor in the success of a finished sound is well‑implemented envelope generators — these govern how a sound develops interest and complexity over time, which is important for a repetitive style such as dance. No worries on that score here: the CS6x's EGs are well specified, with multiple stages yielding as much complexity as you could want, but for speedy programming they can be treated as simple attack‑decay‑sustain‑release EGs, using the quick edit knobs. Editing would have been even more speedy, however, if Yamaha had provided some preset envelope types, as found on their older SY85 workstation.

The CS6x's Element‑specific LFOs (for producing vibrato and tremolo effects and so on) are simple but adequate, offering a choice of three waveforms — triangle, sawtooth and square — plus Speed, Depth and Key Sync parameters. However, a really sophisticated LFO is available for each entire Voice, and this adds MIDI sync and extra waveforms, including sample‑and‑hold waves if you feel the need for them — and they are useful, especially for in‑tempo, bloopy effects when the LFO is assigned to the filter.

When the required Elements have been combined in a Voice — layered, or keygrouped and velocity‑split if desired — an effect treatment can be added, a preset microtuning option selected, and arpeggiator parameters set for that Voice if the arpeggiator is being used.

The next programming level is the Performance (there's no 'Combination' mode as such), which can be used either as a 16‑Part multitimbral setup, for playing MIDI sequences from a connected sequencer, or to create sophisticated collections of layered or split Voices for real‑time playing. The dedicated Layer mode lets you group up to four Voices on one MIDI channel, and still use the remaining CS6x Parts to add sequenced backing. There's further sophistication and flexibility in Master Keyboard mode, which allows seamless integration of external MIDI instruments into a CS6x Performance. These features show the thought that Yamaha have put into making the CS6x a performance synth. There are none of the Performance compromises of the CS1x and 2x (where one strong main synth Voice is augmented by a collection of largely preset GM/XG sounds) which some users find annoying. With the CS6x you can pretty much have any sound on the instrument anywhere you want it.

One minor gripe is that the two‑line LCD display is not best suited to conveying all the complex information the CS6x has to impart at any one time — as you can see here!One minor gripe is that the two‑line LCD display is not best suited to conveying all the complex information the CS6x has to impart at any one time — as you can see here!

As you can infer from the above, there are some significant differences between the 6x and its two predecessors, and programming it is not quite the same. Even those familiar with Yamaha instruments may find the process not as intuitive as it could be. It might have helped if Yamaha had retained the editing matrix of the 1x and 2x — which arranged parameters in a front‑panel X/Y grid — since this at least made it very clear which parameter was being selected at any time. The CS6x's small two‑line x 40‑character display isn't really adequate given the synth's complexity, and it's all too easy to get lost in nested pages.

The organisation of parameters doesn't always seem logical, either, though Yamaha have provided handy shortcuts involving the soft‑knobs under the display and the patch‑select buttons to the right of the front panel (some of which jump to parameter groups in Voice‑edit mode). These shortcuts mean you can quickly get out of any dead‑ends you might stray into. Also on the plus side, those not needing in‑depth programming will manage with the 'quick edit' options offered by the eight main control knobs: they're set up to edit filter cutoff and resonance, EG attack, decay, sustain and release, plus reverb and chorus send amounts. The soft knobs also alter a handful of user‑definable parameters per Voice or Performance.

Treat Yourself: The Effects

Yamaha have an extensive background in effects processing, so CS6x effects have a good pedigree. In practice, they sound great and are comprehensively editable. Two global and two 'insert' processors are on offer, insert processing allowing Elements in a Voice, or Voices in a Performance, to receive their own treatment. Though there are only two insert effects, it is possible to route more than one Element, or Voice, through either or both of them.

Our main reservation on the effects front is that the global processors are slightly restricted: one provides reverb alone (albeit with 12 varieties), while the second, dubbed 'chorus', offers 23 modulation and delay treatments. It would be more useful, surely, if each global processor was a true multi‑effects device, capable of producing a range of common effects — for times when you really would like two different reverb treatments, for example.

The Insert processors offer more potential, although, again, the two are not identical. Insert 1 offers 24 treatments, including choruses, tremolos, distortion and compression, but it's only when we reach Insert 2 that the possibilities become really interesting. There are 92 choices here, including simple chains (compressor + distortion + delay, for example), pitch‑shifting, and some truly weird munging processes inherited from the A3000 sampler: Beat Change, Jump, Lo‑Fi, Low Resolution, Digital Turntable, Auto Synth and Tech Modulation. All do something drastic — distorting sound in particular ways, reducing its apparent sample rate, or chopping it up into delayed and pitch‑shifted sections, for example — though you have no concrete idea of what will happen when you start editing these effects, because the manual doesn't address what their parameters actually do

Aside from this minor gripe (and wishing that the global effects were a bit more sophisticated) there's little to complain about here. It's worth noting that the audio output of the entire synth, effects and all, can be recorded as a Phrase Clip, potentially freeing up effects for further usage. Yamaha have provided an Effect Bypass switch, too, which can be invaluable during editing.

Like the previous CS synths, the 6x offers plenty of scope for real‑time manipulation of effects, filters and envelopes via its generous complement of knobs.Like the previous CS synths, the 6x offers plenty of scope for real‑time manipulation of effects, filters and envelopes via its generous complement of knobs.

A Clip Round The Ear

The basic sampling offered by the Phrase Clip section is a welcome addition on a synth such as this. While it's not a full‑blown sampler such as that offered by Korg's Triton, it provides plenty of room for snatches of audio, drum loops and what have you in its (unexpandable) 4Mb of RAM. In total 256 Clip slots are provided, and there's a 2Mb limit on individual Clip size.

External audio can be recorded via the audio inputs from virtually any source — line, mic or guitar. The biggest disappointment here is that recorded audio is always mono, even though there are two inputs; a stereo source attached to both inputs at the same time is summed to mono. As mentioned earlier, the output of the synth itself can be sampled, but this, too, is summed to mono. Clips are assigned to keys and arranged by the user into Kits, four of which are available, but there's no keygrouping — it's not possible to automatically or easily assign a single Clip to a range of keys and play a tune with it. The best you can do is manually assign the clip to each key in your 'keygroup' and individually tune it to produce the desired result.

Clip‑editing options are pretty much the same as for a Voice — filter, EGs, effects, arpeggiator, and so on. A few genuine sample‑manipulation facilities are also available, including looping, normalisation, frequency conversion (halves sample rate, and therefore sample size), and a pair of processes ported from the A3000, namely Loop Divide and Loop Remix. Both are most welcome: the former divides a Clip into equal chunks and remaps them to consecutive keys, while the latter chops up, reverses and reassembles a Clip. The user doesn't have much control over either process — Loop Remix, for example, has just two limited parameters — but the results can be extraordinary. Think of it as a randomiser that just happens to work by chopping your Clip up — but the Clip is never overwritten and the result always comes out the same length as the original. Try layering drum patterns with their remixed offspring!

Further mileage can be had from Clips courtesy of so‑called Variation Settings; each Clip can have up to eight different sets of playback parameters (start point, loop, reverse mode, and so on), which extend a Clip's usefulness without eating more RAM. This is rather like the sub‑tone concept of Roland's sampler family.

As already mentioned, the best way of transferring samples between the synth and a computer is via Card Filer. The much slower MIDI Sample Dump can send samples to the CS6x, but they can't be transferred out using the same method. The synth's RAM is volatile, so save Clips to a SmartMedia card before switching off.

The Card Filer utility, which you can use to transfer files between your computer and SmartMedia cards inserted in the CS6x via the latter's direct computer interface.The Card Filer utility, which you can use to transfer files between your computer and SmartMedia cards inserted in the CS6x via the latter's direct computer interface.

Taking Notes: Arpeggiator & Playback Sequencer

Not surprisingly for a modern performance synth aimed at the dance market, the CS6x has an arpeggiator, plus a MIDI‑file playback sequencer.

The MIDI‑sync'able arpeggiator is most useful, with 128 patterns ranging from standard arpeggiator fare to instant sequences — bass lines, dance‑style phrases, and drum patterns. You can't create custom arpeggio patterns, but the preset ones can be modified with a handful of user controls including note range and value, gate time, velocity response, and note order.

Normally, a playback sequencer like the 6x's would be used by gigging musos to play commercial MIDI files live, but this may not happen in the case of the CS6x, mainly because in its unexpanded state the synth is resolutely not General MIDI‑compatible. However (and this shows again how Yamaha have sought to make the 6x useful to a wider range of people), with the optional XG board installed it would be a GM synth, and gigging musos could play back their GM/XG MIDI files off SmartMedia cards.

Of course, the average non‑GM‑compatible dance musician could also use the playback sequencer on stage. Sequences created with a computer package, say, using the CS6x as sound source, would have to be saved as MIDI Files and downloaded to SmartMedia. Once the sequences were on the card, the playback sequencer could be used to create a chain of up to 100 steps, each of which would be assigned a sequence, a Performance, and a tempo.

Staying with MIDI for a moment, the 6x's spec is comprehensive. Notes generated by the arpeggiator and movements of the front‑panel knobs are all transmitted over MIDI, and the synth accepts direction from external MIDI controllers.

GM‑Free Zone: The Sounds

The sound of the CS6x is contemporary and rather pleasing, with a refreshing lack of buzzy waveform loops. We hear that Yamaha created a lot of new samples for the synth: the effort has paid off.

It's a huge relief not to have to scroll through yet another collection of GM patches. Nevertheless, if you need standard, non‑synth, non‑dance material, it's here: there are some brilliant orchestral string sections, excellent basses, functional winds, decent organs, and fine electric pianos. Not so great are the acoustic pianos: there's something faintly unnatural about them — to these ears, at least. However, for those who demand more on the piano front, one of the optional plug‑in boards just happens to be a high‑quality piano set...

On the purely synth side, you get the works: squelchiness, fatness, TB303‑ness, trouser‑flapping bass‑ness... you name it. Clever programming means that individual Voices can produce quite complex results — the trick is to keep the keys held down so that you hear a Voice's full development. But if you're interested in really expansive, evolving, involving soundscapes, check out the Performances, the majority of which are layered/split collections of Voices for real‑time playing. Some also make a good stab at creating 'instant tracks', reminiscent of those found on Korg's Z1, by layering arpeggiated drums with other Voices. Part of our opinion of a new synth is formed by whether or not we create a new track with it — and with the CS6x, we did! There's occasional intrusion by zipper noise when the real‑time controllers are being used — reminding us that this is, after all, a digital instrument — but on the whole, the vibe is good and the sound is great.

The Bottom Line

The CS6x is Yamaha's most individual synth for some time. Though it borrows ideas from other quarters, Yamaha have done plenty of borrowing from their own roster, as well as adding new features. And, as is almost always the case with Yamaha instruments, there are a lot of features here for the price. The 6x scores high as a performance keyboard — it has all the right knobs, and the four foot‑controller sockets are a real bonus on a mid‑priced instrument. The sampling facility doesn't rival a full sampler, but it is reasonably easy to use and boasts some excellent processing tools.

Soundwise, the synth hits the spot, and is capable of being quite inspiring. It's perhaps what the CS1x and CS2x should have been the first time around — a real synth, usable multitimbrally, without any trace of GM. (The optional board slots, of course, mean you can add a trace of GM if that's your poison, as well as accessing different synthesis systems.) The 6x's styling, with all its silver splendour, is sharp, so it looks the part for dance artists, and it has a more expensive feel than the 2x (well, it is more expensive!). £1299 is a fair way from the frankly bargain £599 of the 2x, and while a price of around £1000 would have made the 6x a similar bargain, it is still around £500 less than the next level of workstation‑status instruments on the market. The facilities of the latter type, especially their feature‑packed sequencers, are probably overkill for people with a computer sequencer at home, so an instrument like the CS6x strikes the right balance.

In their usual efficient way, Yamaha have looked at the unique selling points of their competition and made sure their new instrument matches or exceeds them, but the CS6x is more than just a collection of the right features for the time. It all hangs together remarkably well, is largely a pleasure to use, and would slot beautifully into many a setup for stage and/or studio.

Feature Summary

  • 61‑note, velocity‑ and aftertouch‑sensitive keyboard.
  • 479 raw sampled waveforms.
  • 384 factory presets, 128 overwritable.
  • 128 factory Performances, all overwritable.
  • 10 factory drum kits, 2 overwritable.
  • 16‑part multitimbral.
  • 2 audio ins, 4 audio outs.
  • MIDI In/Out/Thru.
  • 4Mb Phrase Clip RAM.
  • Arpeggiator with 128 preset patterns.
  • Playback sequencer.
  • 2 global, 2 insert effects processors.
  • 8 real‑time control knobs.
  • Mod and pitch‑bend wheels, ribbon controller, four foot‑controller inputs, breath‑controller input.
  • Accepts expansion boards.
  • SmartMedia card slot; 4Mb card supplied.
  • Free CD‑ROM software suite.
  • PC/Mac computer interface.
  • Headphone output.

Expanding Universe: Plug‑In Boards

The rear panel, with the SmartMedia card slot for patch and sample clip storage. The mysterious blanking panel, clearly reserved for an as‑yet‑unspecified expansion of some kind (see the 'Expanding Universe' box), can be seen to the right of the picture.The rear panel, with the SmartMedia card slot for patch and sample clip storage. The mysterious blanking panel, clearly reserved for an as‑yet‑unspecified expansion of some kind (see the 'Expanding Universe' box), can be seen to the right of the picture.

As mentioned in the main text, the CS6x can host up to two optional boards. Six are currently available, with prices that make them a very attractive way of accessing basically new synths. Fitting a synth board also adds extra Voice memory slots.

  • PLG150AN analogue physical modelling (£199): based on the AN1x synth (reviewed SOS August 1997), adds five notes of polyphony.
  • PLG150PF piano (£229): offers 136 preset acoustic and electric pianos and harpsichords and adds an extra 64 notes of polyphony.
  • PLG100VL virtual acoustic (£119): adds just one voice to the CS6x's polyphony.
  • PLG100DX 6‑operator FM (£199): adds 16 voices of polyphony.
  • PLG100VH vocal harmony (£99): offers real‑time voice effects, including vocoding and gender‑bending.
  • PLG100XG (£199): with GM/XG compatible sound set. Adds 16 parts of multitimbrality and 32 voices of polyphony.

We were supplied with the PLG150AN AN1x board to check out — the same one that Martin Walker reviews as a soundcard daughterboard on page 206 of this issue. Fitting it was a doddle — the plate on the bottom of the synth is easily removable, using a coin if necessary. In addition to the access plate for plug‑in boards, there's a curious blanking panel at the rear of the synth. What will fill the space is not clear yet, but when you're routing audio to the outputs during programming, the choice of individual outputs 3‑6 is offered in addition to the synth's main stereo and two individual outs. Obviously, a multiple‑output board of some kind is on the cards. The Yamaha US web site is also bandying about words like "Firewire". Draw your own conclusions!

Going A Bundle: The Software

A fine CD‑ROM collection of software for PC and Mac users ships with each CS6x. A Voice editor/librarian (but no Performance editor, sadly) is provided for both platforms, as is the Card Filer utility mentioned in the main review. PC users benefit from XGWorks Lite, offering basic sequencing functions and a plug‑in system that accommodates editor add‑ons for the CS6x's optional boards; these editors are also included. There is no equivalent of the latter for the Mac, though XG Editor and VL Editor for the Mac are included. These can be used to edit the XG and virtual acoustic boards. Apparently, Yamaha's AN1x editor for Mac will work with its PLG‑board equivalent, though a dedicated Mac editor for the board will also be forthcoming. (Note that installed boards can also be edited using the synth's front‑panel controls.)

Scene This?

One excellent real‑time play feature that the CS6x shares with the CS1x and 2x (albeit in a slightly different implementation) is its Scene system. Once a Voice is created, it's possible to create two lots of settings of selected front‑panel controls and save them as Scenes. These Scenes are then recalled via two dedicated buttons, a facility which is great for making instant sound changes. In addition, turning the Scene Control knob morphs between the two Scenes — a superb feature.

Need Input...

As well as being used for sampling real‑world sounds, the CS6x's 'AD' input allows external audio to be routed through the synth, as part of a Performance. One use for this feature is routing the output from another synth, sampler or sub‑mixer through the 6x. Once so routed, the audio can be effected, panned, levelled and EQ'd. Yamaha even provide a collection of preset effect and EQ configurations tailored for different audio sources — for example, guitar‑amp simulation effects for guitar input. Still, the AD input would be a lot more useful in general if it were stereo.

Sum & Difference: How Many Parts?

According to Yamaha, the CS6x is capable of being 20‑part multitimbral, but this assertion needs further examination. For a start, they're counting the audio input as one part, so we'd be inclined to disallow that (though the input's limited parameters — including effect routing — can be controlled via MIDI). This leaves 19 parts. The first 16 are easy — they're the standard 16 parts of multitimbrality you'd expect from any modern synth. Yamaha then add a part for the Phrase Clip section and one each for the two possible plug‑in boards. However, it's not obvious how these are accessed independently of the main 16 parts. In a Performance, each extra part can be assigned a MIDI channel, but seemingly at the expense of MIDI channels used by one of the main 16 parts. This is especially frustrating when using a computer; we expected that when the CS6x was interfaced to our Mac via OMS there would be some way of addressing MIDI channels 1‑16, plus the Phrase Clip and the plug‑in sections, creating a 19‑part Performance. This doesn't seem to be the case. Rather, a Performance can have up to 20 parts, including the audio input, but you still only have 16 MIDI channels to play with. The only way all 19 (or 20) Parts can play at once is if some of them share a MIDI channel. There is an exception: installing the XG plug‑in board causes the CS6x to grow Parts 17‑32. We weren't able to try this board, but presumably special drivers will allow an attached computer to address the extra channels.

There are a couple of other oddities when it comes to using Performances with PLG boards. For example, the AN1x board has its own arpeggiator, which can be fun — it's possible to use the CS6x's arpeggiator to arpeggiate that on the board! But, in Performance mode, there's no easy way to turn the AN arpeggiator off — you have to go in and actually edit the associated voice. Also, a monophonic PLG board Voice (AN1x voices can be monophonic or up to 5‑note polyphonic) remains monophonic in a Performance: turning the mono/poly Part parameter on or off has no effect. Perhaps these are just little bugs that can be fixed in an update.


  • A true synth, without the GM limitations of the 1x and 2x.
  • Lots of very good sounds.
  • Useful sampling facility, with some off‑the‑wall processing tools.
  • Fun arpeggiator.
  • Good MIDI‑file playback facilities.
  • Plenty of real‑time control.
  • Nicely priced expansion boards.
  • Makes a good master keyboard.


  • Could be easier to program.
  • Poky display.
  • It's not really fair to call it 20‑part multitimbral, even with two boards.
  • Audio input (and therefore sampling) not stereo.
  • Uses relatively expensive SmartMedia storage cards.


The pros outweigh the cons in the case of this appealing instrument, which should find a ready market, and not just in dance music circles. A very good bet for both studio and stage use.


CS6x £1299; CS6R £999. Prices include VAT. See the 'Expanding Universe' box for prices of the optional expansion boards.