Yamaha CP4 Stage

The CP4 is Yamaha’s best stage piano yet, and it’s also significantly cheaper than its predecessor.

Yamaha’s CP range goes way back to the electro–acoustic grands and all–analogue electronic pianos of the mid-1970s, when MIDI and commercially available sampling were still hopeful glints in a designer’s eye. The name went away for two decades, before being relaunched with a range of digital stage pianos that included the CP1, which I reviewed in SOS in the June 2010 issue. And now it seems the legacy has passed to just two new models, the CP4 Stage and CP40 Stage. They have a lot in common, though it’s the CP4 that is the more capable, and which is the subject of this review. That previous generation of CPs, though still listed as current on Yamaha’s web site, seems to have been quietly discontinued — certainly they’re not readily available in retail channels.

So what do we have on offer with the CP4 Stage? Well, it’s an 88–note stage keyboard with one of Yamaha’s NW (natural wood) velocity-sensitive actions built into a weight–saving chassis made mostly of plastic. There’s a broad soundset on board that can be recalled from dedicated front-panel category buttons, keyboard splits and sound layering, and quite extensive effects processing. It’s not strictly a preset machine either: some degree of sound tweaking is possible via a menu system based around a two–line 80–character LCD display. Add in MIDI features, some real–time controls, USB MIDI and storage and you probably begin to see where the CP4 Stage fits into the market: substantially more flexible than basic domestic pianos, but offering nowhere near the complexity (or potential for bafflement) of a workstation synth, and with a front panel that’s geared towards clarity and immediacy, but which allows for a bit of programming when required. Essentially, the apparent mix of features that should be just right for many gigging keyboardists, studios and educational establishments. Have Yamaha got the balance right though? Let’s dig in and find out.

Action

The CP4 Stage uses Yamaha’s 88-key NW–GH (Natural Wood Graded Hammer) keyboard action. Wood is indeed visible on the sides of the white keys when an adjacent key is depressed — probably a thin veneer bonded to plastic underneath. I’m not sure about the ‘synthetic ivory’ claim though. It’s a lot like many modern acoustic piano keyboards, quite shiny, and nothing like as textured to the eye or touch as my Roland RD700NX, let alone a 1900 Steinway. Exploring the keyboard further, there’s no mid–stroke escapement feel, and my subjective impression is of a relatively shallow action with as much ‘spring’ and ‘swing’ (so to speak) above a firm but quiet and supportive keybed.

If some of that sounds negative, I don’t mean it to. Having played the CP4 for many hours I think it has one of the best stage piano actions currently available. Velocity gradation for the acoustic pianos is really wonderful, and it’s easy to control the very loud, the very quiet, and everything in between. That was true, I found, for the internal voices as well as for controlling computer–based piano libraries via MIDI. Crucially, though, the action does not seem too indulgent or luxurious for the electric piano sounds. On the contrary, it feels fast and light with those sounds, and I like the way the velocity response behaves here too. That ‘extra push over the cliff’ (to coin a phrase from rock–lore) seems to be always available to dig out a really snarling, barking tone, when you lay into or slap the keys. And for the organs and non–keyboard sounds this action is fine too. A compromise always has to be found when so many different kinds of voices are on offer, but this one must be one of the best–judged yet.

Sustain pedal behaviour is fine, though not without some quirks. While the CP4 Stage and its bundled FC3 pedal will generate and transmit continuous pedal controller values across MIDI, its own pianos don’t respond to them. Half–pedalling, the partial damping associated with a very quick up–down pedal stroke, is certainly possible, but you can’t do it as many times in succession as a real piano, or some other digital pianos. It’s also possible, I discovered, to generate a strange sonic artifact through rapid half–pedalling with some of the acoustic piano sounds — an unnatural chattering, almost like a rhythmic gate effect. It’d be hard to achieve in any normal playing conditions, but those with an insatiable half–pedal fetish might want to make note of it.

The CP4's back panel features a power button and IEC mains socket, a quarter-inch headphone output, unbalanced quarter-inch stereo outputs, a pair of XLR outputs, USB A and B ports for external drives and connection to a computer, MIDI I/O ports and four quarter-inch jack sockets for connecting footswitches and controllers. The CP4 measures 133 x 35 x 16 cm, and manages to save some horizontal space by putting the pitch-bend and modulation wheels above the keyboard.

Sounds

Acoustic pianos based on Yamaha’s CFX, CF and S6 grands are available in the CP4 Stage, called up with three dedicated front-panel buttons. But then each has 14 alternative versions, accessed with a spin of the front-panel dial or the –1/+1 buttons next to it. There are mono, ‘comp[ressed]’, ’rock’ and ‘dark’ variants, along with others that get a suffix of ‘Fl’, ‘+’ and ‘–’. I’m not sure what ‘Fl’ stands for, but ‘+’ and ‘-’ seem to shift the whole sample set up or down, skewing the harmonic spectrum a little, and making for either a slightly strident or plummy effect. Also, I say samples, but the technology here is actually Yamaha’s Spectral Component Modelling, which no doubt uses samples in some part of the sound generation process, but avoids all obvious velocity switching and sudden key–mapping lurches. Very successfully, too.

The quality and playability is jolly impressive. ‘CFX St’, based on Yamaha’s most expensive acoustic grand, is just a lovely piano to play for pop, jazz or classical. Coincidentally, I had the CP4 Stage on hand while I was also reviewing Garritan’s very fine (and very large) CFX Concert Grand sample library, and there wasn’t much to choose between them. Both proved capable of exciting clarity alongside warm presence and silky sustain, and offered an impressive dynamic range and responsiveness. The CP4 Stage’s CFX has a slightly less convincing decay phase, with a note of artificiality if you really listen for it, but few digital pianos do much better, and it’s miles better than what I heard from the much more expensive CP1 four years ago.

The ‘CF’ variants are good too — a sweeter and less ostentatious sound, but just as usable. ‘S6’ is a piano on a smaller scale again and notably less biting and attacking; a useful alternative for some genres.

All the pianos offer sustain resonance, so you get some extra breadth and complexity just by playing with the damper pedal down. Sympathetic resonance, the harmonic interactions between held notes, is sadly not part of the CP4 sound engine, though. You do find it implemented in competing stage keyboards by Nord and Roland, where it arguably adds something to the sense of realism. It’s probably more telling in solo performance than in an ensemble or band context, so again it’s something to be aware of rather than a deal–breaking omission.

Moving to the electric pianos, it’s a rosy and, at times, appropriately psychedelic picture here too. Fifteen Rhodes variants cover models from 1971, ’73, ’75, ’78 and a ‘dyno’ mod, and a few have pre–programmed drive, tremolo and chorus effects. With the exception of one curiously noisy preset they’re all immediately usable and likeable, dynamic, and subtly complex. Six Wurlitzers are also nicely energetic and elastic, based on 1969 and ’77 originals. Then there are eight bright and entertainingly inharmonic CP80 and CP88 electro-acoustics, and 18 sparkly/cheesy (delete as appropriate) DX–inspired FM tones.

From here on, the CP4’s sound set begins to stray into more familiar ROMpler territory. The CLAV button accesses 11 clavinets: two basic timbres, plus a muted version, with various wahs and phasers thrown in. They’ll get you through a ‘Superstition’ cover, but there’s not the same attention to detail here as in the pianos. The same is true of the six functional harpsichords and 50 or so organs. A good helping of Hammond tones is joined by buzzy transistors, a small but varied collection of pipe organs, and three squeezeboxes. Many benefit from a Leslie speaker effect, with the rotor speed mapped by default to the modulation wheel. The implementation isn’t perfect, though — rotor acceleration seems to kick in sometimes with a tiny glitch in the sound. It’s worth mentioning too that all organ registrations are absolutely preset, and some Hammond sounds have a very obvious percussion key click up to the C above middle-C, but almost nothing above, which is perhaps a sample–mapping quirk.

The second row of preset buttons begins with dozens of chromatic percussion sounds that include various bells as well as marimbas and vibes, then 29 acoustic string sounds variously slow and scything, baroque and modern, with a single solo violin, a harp, and a pizz section. There are many useful choir and vocal tones, 46 pads of varying extravagance, and 46 synths which bolster the pad selection still further and add some analogue–style Moogy leads. The Brass category has good trumpet and horn sections (the patch ‘Sfz Brass’ will be especially useful for those Steely Dan tributes) and even more Oberheim and ARP–style pads. The Guitar group offers five acoustic, five clean and five distorted tones as well as jazz guitars, banjo, a horrible mandolin, and many good acoustic, fingered, picked, slap and synth basses. And at the end of it all, ‘Other’ collects up 14 drum kits (acoustic, brush, jazz, electronic and vinyl) with a few eastern instruments and a very tired Glasgow–on–a–wet–day bagpipe.

All joking aside, this is a ‘production’ sound set if ever there was one, offering quality as well as variety, and with very few duds. Not the same as having a workstation, of course, where all this could be tweaked and edited out of recognition, or dreamt up from scratch, but a highly useful selection none the less.

Performance Enhancement

As a simple, mono–timbral preset machine the CP4 Stage works well. But for more flexibility you can layer two sounds, set up keyboard splits, or do both at once. This is easy to do on an ad hoc basis using the group of Main, Layer and Split ‘part’ controls towards the left side of the front panel, in conjunction with clear information from the LCD display. You can switch patches, turn parts on and off, and set relative volumes, and it all feels very intuitive and straightforward. The trade–off of this ease of use is that you don’t get the truly independent zone–driven control that some stage keyboards offer. Another slight drawback is that, whilst the Split and Layer parts can quickly be turned off with their dedicated buttons, the Main is permanently on, which prevents the easy toggling of Layer and Main tones that could be useful in some situations.

These setups, even when just a single Main part is active, can be stored in and recalled from 128 Performance memory slots. From the factory they’re all occupied, but all can be overwritten if you wish, and the whole lot dumped to or loaded from a USB stick (of which, more later). Performances are not as immediately accessible from the front panel as the presets, as they’re selected with the data wheel and +1/–1 buttons, but gigging keyboardists will be pleased to know there’s an option to advance incrementally through Performances with the press of a pedal attached to the CP4’s assignable footswitch socket. That works fine, though recall takes a second or so, and causes any held voices to be abruptly silenced.

Effective

Adding a great deal of flexibility to the basic sound palette is a range of effects that can be applied in several different ways. At a kind of global level, and accessible simultaneously from the Main, Split and Layer parts, are the System effects: Chorus, Reverb and a compressor. The Chorus has multiple algorithms that run to flanging, phasing and straight delays too, while the reverb has 11 different characters including quite respectable rooms, halls, stages and plates. Then there are two multi–effects generators that can be flexibly allocated to any of the three Main/Split/Layer parts, which can be loaded up with reverbs, delays, tremolos and Leslie speakers, distortion, lo–fi treatments, wahs, EQs and more. The quality is generally good too.

Extra flexibility for the System effects comes from there being independent send levels for each part, which are recallable as part of a Performance and easily adjusted on the fly when the part sliders are switched to a dedicated send–level mode. However, while I loved having the more capable part effects to play with as well, I was disappointed to discover that turning them on and off with their front-panel buttons causes a short interruption in the audio output. So they’re clearly meant to be set up and left, rather than actively toggled. That’s confirmed when you notice that the acoustic pianos’ sustain resonance is in fact delivered via an effect, taking up one of the slots — it’s the same for the organs’ rotary speaker effect.

I’ll also mention here the CP4’s master EQ, which takes the form of five dedicated sliders at the far right of the panel. While they undoubtedly control a digital EQ effect, their behaviour is near as damn–it analogue in the sense that settings you dial in (which can be pretty extreme, believe me) survive even a power–cycle. So the master EQ fulfils perfectly the requirement of matching the CP4 to typical less–than–perfect PAs, as the curve is completely independent of any preset or Performance changes you might make. A good feature to have.

Tweak Time

It’s becoming clear, I hope, that the CP4 Stage is more about delivering good results quickly rather than offering the nth degree of flexibility. However, if you’re prepared to get your hands dirty with a menu–driven programming system, a fair amount of sound tweaking can be carried out.

As you’d hope, there are ways to alter transposition, tuning, temperament, pitch–bend range, portamento and keyboard velocity response. But, more surprisingly perhaps, also parameters for a single LFO, and how, via the modulation wheel, that controls pitch, filter cutoff or level. Filter cutoff and resonance can also be tweaked, as well as a single ADR envelope that seems to be shared between filter and amplifier. Additionally, most pianos get a key–off volume parameter, and the Rhodes and Wurlitzers an adjustable ‘strike position’, which hugely changes the character of the sound. There’s clearly a capable synth architecture in there somewhere, and I wondered if Yamaha might expose it via an iPad or PC app, but the official word is that there are no plans.

More flexibility is delivered courtesy of the two foot-controller inputs, which I tested successful with a Behringer FCV100 pedal. On the one hand (or should that be foot?) you can take control of part volume and certain part effect parameters (mostly wet/dry mix). On the other, global–level parameters. For example, by default FC1 is mapped to adjust the output level of a mix of the parts. But it can also globally tweak filter cutoff, or modulation depth, or one of many other parameters mapped to standard MIDI controller message values. Surprisingly powerful, if not exactly predictable in how different sounds will respond across the three internal parts.

Also lurking in the depths of the menu system is a full–on four–zone Master Keyboard function, with each zone programmable for MIDI channel, transposition, key range, volume and pan, and capable of sending bank and patch change messages. These setups are stored as part of individual Performances too, and available alongside or instead of the internal sound engine. So in fact this makes the CP4 Stage a pretty capable master keyboard, though not one that’s necessarily quick or easy to program, and with a distinct lack of performance–friendly knobs, sliders and buttons. It’s a shame too that you’re forced to choose whether to use USB or the five-pin DIN-out sockets for MIDI communication — you can’t have both simultaneously.

Audio & Storage

It’s not uncommon for stage keyboards to be decked out with preset drum patterns, primitive sequencers, MIDI replay abilities, or indeed all of these. The CP4 ignores all those, though, and takes a different and quite useful tack: it has audio recording and playback features. They rely on you inserting a USB ‘thumb’ drive in the rear-panel USB A–type socket, where it’ll stick out in an alarmingly unprotected way, incidentally. Then, the whole thing is managed with just the simplest transport controls imaginable, a trio of buttons for play, record and stop.

A USB recording from the CP4 Stage is a mirror of what you hear from the main stereo output, so all three parts and effects are captured. The only exception is that the useful and configurable on–board metronome is not recorded, so that can safely be used as a time or tempo reference. The resulting file on the USB stick is a 16–bit 44.1kHz WAV, which can be easily played on a PC, dropped into your DAW, or whatever. And the CP4 Stage is also happy to play back both its own and other WAVs, so long as they meet that same specification, which makes playback of commercial tracks or pre–programmed backing tracks completely viable.

There is a limitation, unfortunately, in that during recording or playback you can’t switch Performances. You can change part voices though, so all is not lost.

Alongside the audio features, snapshots of all Performance and global–level settings can be saved to and loaded from a USB drive as a file with the suffix .C7A. So if you’ve spent a long time programming a complex show–length set you can save it for posterity, back it up if necessary, and recall at a later date.

Notes & Queries

Stage keyboards are always exercises in compromise, and it’s impossible for manufacturers to please all people all of the time. The same feature that to one player might seem beautifully simple and easy to use, could be to another overly simplistic and infuriatingly limiting.

However, I think Yamaha have hit on a fine balance with the CP4 Stage. The keyboard action is excellent, and it’s built into a chassis that’s surprisingly light. It’s got high-quality, ultra–playable pianos, and plenty of them. And not just pianos; nearly all the rest of that big, varied soundset it good, and might be all that many players will need for typical band, pit and educational use. I like the way the easy-to-use split/layer Performance capabilities co–exist with simple single–sound use, with no confusing, convoluted memory structures. And if you like dressing up your sounds with effects there’s a good deal of independence and flexibility.

Not everything is perfect. You’ll still have to buy a Nord if you want the ability to load completely new, character pianos, or take real control over drawbar organ sounds. It’s also arguable that the pianos, with no sympathetic resonance, effect–generated pedal resonance and limited half–pedalling support, are some way from the cutting edge. Would it have broken the bank, too, for each part to have had its own truly independent effects generators?

However, all that would be to miss the point of this keyboard. It’s not meant to be a specialist tool, but a sort of willing and unfussy all–rounder. I found it overtly musical, very easy to live with, and enjoyed having it around immensely during the review period. It’s a nice renaissance for the CP series, and I’d buy one like a shot.