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Casio Privia PX5S

Stage Piano & Synthesizer By Nick Magnus
Published July 2014

The PX5S isn't just a stage piano — it's an instrument that might force you to rethink everything you know about Casio.

Casio first entered the world's musical consciousness with their toy VL1 keyboard in 1980, featured on Trio's 1982 novelty hit 'Da Da Da'. They subsequently gained an appreciative following for their innovative phase distortion synths, the first being the CZ101, introduced in 1984. Latterly Casio have assumed a fairly low profile in the pro-MI keyboard market, and are arguably best known for their well‑respected range of stage and domestic digital pianos. Less well known, perhaps, is their current range of synthesizers, comprising the XWG1 and the XWP1. Hold that thought...

At first glance, the PX5S appears to conform to the standard modus operandum for digital stage pianos; a selection of acoustic and electric pianos are the main act, with additional support from sounds covering the usual gamut of strings, organs, guitars, basses and synth textures. However, a number of factors set the PX5S apart from the crowd. So much so, in fact, that they may even give the big players such as Roland and Yamaha a run for their money. Firstly, let's look at the physical construction.

Look Ma, One Hand!

Well maybe not one hand exactly, but certainly one arm. The PX5S, despite having an 88‑note keyboard with weighted hammer action, is actually light enough at 11.1kg (24lb) to carry under one arm. The main reason for this is the entirely plastic construction of its bodywork, which, together with the scaled‑down controls, give it the appearance of a stretched‑out pocket calculator. It's a look, granted, and it's also clean, fresh and unfussy. Another concession to portability is that it can be powered not only by the supplied 12V PSU, but also from batteries. Removing the top right‑hand cover reveals a compartment for eight AA‑type batteries, which provide around three hours of use. When running on batteries, the Auto Power Off feature turns the PX5S off after six minutes of inactivity.

Around the back are a stereo mini‑jack audio input, a pair of quarter‑inch jack inputs, 12V PSU input, stereo quarter‑inch output jacks, MIDI In, Out and Thru sockets, two quarter‑inch footpedal jacks and a USB port. On the front panel are pitch and modulation wheels, six sliders, four knobs, volume, two groups of sliver‑like buttons for sound selection and editing functions, and a small backlit LCD display. A recessed USB socket provides additional features, described later.

The keyboard itself is particularly worthy of mention: its Tri‑Sensor scaled hammer action is surprisingly firm,positive and bouncy for one with such a short front‑to‑back scale, with a simulated ebony/ivory finish providing a pleasant, slightly rough feeling to the touch which should also help to reduce finger slippage when things get sweaty.

Vive La Difference!

The PX5S's sound engine has a few surprises in store. Firstly, it employs what Casio call (takes a deep breath...) 'AiR Multidimensional Morphing Sound Source technology', in which AiR stands for Acoustic and Intelligent Resonator. Essentially this means the modelling of body resonance, sympathetic string resonance, pedal noises and other artifacts associated with acoustic pianos. It also provides seamless timbral variations across the dynamic range; ie. no audible jumps between velocity layers, as well as a smooth tonal gradation across the entire keyboard range. This AiR engine is applied to a selection of 'premium' piano and electric piano tones; the remaining 'supporting' sounds (strings, guitars, organs, et cetera) employ the standard PCM approach. The unexpected factor, however, is that all the PX5S's sounds (including the supporting sounds, usually provided on a 'take it as it comes' basis) are in fact the product of a surprisingly well‑specified synth engine. And it's not just basic filter and envelope offsets, but an architecture that bears more than a passing resemblance to Roland's JV and XV synths. Further research revealed that Casio have transplanted huge swathes of features from their XWG1 and XWP1 synths to the PX5S. It's not so much a piano as a wolf in sheep's clothing — or maybe that should be a synth in piano's clothing.

Architecture & Synth Engine

The PX5S is always operating in Stage Setup mode; Stage Setups are patches that define everything about the instrument: sounds, effects, controller assignments, key ranges, arpeggiators, inside leg measurement... the lot. Each Stage Setup comprises four Zones, which can be layered or split, with each Zone containing a synth engine (referred to as a Tone). Tones come in three varieties: the Melody types consist of 300 multisampled sounds encompassing the pianos, organ, string/brass, guitar/bass and synth/various sound categories. These each have their own set of editable synth parameters including key range, tuning, velocity range, pan, volume, pitch AR envelope, a low‑pass resonant filter, two ADSR envelopes for filter and amplifier, a pitch LFO and filter/amp LFO each offering seven waveforms, and portamento. The Drum category draws on a pool of 290 samples, offering 20 kits styled after various musical genres. The architecture of Drum Kits affords each drum its own set of synth parameters including pitch, pan, volume, LPF filter and two envelope generators, as well as individual control over system effects sends and access to an insert (DSP) effect. You can even reassign keys to play different drum samples if you wish.

The third type, HexLayer, is the Big Surprise up PX5S's sleeve. Unlike the single‑synth structure of Melody Tones, HexLayers are made up of six (yes, six) independent synths, all running within a single Tone. Each synth layer enjoys its own set of parameters, similar to the Melody Tones, only this time they have a choice of three low‑pass filter types, plus band‑ and high‑pass filters. The pitch envelope is a full ADSR type, whilst the filter and amplifier envelopes are impressively detailed, having an IADDDSRR configuration with initial level, attack time/level, three decay times/levels and two release times/levels. The pitch and filter/amp LFOs operate uniformly upon all six layers, but you can control their depths individually for each layer. HexLayers use the PX5S's raw waveforms, 418 in all, as opposed to the 'ready‑rolled' Tones of the Melody category.

This all adds up to an enormously powerful resource, and the potential for sounds of great detail and animation. Of course, you don't have to have all six layers running — you can easily disable unwanted layers. Unfortunately, you can't have all four Zones in a Stage Setup playing HexLayers — you're restrictedThis composite screenshot shows the full parameter strips for all six synth layers of a HexLayer. to a maximum of two. Nevertheless, two HexLayer Tones plus two Melody Tones adds up to a substantial 14 voices, all doing something completely different, on each note! It might be just a tad over the top, but rest assured that the PX5S's 256 notes of polyphony will still allow you to generate an apocalyptic eighteen‑note chord with this monstrous din. To add to all this synthy goodness, there's a whole raft of options for assigning parameters to the front-panel controllers, routing to system and insert effects, activating each Zone's own independent arpeggiator or phrase sequence, and individually setting the status of their audio, USB and MIDI outputs. Given all this sound-sculpting potential, it's good to know you can save your creations; there are User locations for 100 Stage Setups, 300 Melody Tones, 50 HexLayers and 20 Drumkits.

If there's any shortcoming to the PX5S synth engine, it's that some of the looped waveforms, particularly ensemble sounds like strings, choirs and pads, suffer from very short loops — often well under a second long — which pulse noticeably in isolation. On the plus side it's rather less noticeable once you start layering, but it can get rather irritating.

Preset Sounds

The AiR Concert Grand piano would be the star turn on instruments costing twice as much (and weighing twice as much). The tone is full‑bodied and bright, with a good long sustain and no discernible looping. From the delightfully raucous and powerful low‑end, to the firm and confident mid‑range through to the well‑balanced and bell‑like top end, there are no dead notes, tonal inconsistencies or obvious flaws that one might expect to encounter in a keyboard of this price. It's remarkable that despite being based on only four sampled velocities, Casio's morphing technology manages to make the dynamic transition from pp to ff completely smooth, which makes for a very believable and satisfying playing experience. Different piano voicings can be selected by clicking through the Tone list; there are 20 variations in all, including Rock, Studio, Classic, Dolce, Bright, Mellow, Tack, Honky‑Tonk and a couple of piano/pad layers, though to my ears it's those with the 'GrPno' prefix in their name that have the same level of detail and realism as the first Concert Grand Tone. Nevertheless, there's plenty of tonal variation here to suit most styles and needs.

Equally as impressive as the Concert Grand Piano are the two types of AiR Electric pianos. 'AiR E.Piano' is a vintage‑sounding Rhodes, with a distinctive tone favouring the second harmonic, typical of one whose tines are angled close to the centre of the pickups. 'AiR 60s EP' is that other electro‑mechanical stalwart, the Wurlitzer, which effectively reproduces that instrument's wide dynamic range from soft and harp‑like to an angry bark. Various Stage Setups demonstrate these electric pianos well, using the PX5S's DSP effects (more on which later) to replicate those classic EP sounds we know and love. FM fans will enjoy the DX7‑type EPs, which layer nicely with the Grand Piano to make that famous 'LA' ballad piano sound. Other highlights include some excellent funky Clavinets, presented in both natural and wah‑wah flavours, and a rather lovely Flemish‑sounding harpsichord. Special versions of the Clavs and harpsichord with key‑off release noises are particularly realistic. If you want Hammond organs, the PX5S has them, with Stage Setups making use of the front-panel sliders to control the levels of HexLayer elements, providing drawbar‑style control over the sound. Although lacking the detail and refinement of a dedicated Hammond clone, the PX5S makes a fair crack at it, and Casio have even created a DSP simulation of the Hammond chorus vibrato effect. However, the all‑important rotary effect is a tad indifferent and slightly lets the side down. I suspect that if these organ Setups were fed through a dedicated Leslie simulator such as the Neo Ventilator, they would sound jolly convincing.

A selection of synth textures demonstrate the PX5S's layering features and DSP effects, also showcasing the arpeggiator and phrase sequences, whilst the remainder of the Presets are constructed from more conventional sounds (strings, brass, guitars), some of which are derived from the ubiquitous GM soundset.

Master Keyboard Controller

Aside from its role as a musical instrument, the PX5S also functions as a versatile master controller keyboard. Each of the six sliders, four knobs, two footpedal jacks and the mod wheel can be assigned separately to control two different parameters simultaneously. These range from a set selection of internal synth and effect parameters to MIDI CCs (CC00 to CC97) with Min and Max values for each assignment. Additionally, you can choose the output of any Zone (USB, MIDI, Audio or any combination); so for example you could mute the audio output of a couple of Zones and have them control two external MIDI synths on separate MIDI channels, while the other two Zones control the PX5S's internal sounds.

Casio have curiously chosen to make the second of the two foot-controller jacksThe PX5S measures 132 x 28 x 13 cm and weighs just 11.1kgs. (the first is for the sustain pedal) responsive only to momentary types, rather than continuous controllers. Assigned parameters, therefore, modulate between two user-definable values, with the ramp up/down time also being user-definable. I'm not sure everyone will find this particularly appealing, but Casio must have had their reasons for this decision. However, you do adapt to it eventually — it's all in the timing.

Arpeggiator/Phrase Sequencer

Each Zone in a Setup offers the choice of either an Arpeggiator or a Phrase Sequence. All four Zones' arpeggiators/phrase sequences are entirely independent and can be used simultaneously. The Arpeggiator is an absolute triumph, and a creative goldmine. One hundred preset arpeggios contain imaginative patterns that go way beyond the usual up/down variety, and being fully editable, there's room for 100 of your own. Arpeggios can be up to 16 steps in length with definable pitch offsets and velocity values per step. Further refinements include step size, note length and groove, plus an innovative (surely unique) feature that allows you to not only customise the note order, but specify any steps to play all held notes polyphonically. There's even a separate control 'track' for each step assignable to pitch‑bend or MIDI CCs 00 to 97, with a smoothing parameter to soften the transition from one value to the next.

As an alternative to the Arpeggiator, Zones can use Phrases: mini‑sequences of up to 16 measures long. There are 100 Preset Phrases to get you going, some designed to suit specific instruments. Chances are you'll want to programme your own, and a generous 900 user locations are provided for this. Overdubbing onto the same phrase is possible, so you can set it to loop and build up the Phrase bit by bit (for example recording a drum pattern one drum at a time) with options to quantise or leave your performance in real time. The metronome, however, is impossibly quiet with no means of adjusting its level. Casio are aware of this, so hopefully it will be corrected in a software update.


The PX5S is equipped with Master, System and Insert (referred to as DSP) effects. System effects are applied globally to a Stage Setup, whereas the DSP effects are applied to individual Zones, meaning you can have four DSPs running simultaneously. There are 20 types of DSP including reverb, delay, distortion, compressor and chorus, and an interesting Piano Effect that simulates a piano lid in various open/closed positions, with adjustable reflection amount. The Distortion effect is especially good for adding a vintage colour to the electric pianos, having built‑in wah and nine speaker-cabinet emulations. The Master Equaliser and Compressor effects process the total output.

What Else Does It Do?

Recessed on the front panel is a socket for a standard USB stick, which provides several functions. It can store all your Setups, Arpeggios and Phrases. You can also play MIDI files directly from the USB stick, and of course the PX5S is 16‑part multitimbral, with its own Mixer page. A useful Audio Recorder lets you record performances and save them to the USB stick as WAV files; very handy for sharing ideas with other people. And should you wish to jam along with pre‑recorded material there are two sets of audio inputs on the back: a stereo mini‑jack and a pair of regular line-input jacks.


It may look toy‑like, but don't be misled by the PX5S's appearance. Casio have managed to combine excellent piano sounds, a superb keyboard, an assignable control surface, an interesting and highly programmable synth engine, arpeggiators, phrase sequencers, DSP effects and a whole lot more into a package at a cost and weight that's half that of comparable instruments. In fact I'm having trouble thinking of any comparable digital pianos that offer this degree of versatility and potential for sound creation — especially for the price, at well under £1000under $1000. It's a remarkable achievement. What more to say than well done, Casio!  


To find anything offering facilities similar to the PX5S, you'd have to look at instruments costing two to four times the price from manufacturers such as Kurzweil, Korg, Roland, Yamaha and Nord. If we're talking alternatives in the same price bracket as the PX5S, as far as I'm aware, there aren't any.

PX5S Editing Software

Every aspect of the PX5S can be edited from the front panel; although given the instrument's depth and complexity it's a lengthy task on such a small LCD display. Fortunately, the freely downloadable PX5S Editor (for Mac and PC) comes to the rescue. Compared to the slick GUIs we've come to expect these days, it's not the most fetching design, looking rather dull and clunky. It really needs to be displayed at full screen, and even then it requires scrolling to see all the parameters. However, dull and clunky has its plus side — it's very clear and uncluttered, and most importantly, it works. Certain sophistications are missing, for example controls don't work bi‑directionally, so if you change something on the PX5S, there's no corresponding response in the Editor. Some features of the PX5S can't be edited from the Editor, namely the programming of custom arpeggios and Phrase Sequences, which must be done from the instrument's front panel. Using the Editor also requires quitting your DAW program (or at least it does in my case), as the two programs seem unable to share the same USB driver.

Online Resources

Casio Music Forums. This is a discussion area for all Casio products including the PX5S. In addition this is the official site to Download new Tones and Stage Settings for the PX5S.

Privia Pro Blog. This site contains several tutorials, links to videos and more.

Privia PX5S Facebook Users Group.

Casio PX5S Portal. This has links to all of these sites as well as videos, manuals and more.


  • High‑quality acoustic and electric pianos.
  • Low cost, low weight.
  • Versatile master controller facilities.
  • Superb weighted keyboard.
  • There's a deeply editable sample‑based synth lurking inside!


  • Short, audible looping on some samples.
  • Can't use continuous controller pedals.


Top‑notch acoustic and electric pianos rub shoulders with a wide range of essential instrumental sounds, drums, arpeggiators, phrase sequencers and effects. Add to that a very powerful multi‑layered editable synth engine, a superb 88‑note weighted keyboard, flexible master controller facilities, and it's incredible that Casio have brought all this in at well under a grand. Even if your budget stretches to more stratospheric heights, it would be churlish to ignore the PX5S.


£899 including VAT.