Stage Pianos

Probably one of the most common ‘complements’ to the VR is a stage piano, especially as the VR acoustic pianos sound anything but good.
This aricle sheds light on the technical aspects of stage pianos, the difference to real acoustics, presents an overview of ‘stage piano hammer actions’ and terminates with a BUYERS GUIDE

With dozens of stage pianos on the market you are spoiled for the choice. How do you decide? You can:
– listen to a sales representative or YouTubers – feeding you with superlatives cool, great, amazing, fantastic, best ever…
– ask friends or VR colleagues – many of whom will swear that ‘their’ piano is best
– get an insight in stage piano technology and get an idea at which features to look at before taking a buying decision

We go for the last and start with the question: what is a ‘stage piano’? Basically it’s a mobile digital piano that

is easy to transport (10-15 kilograms in case of ‘hammer actions’)
has focus on ‘realistic’ piano sound
has piano shaped keys
has either a lightweight synth-type action or a piano-like hammer action
has a set of other sounds like electric pianos (Wurly, FM-EPs etc) and ‘bread & butter’ sounds, or even enhanced features like built-in synthesizer, modulation wheels, midi controller options etc.

There are dedicated multipurpose stage pianos like Nord Stage, Roland RD88 and RD2000, Casio PX5S, etc., and more ‘piano-centric’ pianos like Nord Piano and Grand, Kawai MP7 and MP11 – but basically any transportable home digital like Roland FP series, Yamaha P series (P like portable) etc can be used on stage.

Now let’s take a look at the two fundamental aspects of a digital (stage) piano: the piano sound and the piano-like keybed, also called ‘action‘:

(A) The ‘piano sound’

A good piano sound has:

Highly resolved samples (sophisticated recordings of real pianos, high bit rates, long samples, etc)
Multisamples: any tone of the piano has a different timbre. In theory you would have to record every single note. In reality (limitation of available memory) the same record (sample) is used for an interval of notes (e.g. 5 notes up to one octave), then the next interval uses the next sample. You can hear the ‘jump’ in timbre when crossing from one interval to the next. Higher spec pianos use ‘modelling’ techniques that soften (interpolate) the change between multisamples (e.g. Roland ‘SuperNatural’ technology)
Velocity samples: a tone changes its timbre depending on how hard the key is hit. It’s not just louder – it also sounds differently (the harder the key is hit, the more ‘brilliant’ the sound). In theory you would have to use an infinite number of samples for each nuance of ‘key pressure’ – which is of course not possible. In practice the ‘key pressure’ – or velocity – is split into ranges and for each range one sample is used – which are then called velocity-samples or velocity-layers. Entry level pianos usually use 3 velocity-layers, e.g. 3 samples for the ‘ranges’ ppp-to-piano, piano-to-mezzoforte and mezzoforte-to-fortsissimo. Higher spec pianos use 5 or more layers and the most expensive – well that’s another story…. On lower spec pianos you can hear the abrupt change from one velocity-sample to the next by repeatedly hitting the key harder and harder. Higher spec pianos use modelling techniques to soften the change (Yamaha, Rolands SuperNatural, etc)
Sample-Loops: In theroy if you make RAM memory big enough for storing big samples, a decaying (sustained) piano tone could be recorded in its full length (Boesendorfer once did a prototype). Real digital pianos with non-infinite memory use short samples (usually 2-7 seconds, Dexibell actually uses 15 seconds). To simulate a tone decaying 30 seconds, an initial ‘attack’ sample is followed by a ‘decay sample’ that is repeated several times with decreasing volume – the so called (sample) loop. Yet again when listening carefully (headphones) you can hear the restart of each decay loop. Higher spec pianos use modelling techniques to smoothen the transitions – we already know who: Roland SuperNatural: even on their entry-spec piano FP10 there is no noticable ‘looping’.
Decay sample looping of VR09 ‘Grand’: obvisously NO SuperNatural modelling
Sympathetic and Damper resonance (also called ‘string resonance’): this is an effect where a sounding tone excites other strings which will also start to sound (at much lower volume though). You can find that ‘resonance’ effect on a lot of instruments, even acoustic drum kits, when e.g. hitting the the bass drum also excites toms, resulting in a complex sound of the drum set as a whole. Piano sympathetic resonance is much more effective when the dampers are off the strings so that they vibrate freely. The interaction can happen between 2 notes: slowly press down note C5 until its damper lifts off the string (without triggering the tone) and hold the key down. Now give C4 a short hit (release immediately): as long as you continue to hold down C5 you will hear C5 sounding – C5 was ‘excited’ by C4. When you press the damper pedal, lifting the dampers off for ALL keys, the effect is highly multiplied and (more or less) ALL strings sum up to a very complex sound full of beauty and finesse.
In a real piano, ‘damper pedal released’ and ‘damper pedal pressed’ is the SAME effect (named ‘sympathetic string resonance’).
In a DP the effect ‘damper pedal released’ is called ‘string’ or ‘sympathetic’ resonance (note the confusing wording), and the effect with ‘damper pedal pressed’ is called ‘damper resonance’. The reason is that 2 types of ‘simulations’ are used :’damper resonance’ can be simulated in a very primitive way by adding ‘background noise’ samples, so it can be found in some basic ‘piano keyboards’ (Roland GO:piano). Higher speced DPs have more sophisticated algorithms for simulating damper resonance. String resonance (pedal released) simulation needs more complex ‘calculation’ not feasable in a ‘keyboard’ hardware – albeit it became a standard even in entry level DPs (FP10, Casio Privia, etc)
‘Mechanical noise’: e.g. a ‘hall’ effect of the chassis of a real piano, mechanical noise of the key hit, a ‘klonk’ noise when the sustain mechanism is activated etc.

(B) The keybed, or ‘action’

On digital pianos we find 3 types of actions:

Synth-type action with a (usually unweighted) plastic keys in typical rectangular ‘piano shape’. In this action, the keys are pushed back by simple springs. Representatives of this action are Yamaha NP12/35 and Roland GO. The feeling of such a keybed is that of a synthesizer and miles away from any ‘real’ piano.
(Simple) Hammer-Action: these actions consist of two mechanical parts: a key and a ‘hammer’: the key kicks the hammer, that, falling back by graviity, pushes the key back to rest position. Albeit being far away from the ultra-complex mechanics of a Grand or Upright, the ‘feel’ comes closer to a ‘real’ piano
Hybrid Actions: they are only found in expensive top home/concert models. The most elaborate are the Kawai ‘Millennium Hybrid’ and Yamaha ‘Avant Grand’ actions built like the actions of their ‘real Grands’ including the complex ‘double escapement’ mechanism. Two steps down comes Casios ‘Hybrid Grand Action’ with wooden keys turning on a wooden balance rail (like the real thing) but missing a mechanical escapement mechanism. Yet another step down (by mechanical aspects) is Kawai’s ‘Grand-Feel’ action and finally Rolands ‘Hybrid Grand’ which is basically a ‘stretched PHA’ action (with plastic keys – it’s questionable is if this still can be called ‘hybrid action’ …)


The chinese entry level action Medeli K6 (used in stage pianos like M-Audio 88, Kurzweil SP6 etc)	The amazing Kawai ‘Millennium’ hybrid action, identical to their acoustic Grands

(Simple) Hammer-Actions

As synth-type actions are evident in their ‘working principles’ and the huge and heavy hybrid actions out of scope for ‘stage pianos’ we concentrate on the (simple) hammer actions that are used in entry-to-mid level digitals and stage-pianos:

A ‘simple’ hammer mechanism is composed of very few mechanical parts:

the key – usually rotating on an axis
the ‘hammer’
the sensors that capture the key stroke

This ‘3 parts-per-key’ mechanics does not have much in common with a real piano or hybrid action. It’s in fact a construction that just tries to emulate the feel of a ‘Grand’ action. Although being so simple, there are differences in the way simple actions work:

The surface (‘texture’) of the keys
The weighting of the keys (graded/ungraded action)
The behaviour of the action: key pressure, inertia, rebound, repetition, pivot length
The position of the ‘action points’ of a key: damper off/on, escapement, repetition
The number and position of sensors
The mechanical feel of escapement
etc etc etc

Texture of the keys

Real piano keys have a ‘rough’ textured surface: in former days ivory was used to cover the wooden keys (today keys are covered with synthetic materials or …. mammoth teeth!) . The texture makes the key feel ‘warm’ and ‘unslippery’. Very basic (cheap) DPs, generally the ‘synth-action’ type (e.g. Yamaha NP series), have a polished surface without any texture: the keys feel ‘cold’ and slippery (especially with sweat and grease from the hands). Hammer-Action type DPs normally have textured keys. In the Yamaha GHS action (e.g P115 and P125) the white keys are polished and the black have a light texture

The weighting

In a real piano, the hammers of bass keys have more weight (more inertia for strong hits on the bass strings) than those of the treble keys. This is called graded (or scaled) action. The weight does not change continuously over the 88 keys but is grouped in ‘zones’: groups of keys with equally weighted hammers. Acoustic Grands have e.g. 7 zones. The majority of digital pianos also have graded actions. A few actions have ungraded actions where all hammers are equal, e.g. Medeli K6 action and Yamaha BHS action (used in CP73 stage piano): this is not necessarily a downsizing: ungraded actions are lighter, reducing the weight of the piano, and are better suited for playing synth sounds (e.g. in the ‘multipurpose’ instruments).

Behaviour of the action

The ‘feel’ – or behaviour of an action is the very first impression a potential buyer gets: are keys hard or easy to press? How do they rebound? How fast can I do repetitions (‘trills’)? Do I feel fatigue? etc. There are technical parameters for all those points but finally it’s much of individual ‘taste’. Some aspects:

key pressure: in acoustic pianos key pressure is the down force needed to press down the key until it’s stopped by the escapement point (see below). Key pressure is measured by putting gram-weights onto the front end of a key (you can use coins or rim balance-weights for this). The standard for acoustic is 40 – 50 grams (for any key). Less downforce is easier to play but reduces the rebound speed of the key. On stage pianos with very short keys resulting in a big variation of key pressure depending on key touch position the theoretical numbers become less important (see next : pivot length)
pivot length: the key is a lever turning on a pivot (axle) in the back of the piano. The more the key is pressed near its rear end (‘near the fallboard’) the more it’s pressed near the pivot, reducing the leverage and needing more down force. On acoustics or hybrid DP with very long keys (pivot length), key pressure at the fallboard is approx. twice the pressure at the front end. Compact stage pianos have much shorter keys (pivot length): some extreme like the Casio PX 1000/PX3000 are so short that key pressure at the fallboard is ca 7 times the front end pressure which makes ‘playing in the keys’ very difficult.
rebound: this is how fast the key returns back. This is important for a player to keep ‘contact’ to the key and has an impact on the repetition rate
repetition: this is the rate at which you can repeat (‘trill’) a single key: a high repetition rate is vital for playing classical pices, rock&roll and boogie

The key action positions

Between the ‘rest point’ of a key (at 0mm key travel) and its end point (at ca. 10mm of key travel) there are points where something is ‘happening’:
On an acoustic piano the ‘action points’ in relation to key position measured to rest position are :
– key down movement:
   1. the damper comes off the strings at ca. 3-5 mm
   2. the escapements releases (the hammer ‘leaves’ the key and starts its free flight against the string) at ca. 7-8 mm
– key up movement:
   – the escapement re-engages (hammer and key are recoupled) at 1-3 mm or 7-8 mm depending on escapement mechanism
   – the damper resettles on the strings at ca. 3-5 mm
Damper on/off is pretty clear, but what is escapement (also called ‘let-off’) ? In acoustic pianos, the escapement is the position where the hammer separates from the key (and starts its free flight towards the string) or re-engages when the key is released. On release, if you don’t lift the key above the escapement, the tone cannot be retriggered (you can push the key but there is no sound).

In a ‘simple escapement’ action (e.g. Uprights) the escapement is such that the key has to be released to (nearly) rest position to re-engage with the hammer.
Actions of Grand pianos have a (complex) ‘repetition mechanism’, also called double escapement: the key has to be lifted only 2-3 mm to re-engage hammer and key, which means that repetitions (‘trills’) can be done much faster because the key does not have to travel back the whole distance to rest position. As long as you play (trill) the key between the damper point and escapement point (ca 2-3 mm) the previous note is not damped, e.g. you can make trills on a permanently sustained note.
Nearly all digital pianos try to imitate the behaviour of ‘Grand’ pianos (only a few ‘hybrids’ that imitate uprights).

The sensors

In digitals the key positions (actions) are captured by pressure sensitive sensors. There are two types of sensor key position capturing:
double-sensor and triple-sensor


Casio Tri-Sensor Scaled Hammer Action I(2009-2011) the damper sensor is actuated by the key, the double-sensor with escapement (note trigger) and repetition (double escapement) is actuated by the hammer	Casio Tri-Sensor Scaled Hammer Action II (2012 bis) all sensors (damper, escapement and repetition) are actuated by the key

In triple (3-) sensor actions, one sensor captures the key position of damper on/off, one the position of escapement (‘note trigger’) and the third the position of ‘repetition’ (double-escapement)
In double (2-) sensor actions, key position for the damper and ‘repetition’ (double-escapement) are captured by the same sensor, which means it’s not possible to play a ‘sustained’ trill between the key positions of damper-action and escapement
The following table shows the typical key positions (with respect to rest) for acoustic (AP) and digital (DPS). In the last line is shown the concrete values of the Casio Tri-Sensor Scaled Hammer Action II that is used in the Privia and Celviano stage and home pianos (sensor number in brackets):

key action:	damper on/off		escapement
key movement:	down (off)	up (on)	down (hammer flight / note-trigger)	up (repetition)
AP Upright (simple escap.)	3-5 mm	3-5 mm	7-8 mm	0-2mm
AP Grand (double escap.)	3-5 mm	3-5 mm	7-8 mm	7-8 mm
DP 2-sensor action	3-5 mm (1)	3-5 mm (1)	7-8 mm (2)	= damper (1)
DP 3-sensor action	3-5 mm (1)	3-5 mm (1)	7-8 mm (2)	7-8 mm (3)
Casio Tri-Sensor SHA II	5 mm	5 mm	9 mm	6 mm

The ‘key actions’ (shown with sensor number):

Not only the number but also the position has an impact on the reaction of an action: for 3-sensor action there the following types:

all 3 sensors are actuated by the key (upper picture, Casio action II)
all 3 sensors are actuated by the hammer (e.g. Kawai RH III actions)
1 sensor (damper) is actuated by the key, 2 sensors (escapement sensors) are actuated by the hammer (upper picture, Casio action I)

Which configuration is the best – most ‘realistic’? Well – in all higher spec actions it’s the hammers that push on the sensors. In theory you can ‘short kick’ a key that then throws the hammer against the sensors. With sensors activated by key only the key always has to be pressed to the latest sensor. On the other hand, the ‘damper’ is clearly directed by the key, not the hammer. From this considerations, sensor type ‘3’ should be the ‘most realistic’ (only realised on the Casio Action I’)
The questions is: are those details really important on the rather primitive DP actions???

The (mechanical) escapement

In recent years ‘escapement simulation’ became a big hype in marketing. As explained above, in an AP escapement is when the hammer detaches from the keys push mechanism. Mechanical friction in the mechanism implies a small resistance in the keys way down at ca. 2-3 mm above end position.
That resistance is not necessarily something one desires: on worn out pianos that friction could be so high that a slowly pressed key gets stuck.
What is the ‘Escapement simulation’ on digital pianos? In lower grade actions (e.g. Roland PHA4 standard, Casio) the ‘friction point’ is simply the elastic resistance of the silicone contact strip of the sensors. Despite what the PR guys claim the effect of this ‘simulation’ is squashy and barely noticeable. Higher spec actions (e.g. Roland PHA4-concert, Kawai, etc) add a device in form of a little rubber nipple or tongue, that, by passing, emulates a ‘friction point’.

Kawai ‘let off’ simulation ‘rubber nipple’

OVERVIEW: ACTIONS

The next table shows actions used in recent years on stage pianos, ordered by ‘complexity of construction’ and ‘level’.
Note 1: in column ‘escapement sim: ‘crs’ = contact rubber strip (see previous paragraph)
Note 2: the same actions might feel different in a different DP model: this can be due to model specific variations (e.g. different spring rates) or simply because the actions feels different because of a different housing

action	scaled/ graded	sen-sors	escp. sim	pivot length	remarks	pianos (examples)
Yamaha BHS	n	2	crs	17 cm	very short pivot, no key texture	Yamaha CP73
Medeli K6	n	2	crs	17 cm	very short pivot, no key texture. Used in Medeli DPs (+ rebranded units/’eigen makes’, eg. Thomann DP 3xx/DP26, Alesis) and other keys (Kurzweil, M-Audio …)	Medeli SP-4k, various
Fatar TP/100 2-sensor	n	2	crs	?	‘supplier action’ (–2015). Lightweight ‘non graded’ action used on numberless DPs like Nord Electro/Stage ‘HP;, Numa Stage, etc.	various
Fatar TP/100 3-sensor	n	3	crs	?	‘supplier action’ (version 2015–). Lightweight ‘non graded’ action used on numberless DPs like Nord Electro/Stage ‘HP’, Dexibell S3/P3	various
Medeli K6S	y	2	crs	17 cm	graded version of K6. Very short pivot, no key texture. Used in Medeli DPs (+ rebranded units/’eigen makes’, eg. Thomann DP28) and other keys (Kurzweil, M-Audio …)	Medeli SP201, Thomann DP28, various
Yamaha GHS	y	2	crs	17 cm	very short pivot, no key texture, keys pivot is no axle but ‘bending plastic toungs’	Yamaha P45, P125
Casio SHA II	y	2	crs	17 cm	Identical to the SMART action but with keys mounted in the housing (no proper ‘keybed frame’)	Casio CDP100, CDP150, CDP350
Casio SMART SHA	y	2	crs	17 cm	very short pivot, rough texture (might become smoother with usage), rather light (nice for weak fingers or keyboard players). Note about the Youtube ‘Shawcross-Casio-war’ on ‘key weights’: the short pivot point is a much more important ‘problem’ of the SMART action	Casio PX-S1000, PX-S3000, PX-S1100, PX-S3100
Casio SMART HYBRID	y	2	crs	17 cm	improved SMART action. Maybe the most silent action on the market. ‘Wood-keys’ (only lateral applications, no real ‘wood core’), better ‘response’, smoother texture, still the same ultra-short pivot length	Casio PX-S5000, PX-S6000, PX-S7000
Kawai RH-Compact	y	2	crs	18 cm	Kawai entry level action. Reported mechanical failures	Kawai ES110
Korg NH	y	2	crs	22 cm	Keys are mounted in the housing (no proper frame), no key texture, pivot is no axle but ‘bending plastic toungs’	Korg B1/B2, SP170, SP280
Korg RH3	y	2	crs	22 cm	Decent action, a bit comparable to Roland Pha4 standard	Korg SV, D1, SP250
Casio Tri-Sensor SHA II	y	3	crs	18.5cm	Highly praised action, feels a bit ‘clonky’ and needs force and endurance to play (like some old uprights). A bit noisy	Casio PX160, PX350, PX350M PX560M, PX5S
Roland Ivoy-Feel-G	y	3	crs	20 cm	Roland entry level action	Roland FP20
Roland PHA4-standard	y	3	crs	20 cm	renamed Ivoy-Feel-G	Roland FP10/30/60, RD88, …
Roland PHA1-3	y	3	nipple	22 cm	(elder) upper class actions	Roland FP80
Roland PHA4-concert	y	3	nipple	22 cm	renamed PHA3	Roland home digitals
Roland PHA50	y	3	nipple	22 cm	improved PHA4-concert	Roland RD2000, FP90
Fatar TP/40	y	3	option	?	‘supplier action’. Versions with varying ‘options’: with or without escapement, plastic or wood keys, etc. Used on numberless DPs like Nord Stage/Piano, Kurzweil Forte, Numa Concert etc.	various
Kawai RH III	y	3	nipple	20 cm	–	Kawai MP7
Grand Feel/II	y	3	nipple	26 cm	premier class, big, heavy	Kawai MP11

BUYERS GUIDE

Marketing speech tries to make you believe that stage piano actions feel like ‘real’ acoustic pianos. In fact none of those ‘primitive hammer action wannabees’ fully reproduce the complex feedback of a real piano – the ‘touch’, the rebound, the repetition, the tone-modulation, etc. etc.
So the most important is that you ‘feel good’ with the digital piano action (that’s not different from real pianos – just another level…)
In order to find ‘your’ action you need to go to a lot of stores and do even more hours of testing

Some advice for testing:
– do A:B testing. Use your own headphones to have a reference. The headphones should have a ‘classical’ frequency response with clear highs to properly resolve details
– don’t noodle around, instead play songs that you know: noodling hides sound issues !
– if you’re an organ or synth player you might have ambition to learn ‘classical piano’: try playing some simple pieces, like Satie Gymnopedie
– do ‘sound tests’ with single chords and single notes
– test EVERY single note: do notes sound bizarre ? (ex.: RD 2000 has a A6 note that sounds terribly false – and VR09/730 has a lot of them 🙂 )
– turn volume off and play the action without sound – the action will eventually feel completely different – do you like it?
ask yourself:
– do I like the tactile feel (texture) of the keys?
– do I mind the mechanical noise of the action? Does it really bother me?
– do I hear sample loops (not everybody can hear them!) and if so, do they annoy me?
– are the tone decays long enough?
– do I like the overall timbre of bass/mid/treble tones?
– can I hear ‘sound artefacts’ that annoy me?
– do I have problems (because I play a lot ‘in the keys’) with short pivot length (see table of actions)?
– are fast repetitions (‘trills’) part of my playing style and if so can I perform them on that action?

LIGHTWHEIGT ‘BUDGET’ STAGE PIANOS

The following table is an overview of lightweight (max 15 kilos) stage pianos in the sub-1000 USD/Euro range, that are good complements to a VR organ

Most of the listed models have build-in speakers: due to their low volume those speakers are not suited for stage (even not as monitor) but could be useful for practicing at home or performing a birthday song to your beloved mother-in-law …

Tips:
minimal 61-key synth-action piano : Casio CT-S1: a very nice piano sound (less harsh than GO:Piano), good keybed
leightweight 88-key synth-action piano, midi controller, bred&butter : Numa Compact 2: ‘vintage-piano’ patch is ok, many sounds, only 7 kilo
‘bargain’ hammer action piano with 5-pin midi-out : Thomann DP-28 plus (Medelli 201+), 400 euros: the piano sound is decent and clear, action is on par with Yamaha GHS, can be split and layered
hammer action piano + synthesizer + full-fledged midi controller : Casio PX5S: the piano sound is still very capable on stage, the action is excellent.

Notes for the table:
– action type: “spring” = synth-type actions with piano-like ‘box shape’ keys
– sym reso: sympathetic resonance (not necessary in band context but crucial for a ‘decent’ home piano):
d: damper resonance ; s+d: full string+damper resonance
– 5pin midi: key has at least a 5-pin midi out socket for directly controlling other keys (e.g. VR, modules etc)
– price: average ca. prices European market 2021

piano	action type	weight	width	spea- kers	sym reso	5pin midi	price (€)	remarks
Yamaha NP 12	spring	4.5 kg	104 cm	y	–	–	200	61 keys. GRAND sound: nice, warm, no sympathetic resonance, ultra-light
Yamaha NP 32	spring	6 kg	124 cm	y	–	–	300	like NP12 but with 76 keys in semiweighted ‘graded’ action. Note: because of lateral speakers NP32 is nearly as large as an 88 key piano
Casio XW-P1 XW-G1	spring	5.5 kg	95 cm	–	–	y	~250	compact synthesizer-workstations with nicely working 61 ‘spring action’ piano-keys. GRAND sound: not too bad: typical ‘Casio sound’, 3 (P1) or 2 (G1) discrete velocity layers without modeling, sustain is too short (10 sec/C4). ‘like-new’ keys can be found 2nd hand for ca. 200-300 Euros. P1 is the ‘performance model’ with Tonewheel organ and hex-synth, G1 the ‘groove’ model (no organ, no hex-synth but more live controls for the mono-synth). XW can run on batteries. Ultra-light
Casio CT S500 CT S1000V	spring	4.5 kg	93 cm	y	–	–	270 320	CT S500 has the same Grand sound (and legacy VZ/CZ sounds) as CT-S1 (see below) plus 800 sounds, accompaniment (styles) and a very new approach to ‘user interface’. Limited polyphony of 64 can become an issue with layered sounds. Can run on batteries. Ultra-light. S1000V is S500 plus Casio ‘voice synthesis’
Casio CT-S1 CT-S1 76	spring	4.5 kg 5.3kg	93 cm 114cm	y	–	–	220 350	61 keys: compact ‘stage piano’ with ‘mat’ (no real ‘texture’) spring action piano-keys with good dynamic control for piano. AIR sound engine. GRAND sound: natural sound, elegant with some warmth, bass octaves are a bit weak, higher octaves sound artificial, high velocity could have more ‘bite’, sustain is pretty long for an entry level key (17 sec/C4). Professional ‘stage’ orientated selection of sounds, very good EPs and exiting ‘vintage Casio synth sounds’. 2-voice Layer adds a lot to creativity. Limited polyphony of 64 can become an issue with layered sounds. Can run on batteries. Ultra-light. Roland GO competitor. 76 keys version has bigger speakers
Roland GO:Piano GO:Piano88	spring	4 kg 7 kg	88 cm 128cm	y	d	–	280 350	61 keys: compact ‘stage piano’ with’mat’ (no real ‘texture’) spring type piano-keys with firm action but ‘delicate’ velocity control. GRAND sound: powerful bass, higher octaves artificial, high velocity sample is harsh and biting and kicks in too soon. Sustain is ridiculously short (8 sec/C4). Damper resonance (with pedal pressed) does not sound very nice. Can run on batteries. Ultralight 61key version. 88-keys version has bigger speakers but only 4(!) sounds – take a look at Numa Compact 2
Korg Liano	spring	6 kg	128 cm	y	d	–	400	Semiweighted ‘graded’ (Korg ‘Natural Touch’) synth action, nice sounding piano, superflat (7cm), can run on batteries
Korg B2N	spring	9 kg	131 cm	y	s+d	–	350	Semiweighted ‘graded’ (Korg ‘Natural Touch’) synth action, nice ‘mellow’ sounding piano, decent EPs (see also ‘B2’)
Numa Compact 2 Compact 2X	spring	7 kg	127 cm	y	d	y	400 700	digital piano+midi-controller. Semiweighted synth action (Fatar TP/9) with split, layer, aftertouch. GRAND sound: nice in the bass, very digital and cold in the decant (‘vintage-piano’ is better). Good rock-pianos, 90 bread&butter sounds (+ downloadable sounds), Effects, simple midi controllers. 2X has drawbar organ and synth controllers (env, filter, LFO).
Kurzweil SP6-7	spring	8 kg	118 cm	–	s+d	y	1000	76 keys spring action version of Kurzweil SP6 (see further down in table)
Dexibell Vivo S1	spring	8.5 kg	109 cm	–	s+d	–	1200	compact 68 keys spring action. PRO instrument (same sound engine and GRAND sounds as Dex flagship DPs). 80 add. sounds, SF2-soundfonts, split/3layers. Metal housing. Can run on batteries
Medeli SP 201+ Thomann DP 28+	Medeli K6S	12 kg	133 cm	y	s+d	y	400	88 key (graded) action (Medeli K6S). GRAND sound: on the level of other ‘entry level’ DPs like Yamaha and Korg. Full sympathetic resonance, decent EPs, big polyphony (192), split/layer, usb-audio and the only budget grand with 5-pin Midi-out (+local-off) to control other keys.
Yamaha P 45	GHS	12 kg	133 cm	y	d	–	430	88 key ‘entry level’ hammer action. GRAND sound: usable clean Yamaha sound (inferior to P125)
Yamaha P 125	GHS	12 kg	133 cm	y	s+d	–	570	entry level’ hammer action (GHS). GRAND sound: decent ‘Yamaha’ piano sound
Yamaha P 121	GHS	10 kg	111 cm	y	s+d	–	500	compact 73 key version of P125
Casio CDP S100 CDP S110	SHA-II	11 kg	132 cm	y	–	–	400	hammer action like Casio SMART (!) action (light, very short pivot point – see PX1000). GRAND sound: timbre like PX S1000/3000 but not same ‘richness’ (e.g. no resonance). Limited polyphony of 64. 10 extra sounds (recent S110 with minor upgrades)
Casio CDP S350 CDP S360	SHA-II	11 kg	132 cm	y	–	–	500	like CDP S100 but with 700 sounds, accompaniment, etc. Recent S360 has increased polyphony to 128 (S350: 64)
Casio PX5S	3-Sens SHA-II	11 kg	132 cm	–	s+d	y	850	digital piano/synth+midi-controller. Good hammer action. GRAND sound: generally good and detailed, a bit ‘sharp’ and guitar-like sound, especially middle octaves with too abrupt decay. Incredible set of features: hundrets of sounds and customisations, 4 key zones, controllers, arpeggiator, recorder, 6-oscillator synthesizer etc. Few NOS still available
Casio PX M360	3-Sens SHA-II	12 kg	132 cm	y	s+d	y	800	stripped down version of M560 (see next), e.g. no ‘hex layer synth’, buggy audio mixer etc. Few NOS still available
Casio PX M560	3-Sens SHA-II	12 kg	132 cm	y	s+d	y	1000	‘mini’-workstation, action and grand/piano sound identical to PX5S, touch-display menu with ‘class leading ergonomics’, hundreds of sounds and customisations, 2 zones, rhythms/accompaniment, 6-oscillator synth etc. Few NOS still available
Casio PX S1000 PX S1100	SMART SHA	11 kg	132 cm	y	s+d	–	650	hammer action with some issues (very short pivot point – like it or hate it). GRAND sound: excellent, much improved over previous PX generation, fuller sound. Board is extremely compact and easy to carry (recent S1100 got functional upgrades)
Casio PX S3000 PX S3100	SMART SHA	11 kg	132 cm	y	s+d	–	800	hammer action and piano sound like S1000, hundreds of sounds and customisations, 2 zones, rhythms/accompaniment, 6-osc synth (S3100 got functional upgrades)
Casio PX S5000	SMART HYBRID	11 kg	132 cm	y	s+d	–	1000	Like PX S3100 but with the ‘hybrid’ action
Casio PX S6000	SMART HYBRID	15 kg	134 cm	y	s+d	–	1500	Singificantly improved pianos and speakers compared to PX S3100/5000
Roland FP10	PHA4 standard	12 kg	128 cm	y	s+d	–	500	good hammer action. GRAND sound: typical Roland ‘FP’ sound: good but a bit dull, looping-free. Very few ‘other’ sounds. Slighlty limited polyphony
Roland FP30 (X)	PHA4 standard	14 kg	130 cm	y	s+d	–	700	good hammer action. GRAND sound: typical Roland ‘FP’ sound: good but a bit dull, looping-free. More ‘other’ sounds than FP10. ‘X’: upgraded model with more brilliance in the sound
Roland RD 88	PHA4 standard	13.5 kg	128 cm	y	s+d	y	1150	good hammer action (like FP). GRAND sound: (new) Roland philosophy of stage sounds: not very elegant but rather shrill and biting (for ‘being heard in the band’), looping-free. 3 zones, many other sounds, ZEN-core for loading (buying :)) unlimited number of ‘ZEN’ sound packs. A bit limited as midi-controller, uncomfortable menu-diving
Roland RD 64	PHA4 standard	13 kg	111 cm	–	s+d	y	n.n.	good hammer action (like FP10/30, RD88), 64 keys, but heavy&bulky like a 76 key. GRAND sound: typical Roland ‘FP’ sound, good but a bit dull, looping-free. Not produced anymore
Kawai ES110	RH-C	12 kg	131 cm	y	s+d	–	600	decent hammer action (RH-compact). GRAND sound: –
Numa Stage	TP/100	13 kg	130 cm	–	s+d	y	900	digital piano+midi-controller. Light ungraded action (Fatar TP/100). GRAND sound: very good, detailed, quite warm (as Numa Concert). 12 bread&butter sounds. Enhanced midi controls
Numa X-Piano 73	TP/110	12 kg	105 cm	–	s+d	y	1100	modern digital piano/stage keyboard. ungraded 73 key action (Fatar TP/110). GRAND sound: very good, detailed. 4 Zones, 200 sounds, MFX, integrated mixer
Numa X-Piano 88	TP/110	14 kg	126 cm	–	s+d	y	1300	modern digital piano/stage keyboard. ungraded 88 key action (Fatar TP/110). GRAND sound: very good, detailed. 4 Zones, 200 sounds, MFX, integrated mixer
Kurzweil SP1	Medeli K6	12 kg	133 cm	–	s+d	y	800	digital piano, economy version of SP6. Light ungraded action (Medeli K6). GRAND sound: good. 16 sounds in total. Split+layer
Kurzweil SP6	Medeli K6	12 kg	133 cm	–	s+d	y	1000	digital piano and bread+butter key. Light ungraded action (Medeli K6). GRAND sound: good. Concept of non-piano sounds comparable to VR700 (sounds with fix assigned FX). 4 Zones, arpeggiator, limited as midi controller (fixed CC)
Korg B2	NH	11 kg	131 cm	y	s+d	–	450	basic hammer action (NH), nice ‘mellow’ sounding piano, decent EPs (see also ‘B2N’). Con: ‘proprietary socket’ for sustain pedal (no TRS!)
Korg D1	RH3	16 kg	133 cm	–	s+d	y	600	decent hammer action (RH3), heavy

Demystifications …

“On youtube VR acoustic pianos sounded great – I bought it and now I’m disappointed”: youtube reviews are made to sound great – by noodling with the sustain pedal permanently pressed – the bigger the chords and the more the sustain, the better it hides ‘the true sound’

“Roland FP10 (30…) has the new amazing PHA-4 action” : fact – it has a PHA-4 ‘standard’ which is a renamed ‘Ivory-Feel-G’ entry level action which (when Feel-G was still called Feel-G) was regarded as ‘oufff’-action… PHA4-standard has nothing to do with PHA4 ‘concert’ or ‘premium’.

“OMG the action has escapement simulation”: well, on the cheaper actions (GHS, PHA4-standard, Casio etc) what you feel as “escapement point” when pressing down a key is simply the “squeezing” of the silicone contact strip (higher grade actions have a mechanical device). In that regard ANY keybed has ‘escapement simulation’ (even the worst synth action….)

“Roland PHA 50 has WOODEN KEYS” : no – it has full plastic keys – with thin wooden side covers for a nice look (ditto: Grand Concert)

“Casio Tri-Sensor Scaled Hammer Action II has much improved over Tri-Sensor I and feel it”: really? Both actions are a carbon copy (same frame, keys, hammers, probably same grease…). The only difference: in Action II, Casio economised one of two sensor boards present in Action I by placing all 3 sensors on one board…

“Casio CDPs have the ‘Scaled Hammer Action II’ from old PX”: even if it’s called “SHA II” it’s nearly identical to the new ‘Smart Action’ – nearly, because “SHA II” has no proper frame but all parts are directly mounted into the case …