A hybrid piano can be created from either an acoustic or a digital piano, but we need to be clear about our definitions of acoustic and digital. The essential difference between acoustic and digital pianos is in how the sound is produced. In an acoustic piano, a sound is produced by the mechanical act of a hammer hitting strings, causing the strings to vibrate. In a digital piano, the sound is produced electronically, either from previously sampled acoustic pianos, or by physical modeling that employs a mathematical algorithm to produce sounds like those of an acoustic piano. (Here we’re speaking only of that aspect of a digital piano that is designed to produce a piano-like sound. Digitals typically also can produce many other instrumental and non-instrumental sounds.)
Acoustic-based Hybrids: the MIDI Controller
On the acoustic side, the original hybrid instruments were not new pianos, but modifications of already existing pianos. In 1982, with the advent of Musical Instrument Digital Interface (MIDI), a computer language for musical instruments, instruments from different makers could “speak” to one another. Soon after, various kinds of mechanical contacts were invented for placement under the keys to sense keystroke information such as note, key velocity, and duration, and convert it into MIDI data. This MIDI information was then routed to synthesizers, which turned the information into whatever instrumental sounds the attached synthesizer was programmed to produce. When one instrument is used to control another in this manner through the transmission of MIDI information, the first instrument is called a MIDI controller. At the beginning, however, the sound of the acoustic piano could not be turned off, though it could be muffled in vertical pianos.
Early mechanical key contacts were subject to breakdown, or infiltration by dust, and their presence could sometimes be felt by sensitive players and interfere with their playing. The more advanced key contacts or sensors used today involve touch films or optical sensors that are more reliable and accurate, and add no significant weight to the touch. In time, also, mechanisms were invented for shutting off the acoustic piano sound entirely, either by blocking the hammers from hitting the strings, or by tripping (escaping) the action train of force earlier than normal, so that the hammers lacked the velocity needed to reach the strings. Headphones would block out any remaining mechanical noise, leaving only the sounds of the electronic instrument.
Not surprisingly, most makers of these MIDI controller/acoustic hybrid systems have been manufacturers of electronic player-piano systems. The same MIDI sensor strip used under the keys of these systems for their Record feature (which allows players to record their own playing for later playback) can also transmit the MIDI information to a digital sound source: either an internal source that comes with the piano (a sound card) or an external one, such as a synthesizer or a computer with appropriate software installed. All player-piano systems today allow, through MIDI control, for the accompaniment of the acoustic piano sound by digitally produced sound, be they other piano-like sounds, other instrumental sounds, or even entire orchestras.
In addition to the accompaniment function, it turns out that these hybrid systems in which the acoustic piano can be silenced potentially have another very practical function. If your playing is likely to meet with objections from neighbors or family, being able to silence the piano and then play as loudly as you want, while listening through headphones, can be very handy. Realizing this, the major player-piano manufacturers make the MIDI controller feature available — without the player piano — relatively inexpensively. These MIDI controllers include a MIDI sensor strip under the keys, or optical sensors for keys and hammers, but no hardware and electronics that would make the piano keys move on their own. Usually, these systems come with a “stop rail” or other mechanical device to prevent the hammers from hitting the strings, an internal digital sound source, and headphones. When you move a lever to stop the acoustic piano sound, you turn on the digital sound source, which is heard through the headphones. Yamaha calls this instrument Silent Piano; a version whose digital piano sound is broadcast by the acoustic piano’s soundboard is called TransAcoustic. Kawai calls its hybrid-piano series (including one model with a soundboard speaker system) AnyTime. PianoDisc calls its two add-on systems QuietTime and ProRecord; QRS’s version is called SilentPNO.
The Yamaha Silent Pianos have sensors associated with their keys, hammers, and pedals that record their movements in MIDI format and output the information through a digital-piano sound chip to headphones or speakers, or to a computer for editing. With the addition of Yamaha’s Silent System, the acoustic piano can be silenced and the instrument used as a digital piano with a real piano action.
Two new Silent Systems are now available. The SG2 system is available in the b1, b2, and b3 vertical models and the GB1K grand. This system offers a CFIIIS concert grand piano voice, nine additional voices, can record and playback MIDI files, and has USB capability to preserve recorded performances. The SH system, used in all other piano models, offers a piano voice that uses binaural sampling of the CFX concert grand, 18 additional voices, can record and play back MIDI and audio files, and has USB capability to preserve recorded performances. SH grand models also incorporate a QuickEscape mechanism that automatically adjusts the action when the Silent System is engaged so that the touch feels the same whether the piano is being played acoustically or in silent mode.
Yamaha now also offers its TransAcoustic piano series, with several vertical and grand models. Like the Silent Piano, the TransAcoustic (TA) is an acoustic piano that can also send digitally sampled sounds, including Yamaha’s CFX Concert Grand samples, directly to headphones, sound systems, mixers, etc. The TransAcoustic differs from the Silent Piano in having two transducers attached to the piano’s soundboard. The transducers convert the digital signal into an electromechanical impulse that sets the soundboard vibrating — literally turning the soundboard into a loudspeaker. The soundboard, strings, and case provide a natural acoustic resonance for the digital samples, which can be played at even the softest volumes without the use of headphones and, when combined with the piano’s normal acoustic sound, can produce a more richly textured sound.
Kawai's AnyTime (ATX) silent/hybrid pianos are part of its K series of vertical pianos. The K200-ATX2 (45") and K300-ATX2 (48") use the digital sound engine from Kawai’s top-of-the-line CA-95 digital piano, as well as optical key and hammer sensors for the most sensitive control. The K300-AT2X also has a soundboard speaker system, similar in concept to that of Yamaha’s TransAcoustic piano.
QuietTime, from PianoDisc, can mute an acoustic piano and let the user hear his or her performance through headphones via sampled sound. The QuietTime MagicStar V5 S Series, introduced in 2013, has a slimline control unit that includes a touchscreen and iDevice compatibility. It also supports all three pedals, has a port for a USB stick, and comes with 80 demo songs. The control-unit sound module contains 128 sampled instruments, including a full General MIDI (GM) sound set, as well as 11 popular instrument presets, such as piano with strings. It also includes a built-in, adjustable metronome. A MIDI key-sensor strip is installed under the keys, and a padded mute rail prevents the hammers from hitting the strings while retaining the motion and feel of the piano action. The mute rail is activated by moving a small lever under the keyboard, which also turns on the sampled sound. MagicStar comes with a control unit, power supply, MIDI cable, MIDI strip, pedal switches, headphones, and mute rail. When the piano is to be used as a MIDI controller only (i.e., with no sound module or with a separate sound module), the MIDI key-sensor strip can be purchased from PianoDisc separately as ProScan, with or without the mute rail and headphones.
In late 2013, PianoDisc introduced another product in the QuietTime family: ProRecord. ProRecord uses fully optical, no-contact, high-speed key and pedal sensors to capture and record key and pedal movements. The system’s sensitivity can be calibrated to a very fine level, allowing it to be customized to a particular piano action or player so that, for example, trills can be accurately reproduced when playing near the bottom or top of the key, even on a vertical piano. ProRecord comes with a tone generator containing a sound set of 128 General MIDI 2 (GM2) sounds plus 100 additional instrumental sounds and nine drum kits, including sympathetic string and damper resonance. The system is compatible with both Apple and Android smartphones, tablets, and apps, and with the PianoDisc iQ player-piano system. Like MagicStar, ProRecord comes with headphones, and a mute rail for muting the acoustic piano.
SilentPNO, from QRS, consists of the PNOscan record strip, a PNOmation II sound module, a Wi-Fi adapter, and a stop rail for muting the acoustic piano. By muting the piano and turning on the soundcard, the pianist can play in privacy with headphones and enjoy the automatic recording features of PNOcloud and PNOmation, as described in the article, “Buying an Electronic Player-Piano System.”
But the accompaniment and “silent” functions of a hybrid MIDI controller/acoustic piano are only the beginning of what it can do. Just as the MIDI signal can be sent to a synthesizer or sound card, it can also be sent to a personal computer or transmitted over the Internet. Regardless of whether a MIDI controller originates in an acoustic or a digital piano, it enables the instrument to interact with music software to record, produce notation, control instrumental voices on a personal computer, or interact with other pianos in the same room or on different continents. The potential for hybrids in creating and teaching music is limited only by the imagination of the user. Notation softwares — from MakeMusic’s Finale, Avid’s Sibelius, GenieSoft’s Overture, and others — allow the hybrid piano’s key input (playing) to be converted to music notation. This notation can be edited, transposed, split into parts for different instruments, played back, and printed out. The possibilities for teaching are perhaps even more powerful. Taking a lesson from a teacher in a different state or a master class from a performer in a different country becomes possible with hybrid technology, particularly when combined with the player-piano features. Exacting copies of performances can be sent to similarly equipped instruments for playback, and critiques — with musical examples — can be sent back to the student. Some systems enable this interaction in real time over broadband connections, complete with synchronized video.
As we’ve said, most of the activity in the field of acoustic hybrids has been among player-piano makers, whose offerings have been either specialized (Silent Piano) or add-ons (QuietTime, SilentPNO). However, MIDI capabilities are now standard in all acoustic pianos, vertical and grand, made by Story & Clark, a subsidiary of QRS, the only piano maker so far to have done this. If you add a stop rail to silence the piano (available from QRS) and a sound source, you could turn one of these instruments into a “silent” type of hybrid like those described above. But even without those additions, a Story & Clark piano can be used with a personal computer and music software for recording, notation, controlling computerproduced instrumental voices, or any of the myriad other uses possible with a MIDI controller.
Digital-based Hybrids: Replicating the Acoustic Experience
Now, you may wonder: If you’re just going to use a piano to interact with a computer, play piano sounds silently, or make other instrumental sounds, why bother with an acoustic piano at all? Why not just use a digital piano or keyboard of some kind? The reason is: the experience. Digital pianos are long on functionality but short on, shall we say, atmosphere. For those used to the looks, touch, tone, or other, less tangible aspects of acoustic pianos, digital pianos, in their “pure” form, just don’t cut it — so digital piano makers have spent a great deal of time, energy, and money trying to mimic one or more of these aspects of acoustic pianos. The closer they get to duplicating the experience of playing an acoustic piano, the more they earn the right to the hybrid designation — because, when you get down to it, the function of an acoustic piano is the experience.
The first aspect of an acoustic piano that digital piano makers mimicked was, of course, the looks, and a large segment of the digital piano market consists of acoustic piano look-alikes. But that alone isn’t enough to earn the title hybrid. Next, the mechanism of the acoustic piano found its way into the digital piano. Much engineering has gone into the numerous action designs in digitals, always in the attempt to make their feel and response as close as possible to that of a “real” piano. For example, Yamaha’s GranTouch line of digital pianos uses a slightly modified acoustic piano action to trigger the piano’s sensors (the hammers are small and don’t actually strike strings). With such an action, there’s no need to simulate certain action processes, such as escapement, because it actually occurs mechanically. Many digital piano actions these days have weighted and/or wooden keys, and other enhancements that do a reasonable job of emulating an acoustic piano action; still, advanced pianists, especially classical ones, are unlikely to be satisfied by most of them.
Of course, digital piano makers have put more effort into copying the tone of the acoustic piano than any other aspect. How they’ve done this is beyond the scope of this article (see “Digital Piano Basics” for this information), but one interesting attempt is that of adding a soundboard to the digital. The Kawai CA-91, introduced in 2006, with its Soundboard Speaker System; and the Yamaha CGP-1000 Clavinova in 2007, with its Hybrid Active Soundboard System, both use an actual piano soundboard, set in motion by transducers, to augment the conventional speakers and impart a more natural tone to the instrument.
The latest entry in the hybrid arena is also the first instrument to be formally named a Hybrid Piano. Yamaha unveiled its AvantGrand series in 2009. The AvantGrand elevates the digital piano to a new level with a number of hybrid technologies, first of which is a real piano action. As mentioned above, this eliminates any discussion of whether or not it feels like an acoustic piano action — it is one. (However, whether or not the action feels right is still a legitimate topic of discussion.) This action controls the digital voices through the use of optical sensors, which measure the velocity of the keys and hammers without physically contacting any part of the action.
All three AvantGrand models have grand-piano actions, but whereas model N3 is also shaped like a grand, the cabinets of the lower-cost N1 and N2 are closer to that of a vertical piano (which brings up the interesting observation that the decision of whether to call a digital piano a “grand” or a “vertical” is not a simple one). In 2012, Yamaha introduced the model NU1 Hybrid Piano, the first digital piano with a real vertical-piano action.
One aspect of the traditional acoustic-vs.-digital argument that changes with the addition of a real action is the digital’s advantage of rarely needing maintenance. While the AvantGrand and NU1 models will never need to be tuned, eventually their actions will require some degree of adjustment or regulation. (We’ll bet the piano technician will be surprised when, on arriving to regulate an action, he or she finds the “piano” is a digital.)
But there’s more to the feel of an acoustic piano than its action, and this brings us to the last attribute of acoustic pianos that designers of digitals have attempted to copy: the intangibles. With the AvantGrand, one “intangible” — the vibrations generated by the strings and transmitted throughout the instrument — has been made tangible. Yamaha has added this ingredient to the N2 and N3 by connecting transducers to the action to send the appropriate frequency and degree of vibration to the player’s fingers. This is where the experience of playing becomes a bit . . . spooky. Not unlike an amusement-park ride that convinces your brain that you’re dodging asteroids while hurtling through space when you are, in fact, fairly stationary, the AvantGrand’s Tactile Response System quickly convinces you that you’re feeling the vibrations of nonexistent strings.
The illusions don’t stop there. When you depress a digital piano’s sustain pedal, you’re pressing a spring with constant tension. This is not how the sustain pedal feels on most acoustic pianos, in which the initial movement meets little resistance as the pedal takes up a bit of slack in the mechanism that lifts the dampers. Once the mechanism begins to lift the dampers, the resistance increases. Here again, the AvantGrand does a convincing job of conveying the feel and, perhaps more important, the degree of control available with an acoustic’s sustain pedal, including half-pedaling and incremental control. The N3’s four-channel sample set and 12-speaker audio system are also convincing, easily tricking the ears into thinking that considerably more than four feet of piano are in front of you. The AvantGrand and NU1 models all use samples from Yamaha concert grands for their sounds.
One area in which digital pianos are not intended to emulate acoustics is that of price. The Hybrid Pianos, with the sound and, in some cases, perhaps the experience, of a Yamaha concert grand, are priced similarly to some of the company’s least expensive acoustic grands and verticals. Actually, such comparisons are barely possible — the acoustics lack many of the digitals’ features, such as onboard recording, USB memory, transposition, and alternate tunings.
Which Side Are You On?
As the market for hybrid pianos heats up, buyers will increasingly have to choose between acoustic pianos with digital enhancements and digi-tal pianos that try to create the acoustic experience. Decisions will be made by weighing the relative quality, and importance to the buyer, of action, tone, looks, price, and features. More advanced classical pianists whose digital needs are modest, and buyers who, among other things, are looking to fill up a living room with a large, impressive piece of furniture, will probably tend to stick with the acoustic-based hybrid for now. Those whose musical needs are more general, or who have a strong interest in digital features, may find digital-based hybrids more cost-effective.
Another factor that may come into play is that of life expectancy. A good acoustic piano will typically function well for 40 or 50 years, if not longer. Few digital pianos made 15 to 20 years ago are still in use, due either to technological obsolescence or to wear. True, the relevant technologies have evolved, as has the design of digital pianos and the quality of their construction. Realistically, however, if past experience is any guide, pianos that are largely acoustic with digital enhancement may well last for many decades, while those that are digitals enhanced with acoustic-like features are unlikely to last as long.
The piano has evolved a great deal since Bartolomeo Cristofori invented it in 1700, and that evolution continues. Today it is possible to buy a piano with an ABS-Carbon action (Kawai), a carbon-fiber soundboard (Steingraeber Phoenix), or one that looks as if it was made for the Starship Enterprise! The hybrid piano’s blending of acoustic and digital technologies is just another step — or branch — in that evolution.