Digital vs. Acoustic Pianos: An Unbiased Comparison

any people contemplating the piano have asked me which is better: a digital piano or an acoustic piano. This is not an easy question to answer. As you might expect, much of the advice on the Internet, especially on piano websites, is put there not for informational purposes, but to justify the writer's own decision of having bought one or the other. Other sites are just trying to sell you a product. I've owned and played on both types of pianos. In this page, I will give an unbiased comparison based on my personal experience. No doubt some people, unaccustomed to criticism of their beloved pianos, will take issue with some of the opinions expressed here. But that is unavoidable, because there are benefits and drawbacks to either choice.

First some definitions. By “digital“ I mean 88-key digital pianos with weighted keys costing $500 or more. By “acoustic” I mean Japanese, American, or European acoustic pianos, mainly grands but also uprights.

Technology

One of the key advantages of digitals over acoustics is technology. There's no way to beat around the bush: digitals blow away acoustics in terms of technology. Acoustic pianos are basically 19th-century devices, with wooden levers and mechanical brakes, held together by an old-fashioned type of glue that, these days, is only used in pianos--what might be called “covered wagon” technology. If you tried to buy a covered wagon today, you'd find it's tough, because the technology has passed them by. So it is with acoustic pianos. And because they're mostly hand-made as a result of it, acoustics are more expensive than they'd otherwise be.

Their longstanding failure to innovate means the acoustic piano industry is in a state of deep decline these days. A few years ago, Steinway tried a baby step by replacing cloth bushings with Teflon. It was a disaster, and the owners of those pianos faced the expense of having the bushings replaced. Kawai is probably the most innovative manufacturer at the moment, with their carbon fiber parts. But again, these are only baby steps. You won't see electronic actuators or play-by-wire systems on an acoustic piano anytime soon.

Most digitals use computers, integrated circuits, and speakers to replicate sounds that were originally recorded from a perfectly-tuned, high-end acoustic in an anechoic chamber. Recently, some manufacturers have experimented with blending these sounds with synthetic waveforms generated by sophisticated algorithms that model the acoustic interactions in an acoustic piano. By tweaking a parameter, some digitals can change the “strings” from steel to silver, creating sounds impossible to achieve in the real world. You can expect that this modeling will improve as time goes on. Other digitals have a sonar-like feature that identifies the acoustical parameters of the room and tailors the sound accordingly. Of course, for this to work, you have to use the built-in speakers.

Unfortunately, the speakers on some digital pianos frankly sound like carp. You can hear this for yourself by pressing the lowest key. On some digitals, all you will hear is the harmonics. It's rare to find a digital with speakers that can reproduce the 27.5 Hz fundamental frequency of A0 in its correct amplitude. They sound even worse in “Church Organ” mode. What should be a window-rattling vibration comes out as little more than a low hum.

From an engineering standpoint, though, the circuit boards inside a digital are generally very well made. They're designed not to shake loose from vibration. I've owned several digitals over the years and never had a problem with the electronics. Typically, the audio amplifier sections are very high quality: noise is generally at least 90 decibels below the signal, so you can play very quiet passages without being subjected to electronic hiss. That can change, however, if you add an auxiliary device such as an effects processor.

The same cannot be said for an acoustic. When the humidity changes, owners of acoustics consider themselves lucky if the only thing that happens is that it goes out of tune. Sometimes, the keys begin to seize up. If you're somewhere where it's really humid, your strings will eventually rust. You have to maintain strict control of the humidity level in your house to prevent these problems.

On the other hand, you can still play an acoustic during a power failure. And the acoustic looks nicer, especially on the inside. These may be small advantages, but at least there's something.

Auxiliary sound processors

Because digitals can't reproduce the complex acoustic phenomena produced by vibrations bouncing around inside an acoustic piano, many users add effects processors and equalizers. However, unless you like listening to hiss, it's essential to use one that's designed for low noise. A bad audio equalizer will amplify the small amount of noise produced by the piano's amplifier and add its own noise to the mix.

Engineers evaluate noise by taking the ratio of signal, measured in decibels (dB), to noise, giving what's called the S/N ratio. Because amplifiers act as multipliers, and decibels are logarithms, S/N ratios can be added to each other. Suppose your equalizer has a S/N ratio of 60 decibels. This means that for every 85 dB of sound, you're getting 25 dB of added noise. If you amplify the signal by 15 dB at, say, 10 kHz, that means the piano's hiss is now at 40 dB, which is loud enough to be objectionable. So an equalizer with an S/N ratio of at least 90 decibels is essential. There are many manufacturers of equalizers that exceed this range. I happen to be a big fan of Behringer. Even though some audio purists dislike Behringer, their products are affordable and, usually, work satisfactorily. Behringer's Ultracurve Pro DEQ2496 has a remarkable 113 dB S/N ratio, and is highly recommended.

Effects processors can do more than emphasize various frequencies. They use Fourier transforms and digital technology to add reverb, adjust the stereo separation and dynamic range, and many other parameters. An equalizer can improve the sound by brightening or damping certain frequencies to compensate for room acoustics. An effects processor does much more. Their most important function for digital pianos is to replace the crude reverberation effect found in the piano. With a good reverb effect, the sound doesn't just get fainter over time. It becomes progressively more spread out in pitch as it decays, similar to what happens in a real architectural space. Modern effects processors are adjustable, so you can make it sound like you're playing in anything from Gothic cathedral to a closet. Two inexpensive reverb units are Behringer's DSP2024P and V-Verb REV2496. The units have a good S/N ratio, but this vendor is known for quality control problems. I've owned one of each, and both have broken down well within the warranty period. (The vendor replaced one under warranty, and the other one, which was rebooting itself continuously, just had a transistor that needed a bigger heat sink.) Of the two units, the DSP2024P has a slightly better reverb than the V-Verb, but its user interface is a little clumsier. Other vendors include Lexicon, TC, and Alesis.

Prices

Another point where digitals have an obvious advantage over acoustics is in price. There's much more to consider than the initial purchase price. Because acoustic pianos can weigh up to 1000 pounds, and are easily damaged, it can cost thousands of dollars to have one moved. You have to hire a special mover who has experience in moving pianos. People who move across the country generally find it's cheaper to sell or discard their piano and buy a new one. That's why you sometimes find perfectly good pianos out in the woods rotting away, where only the squirrels can play them (needless to say, they stink at it).

Another problem, of course, is that acoustics need constant tuning and frequent maintenance. A typical piano needs tuning, which costs about $100, twice a year. Maintenance can cost from $50 to $50,000, depending on what's needed. And that's a problem when you buy a used acoustic. It's very possible that the reason it's for sale is that it would cost more than the piano's worth to make it play well. These problems don't exist with digital pianos. They are ones and zeros. They either work, or they don't and you throw them away, or you repair them if you're skilled at electronics.

As for the initial purchase price, you have an additional problem with piano dealers. Dealers in piano stores always inflate the prices of digitals and acoustics by 30-40%. True story: I came across a beautiful new piano with a sign on it saying "$32,000." Even though logically I knew they would probably knock the price down to below 20K, it didn't matter. In those first few seconds, I had mentally written off the piano as overpriced. The fact that negotiating with salesmen is unpleasant hard work just gave me another excuse to run away. That piano is still sitting there in the showroom.

Dealers must know their high prices frighten off customers. So why do they do it? The purpose is twofold: first, to maximize their profits by soaking the naïve customers who don't realize they have to negotiate, and second, to make it difficult for customers to do price shopping. Sometimes they're also forced to do it by the manufacturer. Many dealers have nothing but contempt for the class of customer who buys a piano purely for decorative purposes. Unfortunately, they probably lose more by preventing ordinary customers from budgeting than they gain by soaking the rich.

Tone quality

So by now, I'd better say something nice about acoustics before somebody puts a horse's head on my bed.

There's no question that an acoustic, when it's in tune, sounds much nicer than a digital. However, this is only true for the first couple of months after it's been tuned. An acoustic must be tuned regularly, or it will deteriorate drastically in value. Another factor is that acoustics get brighter over time as the hammers harden. You might not even notice it. But if your dog starts howling every time you play Clair de Lune, it's probably not because he's singing along with you. You can buy special acoustic blankets and throw them over top, but they muffle the sound. Having the hammers voiced down also works, but it costs a fair amount of money and invariably damages the hammers. Nonetheless, despite these problems, no digital can match the beauty and dignity of sound that you can get from a well-tuned acoustic. Piano experts always say an acoustic sounds more “alive” because of its acoustic presence. In comparison, a digital can sound like an expensive toy.

That said, there's some stuff some folks out there in the Internet don't realize about digitals. Any half-decent digital has two essential features that are shared with acoustics: first, the tone gets louder and brighter when you press harder; and second, the damper pedal has continuous range, allowing half-pedaling. Unlike an acoustic, the dampers in a digital are always perfect. But digitals can't produce all the acoustic nuances of an acoustic. The sound of your dishes rattling and the dog howling in pain just can't be duplicated electronically. And there's nothing like the sound of your neighbors screaming in frustration when you start practicing Bach's Prelude I in C Major for the 11,000th time.

Speaking of pain, acoustics are designed to be loud. A grand piano with the top raised can produce sounds well above 90 or 100 decibels. These are levels that can permanently damage your hearing. Much of this energy is in the 2-5 kHz region, where the human ear is most sensitive, and many pianists and piano tuners have unknowingly experienced noise-induced hearing loss because of it. Hearing loss causes the piano to sound muffled, so they brighten it up even more to compensate. I came to dread going to piano stores, because the deaf-as-a-post salesmen always played so loudly it literally caused me physical pain. It didn't help that in one store, located in an old warehouse in Columbia, Maryland right off the Interstate, the salesman had to play even louder to compete with their super-powerful MegaBlast 2000 Plus HVAC system. I didn't run screaming from the store, but I definitely considered it.

Because an acoustic is so loud, this rules it out if you're in a townhouse or apartment. It's not worth the aggravation of annoying your neighbors. You'll find yourself constantly patching up bullet holes in your drywall and fishing little pieces of lead out of the fish tank. With a digital, you can use headphones, which if you're in a city have the additional advantage of drowning out the continuous wailing of the fire engines, the police cars, and the neighbors' rock music.

Most digitals also can produce other sounds besides pianos, including church organs, flutes, harpsichords, trumpets, sine waves, thunder, and barking dogs. These extra sounds are generally gimmicks, but can be a refreshing change while you're learning, and kids seem to enjoy them. If it's loud noise you want, you can hook your digital to your stereo system and blast out Toccata and Fugue in D Minor in Church Organ mode all night until the cops come and haul you away.

Touch

Although touch in digitals is improving, the touch in digitals still lags behind the touch in acoustics. The keys on digitals, especially cheap ones, feel springy, and they lack the subtle changes in resistance during the keystroke found in acoustics caused by the double escapement mechanism. On a digital, the springiness and the light weight of the keys means that pianists can't make the same physical connection with the piano as they can with the more massive but well-balanced keys of an acoustic, which provide varying pressure feedback throughout the keystroke. This is very important in achieving the ability to play expressively. On an acoustic, for instance, you can get a totally different sound depending on exactly how you press the key. A gentle keypress creates a more bell-like tone. Hit the key hard, and it sounds more stringy, with more harmonics. Although digitals try to emulate that effect, on a digital all that really matters is the downward force.

These differences can create big problems if you learn to play on a digital, and then try to play on an acoustic. You will find an acoustic is absolutely dependent on velocity: press the key too slowly, and it will not only not sound, but the hammer will grind against the jack and repetition lever, making a lot of friction--an unpleasant sensation that can stop your playing in its tracks.

The inability to create subtle nuances of sound on a digital is one reason many piano teachers refuse to take students who don't have an acoustic. If you're buying a piano for your kids, check with your local piano teachers first to find out their policy.

Another advantage unique to an acoustic grand is the repetition lever, which allows you to play repeated notes very fast. Some advanced pieces of music require you to play ten or even fifteen repetitions of the same note per second. This simply isn't possible on digitals or on vertical pianos. These pieces can only be played on an acoustic grand piano. If you try to play them on a digital or an upright, they sound horrible.

On the other hand, the velocity threshold below which no sound is produced is always exactly the same on a digital, and some digitals allow you to change the threshold, allowing for a “lighter” or “heavier” touch. On an acoustic, the threshold varies from instrument to instrument (and sometimes from note to note). As a piano ages, the threshold tends to increase. This makes it harder and harder to play pianissimo, because a slight reduction in velocity will create a “ghost” note.

Piano technicians

If your piano becomes hard to play, or a key begins to stick, or a string breaks, you need to call a piano technician. Repairing a digital is a simple matter of finding an electronic repair shop and dragging the piano in. Or you can fix it yourself, and nobody will complain.

Acoustics are another matter. While the majority of piano technicians are decent folks and generally helpful, there are some, especially on the Internet, who go ballistic whenever they hear about a piano owner trying to repair their piano. That's because they think it threatens their livelihood. Take a simple task like re-centering a hammer flange pin. Any piano owner who's mechanically inclined can learn to do this safely in a few minutes. You can change all 88 in a few hours. A piano technician will take three weeks and charge $1000--if you can get them to do the work.

If you can't--for instance, if your piano's not a Steinway, or if they're just too busy--good luck finding the procedure on the Internet for doing it properly yourself. The “red mist” descends on those self-proclaimed Internet piano experts if piano owners ask in a discussion forum how to do something themselves, or if somebody posts the procedure in a Web page. So if your piano breaks and there aren't any good techs in your area, you either have to guess how to fix it or leave it broken. It's an important consideration in selecting which type of piano to buy.

Finding a piano tuner is usually not a problem unless you're in a rural area. But finding a tech who's willing to work on your piano can be very difficult. A good rule of thumb is that you'll have trouble if there are fewer than 3 or 4 members of the Piano Technician's Guild within easy driving distance.

Many parts suppliers are also intimidated by those nasty Internet techs and will refuse to sell to anyone who's not a technician. So even if you want to fix it yourself, you have to lie to get the tools and parts.

Pianos as investments

Neither digitals nor acoustics are any good as an investment. Not even a Steinway. Pianos are not like furniture: an antique piano is rarely worth the cost of moving it, regardless of how nice the cabinet is. Over time, the action wears out unevenly, the strings get dirty and corroded, sandwiches get stuck inside it, and it becomes harder and harder to play well. I've seen old Steinways in stores that are among the worst pianos imaginable. The action was so heavy, it was like playing a tank. But people would buy them for their status value. Those expensive used Steinways you see in stores have been laboriously and lovingly restored. Even then, their value is always less than a new one. Whether you buy a digital or an acoustic, it should be because you will use it, not because you expect it to make you rich. And consider this: if you pay $5,000 for a piano and play it two hours a day for ten years, it's only 68 cents an hour. That's what I call cheap torture. I mean entertainment.