Here are some subjects that come up when listening to and playing duo piano music. Also included are short pieces of background information that can be helpful in a variety of listening situations.

One great musical advantage that pianists (as well as organists and other keyboardists) have is the ability to produce music with several simultaneous voices (or tones) over a very wide range of pitches. The possibilities are doubled with two pianists performing on two pianos.

Of course there are passages in music for two pianos where only one person is playing or where both players are playing sparsely. Generally, though, music for two pianos can at times be described as "dense" or "thick" when compared to solo piano music.

Some of the more interesting and subtle passages in duo piano music occur when the music requires just a little more than a solo pianist could produce alone. It is in passages - or even complete pieces - such as these that a listener might not be able to detect the presence of a second pianist. The same listener, though, would notice the absence of the second part after becoming familiar with the piece.

Both members of a duo piano team need to listen not so much as two soloists, but as equal members of an orchestra divided into two halves. A solo pianist has to carefully control the balance between melodic and background sound. In addition to this, duo pianists must match the sounds of their solo piano with those of their partner. In contrast to the advantage of being able to have twice as many voices, the acoustic balance between the two pianos is one of the primary musical challenges a duo piano team faces.

Greater dynamic range

In addition to the potential for more voices, two pianos can produce a greater range of dynamics. The loudest sounds that two pianos can produce together might be the most obvious, but there are other dynamic combinations that occur very differently than those on one piano.

A solo pianist must at times work very hard to get the melody to be heard during loud passages. In direct contrast, there are many examples in two-piano music where the composer reinforces the melody by having both pianists play it. Another compositional technique is to have one pianist play the melody in two or more registers of the piano simultaneously while the other pianist plays the (sometimes very loud!) background parts. In both of these examples the duo piano team usually does not have to work nearly as hard as the solo pianist to create a balanced and "singing" tone.

Another important dynamic that both solo and duo pianists share is silence. Silent passages - including the pauses between multi-movement works - are very important to all musical works. Our ears compare all musical sounds (that the composer may have written in the score as "notes") to what we perceive as silence. There is as much music in the silent parts as there is when there is sound in the air! Some of the most dramatic moments in music occur when there is a sudden silence after a very loud passage. Compare the loud sections in solo piano music to loud sections in two-piano music (and also to orchestral and amplified music). Is there a difference in the "silence" that follows?

The ideal concert setting for a duo piano team is two perfectly matched, recently tuned concert grand pianos in a beautiful, resonant hall. Unfortunately this is not always the case. Frequently there are small (or great) differences between the two pianos and / or their tunings. Here are some differences that occur and how they might affect a two-piano performance.

• Size of pianos

Pianos come in many shapes and sizes, from the tiny "spinet" and common "upright" models to "concert grands" that are nine feet or more in length. The greater the difference in size between the two pianos, the harder a duo must work to balance each other’s sound. In some cases it is very easy for the player of the larger piano to almost completely obscure the sound of the other player. A sensitive duo will work this problem out so that the larger piano is more muted and the smaller piano is more easily heard.

One performance practice is to position the piano lids in ways that help to balance the sound. The following is a brief (and important) discussion on lid positions:

1. Completely off: It is possible to remove the lid of a piano. It is common to do this on at least one of the two pianos. A piano with its lid off produces a brighter tone than one with its lid on.

2. "High stick":

The tone of a piano with the lid in this position is only slightly darker than one with its lid off. This position also serves to reflect the sound toward the audience.

3. "Short stick":

The tone of a piano with the lid in this position is darker and more quiet than when at the other two positions.

4. "Baby stick": The tone of a piano with the lid in this position is darker and more quiet than when at the other three positions.

5. Mostly closed: This position is both darker and quieter than any of the above positions. A portion of the lid is open to allow use of the music desk.

6. Completely closed: This is the darkest and most quiet of all lid positions. Both sections of the lid are completely closed.

Positions 3, 4, and 5 are common when the piano is used with solo voice, flute, violin or other instruments. These lid positions are also common to a variety of other chamber settings (i.e: piano and string quartet, or piano and two solo instruments). Position 2 is preferred for jazz settings when drums are used.

Other acoustic balancing techniques include:

• A blanket can be placed inside the louder piano over the strings (without touching them). A device called a "string cover" is very effective when available and appropriate.

• The stronger player can play the quieter piano and vice versa.

• Balance can be adjusted electronically when amplification is used. Amplification is frequently employed in rock and jazz performance situations. This makes it possible to get a fairly accurate balance between two pianos that may or may not be very different from each other. Of course, as the desired artistic effects are vastly different between acoustic and amplified concerts, so is the quality of sound. In many amplified performances acoustic pianos may not be used at all in favor of electronic instruments.

• The quieter instrument can be placed in front.

Since the positioning of the two pianos can greatly affect the sound this is a good point to mention the basic concert configurations of the two pianos. There are two common ways to position the two pianos on stage.

1. The "butterfly" position:

Advantages to this position include equal visibility of the duo to the audience as well as greater eye contact for the performers.

2. The "parallel" position:

In this position it is easier for the duo to see each other’s keyboard. It is also possible in this position to face both keyboards (and, unfortunately the backs of the pianists) towards the audience.

Acoustically, there are both advantages and disadvantages to both positions. It usually becomes a matter of personal taste on the part of the performers as to how the pianos are situated on stage.

Generally, the larger the piano, the greater the sound. There are, however, great differences in how pianos are constructed, materials used, and other factors that might produce an imbalance in favor of the smaller piano. Since each concert situation is different, a well prepared duo will compare the sound of the two pianos and decide upon their positioning and lid placements after careful consideration.

• Tone: The "colors" of music

Another aspect that pianists must consider is tone. It is important to take note at this point that the "volume" or "dynamic level" (how loud the music is at any point) is distinctly different than "tone" or "timbre" (the qualities of the sound other than the volume).

Just as every person has a unique voice, different pianos have different and unique "tonal qualities." And, as differences in loudness can affect the balance between the two pianos, so can differences in tone. You may ask "What exactly is "tone?" To vividly demonstrate differences in tone, try the following exercises

Listening exercise #1

On a grand piano, hit a few keys (or play a piece of music) and listen to the quality of the sound. Describe the actual sound of the piano - not necessarily how the music makes you feel or whether you are playing loudly or softly. What characteristics do these sounds have? Could you describe the sound of this piano as "rich," "thin," "bright," or "dark?" Can you find better words to describe the sound of this piano?

When you are ready, depress the far left pedal on the piano. This is called the "una corde" or "soft" pedal. Play the same series of keys (or the same piece of music). Compare the sound you are making to the previous series of sounds. If nothing is wrong with the piano you are playing, your use of the soft pedal will create a noticeable change in "tone." The tone of the piano without the soft pedal can be described as "brighter" or "more open" than when you are depressing the soft pedal. You may also notice that the volume level decreases a little - or maybe a lot - when the soft pedal is used.

Listening exercise #2

Go to a music store. Ask a representative to show you different guitars, pianos, percussion, wind and / or stringed instruments. Ask the salesperson to show you the differences in tone - and volume - between different instrument sizes and models.

As they will want you (sooner or later!) to purchase one of their products, they should be only too happy to oblige your questions. Be sure to ask one of their favorite questions: "What acoustic advantages would I get if I bought the more expensive model." Expect a smile.

Listening exercise #3

Get together with a two or more friends who play different musical instruments, i.e: flute, clarinet, violin, oboe, piano, etc. Ask each person separately to play "concert middle C" at a "mezzo piano" dynamic for five seconds. (If you and your musical friends are not sure of this direction ask your local band teacher!)

Compare the sounds of the different instruments to each other. Notice that the shapes, materials used, and sizes of the different instruments - as well as how they produce sound - determine the "tone" of each instrument.

Now try combinations of two, three or more instruments. Notice how the tone - or "timbre" - becomes "fuller" or "richer." Be sure not to confuse this acoustic quality with "louder." (Unless, perhaps, you and your friends actually start playing louder!)

Just as pianists can compensate for volume differences, they can also make musical adjustments that affect the tonal balance. Careful use of the soft pedal, for instance, can create very beautiful effects that "color" the sound of the piano. Pianists can also affect the tone through use of the damper pedal (the right pedal) and various finger techniques. When possible, compare performances of the same piece by different pianists. Notice not only for differences in speeds and dynamics, but in different "tonal approaches."

Compare, for example, (from Whipple’s "Elemental Portraits") the openings of "Katie: The Nightingale" to "Randy: Neon Rain." While both pieces have a wide dynamic range, the tonal qualities are very different from each other. "Katie: The Nightingale" might be descibed as having "a soft tone," while "Randy: Neon Rain" could be said to have a "brash," "edgy," or "aggressive" tone.

One obstacle in concert and in the recording studio that can be challenging to a duo piano team is when the two pianos have very different tonal qualities. Besides having to compensate for differences in the size of the pianos (which affect the dynamics,) the pianists must try to match each other in tonal quality. Here again, as with dynamic considerations, careful placement of the two pianos on stage and attention to lid positions can greatly help the tonal balance.

Also, it is possible to achieve a workable balance with two relatively unmatched pianos in a recording situation and / or amplified concert. Since the main sound that the audience will hear will not be primarily from the pianos themselves, but from electronically amplified speakers or headphones, the basic acoustic qualities of the pianos are sacrificed. The trade-off, however, is that the tone and dynamics of two pianos can be very well matched if the two pianists and the sound engineer are all listening carefully.

• Tuning:

One thing that pianists do not have to deal with from moment to moment in concert is intonation, or the "tuning" of the piano(s). Singers and players of wind and stringed instruments must constantly deal with this particular musical problem. There are, however, tuning considerations that pianists - and especially duo pianists - must all face.

The easiest (and most common) thing for pianists to do before a concert is to call a piano tuner who will deal with the issue. For soloists, this is not a very big consideration. Duo pianists, however, have a few more things to work out.

First of all, let’s picture the ideal duo piano setting, i.e. two nine foot concert grands - same year, same size, same model, and same voicing standard (which plays a big part in determining the tone of the piano). The piano technician arrives in time to have the two pianos tuned together just before the concert. The two pianos are "spot checked" at the intermission, and, since this is our ideal setting, the tuner stays through the concert just in case there is even the most minor of problems. Dream on! Now, for your entertainment, is (unfortunately) a scenario which is all too common.

• A (not completely) true story...

The store that had promised to deliver the two matched 7’4" pianos (on loan from the local university) discovered - on the day before the concert - that their moving crew was only insured to move pianos less than seven feet long. So, besides having to call the gracious administrator at the university (who was hammered for five months about the use of these beautiful instruments!) and cancel this move, the hunt is now on for two other (hopefully) matched grand pianos less than seven feet in length.

The music store has a thirty-five year old 5’8" Horugel grand that they are willing to move at no extra rental charge. After calling every piano teacher on the local Music Teacher Association list, Dr. Byrd agrees to let the duo use her 6’5" Yamaha grand in their concert. The duo breathes a brief sigh of relief, but is not looking forward to the challenge awaiting the piano technician.

Three hours before the concert, the two pianos arrive at the hall. The piano tuner, who got stuck in traffic, arrives an hour and a half before the show. Unfortunately, he usually requires two hours to tune two pianos together for this kind of event. An initial inspection of the two instruments reveals two insidious problems: first, the two pianos are "scaled differently" and, most depressingly, the older Horugel, which has not received much attention over the years is almost a quarter step flatter than the newer Yamaha. Decisions now need to be made.

After coming very close to tears, the two pianists decide not to cancel the concert. They further agree with the music store to pay for any broken strings on the Horugel, since it will have to be raised an eighth of a step. Since later her piano will have to be raised back to pitch (by an eighth of a step) at her home, another agreement is made with Dr. Byrd to pay for (probably) two more tunings after the concert.

The larger and brighter Yamaha is placed in the rear of the "parallel" position, away from the audience with the lid mostly closed. The pianist with the smaller hands (and quieter sound) will play this instrument. The smaller and darker Horugel is placed in front with the lid propped up on the high stick so as to help obscure the sound of the louder Yamaha. The pianist with the larger hands (and bigger sound) will play this instrument.

The piano tuner cannot stay for the concert, so he agrees to loan his tuning hammer to the pianists. (One of them has basic piano tuning skills and will fix "problem notes" at the intermission of the concert.) While one pianist is talking with the piano tuner the other is shutting off the noisy air conditioner.

The concert begins. The pianists give detailed thanks to the impromptu piano providers, thereby alerting the audience to the acoustic challenges that will be faced. The concert begins, and, midway through the first movement of Mozart’s "Sonata in D Major" the pianists notice that the "A" above middle "C" is horribly out of tune on both pianos. Since this is a very exposed note in this piece, the two pianists spontaneously discover extraordinary ways of not playing their two middle "A’s" at the same time. The tuning of both pianos slightly shift during the concert.

At intermission, the pianists decide to substitute Milhaud’s "Scaramouche" for the planned "Rondo in C Major" by Chopin. The duo decides that the sliding tonalities between the two pianos would be more friendly to Milhaud than Chopin in this case. The pianist / novice tuner heads out and fixes as many out-of-tune strings as possible. After a five minute break and costume change, the duo plays the second half of the concert.

In addition to not receiving much recent attention from players or tuners, the old Horugel’s pedal mechanism was in need of repair. The whole pedal action falls off at the beginning of "Brasiliera," the last movement of "Scaramouche." It makes a horrendous clunking noise that can be heard throughout the hall. It’s a good thing that this is the last piece! After a good laugh with the audience, the duo decides to perform an encore together at one piano before leaving the stage and passing out!

Believe it or not, while most concerts go far better than the above example, turns of events like this have actually happened to performers - including the authors of this study guide. This example serves to point out - although using a most extreme example - that differences in piano tunings must also be taken into account by a duo piano team. The following are brief descriptions of important tuning factors mentioned above.

• Scaling

Even when two pianos are matched in size and tone they might be "scaled" differently. This means that they sound "in tune" when played separately, but there are differences, either subtle or very apparent, in their tunings when played together. This is a problem that occurs especially when using pianos of two different brands (i.e. Schimmel and Yamaha) or when the two pianos have been tuned separately - and, especially, by different tuners with, perhaps, different tuning styles.

The "equal tempered system of tuning" is a standard that has been generally accepted worldwide. For the faithful, there are quite a few books and papers that intimately explore the subject of tuning. We suggest the following to name a few: Harmonic Experience by W.A. Mathieu (published by Inner Traditions International), Tuning: The Perfection of Eighteenth-Century Temperament, The Lost Art of Nineteenth Century Temperament, and the Science of Equal Temperament by Owen Jorgensen (published by Michigan State University Press), and The Just Intonation Primer by David B. Doty (available by contacting the Just Intonation Network, 535 Stevenson Street, San Francisco, CA, 94103).

For various reasons of musical effect and taste, pianists, tuners and piano makers can make decisions to alter the standard tuning of any given piano. While the pursuit of knowledge is a good thing, it is not always necessary for listeners to know much detail in matters of tuning. A studious and vigilant listener will, however, come to recognize differences in tunings, tone and volume between pianos. These noticeable differences will enhance the overall listening experience.

Most duos prefer a matched and like-tuned pair of pianos. It is easier to interpret the music when there are fewer differences between the two pianos. There are, however, special situations when "mismatched" pianos may be preferred. A notable example is when two pianists play arrangements of concertoes for piano and orchestra. One pianist will play an arrangement of the orchestra part (usually on the quieter piano) while the other plays the solo part on the louder instrument.

One advantage to "mismatched" pianos is that the listener can more easily isolate and understand the separate parts of the individual performers. While this can useful for analyzing pieces and performers, (and except in cases of pieces written specifically for pianos with differences in size, tone or tuning) most would agree that the more differences that exist between the two pianos, the harder it is relax and fully enjoy the music in its purest form.

In the last two decades of the eighteenth century, two forms of orchestral composition came into prominence: the "concerto" and "concerto grosso" forms. Concertoes are written for a solo instrument accompanied by an orchestra, while a concerto grosso (or "grand concerto") consists of a small group of instrumentalists set against a larger orchestra. In both cases the soloist in the concerto and the featured group of instrumentalists in the concerto grosso play during long sections with the orchestra in the background. Conversely, there are sections where the soloist(s) must wait while the orchestra takes the lead.

In contrast to these above forms, the roles of soloist and accompanist in music for two pianos are passed back and forth between the two players. In other instances the two pianists must create a blend of sound that can be said to approximate that of an orchestra. The attention as to which player (or neither or both) has the lead can take on a "conversational" quality. This aspect of duo piano music, which is not as inherent to solo piano music, can be enhanced by the stereo effect between the two pianos and can be referred to as "question and answer" or "echo."

With four hands on one or two pianos there is also frequently greater rhythmic complexity. This can add to the impression of having "more people in the musical conversation." A famous example of this from the classical two piano literature is "Variations on a Theme of Haydn," (Op. 56b) by Brahms. Two selections from the modern two-piano repertoire that exemplify different blends of rhythmic sophistication are "Wedding Dance," (movement three from "Wedding Music") by W. A. Mathieu and "Helen: Tanzania Dresságe" (from "Elemental Portraits") by Kirk Whipple.

Music that is very "connected" or "legato" can be said to have a very "smoothe texture." In contrast, music that is "disconnected" or "staccato" can be descibed as being "rough" in "texture." While these descriptions are only coarse approximations of musical phrasing, they can serve to shed light on another aspect of duo pianism.

Often in two-piano pieces the players must perform in similar styles, i.e: both legato or both staccato. One musical advantage with two pianos (and, to a lesser degree with one piano/four hands) is the rich pallet of textures where there is a diverse mixture of legato and staccato sounds. Solo pianists can also achieve this, but not with the broad range of effects available to duo pianists.

A classical example is Chopin’s "Rondo in C Major" for two pianos, where there are many rapid textural trades between the two pianists. Whipple’s "Randy: Neon Rain" (from "Elemental Portraits") offers several passages where the two pianists have, at times, very different textural demands. (Also in the Mozart concerto in A Major second movement the piano has long melody notes while the Orchestra has the strings with short notes.)

A particular problem to performing music on two pianos or one piano/four hands is what we call "G-dangs." The life of a musical sound (or tone) can be broken up into four basic parts: (1) Attack time and level, (2) sustain level, (3) decay rate and (4) release time. The "envelope" for a typical piano tone might look like the following diagram:

Notice the (1) quick attack time, (2) decreasing sustain level, (3) long decay rate, and (4) quick release time. Pianists have a good degree of control over the attack level (the starting dynamic of any tone), decay time (the length of time that a tone takes to fade away) and release length (the amount of time it takes for a tone to completely fade out as a key is being released.)

Once a note is struck there is little a pianist can do to increase the sustain level of a tone. This is not nearly as much of a problem, though, for a piano ensemble, as the short attack time of a piano. When a key is struck (or attacked) by the pianist, the tone reaches its full volume very quickly. If two pianists are even slightly out of rhythm with each other the difference between their two attacks can be heard. "g-dang, g-dang, g-dang!..." Too many "g-dangs" can be unsettling to the two pianists - and especially the audience. These inconsistent differences in attacks signal a two piano ensemble that is not very well rehearsed.

In direct comparison, players of bowed string instruments (i.e: violinists) and wind instruments (i.e: oboists) can produce very long attacks. The attacks in slow passages are easier to synchronize for wind and (especially) string ensembles than duo pianists. It can be concluded that there will be very few "G-dangs" in a well rehearsed duo piano performance.

Since capturing a realistic, well-balanced solo piano sound is one of the most daunting of all recording tasks, the problems that an engineer faces in recordings of two-piano music can be even greater. In addition to a great number of decisions that affect the tonal qualities of a recording, choices need to be made as to the quality of the stereo presentation.

In some recordings, the sounds of the two pianos are separated so that they appear to the listener to be coming from two different places. This is called either "hard" or "panned" stereo. Other recordings are produced so that the two pianos sound like they are very close to each other. This method is called "centered" or "true" stereo.

When two pianos are recorded the microphones can be placed so that the sound of the two pianos can be separated. During the "mixing" process the recording engineer can electronically "pan" the individual sound of each piano so that one piano appears to be coming from the left speaker while the other appears to be coming from the right speaker. This kind of stereo presentation is especially noticeable in pieces where the two pianos trade solos with each other. A good example to check is the last movement of Mozart’s Sonata for Two Pianos in D Major, K.V. 448.

The two pianos can be recorded with less separation of sound. Moreover, two pianos that have been recorded with great separation can be "panned" so that their separate sounds are merged into the center of the sound. The two pianos appear to be coming from the same place in the sound, and there is less difference between the speakers when pianists trade solos. A good example of this is "For the Two of Us" from our recording of "Elemental Portraits."

After having tried both stereo versions our personal choice is "true" stereo. We feel that it most closely approximates the way we actually listen to music. We feel that, while the "hard panned" recordings allow the listener a more precise perception of what both pianists are doing, it can be distracting at times. During passages where the two pianists are trading solos the sound can seem to jump back and forth between the two speakers.

This can be especially distracting while listening with headphones as the sound of the two pianos can seem to bounce back and forth between the left and right sides. It can also be somewhat unrealistic as it virtually places the listener almost between the two pianos instead of "in front" of the sound as in "true" stereo.

Listen carefully to a few recordings, and decide for yourself which form of stereo presentation you prefer.

One of the advantages duo piano teams have in performing on only one piano (commonly referred to as a "duet" performance) is the absence of logistical problems that occur two-piano performances. The only imbalances of tuning, volume or tone are those intrinsic to the piano orthose created by the pianists. There are usually less "g-dangs" because the two pianists, being next to each other at the keyboard, have a much easier time hearing rhythms and seeing visual cues. Also, since there is only one set of pedals in use, there are less problems facing the team that have to do with acoustics.

The above notwithstanding, there are limitations and problems with this performance medium. The most recurring technical problem with two pianists at one piano is simply the physical space limitation. Without careful planning it is easy for the two bodies four hands and arms to get into a traffic jam. A small physical mistake made by either player can have immediate and sometimes disastrous results.

Another subtle problem occurs when the composer asks the two pianists to perform passages that conflict with each other. A good example of this is "En Bateau" the first movement of Debussy’s "Petite Suite." There are a few places where the composer asks for smooth, pedalled playing by one player and dry, staccato playing from the other. In this particular case, the two textures are mutually exclusive and the two pianists must decide to play legato, staccato, or to compromise and play "semi-legato" or "semi-staccato." While Debussy was picked on in this example, there is an illustrious list of famous composers that have not completely edited all of the performance problems from their duet pieces.

As concert presenters, most duo piano teams will concur that concerts at one piano are easier to set up and prepare for. As musical artists, however, most would prefer to play concerts at two pianos when the space and instruments are available.