Harmonica/Ensemble Playing

Simple notes of performing
Let's just state this: depending on the situation, the harmonica player is either the most important thing in the ensemble, or a sound effects engineer that no one cares about.

That being said, there are a few other things to make note of:
 * If the audience suddenly gets an uncomfortable, pained look, it is possible that you've just played a "significant" wrong note. Since what's done is done, just focus on continuing. There are two solutions:
 * Play the rest correctly.
 * Next time around, play it wrong again, but adjust the sound such that it will mesh well and louder. The audience will think it's just an innovative improvising.
 * Do not drink alcohol; in fact, drink lots of water.
 * No, I am not a teetotaler, but I found that my mouth gets really dry if I start drinking, which is very bad in terms of harp playing. If you can live with whatever tone you produce with your dry mouth, that's fine, but for optimal performance, keep your mouth wet, by drinking water (or chinese tea, which works just as well). After the gig is done (or you know you will not do any more harmonica parts) drink beer by all means (but be responsible!).
 * On the other hand, some people dislike having so much saliva clogging the reeds.

General Rules of Playing with Others
One of the greatest problems for the harmonicist, especially with blue harp players, is that they quite often "step on toes" of other musicians. While with a few other musicians it amounts to nothing more than a contempt for harp, 90% of the time it is true: Since some of the blues harpists have not learnt music theory, and thus, are unable to communicate with other musicians well. Also, since most blues harp players only know the 12-bar blues, if the playing slightly deviates from 12-bar, blues harp players are usually lost, even if they are told of the chord. Lastly, they are only able to solo, and thus, cannot accompany others well.

As an old Zen koan stated, "No more tea can go in a full cup unless you empty it; no one can show you zen until you empty your past thoughts." This is true here: to be able to play harp well with others, you must be willing to accept that not everyone can accept harmonica, and not everyone is willing to accept blues—-this means, don't be a whiner stating "Well, they can play what they want; I will play my style." it is exactly this attitude that encourages harp players to step on others, and also made others feel that te harmonica is a toy. The key point of playing in a group is to work together, such that the overall music delivered is beautiful. One will have to make compromises somewhere down the road.

Now that we are ready for a new cup of tea, let's begin with an analysis of a music group's composition. No matter what kind of music it is, be it baroque or rock, musical groups typically have two sections: the rhythm section, and the melody section. The melody section can be compared to a line sketch of a drawing: they are the parts that clearly outline the song, though by itself, it's usually "bland". This is where the rhythm section comes in: to make it sound more colorful, just like a paint brush that makes the picture beautiful.

Harmonica can fill both jobs, depending on the situation. However, in most typical situations, especially for the blues harp, harmonica is to be played more as an accompaniment. Even for chromatic, sometimes its job would be closer to either the second violin or the viola. Until people can actually see that the harmonica has great potentials, we have to follow these guidelines, by supporting them. It's not how much you play, but how you play.

Aside from playing the actual notes for accompaniment (aka: playing the appropriate chords with soloing), another great way to ensure one does not overstep other musicians is to play loudly but softly. Sounds like an oxymoron, but easy to do: all it takes is cupping the hands appropriately, and breath properly. If you are using the mike, it's even easier, as you can adjust the volume.

For details as to how to play for certain style, see Music Style

Duet
Simply put, duet is either a performance with two harmonica players, or a harmonica accompanied by another instrument, usually piano. However, unlike other ensemble playing, in duets, both instruments are equally important; more appropriately, they are both leads, and thus when performed properly, there should not be one that plays solo (playing the melody) while the other play accompaniment (chords only or rhythm only). In most case, the most common harmonica used is chromatics, while diatonics or tremolos may be used (and again, depend on where one located; it's rare for diatonic duets in East Asia, while it's equally rare for tremolo in North America).

Trios, quartet, and Quintet
The trio is one of the most common harmonica ensembles, having been popularized by the Harmonicats and the Adler trio. Like many music groups composed of three members, each member of the trio is responsible for a "dimension" of the music: melody, the horizontal movement of the music; harmony, the vertical dimension of the music, that makes the music much richer than melody alone; and rhythm, the timing of the piece. Thus, usually, there are these three categories of harmonicas: Of course, some may prefer to play in the style of duet. In that case, most will use the chromatic harmonica. This is especially common in recent years, with orchestral harmonicas more rare and expensive and decreasing numbers of harmonica players, making traditional trios more difficult.
 * Chromatic harmonica: responsible for melody in the trio. Sometimes, however, additional chromatics are responsible for playing additional notes or harmonics.
 * Chord harmonica: Used to play chords and rhythm. However, due to the rarity of the chord harmonica, some may instead use appropriate diatonics, tremolos, or octave harmonicas for such tasks.
 * Bass harmonica: Used to enhance the rhythm and the contour of the music, and thus make the music even richer. Again, due to the rarity of this instrument in North America, sometimes the trio may use harmonicas that are tuned close to bass octaves (low-octave harmonicas, for example).

Small Ensemble
Usually defined to have six to fifteen players, and usually play chamber musics in small ensemble competitions. However, such rigid definition actually made small ensembles quite difficult to play. First and foremost, most "small ensemble" pieces are chamber music, which is designed for quintet at most, and even when stretched to include more people, the music pieces are usually for nine people. Thus, it's quite often to have the additional players to play same parts as others, and thus decrease the closeness and coordination inherited in chamber music. Additionally, due to the limited category and ability of harmonicas, sme particular parts of the music may be enhenced so much that it decreased the other parts, affecting the overall result of the music. Sometimes, small ensembles may even accept non-harmonicas: usually they are not responsible for the main melody, but for some other purpose. In any case, the question of whether the group is a small ensemble depends not on the instrument departments, but the number of players within. Like Trio performance, the most optimal small ensemble playing would utilize an appropriate amount of chromatics, chords, and basses, but in nowadays it's common to just have everyone play chromatics. Diatonics is rare, while East Asian tremolos are used sometime for the unique tonal quality.

Large ensemble (Orchestra)
Due to the large number of players available, almost all kinds of harmonicas can be used, depend on the piece. In general, the harmonicas to be used are chromatics, chord, bass, and horns; however, when used to designate the appropriate parts for the pieces, they used the tonal range of the music and instrument instead: soprano, alto, tenor, and bass. In Asian ensembles, they would use the appropriate horn harmonica for such purpose. Of course, like many ensemble playing, there are usually other instruments involved, such as percussions, in order to enhance a certain aspect of the piece. All these aspect ultimately fall upon not on the performer, but the arranger who modified a certain piece in order to be more suited for harmonica assembles. Still, playing in a harmonica ensemble help introduce amateurs into the world of ensemble playing, and enhance the community sense among the players.