Why does an orchestra have many people playing the same instruments? How does it add to the overall performance?



Why does an orchestra have many people playing the same instruments? How does it add to the overall performance?

In: Other

Because they’re not all playing the same notes. It allowed for multiple movements at a time, producing a more dynamic presentation. Or when they are playing the same notes at the same time, it creates depth.

Usually those instruments won’t be playing the same thing. For example, you might have one set of violins playing the main melody, another set of violins playing a harmony of that, and another set playing a higher/Lower harmony. If the instruments are playing the same part, it’s usually a choice to add more of one particular timbre (the sound of the instrument for lack of a better explanation)

An alternative answer to the others, most of which assume the musicians are playing different parts – when playing the same part, it adds a more layered/textured effect, like a “chorus” pedal for a guitar. When recording guitar, for example, you’d often record multiple tracks of the same part for a fuller sound. Even copying/pasting the same recording but moving one ever so slightly out of sync has the same effect. It makes a huge difference, and without these layers it’d sound quite thin and underwhelming.

You could even compare it to a crowd chanting the same song at a soccer game vs one lonesome chap.


People are missing the obvious. Orchestras predate sound systems. They were the loudest musical event most people in the western world would experience in their life. Several fellow playing the same line is much louder than one and can be heard clearly throughout the venue.

The other aspects are side effects.

Generally, the main reason is that having more instruments playing the same part creates a richer sound, but there are multiple reasons that vary for different instruments.

For example you have three trumpets, and they often play different parts (different melodies that harmonize with each other) but they can also play the same part, then that melody will usually be heard over the rest of the orchestra.

Now, the instrument that there are the most of in an orchestra is the violin. There are usually around 30 violinists. They are usually only divided into two parts (but can be divided further) so you often have 14 instruments on the same part. One of the reasons is as I’ve mentioned richness, but another is that brass instruments like trumpets are so much freaking louder than strings so having more strings creates a more balanced sound.

Edit: typical number of violins.

Edit 2: clarity

You place the horsehair of your bow atop the violin string and pull. The rosin effects a friction that causes the string to vibrate. This vibration resonates through the cavity of the violin to produce a sound quite different than the simple sine wave of the string’s vibration. It makes a sound that is beautiful and pleasant and musical, reflective of the unique characteristics of the violin’s constituent wood and of the exact shape and size of the resonant cavity within.

Ten people place the horsehairs of their bows atop their strings and pull. They are all playing the same note. Their violins are the same size–or are they? They are almost the same size, but not quite; the margin of error in manufacturing is small, but greater than zero. The violins are made of different wood from different trees, each with its own voice. Each performer is pulling their bow at a slightly different speed. Their fingers are all placed expertly on the exact spot they need to be placed on their fingerboards, but as the violin is a fretless instrument, each finger is placed very slightly differently to all the rest, offering a barely discernible difference in pitch.

The pitch and timbre of each individual tone is unique among the rest. Combined, they are far louder than any one of them could be alone; this is vital in eras before (and venues without) electronic sound reinforcement. But this is not all; combined, they offer variegated and living ideas as to the interpretation of the sterile and static sheet music in front of them. Together, they are something different than they could ever be apart. They are the choir to the soloist; they have crowdsourced greatness.

Trumpets are absurdly loud. In a 1:1 sound-off between any given string or wind instrument and trumpet Trumpet would completely dominate. Now imagine you need 5 violins playing the same thing to overcome the trumpet. But now you need 2 or 3 trumpets to play harmony, so now you need 15 violins… look you see where I’m going right? Trumpets (prep you Jean Ralpheo voice) are the WOOORRRRSSSTTTTTT

I’ll explain in an analogy, imagine each instrument as a separate ingredient for a cake. Some are sugar, eggs, flour, vanilla extract, and some are water. The baking is the performance. You need a different combination of ingredients to bake and you need a different combination of instruments for a performance of different kinds of music. Each ingredient on its own is great but the combination of ingredients is what makes a cake so good.

You also need way more grains of sugar than eggs. With instruments, you need way more string instruments compared to wind instruments for the orchestra.

Same reason a piano has three strings for each note, volume and articulation of the right sound.

And usually, no matter how many violins or tubas you have, you only need one piccolo player. That tiny little flute can dominate the entire band.

Basically, one single trumpet is much much louder than one single violin. So, you generally balance the sound out by adding more violins.

Second reason: one single violin can sound pretty harsh. When you add multiple violins, you end up with a more stable sound. Think of it as adding frequencies together, where all of the frequencies might be off by a hertz or two. Adding enough instruments, the inaccuracy doesn’t matter, because on AVERAGE, the sound will work itself out. This is important for inherently inaccurate instruments like fretless string instruments.

related question: why there is no orchestra of electric guitars?

Many here are explaining the balance for amount of sound produced. I’ll give another reason and analogy. It also helps with the richness of the sound. Imagine a paintbrush with hundreds or more bristles. Each of the bristles is one violin. The type of stroke is very different from one where you drag a piece of cloth dipped in paint across a canvas. Sure you can paint with both, but the texture of the paint will be vastly different from one brush to the next. Each instrument section is like a different brush. They have different colors, textures, timbres, sizes/volumes that different artists want to use differently. This is the difference between a string quartet and a string orchestra. The sound quality is vastly different when there are many of the “same” instrument doing almost exactly the same thing but with minor barely noticeable differences in timing, tone, intonation, volume, etc.

I am the sound engineer for the San Diego symphony. We mic every instrument when we play outside. That is around 80 microphones. There is no way to recreate that symphonic sound through the PA with just a couple instruments of each section directly miced. We have about 25 violins, 14 violas, 10 cellos, 8 double basses, 10 horns, 10 woodwinds, piano, keyboards,percussion, and usually a guest soloist. We run a full Dante rig with a CL5. During the summer at the pops site we use Digico Sd12 consoles with a L’acoustics PA. When inside the symphony hall we don’t mic for amplification (just recording) because the stage walls are designed for acoustic amplification. For recording we do not directly mic instruments. We mic the sections with hanging microphones in an ORTF pattern. In terms of mixing you don’t mix like a normal band. With the symphony everything needs to be even and equal to the other. The conductor is the one truly mixing the symphony. I am there to make sure each instrument is heard by the audience with equal loudness across the section

This is not totally it, but certainly part. In the same way, when you have a crowd of dozens singing something it’s sort of greater than the sum of it’s parts (many people may be off key etc) having multiple players of the same instrument adds slight variations that makes a sound more “broad” and “powerful”.

In audio production some very very very common effects are delay, reverb, and chorus. These are all slightly different, but generally all of them are usually used to take one sound and multiply it in different ways, because it feels more “full”. A simple example, if you have a bland room with way too much absorption, a single instrument playing is very “dead” sounding. Place that instrument in a cathedral, and suddenly the delayed reflections of the “same” sound arriving at your ears at all different times turns it into an incredibly deep, dynamic, emotional experience by comparison.

Then there’s also a matter of chords and the relationship between multiple notes being played at once, and many instruments are best at focusing on only playing a small number of notes (sometimes just one) at once, so having multiple instruments also allows the orchestra to play larger chords than a single instrument could play.

Another ELI5 question: why are orchestras arranged in a “asymmetrical” layout? For example I see that violins are on one side and cellos on the other. Wouldn’t a more simmetrical layout be better?

If you think about it kinda like a choir it might make more sense like if you just had one person on stage singing it’s vastly different than if you had multiple, but not everyone sings the same exact thing the same way the whole time depending on the choir and such of course

The biggest reason is balance. You could have 100 violins going ham on stage but if one trumpet decides she’d like to be heard, she could play over all of them without a huge amount of effort.

Theres a (weak and rarely followed these days, but very prevalent before the 20th century) rule of thumb in orchestral composing that the strings are going to be playing 90+% of the time, the woodwinds about 30-40%, and the brass and percussion no more than about 10-20%. Thats because the way orchestras were built then, if that wasn’t the instrumentation balance, it would just be the Trumpet and Horn show with violin accompaniment. This is even more pronounced the further back you go, largely because orchestras were much smaller then (25-40 people vs today’s 60-80). In a baroque orchestral piece from the early 18th century, the trumpet might have 3 or 4 minutes of silence, then a couple bars of playing something to accentuate how big and exciting the violins sound, followed by another 3 or 4 minutes of silence.

The other reason is color and acoustics, especially for strings. Instruments in the violin family have an incredibly complex sonic profile, also known as the timbre or color. Basically, timbre is what makes a violin sound like a violin. (Fun fact: a flute in the upper register has a timbre very very close to a pure sine wave, which is the simplest form of oscillation). When you have multiple string instruments playing the same thing*, each of those complex sound profiles combine to create a rich, lush bed of sound. None of them are matching the others timbre or pitch *perfectly exactly*, so you get this great chorus effect of a bunch of sound all hovering and kinda shimmering in the same place. If you’ve ever watched an orchestra play, you’ll notice that the string players are all wiggling their hands back and forth — thats called vibrato. The more they do it, the more the sound wobbles back and forth, and the more rich the sound the entire string section will produce. Pay attention the next time you’re watching an orchestra: the more intense and emotional a section is (not necessarily loud!), the more vibrato the strings will use, and vice versa. There’s nothing quite as dead-sounding as a string orchestra playing without any vibrato at all.

Thats part of why composers have them playing all the time — its like a pad synth in EDM; you probably don’t notice that its there, but you’ll definitely notice when its not because it’ll feel empty, hollow, weak, or unstable. Strings are great to put in the lead because they are so rich and versatile, but also great to have as support because they provide sonic presence without dominating the actual lead. Trumpets and any other (cylindrical**) brass just can’t do that; they’re too bright and too piercing, no matter how hard they try to mellow out and play quiet.

* Side note: if you’re ever writing for strings, never ever have two of them play in unison. One is fine; they make for great solos. Three or more is fine because they start to have that nice chorus effect I described above. But with two playing in unison, they will never be able to match the other’s pitch, and even the wobbliest vibrato in the world won’t save them.

** There are two types of brass instruments: cylindrical and conical. All brass instruments have a conical bell (the end) in order to project the sound, like a megaphone, but the shape it takes from the mouthpiece to the bell can either be cylindrical aka the same diameter or conical aka gradually getting wider. Cylindical brass have a much brighter, more piercing sound, while conical brass tend to be mellower and full in tone. Both can play very loud though, so don’t mistake mellow for quiet. Examples of cylindrical brass: trumpet, trombone. Examples of conical brass: French horn, euphonium, tuba.