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Writing Musical Themes · Acedra
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Writing Musical Themes
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0:06
What if I told you that writing a good melody has nothing to do with inspiration? In this video I'll show you the proper techniques to transform any musical idea into a whole theme. Let's get to it!
0:21
The concept of theme is used in a lot of different contexts and with different meanings. For instance in pop music "theme" is usually employed as synonym of song or tune, but it may also be used to refer to any catchy melody within a musical piece. In classical music however we refer to theme as the minimal musical structure within a work that has complete meaning usually ending with a cadence.
0:48
Now, what does complete meaning stand for? if for instance I say "I have to" this has a meaning but it doesn't have a complete meaning: I have to what? I have to study. Now this has complete meaning and it can also be ended with a punctuation mark, which is the equivalent for a cadence in music. depending on the type of punctuation mark we can achieve different kinds of closure, and the same goes
1:15
for cadences in music. From the listener's point of view complete meaning in music is achieved when we feel the music could stop at a certain point without feeling forced or interrupted.
1:56
According to William Caplin there are two main types of themes: loose themes, which don't have a fixed structure and can be found in transitions developments and codettas, and tight knit themes, characterized by a highly stereotyped behavior and structure. In this video we'll focus on the latter, which are the kind of themes usually found at the beginning of a piece in the classical and romantic periods.
2:20
Subjects from fugues, which are also highly stereotyped musical structures, follow a different logic compared to classical and romantic themes, and will not be addressed in this video.
2:33
There are two basic types of tight-knit themes: the sentence and the period. the standard length for both is eight bars, however exceptions can be found often as we shall see later. The sentence presents only one cadence at the end, which can be either a perfect authentic cadence an imperfect authentic cadence or a half cadence. The first half is known as presentation which works as tonic prolongation.
2:58
This means either a sustained tonic harmony or an alternation between tonic and neighbor chords in different specific combinations that we'll get into later. The second half is the continuation, and its main goal is destabilizing the musical flow and prepare the following cadence. The period also has two parts: the first one, the antecedent, ends with a weak cadence, which can be either,
3:21
a half cadence an imperfect authentic cadence and sometimes a deceptive or evaded cadence. The second part, the consequent, begins with the same material than the antecedent either literal or varied, but this time ends with a strong cadence, normally a perfect authentic cadence. Hence, in the period we have a sense of question and answer where the consequent ends what the antecedent had left
3:44
open. In the sentence, on the other hand, the musical flow proceeds more or less uninterrupted.
4:24
The sentence always begins with a two bars long basic idea. Mind that a basic idea is not exactly a motif, but rather a group of them, just like words can be built from morphemes. As a rule of thumb the simpler the basic idea is, the better. Complexity in music often comes not from complex ideas but complex ways to deal with simple ideas.
4:51
Basic ideas are usually built on tonic harmony like in this example. Off tonic beginnings where the basic idea doesn't start on tonic harmony but rather on dominant harmony are also possible but less common.
5:15
Now the big question is, what to do next? The followings are the standard procedures for bars three and four: exact repetition, melodic transposition, sequence and continuous phrase. In the exact repetition the basic idea is repeated next with the same harmony and melody. Minor variations are admitted in this process in order to avoid an excess of monotony
6:14
In the melodic transposition the melody is transposed but the initial harmonic progression is kept.
6:33
In the sequence both, melody and harmony are transposed to a different scale degree.
6:47
When the basic idea is transposed from the tonic to the fifth or fourth degrees we've got what Caplin calls an statement response repetition.
7:17
The final type and my favorite is the continuous phrase. In this case, instead of two musical events we hear one single phrase encompassing four bars. This doesn't mean that we can't reuse the same motifs from the initial basic idea, but we do it in a way that they don't sound like an explicit repetition or sequence. When composer choose this specific approach it's very common to underline it with a tonic pedal all the way.
7:56
For the continuation we've got two main options: sequential continuation and fragmentation. Sequential continuation occurs when the first two bars of the continuation resemble the whole initial basic idea. This usually happens when the presentation was set as a repetition or sequence of the basic idea, so it actually feels like a third repetition.
8:53
It's worth noting that this procedure is a lot more common in the romantic music than in the classical style.
9:43
Fragmentation consists of breaking down the basic idea into smaller segments, which is usually accompanied by a faster harmonic rhythm. When these smaller segments are still motivically related to the basic idea we may speak of a contraction or liquidation process.
10:48
In the classical period it's also common to find fragmentations that are not motivically related to the basic idea.
11:39
As we already mentioned, the sentence can end with three types of different cadences: the perfect authentic cadence is the most conclusive one, akin to the period as punctuation mark. In this type of cadence the bass moves from the fifth to the first degree while the top line resolves to the tonic by a stepwise motion, either upwards or downwards.
12:02
The imperfect authentic cadence is the same but the top line resolves to a different note than the tonic, usually the third of the tonic cord. This cadence is slightly less conclusive than the previous one and is usually compared to the comma.
12:19
And finally the half cadence ends with a dominant triad on the fifth degree, which can be preceded by a tonic or subdominant chord and sometimes its own secondary dominants. Unlike in the previous cadences, in the half cadence the resolution of the top line is not so important, as long as it proceeds by a stepwise motion. Since this cadence is a kind of open ending, as it resolves on dominant harmony instead of tonic, it has been compared to the use of suspension points.
12:49
Now let's listen to all three types of cadences and how they affect the closure sensation.
13:19
In the modulating sentence the last part of the continuation modulates to a different key and cadences on it. The most common keys to modulate are the fifth degree if the initial key is in major mode, and the third degree if it's in minor mode, however other options can also be found in the repertoire
13:51
The antecedent phrase of the period can be set in any of these two patterns: the question answer and the mini sentence. In the question answer pattern we start with a two bars long basic idea, just like in the sentence, and this is replied by a contrasting idea of the same length which leads to a weak cadence. Composers normally look for a strong contrast between both ideas.
14:40
However we can also find examples of antecedents with a strong inner motivic correlation.
15:00
In the mini sentence the whole antecedent is built after the same principles of the sentence but compressed in four bars instead of eight.
15:27
The consequent of a period must start with a basic idea, which can be restated literal, varied or transposed, as long as it can still be recognized. The contrasting idea from the antecedent can be restated too after it or it might be substituted by something else, but in any case the consequent must always end on a strong cadence.
16:37
Just like with the sentence we can also find modulating periods.
17:18
An interesting variation of the period is the so-called anti-period, which is essentially a period in which the order of the cadences is reversed. Here the antecedent ends with a strong cadence and the consequent does with a weak one.
17:56
Another variant, which some authors call the "contrasting period", is when the restatement of the initial basic idea in the consequent is missing. These special types of themes share common features with the period and the sentence at the same time and William Caplin considers them hybrids.
18:28
As we mentioned in the beginning of this video themes don't always stick to the eight bars pattern, and there might be different reasons for it. Firstly, sometimes one of the parts of a theme is simply shorter or longer than usual, and there is absolutely nothing wrong with that.
19:08
Secondly, composers may extend the length of a theme by adding extra material, either new or repeated.
20:44
And finally we must take into account that the written time signatures don't always match the listener's perception.
21:25
Compound themes are built as 16 bars structures in which at least one of the halves can be identified as an stand alone eight bars long theme. The compound sentence is a especially sophisticated case, usually appearing at the beginning of a work. In this type of compound theme we've got an initial eight bars structure which functions as a long presentation, followed by an eight bars long sentence which, as a whole, might be interpreted as a big continuation at the same time.
22:47
The compound period, on the other hand, is built of the repetition of the same sentence, the first time ending with a weak cadence and the second time with a strong cadence.
23:57
Different combinations of of all the principles discussed in this video might be used to form new sophisticated thematic patterns. One of my favorite examples of this is the beginning of Mozart's Piano Sonata in A minor, in which the whole first part of the exposition, encompassing opening and transition, is built as a single thematic unit that combines different procedures discussed in this video.
24:20
Are you able to identify them and give me a name for this special type of theme [Music]
24:54
That's all for now, let me know if this video was helpful and see you next time!
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