Crab Canon

Hi everyone,

After listening to J.S. Bach - Crab Canon I thought I'd have a go and write one too. (It's a good composition challenge, I'd recommend it)

https://soundcloud.com/maxmitchellmusic/crab-canon

NB: To anyone who's interested, a crab canon is a piece where the melody is played, then played backwards (or retrograde), and then the retrograde and original melody are played simultaneously.

It sounds nice...

I don't know about your skills in classic counterpoint. I don't know either how you did this canon. 

The best way (in my opinion) is writing the the two voices at a time in a way you are doing an invertible counterpoint. That means you have to avoid fourths in strong positions (considered dissonant in the style), and to avoid also too many fifths.

In m. 33 we have a C - F# (augmented 4th = tritone). Here also there are semi-hidden parallel octaves D# - F-----3

In m. 35 another D# - A

In m. 39 a parallel octave E - Bb (which conform a tritone).

In m. 40 G - C#

In m. 39 C# - F#

In m. 42 parallel octave Eb - E (tritone),   and in 43  E - F# - (B)

etc...

Well, this is always in the taste. Some people accept augmented 4ths in certain cases.  And parallel octaves, sometimes are less evident, but if you "erase" passing tones or other non-chord tones, they're there.

I don't think this is bad at all.

I only want to say that different canons have different techniques. And the crab canon  is best when written the two voices at a time, considering they're perfectly invertible, and when you reach the changing point, make the double counterpoint a fact.

On the other hand, the changing point in m. 40-41 is nicely done, sometimes the effect is poor because of the phrase is the same (in retrogradation). There are some techniques to make it better (for example, adding a measure which is the very center of the canon and leaving one or two notes in the middle of it as pivotal point). But here is very good.

Other thing I like is the 5/8.

Cheers!

Thanks for the feedback. I haven't heard of invertible counterpoint so I'll definitely do some research on that. 

I probably should have mentioned that I set out to write a neo-baroque piece, hence why there are so many tritones.

9 minutes ago, Luis Hernández said:

I don't know about your skills in classic counterpoint. I don't know either how you did this canon. 

 

I have patchy knowledge of first and second species counterpoint but nothing more than that (I tried to teach myself it from Fux's Study of Counterpoint awhile ago). As I'm not even close to being fluent in classic counterpoint I decided that I wasn't gonna stress myself out about the rules. 

I do want to learn counterpoint though so are there any resources you'd recommend (other than the Fux's book which I don't really like).

50 minutes ago, Luis Hernández said:

Other thing I like is the 5/8.

Glad you like it :)

I studied a whole course on counterpoint without learning al those roles by Fux. In fact I don't know exactly what is racha species.

what matters is managing the intervalos, which are consonantes and which not. And what are chord tones and note chord tones. And how to use them.

invertible or double counterpoint is that one  where you can switch the voces and still goes well, without creating 4ths. To get it the original counterpoint must avoid 5ths in strong positions because it's inversión will bring 4ths.

Sorry, this isn't a proper crab canon. The comes is supposed to be derived from the dux only by retrograde. That way, there is an axis exactly in the middle around which the whole canon is symmetrical, and the voices switch roles - the dux becomes the comes and the comes becomes the dux (here they are separated by two whole octaves). Both voices also usually start simultaneously, although that is a stylistic matter concerning the performance and doesn't really affect the composition as such. In this case, the canon is not correctly conceived though.

1 hour ago, Gylfi said:

Sorry, this isn't a proper crab canon. The comes is supposed to be derived from the dux only by retrograde. That way, there is an axis exactly in the middle around which the whole canon is symmetrical, and the voices switch roles - the dux becomes the comes and the comes becomes the dux (here they are separated by two whole octaves). Both voices also usually start simultaneously, although that is a stylistic matter concerning the performance and doesn't really affect the composition as such. In this case, the canon is not correctly conceived though.

 

I don't agree.

The canon you describe is one type of crab canon. The crab canon can be in many other ways than that. It can be made at different intervals than the unison (even r4th, 5th, etc...), and it can be made in motu contratio, too.

The fact that one of the most famous crab canons is the one by Bach doesn't mean it's the only possibility. Every combination is good to make a canon.

The same happens with invertible counterpoint, that can be made at the octave (or two octaves) but also at other intervals.

Of course the crab canon at the unison is more difficult than at the octave....

Bach was the first to combine different possibilities in canon. For example, BWV1080 which is the canon per aumgentationen in motu contrario.

4 hours ago, Luis Hernández said:

I don't agree.

The canon you describe is one type of crab canon. The crab canon can be in many other ways than that. It can be made at different intervals than the unison (even r4th, 5th, etc...), and it can be made in motu contratio, too.

The fact that one of the most famous crab canons is the one by Bach doesn't mean it's the only possibility. Every combination is good to make a canon.

The same happens with invertible counterpoint, that can be made at the octave (or two octaves) but also at other intervals.

Of course the crab canon at the unison is more difficult than at the octave....

Bach was the first to combine different possibilities in canon. For example, BWV1080 which is the canon per aumgentationen in motu contrario.

What you say is not factual and is based solely on your opinion. The crab canon draws its name from the way crabs normally walk, sideways. In other words, the only operation performed on the principal line to derive the follower is reversing the direction of movement. The canons you described are different types of canons which also happen to apply a retrograde operation. Consider for example that a closed three-part canon at the fifth is not a type of round even though it uses an equivalent procedure. If you don't accept this definition of "crab canon" there is nothing more to discuss.

On 3/13/2017 at 1:42 PM, Gylfi said:

Sorry, this isn't a proper crab canon

Hi Gylfi, thanks for your response.

What type of canon would my piece be then?

3 hours ago, punintentional said:

Hi Gylfi, thanks for your response.

What type of canon would my piece be then?

 

Well, a formal Italian name for it might be something like Canon alla quindicesima al rovescio (canon at the fifteenth/double octave in retrograde?), but don't quote me on that. See, it is a type retrograde canon but the two voices inhabit different pitch spaces, so it is not the same line played in retrograde (which is the definition of a crab canon). It's illusory because the double octave just happens to go by the same name, if it were a canon at the sixth you would probably not call it a crab canon.

9 minutes ago, Gylfi said:

Well, a formal name Italian name for it might be something like Canon alla quindicesima al rovescio (canon at the fifteenth/double octave in retrograde?), but don't quote me on that. See, it is a type retrograde canon but the two voices inhabit different pitch spaces, so it is not the same line played in retrograde (which is the definition of a crab canon). It's illusory because the double octave just happens to go by the same name, if it were a canon at the sixth you would probably not call it a crab canon.

 

 

That makes sense, thanks. :D

If you like canons, one great book is The Technique of Canon by Hugo Norden.

Take it as you like, but according to him, among others, the crab canon at other intervals (different from the unison) exists, in the end it's just a matter of name for a canon. 

@punintentional, I have one question for you: Is the 5/8 really 3+2 for both voices the whole way through? Or is one of the voices really 2+3 due to the retrograde?