1. Articulation . This is the most obvious mistake I see a lot of people make. As you probably know, the ideal articulation for the Baroque music is the articulate legato touch when we make small breaks between each note unless indicated otherwise by the composer.
When playing this prelude, however, at the beginning you can see the legato signs which connect three sixteenth notes. By the way, this articulation should be applied to all places with this piece even though the legato signs appear only at the beginning episode.
What I see a lot of people do is they play the three notes legato, but fail to articulate after the last note in the group of three sixteenths. This of course produces the complete legato touch which is more suitable for Romantic and Modern organ music.
Another articulation mistake is in the fugue - here many people find it difficult to articulate the inner 2 voices out of 4 voice texture. Since the alto and tenor voices can be hard to listen to while playing all of them together, no wonder why precise and consistant articulation is difficult to achieve.
SOLUTION: take a slow tempo and practice in small fragments and in separate voices, then combinations of 2 voices, later 3 voices and only then - the entire 4 part texture. Insist of playing at least 3 times correctly in a row.
2. Fingering . Since the prelude can be played using the general arpeggio fingerings, it is in the fugue that people find difficulties with this issue. The most common mistake I see people make is applying finger substitution in this piece.
SOLUTION: I recommend using early fingerings without substitution. Then it will help you create the ideal articulation naturally even without thinking. Also avoid placing the thumb on the sharp or flat keys. In the mini course, I will also explain how the early fingering techniques work in practice.
3. Pedaling . Similarly to fingering, the most difficult part for choosing the pedaling is the fugue. If you are consistently making mistakes in articulating pedal line in the fugue, chances are you are using toe-heel technique which is suitable for Romantic and Modern organ music.
SOLUTION: Use alternate toe technique in most cases (right-left toes only). The rule to use the same toe pedaling here is this: play with the same foot when the pedal line changes direction. Otherwise play with alternate toes.
4. Tempo . A lot of people take a tempo which is too fast for practicing. The reason for this is that they really want to feel the natural flow of the music. It takes a lot of courage to insist on playing very slowly. I can tell you from experience that the slower you play, the faster your progress will be.
SOLUTION: take such tempo for practice which lets you avoid mistakes. If you make a mistake, go back a few measures, slow down, and check that place again. If you do this regularly, you can overcome any difficulty in the piece.
5. Rhythm . The mistakes with rhythm involve failing to keep the steady pulse while switching between triplets and duplets in the middle episode of the prelude with no pedal part. Since the triplets appear in most measures of the prelude, it is not too difficult to play them correctly.
However, the places I see people make rhythmical mistakes are when triplets change into duplets. Here it is easy to play the duplets too fast. The result is a lack of steady pulse and change in tempo.
SOLUTION: I highly recommend counting out lout the beats of the measure throughout the prelude (and the fugue). In the beginning you will find it exceedingly difficult because you will be multi-tasking. However, there is no shortcuts here and you just have to insist in saying the beats loudly enough so that you can keep the steady pulse.
By the way, there are certain rhythmic devices, such as hemiola which I'm going to be teaching in the mini course as well. Without knowing how to find it in music, it will be very difficult to play the cadences in this piece stylistically correctly.
6. Ornaments . There are two basic mistakes people make when playing ornaments in this piece - either they start the ornaments too early or on the wrong note. By saying too early, I mean they play them before the beat. This comes from the Romantic tradition. The starting notes of the trills also have their rules.
SOLUTION: Start the ornaments on the beat and not too early. The trill for the Bach music usually has to start on the upper note meaning that if you see a sign above the note G (as at the end of the first episode in the prelude), start the trill from A. I recommend playing 4 notes for the trill: A-G-A-G.
7. Practicing . Although I constantly advocate for practicing in short fragments, it is not as easy as it might seem to develop this habit. You see, a lot of people come to me looking for help while they already have developed some incorrect or ineficient practice habits. Therefore, they might play the piece from the beginning until the end without fixing their mistakes they make along the way.
SOLUTION: I think it takes a shift in mindset to practice in short fragments. You see, one thing we have to realize is that practicing is not the same as performing. As you become more and more fluent with this piece and time approaches for performing it in public (either for your friends or family, during church service or recital) you need to get used to play it from the beginning until the end without stopping.
However, if you really want to achieve the best results with BWV 556, the majority of your practice should be done in short fragments.
By the way, as I'm typing this sentence, already 98 people have jumped on board of my new free video mini course which will start on Thursday. Congratulations to everyone - it's going to be an awesome time for the entire Secrets of Organ Playing community. So much interaction, so much communication is going on though emails and comments over the past several days.
If you haven't done so, there are only 2 more days left to register for free. The methods that I will teach in this mini course will be fully applicable to learning other works of Bach: