1) Registration change in the fugue is not necessary. Although it is often possible to add a reed stop in the two-part cycle, such as this, the length of the piece does not suggest the need for stop changes after the prelude. Since this prelude and fugue last only about 3 minutes, it is better to play with one registration throughout.
2) "Organo Pleno" registration. The traditional way of registering a prelude and fugue in the German Baroque style is to use "Organo Pleno" registration or a principal chorus. This concept means that you should build a pyramid of principal stops, starting with the principal 16' or 8' and building upwards (4', 2 2/3', 2 etc.)
3) Use mixtures both in the manuals and the pedals. Try out the mixture alone on the main manual and see if it is based on the 16' (starts at 5 1/3' level) or 8' (starts at 2 2/3' level or higher). If it is based on the 16', then use 16' stop in the manual together with it. Otherwise, playing with 16' is optional.
4) Add flutes if the mixtures are too harsh. Check your mixtures and see if you like their sound. In some Neobaroque-style organs, the mixtures are really high-pitched and sound harsh. In such case sometimes it is OK to omit the mixture and use higher principals and mutations instead (1 1/3' and 1').
5) Check if the principals are not too narrow. In many Neobaroque-style instruments, the principals are quite narrow in diameter. In such case, try to add 8' and 4' flutes for more rounded sound. However, under normal circumstances, principals and flutes should not mix in the Organ Pleno registration.
6) Couple the manuals if you want. If you have more than one manual which has a principal chorus as well, you can couple them both. This way your registration will be even more powerful.
7) Add pedal reeds for more spice. Use the powerful 16' and/or 8' reeds in the pedal division, such as Posaune and Trompete. If you decide to use only one reed stop, the first reed you should add is Posaune 16' and not Trompete 8'. This is because in Central Germany in the Baroque period, even relatively small organs very often had Posaune but not Trompete.
8) Check the balance between manuals and pedals. Once you choose the manual and pedal stops, try to listen to the overall sound ensemble. Since it is a polyphonic composition with highly independent parts, both manuals and pedals should be clearly audible but not too loud in comparison with each other.
9) Practice registration. It is best to practice using only the soft stops, such as 8' and 4' flutes with 16' in the pedals. This way your ears will not become tired and you can practice for a longer period of time.
Remember these tips when you practice or perform the Prelude and Fugue in B flat Major, BWV 560 in public. It is a good practice to listen to different recordings of this piece on historical organs and to compare the registrations in each. Since every organ is different, try to follow your taste and ears based on your idea of the "ideal Baroque sound" for this composition. This way your playing will become more authentic and you will use your organ more convincingly.
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