One of the big cultural changes with weddings in the last ten years has been the increasing expectation for two pieces to mark the beginning of a wedding ceremony. There are good reasons for this. Many weddings now happen in gardens, on beaches, in function centres -- all locations notable for not being the natural habitat of pipe organs. This way of using music is one way cultural change is coming to church weddings.
I think there's a lot to be said for how music is done in these places. It can be used to provide a sense of anticipation, and to comment on the progress of the bridal procession -- Pachelbell means the bridesmaids are floating in, while the cross fade-switch to Wagner now signals the arrival of the bride. This is easy to do because the music is most likely coming from an iPod, which makes these quick transitions easy and effective.
One latent idea in all of this is liturgical movement, and how music can be used to express it. Processions are liturgical movements, and you can find them in any sort of public ceremony, even a wedding on a beach. It's just that in a church service we think about it in a very direct way, and have an inherited approach to how music expresses movement.
Processions are a regular part of the worshiping round of churches. Music is generally associated with these, whether it is singing a hymn at the start of a service, or marking the exit procession with a rousing postlude. Except under very particular circumstances, it is quite rare for a procession in a church service to have more than one piece of music. One reason for this is the need for inclusivenes: the movement of ministers from church door to sanctuary at the beginning of a church service is the capstone in a process of gathering. If each person had a musical motif that had to be precisely timed for their appearance, we would be focusing on the individual at the expense of the gathered community.
The bridal procession at the beginning of a wedding ceremony typically involves several people. There's the bride, obviously. There's also usually a bridesmaid or two. Sometimes there will be a parent, maybe more than one. Occasionally there are page boys, flower girls, morris dancers, maybe a druid or two, and so on. It's very rare for a wedding couple to consider the purpose of the movement, which is simply to deliver the bride to the sanctuary step at the front of the gathering. All the attendants are there as part of the movement of the bride. Without her, what would their purpose be?
When the expectation of multiple pieces is raised, I often ask wedding couples how many processions they are expecting at the beginning of their wedding ceremony. Is the purpose of the music to mark the arrival of the bride, or to provide a commentary on the progress of each individual in the procession? Unless a ceremonial arrival is being contemplated for the couple's parents, or another significant relative, or if the Governor-General is a guest, or if there is a procession for the priest and sanctuary party at the beginning of a nuptial mass, it's safe to say that nine times out of ten there will only be one procession at the start of a wedding ceremony. One piece of music will cover the arrival of bridal attendants and the bride, and helps to mark the procession as a single movement.
Another consideration is the practicalities facing the organist. Contrasts can be achieved on the organ in many ways, but a rapid change from one piece to another depends on having a fully-functional piston system (never guaranteed), or an exceptionally quick change of registration by hand. Either way, you'll probably find that the organist is in the disheartening situation of creating a dead moment right in the middle of the procession. Your organist should be working very hard to make your day sound right: expecting them to behave like an iPod might not be the way to get the best out of them.
There are other ways the music can help to build anticipation and set the scene immediately before the start of a wedding ceremony. Here's one possibility.
You might think about choosing one or two pieces for the end of the prelude, and make sure the titles are printed in the service booklet. If the choice is recognizable, it provides a very clear signal to your guests that it is time to wind down the conversation and focus on the beginning of the ceremony. There is a practical side to this: by the time photographs are taken, excess watchers shooed into the church, dresses adjusted, steps ascended, final sorting-out at the door completed, it can take up to ten minutes from the arrival of the car for the bride to be ready to walk down the aisle. Having someone delegated to let the organist know to play that one or two pieces allows the organist to know when the prelude will be expected to end, and to factor in some expectant silence before the bridal procession begins. The priest or celebrant will be able to marshal people at the front of the gathering, for which a more deliberate and properly-flagged music choice can be a helpful signal.
If you take this approach, then be sure to choose contrasting pieces. A quieter piece will blend in with whatever has come before, which can be fine. A bolder piece will catch peoples' attention and signal that something is about to happen.
