Unfortunately, I did not come across anything pertaining to knighthood conferral in the Middle Ages, but I have a 19th century Pontificale Romanum, and under the section "On the Blessing of a New Knight" it says:
"To create a new knight, he can be blessed any day, place, or time; but if he is to be created within the solemnity of the Mass, the Bishop does so after the end/dismissal of Mass [finita Missa] either in the vestments in which he has celebrated the Mass or in which he took part, at the faldstool in front of the middle of the altar, either standing or sitting, as is convenient. But if it is outside the Mass, the Bishop is to wear a stole..."
And so on. The rite itself is pretty straightforward, with a string of prayers and blessings of the knight but no instructions for music or musical opportunities, such as a psalm or litany. This edition is from the 19th century (1845) as I said, but my guess, and it is only that, is that the medieval equivalent would not have been that different. And I suspect the administration of it would have been a lot like the sacrament of confirmation, which could be accompanied by a Eucharistic liturgy, but probably more often than not wasn't. Hope that helps.
Medieval editions of the Pontificale would be a good place to start for more accurate info.
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