Excellent Article on Sacred Music by Aurelio Porfiri

There have been few topics which have so captured the attention of liturgical experts like that of participation. This term has been impugned by one after another faction as if each one possessed its secret meaning, discovered by and revealed to only a chosen few, who thus turned even legitimate debates on the issue into Gnostic liturgists’ meetings. Gnostic because, especially after the Council, participation has become a battle issue in which lurks every sort of political, sociological, and psychological element.
          For some, “participate” means that everyone does everything. However, this interpretation goes against the true meaning of participation which lies not in the mode of doing but in that of being. This mode does not exclude doing, but rather contains it in a broader, more articulated process. Doing presupposes being and all that goes along with it, but it is not an end in itself. ...
          Unfortunately, while the abovementioned error was made by some of the reformers after the Council, some of those who felt attached to what later would be called the Extraordinary Form of the Roman Rite have often had an equally inappropriate reaction, on the opposite extreme. For them it was a sign of fidelity to “tradition” to simply and passively attend Mass without worrying about singing in this or that part of the celebration, but only enjoying what the choir or organist was able to offer. Now, it seems that both these attitudes hide a basic impropriety, and that recovering a more authentic sense of participation will also clarify important facts about the Mass itself, which otherwise risk being pushed to the background, picked apart by “liturgical wars” that, in the end, lead to no victory.
          To participate, as the word itself says (pars + capere), means "to take part". Now, several important consequences come from the way in which we read this word. Unfortunately, in recent times much emphasis has been placed on “the one who takes part,” rather than “take part in what.” This slipping of the subject has also caused a slipping in value, as if the guests invited to a birthday celebration were more important than the one being celebrated. Actually, as we all know, the one being celebrated is certainly more important, and all the efforts of the guests at the “celebration” (another term widely used and abused in recent decades) are directed to the one celebrated. Otherwise, one runs the risk of what the Servite liturgist Silvano Maggiani calls “participationism”—the insistence on making everyone do everything—with the consequent loss of the center of the actio liturgica, which is not “the one who participates,” but rather that in which one participates. In the liturgy, it is not we who act, but we who are acted upon. ...
          Having said this, and using good common sense, in line with what the popes have asked, we must agree that even exterior participation must be cultivated. Regarding the exterior act, this means answering the priest, but also participating in certain parts of the singing. This requirement is not simply a result of the liturgical reform following Vatican II, but was also solemnly requested by the pre-Conciliar popes. The call to actively drink from the fount of the liturgy came already from St. Pius X, who affirmed the following in his Motu Proprio on sacred music on November 22, 1903: “Filled as We are with a most ardent desire to see the true Christian spirit flourish in every respect and be preserved by all the faithful, We deem it necessary to provide before anything else for the sanctity and dignity of the temple, in which the faithful assemble for no other object than that of acquiring this spirit from its foremost and indispensable font, which is the active participation in the most holy mysteries and in the public and solemn prayer of the Church”.