The following comes from an August 22 Traditional Latin Mass Community of Saint Mary Magdalen blog post:

A Solemn High Mass will be offered by the Priestly Fraternity of Saint Peter at the Cathedral at 555 West Temple Street, Los Angeles on October 1st, Saturday, at 8:00 a.m. 

This Mass is part of the Annual Conference of the Society for Catholic Liturgy. Read more.  This will be the first time the Extraordinary Form will be celebrated in the Cathedral of Our Lady of the Angels.

This Mass enjoys a major placement within the conference.  Father Masutti FSSP will be the celebrant, Father Fryar FSSP will be the deacon and preach.  Father Austin FSSP will be the subdeacon.  The FSSP.LA choir will be singing.