I think they are mostly FSSP, the website says they are in "good standing" with local ordinaries and Rome.
I think it is odd that they won't identify the speaker and that their excuse for not doing so is lame, it makes it look they have something to hide.
Other sites like Traditional Sermons, St. Isidore's, SGG always tell you who has given the sermon. Love 'em or leave 'em at least they are transparent.
Audio Sancto - about us
Fr. Justin Wylie preached against episcopal mistreatment of Traditionalists in the New York archdiocese and, within the week, Dolan shipped him unceremoniously back to South Africa.
Fr. James Meara, a very good and holy priest, was permanently banned from offering the TLM at St. Agnes in NYC a decade or so ago when he condemned the "gαy Pride" parade, (rightly) calling it the "Sodomite Parade" (I was there for that one).
FSSP priests who preach the Catholic Faith and condemn modernist errors have every reason to keep a low profile. The reprisals they face from modernist bishops are very real, and are a threat not only to themselves, but also to the faithful who would be robbed of real Catholic shepherds if they are removed. Case in point - St. Agnes now largely relies on regular diocesan priests trained to offer the TLM, and the sermons the faithful must endure there are of the same maudlin, treacly non-substance as the average NO fare.
As to the OP - Audio Sancto (and romans10seventeen.org) offer a large selection of FSSP sermons, and most of them (with some notable exceptions) are excellent, irrespective of whatever one thinks of the FSSP itself.