As a brass player myself,(trombone & tuba) I have always sensed we have little repertoire to play of any interest,but Jacobs in a lecture here reveals this problem and one way to solve it, is to consciously search for things to play,like an aria from Puccini,or a particular non-tuba passage,to duplicate it,a piano or violin solo. What this approach implies is then for the brass player to develop skills as a consummate musician/ virtuoso,for you are forever challenged then to expand your repertoire endlessly,as much as the instrument or your technique will allow. I now find myself playing Chopin Preludes(Eb-minor,B-minor melodies only) on the trombone,and contrabass orchestral excerpts or trumpet etudes on the tuba,and Jacobs encourages tuba players to learn to read treble clef to be able to read any melody.
There are wonderful examples here from all genres in music from solo etudes in his studio to Berlioz and Wagner excerpts, solo and within the context of the orchestra. It all reveals the seemless consistent sound Jacobs was able to summon from his York tuba. Every attach was uniform,every tone even and pure,at least that is what he heard in his ear. That's another Jacobs credo,you have to have the sound in your head,what do you want your listener to hear. You command that.
The Bozza Sonatine(brass quintet) is also a wonderful performance of great brass music,great use of colours and entrances,breaking down the quintet into smaller duets and trios.This all with Chicago Symphony players makes it all the more interesting,a vintage performance from 1966.I recall those days where solo brass was considered an oddity,and unaccompanied solos even more so.
Jacob's sound should remain in your mind's hearing to duplicate it. Eugene Pokorny (Jacob's Chicago Symphony successor) also provides insightful interesting notes here.