The Kopprasch etudes are a staple of horn (and brass) teaching, yet they are a conundrum; some love them, some hate them. Those that love them tend to like the range and length of the etudes, combined with the clear articulation and dynamic requests. Those that hate them tend to dislike the boring predictability of the early 19th century musical language.
The good news is that I believe players from either category will find this new publication by Jeffrey Agrell, Rhythm Kopprasch, very intriguing. Essentially what Agrell has done is take the notes that Kopprasch wrote (occasionally changing an octave) and change the meters and durations, often radically. The rests still fall in the same places, but with the rhythm changes the underlying harmonies evident in the original are shifted around, creating quite a different sound and effect.
I think the book will be perceived differently by a student who has only recently learned Kopprasch than it is by an older teacher such as myself. For me personally playing these, the biggest challenge is that the underlying harmonies I imagine in my mind are often not changing at the bar lines. It is not a negative really, it has been an interesting summer challenge to erase those mental harmonies and play them in the new configuration.
It should be noted that those that love the dynamic and articulation requests of the original will be disappointed, as they are absent from this volume. The focus here is rhythm! Presumably later volumes in the Millennium Kopprasch Series will focus on dynamics and articulations.
Nicely bound and printed, and very affordably priced, Rhythm Kopprasch is certainly worth a look! More on the publication may be found here on Amazon, it is available in hard copy or for Kindle.