Recently a video link was posted to the Horn People group that caught my attention, a group of Trompes de Chasse performing Telemann with organ.
The horns sound pretty extreme by modern Baroque interpretation standards on the work, and I can only imagine the actual decibel level in the venue. But it gets at a point that is made periodically and very correctly: we have no idea how the horn really sounded back in say 1720.
The video is worth sticking with for a few minutes before you decide if you like it or not; they do play with a lot of character, and it looks like a lot of fun to play this work on Trompe. Consider this video a palate cleanser!
UPDATE: That specific video is off YouTube now, but the version below is very similar, featuring the Rallye Louvarts de Paris & Orchestre de Chambre, dir. Jean Francois Paillard (Erato, 1967).
The stylized rhythms are extremely interesting to me, and overall the performance really says again that we have no idea what this music might have actually been played like in Telemann’s day. At some point things changed, but initially the out of tune notes and tone color could have simply been seen by the audience as “that’s just how horns sound.”
For more on Telemann and the horn see Telemann Wrote a Lot of Music for the Horn, and for an overview of the horn in the Baroque see University of Horn Matters: The Horn Before 1750.