If you want a dark soprano sound, just ask.
Now, you can chase all the esoteric ideas that a million players who have played 20 soprano mouthpieces in their lives and maybe 20 different horns (of course, not close to ALL pieces on ALL horns), or you can go at this clearly and rationally. The fact is, I can make your mouthpiece as dark as you want it, I can tell you what that will do to how it performs and I can guarantee it.
Yes, I am The Prince of Soprano Darkness. But only when asked.
Here’s the short of it: the mouthpiece chamber will promote more or fewer harmonic partials according to its design. If you really want to darken your soprano sound, then you need to have your mouthpiece set up correctly.
Can a player darken their sound just by changes in their oral cavity? Yes. But that requires an amazing amount of subtle changes over the entire range of the horn, and there are almost always unintended consequences, like very ‘exotic’ intonation issues.
By having the mouthpiece chamber configured to do that work, the player is left to focus on the music. Small and subtle changes in the oral cavity are still useful and available, but gross manipulation and the associated problems are avoided completely. Constant movement of the embouchure and constant changes in the air column are the very things that play havoc on soprano, and they are almost always ‘workarounds” for real mouthpiece problems. Once the mouthpiece is right, you’ll see how quickly things fall into place. Read what players are saying, worldwide, about their experience with getting the sound and the freedom to use it.
Want just a little darker sound? Try a darker reed, like Hemke. It may be all you want.
But if you want that deep, hollow darkness from your soprano, see The Prince of Soprano darkness, me.