Early days for me but it's a stunningly beautiful pairup. I haven't heard the 21 Anni since I owned it last year and from memory the 23 seems to fix what was the only real issue with that IEM-- the bass. Previously it was what I would call "minimally acceptable" but here it's something of a highlight. Tighter, better extended, more present. Annihilator doesn't "need" lots of power but it sure does benefit from it. Trhough the RS8 on high gain/turbo it makes for a hell of an experience. RS8 has a really natural, analogue, authoritative yet liquid tonality that suits this IEM like a charm.
In other news we're two weeks into fall and two days past CanJam SoCal-- it's time for our seasonal 3 IEMs that own your heart at this moment poll. I'm not looking for your all time favorite 3 or anything (though of course you can submit those if you want). This poll is more meant to take the temp of the Watercooler at this moment in time.
Bass: Trifecta. Slams hard and deep.
Mids: Phonix OG. Emotion Pro Max.
Highs: Anni 23. The definition of treble extension.