I want to shine some light onto Bell Serratus
. Mine is not the aluminium shell but stainless steel version though I think it most likely will sound 99% the same.
To me, tonality wise is quite similar to the OG Serratus (compared with Red Serratus) but it has smoother trebles, better bass texture and better extension on both ends of frequency.
Stage width is slightly narrower than the OG which is wider and more expansive. However, stage depth of Bell Serratus instead is deeper than the OG, makes it feel more rounded.
A good complimentary to Sunniva as this is not as intense and engaging as Sunniva, instead what Bell Serra provides is an overall comfortable, laid back immersive experience. I believe this is due to the nature of Serratus mids which is slightly recessed.
An analogy I can give.. is that SSB Serratus feels like I'm sitting in a concert listening to performers playing on stage in front and away from me.
The bell fit could be a bit challenging to get the best fit but don't be discouraged. You can always play around with foams, rubber rings and wings, and in my experience it definitely helps finding that secure fit. As the saying goes, thick foams save lives. jk.
Cheers