We seem to have very different definitions going on here.

The original poster said that it cranks, that is the title of the thread. Starters spin if they have juice, then the starter engages the ring gear, and that cranks the engine. Cranking doesn't refer to a starter, it refers to a crankshaft.

If the engine is cranking, in our diagnostic process, by definition we are already past the battery, starter, and engagement of the ring gear.

If it doesn't sound normal when the engine is cranking, it is either because the compression isn't as expected (for a variety of reasons) or the engine just isn't catching as it usually does, and the noise is normal, but not commonly heard, ie just not the same as it usually sounds.

I'm with the above recommendations to get a professional diagnosis.

__________________
2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue