What defines voluntary manslaughter and Involuntary manslaughter?

Voluntary manslaughter is statutorily defined as the "unlawful killing of a human being without malice" that occurs "upon a sudden quarrel or heat of passion." ( 192, subd. (a).) It may also be found "when the defendant kills in 'unreasonable self-defense'the unreasonable but good faith belief in having to act in self-defense." (People v. Barton, supra, 12 Cal.4th at p. 199.) Involuntary manslaughter is statutorily defined as the "unlawful killing of a human being without malice" that occurs in the commission of (1) "an unlawful act, not amounting to a felony" or (2) "a lawful act which might produce death, in an unlawful manner, or without due caution and circumspection." ( 192, subd. (b).)