Guess stability based on filter coefficients

is it possible to guess the stability of a filter with given coefficients a and b? I know that the right way would be to calculate the pole positions and check if they are in the unit circle but I think I read that there also is another method.

Cheers

• What research have you done so far? The non-recursive coefficients (what you call b) do not affect stability (except for the case of a zero-pole cancellation). – Juancho Feb 10 '16 at 18:36
• I've read that it's sufficient to check if the sum of the recursive coefficients stay bellow 1. Sadly, I have no clue where I read this and as far as I know, that's just not a legit way to check stability. However, I might overlook something as most scientific source in the web overcomplicate everything.... So you don't know of such a method either? – ruhig brauner Feb 10 '16 at 20:14