▁produced ▁for ▁other ▁artists , ▁they ▁recorded ▁what ▁would ▁later ▁be ▁regarded ▁the ▁California ▁Sound . ▁Author ▁Ir win ▁Ch us id ▁noted ▁Wilson ▁as ▁an ▁" ir onic " ▁example ▁of ▁out s ider ▁music ▁for ▁perhaps ▁being ▁one ▁of ▁its ▁biggest - s elling ▁artists . ▁He ▁explains ▁that ▁Wilson ' s ▁history ▁of ▁tor ment , ▁subst ance ▁ab use , ▁and ▁" lo opy " ▁material ▁" cert ify " ▁him ▁as ▁an ▁out s ider ▁artist . ▁ ▁Or ch estr ations ▁It ▁was ▁unusual ▁among ▁rock ▁groups ▁that ▁Brian ▁wrote ▁his ▁own ▁arrang ements . ▁This ▁included ▁his ▁own ▁string ▁orch estr ations , ▁which ▁ly ric ▁collabor ator ▁Tony ▁Ash er ▁referred ▁to ▁for ▁their ▁odd ▁vo ic ings ▁and ▁classical ▁style . ▁He ▁was ▁surprised ▁to ▁learn ▁of ▁Brian ' s ▁arr anging ▁ability , ▁recall ing ▁Brian ' s ▁" e conom ic " ▁use ▁of ▁a ▁relatively ▁low ▁number ▁of ▁players : ▁" B ecause ▁if ▁you ' ve ▁got ▁ 4 0 ▁strings , ▁somebody ' ll ▁be ▁playing ▁the ▁right ▁notes . ▁But ▁when ▁you ' ve ▁only ▁got ▁ 4 ▁or ▁ 5 ▁or ▁a ▁small ▁number ▁of ▁voices , ▁everything ' s ▁aud ible , ▁and ▁there ' s ▁nothing ▁to ▁dist ract ▁people ' s ▁ear ▁from ▁what ▁you ' re ▁writing ." ▁ ▁Session ▁bass ist ▁Carol ▁K aye ▁noted , ▁" We ▁had ▁to ▁create ▁[ inst rument al ] ▁parts ▁for ▁all ▁the ▁other ▁groups