My PDX-5 will only accept line level input i.e. low level rca input, if you feed it speaker level input it will be too loud. Not sure if this answers your question.
535d LCI, Xenon Adaptive Headlights, ACC 2 (Stop and Go), Lane Departure Warning
Retrofits M5 heated/lumbar/memory and active backrest adjustment seats, rear heated and folding g seats, SAT Shifter, paddles (SA2TB), HUD, Rear blinds, Electric steering column, SA430 Folding and EC Mirrors, High Beam Assist, CIC, COMBOX Telematics, DVB-T TV, JBL MS-8, JL HD900/5 + HD600/4, Morel HO II, Morel Integra XO, JL 12W6v2 and Jehnert in Audio.