I have a 2004 RX330 without the ML system and without navigation. Has been working fine but all of the sudden, the right door speaker began to sound CRACKED, terribly! I figured after 10 years that the speaker was blown. Replaced that one speaker and the noise is the same. Went to Car Audio shop. They said that maybe it is the Amp? Could the amp be causing only one speaker to sound terrible or is it the radio itself?

Hate to replace the amp and it be the radio or vice versa. Is there anyway to test this?

If it is the amp, is there a relatively inexpensive amp that I could replace with and is that difficult to do?

Thanks