Here's a cheap isolator :
Get a block of concrete or a marble chopping board.
Place on top of 2-3 inches sheet of soft foam, or
inflated bike inner tube.
Place CD player on top of the concrete / marble.
Not perfect, but worked for my turntable, when I suffered from bass feedback, and only costs about $10.
If it works but it is visually offensive then replace with a high-cost audio isolation platform.
Get a block of concrete or a marble chopping board.
Place on top of 2-3 inches sheet of soft foam, or
inflated bike inner tube.
Place CD player on top of the concrete / marble.
Not perfect, but worked for my turntable, when I suffered from bass feedback, and only costs about $10.
If it works but it is visually offensive then replace with a high-cost audio isolation platform.