Originally Posted by
Ian Mackenzie
Can you post the schematic?
Typically they bypass non polarised capacitors in the mid and Hf filters with small value polypropylene caps.
If they are not bypassed you could try that as a first option. If your budget will cover it use film caps in the mids and highs and Change couple with Solen Fast capacitors gives a good result
Non polarised capacitors usual have a low esr at low frequencies with large values so they are okay for low crossover points > 300 hertz. People have lots of opinions on the subject mind you and l prefer to Biamp removing the L (inductor).