Equipment insurance coverage

Talk to a qualified home insurance broker.  I’m fairly sure that you don’t go onto insurance forums and ask for audio advice.  

Already did. And they can't find coverage. Thank you for your response test pilot.

FWIW, most property policies are fairly broad and include coverage for all risks, and property, which are not specifically excluded within the policy. I suggest you read your policy! Then I suggest that you try contacting your insurance company direct if you can and ask them. It looks to me as if your agent is reading your policy looking for an affirmative statement which sez that audio equipment is insured. I'm not surprised that he didn't find such a statement. 

Typically (in the UK) 'valuable items' over a certain amount need to be listed individually, but there isn't necessarily an exclusion under an 'all risks' policy. You just need to let your insurer know that you have X, Y and Z among your household content. I have never seen an exclusion specifically aimed at audio equipment.