Sub very quiet help!!

• RCA setting set to speakers (does the head unit opt you to chose either speakers / subwoofer???
  
• If it does not give you the option, chances are, you are running them as speaker and it only jumps when there is bass thump
  
• Low voltage from head unit - Those and most head units these days don't have a high voltage output hence your only hear something when you turn it up 3/4 volume and your amp gains set high
  
• Again, agree with my man, Jeffdachef to try another head unit to see if the problem persists,   If you can borrow from a mate and run one, then that can be confirmed as well
  
• The head unit could be faulty too, so get a replacement and / or upgrade to a higher spec unit with more RCA's as the one you have is only entry level one and does not offer other features such as subwoofer volume / subwoofer frequency choice,/ subwoofer volume/ phase option. Also get a unit with built in high pass filter so you can run your front and rear speakers on high pass.
  

Steve McCarthy said:

Hu is a jvc  kw-m24bt 

There is a volume control and it's all the way up. Thanks for the reply

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