I have a KLH R5100 Receiver. The manual says to only use 8-ohm
speakers, but I have a 4-ohm JBL Pro Performer series subwoofer (note
- it is an older, non-powered subwoofer). What would happen if I
connected the subwoofer to the receiver?

Also, is there any KLH support on the internet? I can't find anything,
even at the KLH website. Are they still in the receiver business?

Thanks in advance for any help.