Bought 1978 kornerhorns with Crown pre-amp and McIntosh MC2300. Early years I used system more. Had system in storage for 5 yrs. Gave it to son-in-law. It has been sitting in his home for 3 yrs. Recently connected Sony CD player, Crown Tuner and Bluetooth reciever. Seems to play mid-range and upper but no bass. Had pre-amp and amp checked. They both meet specs. What could be wrong with speakers?