Car Starting Problem

My 1998 Toyota Corola has a starting problem. When I turn the key to start my car after a few hours of being shut off, it makes a clicking noise, and everything in the car including the sound system and dash lights turn on but the engine doesn't crank over. There is no response from the engine. When I turn the key for a second time, the car starts up fine. Every now and then I need to turn the key more then twice in order to turn on the car but not very often. I have had my battery and alternator tested and they all came back as working and charged properly. I also just replaced the spark plugs. The problem still persists. Would You be able to help me?

(I also have an aftermarket audio system in the car with an amplifier and a subwoofer)