Depending on the sub you can you a speaker out like you mentioned or I prefer a preamp output if available, that way the volume will go up and down with the volume control on the amplifier.. Or you can use a tape out and adjust the volume on the sub. I would suggest that you teach him not to overwhelm the music with the sub.
Woof Woof need a little help
Looking to buy a powered subwoofer for my son so he can hear his rap in all its "glory". I am unsure if he can use it with his current equipment. He has an old Yamaha (1979) integrated amp. Can he plug the sub into the "B" speaker inputs and set output to A & B or do subs require a special input? Thanks for helping the ignorant.