Looking for a good 15" speaker for using with my 25 watt push pull tube amp 6l6 intended for hi fi,of course I know I need a high efficient one. but what about wattage rating,Can you give me a rundown on specs I need to look for. What is the difference in Guitar and Hi fi?, I am building vented cabinets or possibly open back cabinets and am plan on using a horn for a 2 way system. Nothing fancy just a 30X24 box Any brand or specific speaker I should look at? used or new?