Any top amp tech, thoughtful manufacturer, or clued-in player will tell you that your speakers are responsible for an enormous chunk of your tone. Despite this fact, the speaker is often the last thing a player considers in any quest to overhaul an unsatisfactory sound. Replacing a stock speaker with a different type can instantly alter your amp’s sound more than any other single change, and it can be the simplest, quickest, and potentially cheapest means of converting a mediocre combo into a raging tone machine.
All About Speakers
Source: Guitar Player