First you will need a new set of reeds in the key you wish to switch to and of coarse the sound will change, you are switching to a different key. Concerning the volume, it may change also especially if you are changing to a lower key there may be a slight drop. However, not to worry, just hook yourself up to the biggest and most powerful amp you can find and I assure you that you will not have any low volume problems. You will truly have the accordion from hell. If you play acoustically, just have your friends sit a little closer and I am sure that they will be able to hear every wrong note you play.