Tweeters with a lower impedance rating allow more electrical signal through and a better ‘flow’ of sound. While you should always remember that a lower impedance rating will allow more electricity through the speaker, this doesn’t mean that you should always go for the lowest option available. You need to match it up with your existing sound system. A lot of audio systems are designed to work with a specific level of tweeter. Using mismatched devices can end up causing problems as your sound system may not be able to handle the impedance rating of the tweeter which you have bought.