hi just put a sony h/unit cdx-m8805x into the car and on the back of the unit it has a sub out(mono)lead. can i connect my sub speakers to this lead or do i need an amp? thanks.
If you are talking about your sub preout, the one that you hook your rca cable to, you can't hook speakers up to them. As far as bridging tweeters, that wouldn't be a good idea. For one, the amp in the head unit isn't designed to be bridged and in doing so, you will do irreverible damage. Second, you will not gain anything out of bridging tweeters. It will not increase the power or volume. I assume you are bridging two tweeters with two channels. If this is the case, all you did was take two channels and make them one. That doesn't increase you power. Bridging only works if you using one speaker.