Powered mixers are necessary for driving unpowered Speakers, usually in a live situation. Many of the mixers we have in stock contain on-board effects, especially Behringer Powered Mixers and Yamaha Powered Mixers . This is a useful space (and money) saving feature & means it isn't necessary to run your mix through external effects processors. The only slight drawback to a powered mixer is weight, but once it is installed in the club or bar, that should not be an issue. As with everything we sell, all our powered mixers are supported by our price & satisfaction guarantees and free standard shipping now applies to all orders over $25, including many heavy items.