Sometimes the speakers sound clean, sometimes garbled with one or two losing signal at random. It all seems very dependent on speaker and transmitter placement and how much signal inference there is from other devices. All volume wheels/buttons, channel select and speaker output have been tested and are working. Only channels 2 & 3 would connect to both speakers. Channel 1 would connect to only one speaker. The speakers seem to work best with about a foot of separation and at a minimum distance of about 6 feet from the transmitter. There seems to be an issue with the transmitter output cable that can cause signal loss if bumped, though the interior connection looks good. If you have any requests or questions, ask before purchasing. Requests to remove packing slips or invoices will be ignored.