L3t speaker returned shipping from Line6 today, tested it and found the same results. Plugged in bass guitar and no top speaker sound 'or possibly very faint sound'. Plugged in a mic, same results. Top speaker has no hissing sound like the horn and bottom speaker when volume is cranked up. I'll check with Line6 tomorrow on the status, the PO had no information on what was done. It's possible it may have been tested and this is the expected result. Nevertheless, if anyone from the 250 plus hits has an L3t please plug in a bass or mic and test the top speaker, it takes about two minutes to test. I have renewed interest in your findings.