I'm running a 4x10 hlf series cab through svt 4pro. running it mono, so im not pushing it too hard or anything. Did a quick search on the subject, found no help. I'm not too familiar with horns, i don't really use it, but is that hum and or buzzing normal when you turn it on? Or is it about time to replace it.... when i bought it, it was used. So im not exactly sure on the history of the cab. Thanks much.