Who said anything about "speaker output"? I'm talking about
line-level output between the unit and a PC for streaming/recording purposes. A 300Hz high-pass filter on said line would virtually eliminate PL hum (60Hz ground loop hum is already filtered out with a ground loop isolator/isolation transformer). I'm well aware of communication speakers whose frequency response starts at 300Hz, but again, this thread isn't about amplified signals. In fact, being a musician for nearly 30 years gives me some insight most don't have with regard to these applications dealing with audio signals.
