What Is Bridge Tied Load, or BTL?

Darren answers a question that has been in Duncan's mind for a while: What does Bridge Tied Load or BTL mean as it relates to amplifier design? The guys answer a question about properly powering a big set of Dunlavy speakers from a listener who stumbled across a big pair for a great price. The album of the week is only found on Bandcamp, and it features a couple acoustic virtuosos Duncan has followed for years.