Excellent listener questions have been flowing in, and Darren and Duncan pick two good ones to discuss at length in this episode of The Hifi Podcast.Will asks what elements of different products the guys have seen when popping the hood of a device or poking around the inside of a speaker. Darren shares his feelings about Audio Research PC boards and layout, and Duncan brings up the inside of Vinnie Rossi equipment and some elements of his favorite speakers.The discussion wanders toward packaging, where excellent design can make a difference, and then wanders further into SNAFUs and ways that package and product design can go horribly wrong.The second question centers around tubes - where to add them, whether to go modern or vintage, whether to go all-tube or hybrid and asks for opinions on several modern tube amplifiers. The guys tee off on this one, as they are both big fans of tubes in a system, and each of the points is covered in detail.Before the questions, the episode begins with Darren's ongoing DIY super subwoofer project and Duncan's latest DIY endeavor, a speed build of a pair of mini monitors for his testing system at The Music Room.This week's album pick centers around a wild guitarist from Norway, and highlights the breadth and depth of his discography.