Purpose of this thread and my title question are purely theoretical. I hope people keep this premise in their mind, if and when this thread starts to have opinionated comments favoring or bashing either one of the formats. Feel free to tell your opinion about CD or LP, even though the purpose...

I have a few sound science questions related to speaker voice coil and magnet. I have been told that speaker sensitivity is mostly determined by how "strong motor" the voice coil and magnet together are. Some other aspects also affect speaker sensitivity (like weight of the moving mass), but...

Why toroidal transformer is supposedly the best type of transformer? What is the scientific evidence behind this common claim?

I stumbled to this on-line, Harmony Design's Ear 909, fully balanced/bridged headphone-amp.   More info here: http://www.harmonydesign.se/index.php?sid=62&katID=9&prodID=22 http://www.harmonydesign.se/press/pdf_33.pdf   Harmony Design calls it kompromisslös hörlursförstärkare...