Linear Audio, your tech audio resource, continues to offer you stimulating, interesting and thought-provoking articles as well as projects you can build. Volume 7 is our 8th issue. Volume 7 starts of with a guest editorial by Joachim Gerhard who documents, from a personal view, his year long adventure through listening space to end up with theG-pole speaker. We welcome several new authors: Barrie Gilbert contributes the 1st part of several, starting with explaining how to use simulation for design in an intelligent way. Malcolm Hawksford draws on many years of teaching to give us an overview of equalization in audio. Giovanni Stochino reviews the results of many years of research covering different error correction topologies and discussing their pro's and con's.Several circuit design articles discuss advanced power amplifiers (David Zan), a simple yet effective low noise measurement amplifier (Burkhard Vogel), and a hybrid phono preamp (Stuart Yaniger). George Ntanavaras went on a quest for the ideal speaker enclosure shape for surround use and came up with the Prisma loudspeaker. Vol 7 has two reviews: Marcel van de Gevel read Morgan Jones's 2nd edition of Building Valve Amplifiers, and Stuart Yaniger and yours truly reviewed the Smyth Research Realiser A8, a 'listening room / speaker virtualiser'. And, traditionally, Stan Curtis in his column throws down a gauntlet with a possible way to explain (and cure) audible differences between different implementations of the same circuit. If you have an idea on how to verify his solution in a controlled way, let me know!