A couple of non spiritual (read:practicle or realistic) things to keep in mind. 1)Your electricity varies all day, every day. The more it varies, the more your system will change. I believe audiophiles in general still don't understand how important power delivery is to the performance of their systems. 2)Your hearing can vary day to day as well. Spend an entire day listening to a jack hammer outside your window? Better believe this won't be a championship listening session day. Try this on for size: listen as late at night as you can, the electricity is cleaner and the ambient noise is lower. Turn off as many electrical items in your home as you can and wear ear plugs for 20 or 30 minutes before sitting down to listen. Remember to remove them SLOWLY and carefully to avoid a light pop that will negate the usefulness of having worn them. By the way, buying a power generator usually isn't helpful, having a beer or a glass of wine usually is!
Mario
Mario