Thanks, exactly what I wanted to know. It might have been the amps I used in the past but I was running a Fosgate 500x2 at 2 ohms vs 250x2 at 4 ohms but couldn't audibly hear a difference other than SPL. I understand an amp will work harder. I ran that amp for years. Aside from metering differences with various equipment seeing the difference how much difference can someone hear with 2 ohms vs 4 ohms given the same quality and power output is equal?