Mark,

"Low noise floor makes a huge difference. "

Agreed.

"Measured mine using Earthworks M30BX mic, 1021 ZDT pre-amp and TrueRTA."

I will have to try that at some point. I have TrueRTA and the ETF mic/pre-amp but never used TrueRTA for SPL since it has to be calibrated every time you use it for SPL.

Shawn

.