The nominal level at which an audio system operates. See Standard Operating Level.
"I just received my CD's on Friday. It was an awesome experience!!! The quality was unbeleivable, much better than the originals. I also like the way you reproduced the cover material so well. And above all your service was, quick, reliable and high quality!!! I am preparing my next batch to send to you as soon as I can. Thanks again for the ..."