Dave Paananen, who directs our engineering, and I were in Music Room One auditioning a couple of changes to circuitry recently.
We were trying to figure out which, of several types of op amps, were more musically correct. Of course we do this by simply gain matching and then listening to the same track of music and comparing the two for best presentation. Sometimes it's difficult because you'll hear one aspect that is better in one amp while another aspect is better in the other. Which is right?
We were listening to Harry Belafonte's live performance at Carnegie Hall when Dave asked me to play the audience clapping again. "Not the music?" I asked.
"No, the clapping. Let's hear that on both units." While I was focusing on Belafonte's voice and the small orchestra playing, Dave had been questioning the audience response. As we went back and forth I was astounded by the results. This was not something small. Indeed, the difference between the two areas of the recording were huge. In one example the clapping of the audience was sharp, bright, confused and almost irritating. Playing the exact same part at exactly the same level on example B sounded entirely correct.
What's interesting and new to me about this test is two fold: the magnitude of difference and how the aggregated clapping seemed to so disturb the amplifier's performance.
With respect to magnitude we are not talking about shades of gray here, we're talking night and day. And that's really interesting to me. It was far easier to discern which amplifier was right using the clapping than it was music, which tends to be a bit more subjective.
But what really gets me is how one amplification device could get so "upset" when the activity level on the recording got so complex. I want to say intermodulation distortion but we've measured both of these amplifiers and they are nearly identical in this respect (as well as others we can measure).
My conclusion is that we've found yet another benchmark for audio amplification devices to pass before they can go out the door. It's just strange that it should be such a surprise after all these many years of doing this.
Thankfully there's always something new to learn. I'll give a round of applause to Dave for this discovery.