The spectrum you see here is an ostinato bass-line from a Boards of Canada track called Happy Cycling. (The really low stuff starts around the 5:00 mark.)
The lowest note in the bass line is centered around 25Hz, is pretty loud, and it is absolutely musical in nature. Lacking a subwoofer, or suitably large main speakers, these musical notes are never heard. Many systems struggle to cope with such energy, and transform these sounds into higher-frequency harmonic distortions.
I believe “Golden Ears” are a bit of a myth. Listening takes practice and experience, and there is nothing special about the ears attached to a sound engineer or musician. I mean, we don’t say that visual artists or critics have “Golden eyes” now, do we? No, they’ve spent a lifetime learning their craft, from crayon scribbles to oil paints.
This program from Harman International trains your ears to be sensitive to various kinds of sound processing and distortions.
Folks, I have another refurbished Adcom GFA-555 II ready for a new home! This is a terrific amp. Not only is it 110% electrically, but as you can see, it’s in excellent cosmetic condition. The face is nearly perfect, and there are just a few minor ticks here and there. Click on the photos to see it in high-resolution.
This is a thorough refurbishing! All electrolytic capacitors have been replaced with audio-grade types from Nichicon, WIMA or Panasonic. Even the big power-supply filter capacitors are new, something many refurbishers leave out, or charge extra for, because they are expensive. Output transistors changed to the excellent On Semicondutor MJ21193/94. Drivers changed to ON Semiconductor NJW3281G and NJW1302G for greater voltage headroom.
If you’re like me, and you like huge stacks of stereo equipment, you may be wondering how to keep it cool! My quad-amplified system requires four amplifiers, and I can’t really give them all enough room to breathe. Plus, they look pretty sweet stacked on top of one another!