On 3/25/2014 7:30 PM, Tom Fine wrote: > > You must have sent that message from a "smart" device, or you've taken > up typing with your tongue! ;) > > To your point, that's what I was saying, that I suspect the problems > Emerick heard were in the audible band, driven by what was happening in > the ultrasonics, or causing the ultrasonics (that may be more directly > your point). > > I think it's also been shown that a big problem with early CD technology > was the design of the low-pass filtering on the DAC side of things. If I > recall, Sony's design did it in the analog realm and sounded particuarly > "harsh," "brittle" and "metallic." Philips did someting additional in > the digital realm (I might have it reversed), and their DACs tended to > sound better, according to reviews of the time. I suspect what people > were hearing was ringing from the brickwall filter, in the audible bands. No, you have it right -- Sony did it in the analog realm in the first CD players and D/A converters (PCM-F1), while Philips did digital, then much milder analog filtering in its players. Sony also did its anti-alias filtering in the analog realm, which may account for more problems. I didn't hear a digital recording I could stand until Sony brought out its second generation of DAT recorders, with 1-bit A/D conversion followed by decimation/dithering to a 16-bit word, in about 1991. My tongue is sore. Peace, Paul