On 8/7/2013 10:40 AM, Alan Jump wrote:
As I recall from my broadcasting classes years ago, human speech has a
"typical" bandwidth of just 3KHz. "Normal" human hearing, IIRC, picks up
frequencies from 20Hz to 20KHz.
If someone has a copy of Schrader's "Electronic Communications" ready to
hand, the specifics should be in there somewhere.
Not quite -- audio and acoustics professionals know that there are
components of human speech from around 100 Hz to 10 kHz. What IS correct
is that audio bandwidth of about 500 Hz to 3 kHz is entirely sufficient
for good speech intelligibility. Bell Labs, the R & D arm of AT&T, and
the greatest such lab on the planet for the first 80 or so years of the
20th century, learned this more than 100 years ago. Extending bandwidth
at both ends makes the voice more natural, and usually more pleasing,
and extending highs to 5-6 kHz improves intelligibility slightly, but
extending lows often hurts intelligibility.
73, Jim K9YC
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