> audio without EQ> > Any thoughts?
>Edwin MarzanAB2VW
According to hams on both sides of the issue, bandwidth is both the problem and
the cure, but you can't argue with the modern science of sound, based on almost
80 years of solid research since those outdated telephone studies were created:
"By extending telephone bandwidth to 7 kHz and beyond, it is clear that one
can markedly reduce fatigue, improve concentration, and increase
intelligibility. It is also clear that this improvement is even more
significant in real-world room situations, where the sound is often degraded by
reverberation, projector or air conditioner noise, accented speech, and other
acoustic problems that are encountered in business telephony. Additionally,
extending telephone bandwidth below 300 Hz brings a significant increase in
presence and realism. In his 1938 paper discussing the bandwidth of the
telephone system, AT&T's Inglis noted that, 'Frequency limitation is
essentially an economic one, subject to change as conditions change.' Here in
the twenty-first century, economics and conditions have changed as Inglis
predicted, and modern telephony is now in a position to deliver on the promises
of wider bandwidth and clearer speech."
http://www.polycom.com/common/documents/whitepapers/effect_of_bandwidth_on_speech_intelligibility_1.pdf
That said, everyone knows wider bandwidths should not be employed on very
crowded amateur bands, nonetheless, the key to intelligibility and fidelity is
b a n d w i d t h. About 8 KHz is super and 6 KHz is very good. When
transmitting through a 3 KHz filter, some kind of EQ is necessary to relieve
muddiness, unless the microphone element attenuates the low end dramatically,
beginning at about 150 Hz and as long as it has a corresponding rise of about 6
dB at about 2 KHz. Bob Heil knows this and his mic's are designed accordingly.
The EQ built into the PowerSDR software does a great job. If the next hardware
edition of Flex-SDR has a preamp and 48v phantom power, I'm there.
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