Re: [IRCA] [NRC-AM] NAB proposes TIS Filter change to 5 KHz

["T. Hills" <"thills"@sio.midco.net>]

I remember reading a paper from NASA about understandability and 
frequency when I was in college (Many Moons ago).
I think the numbers I state are the same as in the paper but could be 
off but the general idea is the same.
It was found that the understandability of the average male voice was 
not decreased when frequencies above 3000Hz and below 300Hz were 
filtered out but for the "average woman" it was 400Hz and 4500Hz 
respectively. The Author of the paper suggested a switchable voice 
filter that could be set for male or female 
Operators/CapComs/Astronauts. I sometimes wonder if men tending to lose 
hearing on the higher end first isn't a survival tactic ;)
This wasn't an issue until the Shuttle for the US and if I recall it was 
suggested that the Soviets had been using either a switchable filter or 
a wider one since the early days of human space flight.
Tim Hills
Sioux Falls, SD

On 4/23/2014 11:02 AM, Russ Edmunds wrote:
> I'm puzzled as to why 3 kHz isn't good enough. I can't say that I've heard any TIS stations which
> were functioning properly which were difficult to hear. I'd guess this might be an economic issue
> relating to the added costs of filtering, in which case a change to 5 kHz won't change anything.
>
>
> Russ Edmunds
> 15 mi NNW of Philadelphia
> Grid FN20id
> <wb2bjh@xxxxxxxxx>

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