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

[Russ Edmunds <wb2bjh@xxxxxxxxx>]

I recall something similar from long ago. However I routinely use audio
filtering on my DX
recordings in playback mode, and even with a female voice, I rarely let
anything through
above 3 kHz, and it's very readable.

I still maintain the issue is economics, not audio intelligibility. That's
just a convenient
cover.


On Wed, Apr 23, 2014 at 12:58 PM, T. Hills <"thills"@sio.midco.net> wrote:

> 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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-- 
Russ Edmunds
15 mi NW Phila
Grid FN20id
<wb2bjh@xxxxxxxxx>

AM: Modified Sony ICF2010's (2) barefoot w/whip
FM: Yamaha T-80 & T-85, each w/ Conrad RDS Decoder;
Onkyo T-450RDS; Tecsun PL-310 ( 2);
modified Sony ICF2010 w/APS9B @ 15';
Grundig G8 w/whip; modified Sony ICF2010 w/whip
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