[Elecraft] Conditions, shmonditions: DXing anyway

Jim Brown jim at audiosystemsgroup.com
Fri Sep 21 04:03:53 EDT 2018


On 9/21/2018 12:22 AM, David Cutter via Elecraft wrote:
> On a related tack, I am often surprised at how high the radio volume has
> become in the club shack. On turning it down, it is quite a relief on the
> ears and yet perception of the signal we are listening to improves.
Two possible reasons. First, if a radio has a relatively low power audio 
output stage, higher sound levels are more likely to drive it into 
distortion. Loudspeakers, especially cheaper ones, also distort more at 
higher power levels.  Second, reverberation and echoes are "noise" as 
far as speech intelligibility is concerned; while that IS a linear 
ratio, human hearing is not, so reducing the level may bring those 
echoes/reverb down to a level where it is less perceived.
>   It is also significant that a separate loudspeaker on a shelf being more in line with our ears provides significant improvement in our ability to "hear" the station.

Exactly right, and that is ENTIRELY the result of 1) loudspeaker 
directivity -- lows are more omni-directional from nearly all 
loudspeakers, while the highs becomes increasing directional. [This is 
due to wavelength of the sounds as compared to the size of the 
loudspeaker diaphragm.] When we and the loudspeaker are facing each 
other, we're getting both highs and lows. When the speaker is turned 
away from you,  we hear the lows but not the highs, AND those highs 
spray to whatever surface they face, and bounce around to create echoes.

2) The higher speech  frequencies are most responsible for speech 
intelligibility, lows provide almost none.

>   Louder is not better.

Louder is only one part it.

73, Jim K9YC



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