[ARC5] dB Power Apples and dB Voltage Oranges, was Re: Selectivity Ratings...

[Brian Clarke]

You may be referring to the work of Fletcher and Munson in the Bell labs in about 1938. However, their work was based on laboratory experiments with young listeners. 

We now know that the ear's ability to pick up slight differences depends on, among other things:
  a.. age (presbycusis)
  b.. frequency
  c.. purity of the frequency (bandwidth, distortion within hearing range)
  d.. genetic differences
  e.. one ear or both
  f.. history of noise exposure (eg, working around tin bashing shops, repairing naval vessels, working on rocket motors)
  g.. history of hearing damage (eg, tinnitus)
  h.. disease of cochlear nerve and other parts of the hearing apparatus
  i.. duration at particular ambient noise levels
  j.. the 'reward' for hearing something.

1 dB is a purely mathematical definition and has nothing whatever to do with human hearing acuity, consensual or otherwise. WRT your last sentence, keep wondering.

My own experience from working in sound recording studios is that a 2 dB difference is about the limit that any reasonably experienced person can reliably discern.

73 de Brian, VK2GCE.

On Wednesday, October 30, 2013 12:25 PM, Wayne said:


> Good CW operators  
> can hear as little as 1.5dB change and oft times even under 1 dB will bring  
> a very marginal signal out of the noise. 
>  
> I seem to recall that the original 1 dB definition was based on a consensus of the smallest power change in an audio circuit that could be discerned by the human ear. I've always wondered how they conducted the tests to arrive at that, though.
> 
> Wayne
> WB4OGM