On 3/30/2014 10:38 PM, Stephen Bloom wrote:
especially something like "fatigue" is pretty subjective
As a retired pro audio engineer and member of both the AES and the Acoustical Society, I've had to understand issues like this. The study of human perception and reaction to sound is called psychoacoustics, and the Acoustical Society has many members studying this stuff at very high levels.
It is VERY well known that listening fatigue related to the listening system correlates with two factors -- distortion and loudness. Poor spectral balance is a form of distortion, but the most obnoxious distortions are non-linear distortion -- what we try to describe as harmonic distortion and intermodulation distortion -- and distortions associated with A/D and D/A conversions.
As Al Lorona has noted, the distortion produced in ANY system is strongly related to signal levels, and how gains are set. Do it wrong and you can make things sound nasty in a hurry; do it well and everything is mellow. if you think your radio is fatiguing, you probably don't know about all that great stuff that Al posted. As to the digital distortions -- much of what we hear occurs if we are listening too close to the the top or bottom of the converters. Again, getting the gains set right avoids that.
I measured my first K3 (in the first year of production) and found excessive distortion in the Line Outputs that resulted from wrong-headed design of the output stage (it was done by a digital guy, who added resistors between the output stage and the transformer because he incorrectly thought audio stages were"600 ohms" -- they have not been for at least 50 years). I communicated that to Wayne, and it was quickly corrected.
73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
