On 5/1/2012 8:44 AM, Fred Jensen wrote: > Jim, K9YC, pointed out to me that I can get > close to 30 dB of equalization from the RX equalizer simply by starting > the lower freqs, which is where I hear, at -16 dB, and then setting the > overall audio level to HI and running the AF gain higher. This > theoretically gives me 32 dB of differential equalization. I've done > it, it's nowhere near enough for me, but it sure does does help.
An additional clarification about why and how this works. Hearing loss tends to vary with frequency from person to person, depending on their noise exposure and various physical conditions that can cause hearing loss. In general, hearing loss tends to be greatest at the higher frequencies. The best hearing aids use very sophisticated DSP to compensate for the frequency response of he loss, and use directional mics. Etymotic Research is one of the major mfrs of the DSP and the mics, and their engineers are members of the Chicago section of the Audio Engineering Society. I know some of them fairly well on a professional basis. The frequencies that carry nearly all of the intelligibility of human speech are between 400 Hz and 5 kHz, and the range between about 700 Hz and 3 kHz is the most critical. From an intelligibility point of view, everything below 400 Hz is noise. Since hearing loss is greatest at higher audio frequencies, we can set the RXEQ in the K3 for maximum suppression of the four lowest bands and maximum boost of the three highest bands. This provides about 32dB of compensation for "typical" hearing loss. Fred has pretty severe hearing loss, so it's not enough for him, but as he notes, it helps. For many it may be enough. I have moderate hearing loss, and when my wife and I are listening to NPR or watching movies on Netflix, I turn up the highs and turn down the lows to improve or understanding of speech. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
