Keith KD1E wrote: I don't like the phrase "communication quality". It lower's the bar to accept anything that is marginal.
-------------------- It can mean that to many Hams. That term, like so many, are misused in Ham circles. Actually, "communications quality" is a very demanding level of quality. It means conveying all the critical information for *natural* sounding audio with limited bandwidth. "Natural" is a very important part of the definition. A really high-quality telephone is an excellent example of good "communications quality". Unfortunately, many cellular providers have "taught" us that less is better. Call up someone on a good wired "landline" and you'll hear what real communications quality audio is all about. That bandwidth is close to the same as we're using. I do very little SSB work too. My K2 has the SSB module in it, however, so I had to see how good it is. It's 'stock Elecraft' although I equipped the wideband capacitor set Elecraft sells for it. My K2 is equipped with the 160 meter module, so I can tune the upper end of the AM broadcast band with it here in the USA. Plugging a bookshelf speaker into it, my K2 produces broadcast audio every bit as good as most portable AM radios with similar speakers. The limitation is, of course, the 2.6 kHz bandwidth of the I.F. filter, but it's amazing how little that narrow bandwidth is noticed! That same I.F. filter is what shapes the transmit signal. The only remaining variable is the xmit audio channel from the microphone to the balanced modulator. We can turn the compression off, leaving the microphone as the major variable. And, in my experience, microphones tend to vary a great deal when it comes to quality! I use an electret element on my K2. I found that if I set up spectrogram so the waveforms exactly match those shared by many others, my voice sounds muffled. Like a lot of guys I have a very strong drone in my voice. We all do, but with guys it tends to be lower pitched. Lower frequencies use more audio power. The drone basically a "carrier" sound created by the vocal cords that we modulate with our mouth and lips. It carries most of the audio power and virtually *none* of the intelligence (the modulated part of the voice might not carry much intelligence either, but that's a judgment call for the listener to make). The problem I hear with my voice is that the drone hogs too much of the PEP if I set the filters to roll off as usually shown, and so the higher frequencies, the sibilances (the sound found in the letter "s" for example), are suppressed. That makes the audio sounds "muddy" or muffled. Moving the bandpass farther from the carrier reduces the drone and improves the sibilance. It makes a huge difference in the audio, IMO. That goes back to that line in the SSB manual about setting up the filters that I think is all-important: "...experiment with these settings, adjusting them slightly to obtain best voice quality." Ron AC7AC _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
