>>> The End-to-End audio path is flat through the repeater. >>> There is no de-emphasis or pre-emphasis going on inside >>> the repeater audio path. The repeater receiver leaves the >>> audio alone, the controller leaves it alone, and the >>> repeater transmitter leaves it alone. >> In reality that never happens 100%... the receiver, audio >> interface circuit and the transmitter modulator always "color" >> the audio to some degree.
> But they don't do it intentionally as a pre/de-emph circuit does. True... but it happens and how pure does one want to get with labels? People are sticking the flat audio label on a hopefully "transparent to voice audio" repeater operation and they assume all is well and dandy in the suburbs. But in reality every type of repeater audio layout is colored to some extent. Just a question of how much and if you also consider just the voice audio or the composite with ctcss. > If the interface is done right, it won't color it at all. I have yet to see the 100% transparent audio repeater. I do know that a lot of people have spent a lot of time trying. Maybe close but no cigar... >>> That is flat audio through a repeater. >> Actually... it's better described as "transparent audio through a >> repeater" > Actually, 'flat response' is better. Since the de-emph/pre-emph > changes the audio intentionally, the term 'processed audio' is > more applicable to such a repeater. I and probably most of the two-way radio industry do not agree. It's really about what part of the hardware you are actually talking about. Most times when we hear or read about the term flat audio... our attention is normally directed toward the demodulated audio sections of the repeater hardware. Or at least our attention should normally be directed at the demodulated audio stages. When you look at the global repeater audio through-put as being flat you should probably learn to call it transparent. A much better label, which doesn't give people information converse to conventional or traditional two-way radio industry terms. When you say flat audio... we're normally thinking in and around the repeater demodulated audio stages. When you say transparent to voice audio we're normally thinking about the overall operation of the repeater system. >>> In practical real-world service, every users transmitter >>> pre-emphasizes the audio on transmit, and every users radio >>> de-emphasizes the audio on receive. The repeater should leave >>> the through-put audio alone, and your repeater will sound just >>> like simplex does. >> I hope not... most ham radios are over deviated. I depend on my >> settings to clean/limit many of the users ctcss and voice >> deviations up quite a bit. Simplex audio sounds dull and weak >> compared to a well thought out repeater audio chain. > If it sounds dull and weak, that is because the USER RADIOS made > it that way. A properly set up repeater will not alter the audio > at all. So... are you going to hold a clinic for user radios to crank down (properly set) the voice, ctcss deviation and audio levels? We did at local club meetings for many years and could never seem to keep up with all the new radios. So we set our repeaters up to clean up most of the average radios. Everyone sounds like a breath of spring... well most everyone. A few guys still need to brush their teeth more often. What we like as our properly set up repeater does alter the average users audio so we can better keep our sanity in check. But that's what we like and use based on our experience. > Any change you make to the audio will have a negative effect on > half of the users. For example, if you boost the highs, you will > make a bassy radio sound better, but a tinny radio will sound even > more tinny and a properly set up radio will be made to sound tinny. We don't mess with repeater audio as you decribe above. > Fix the problem at the source - don't try to make the repeater > correct for problems in the user radios. Typical voice and ctcss over deviation? Not going to happen in most cases. Just just learn to expect and deal with it... Most Amateur Radios are cranked up as sent-out or sold from the Dealers. Pretty much like the Borg... >>> No audio processing should be done inside the repeater, period. >> Another whole topic... but I like the sound of repeater audio with >> a slight amount of voice audio processing/compression. > Then add such processing to *your* receiver. Don't try to 'force' > your tastes on everyone else. Someone else may think what you > think sounds good sounds terrible. > Joe M. Never had anyone say our repeater audio sounds bad Joe. Everyone likes (so far) what we do. Everyone goes in different and everyone comes out standard deviation clean, clear and loud. No squelch crash and real ctcss with revese burst. It's very sexy... cheers, skipp
