As has been pointed out, there are many conflicting standards for audio metering. One major issue is: just what are you expecting to see? Do you want an indication of loudness (maybe some type of "average" level) or are you interested in peaks? Or maybe some (hopefully useful) combination or permutation of loudness/average/peaks. The VU meter gives a type of average indication (some will say VU is not necessarily a good indication of loudness).
Years ago, as sort of an experiement, I replaced the VU meters in one of the boards at a radio station I worked for with BBC-style Peak Programme Meters. IMHO they were a major improvement. They had much better high-frequency response, the were much more responsive to peaks and the scale was much more linear. (I had custom scales made with -20 to +4 markings, rather than the BBC-standard 1 to 7 marks.) Anyway, I found that the ballistics of the PPMs vs VUs such that it was best to adjust the PPMs so that "0" was +8 dBm, rather than +4 dBm as on a standard VU meter. When operators used them as they would normally operate, that is, trying to keep the level below 0 most of the time, it actually ended of being a little conservative compared to a normal +4 dBm VU meter. With normal program audio "0" on the +8 dBm PPM would generally run around -3 or -4 on a +4 dBm VU. This is a very general split because it would vary with the type of audio. Of course, with sine wave "0" on the +4 dBm VU would be -4 on the +8 dBm PPM. So in fact, had the PPM and the VU both been calibrated to +4 dBm, the PPM would have averaged about 7 to 8 dB higher with program audio even though they would have matched with sine wave. Metering on digital audio equipment often shows three simultaneous indications. A bar to indicate the "persistant" level, a peak-hold dot to indicate the recent "peak" level, and an "over" indicator with very fast response. So far as the "eye candy" argument, there are some who might argue that VU meters have always been "eye candy" to some degree, when it comes to measuring real world program audio levels. -- Timothy Stockman ------------------------------------------------------------------------ Timothy Stockman's Profile: http://forums.slimdevices.com/member.php?userid=8867 View this thread: http://forums.slimdevices.com/showthread.php?t=35742 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
