The best word to use IMO is audio LEVEL, since it is a less ambiguous term. Level is traditionally expressed in decibels in the audio engineer world.Thousand Ways wrote:Thanks, Selig. Re: Boggg1's post, I meant only the reference to the flow diagram. Agreed, his post is very interesting.
Anyone have any thoughts on my questions above (post dated Tue Sep 29, 2015 1:10 am)? Any answers much appreciated. This gain versus volume issue is melting my brain.
Gain was traditionally used for amplifiers to specify the ability to increase the level, but is now pretty much synonymous with level.
Volume is a term that is similar to gain and loudness, and has also become fairly synonymous with level. It is typically a dimensionless value often expressed as a percentage.
Loudness is a more specific term (while also being a more ambiguous value), as it is the human perception of level/volume. As such it is more difficult to quantify. Like temperature, it is difficult to get all listeners to agree on what is half as loud or twice as loud, as it is difficult to get folks to agree on what is twice as hot, or half as cold. There are attempts to define loudness over the years, but as humans tend to average what we hear when perceiving loudness and therefore there are many variables involved. A steady tone would be the easiest to measure, but things get more complex with music as the level may change drastically from bar to bar - if you measure one bar you get one value, measure the next you'll get another. Since humans average what we hear, loudness measuring tools also must do this, but there has always been some disagreement over exactly how to do this. Even the current standards have various ways to interpret the reading of "loudness" depending on what you are attempting to do - are you measuring a single song, a broadcast stream, a TV commercial, etc. As one example, imagine an extreme example: a TV commercial with a loud sound at the beginning and then silence for the remainder of the commercial while there is text on the screen - how loud is it?
To make matters more confusing, let's just focus on how audio level is measured. There are different metering systems to measure level, including VU and Peak which can show widely different values for the same audio signal. This is why it's so important to understand this issue and to use the correct metering tool for the job. VU was an early attempt to measure loudness, and so it's an "average" value. As such it will always read lower than Peak levels. In analog systems this system was more important since there wasn't a well defined clipping point. But in digital systems the clipping point is very specific, and as such peak levels are widely regarded as the best way to measure signal level in a digital system. After all, it's the peaks that will clip first!
The difference between Peak and VU levels isn't fixed and can range anywhere from 6- 30 dB or more! Because of this discrepancy you can have a VU level that is WELL below clipping while the actual signal level is well above clipping! This becomes frustrating in Reason because the channel meters show VU, and well intentioned folks will tell you to set all channel levels to a specific point such as - 10 dBFS. The problem here as I've already mentioned is that at that VU level you are most likely already clipping the mix. Additionally, with all tracks at the same VU level, some will be wildly clipping and others may only just clip in a few places if at all! It is for this reason it is suggested to use PEAK levels when working with digital audio in regards to setting levels, and VU when judging relative loudness. Folks like Paul White at Sound on Sound have even gone so far as to suggest that in digital systems, VU stands for "Virtually Useless" !