>No, that's not it. Standard notation tells you how >long to hold the current note/rest. It does not tell >you absolutely when in the measure the note/rest >starts. The note/rest starts after all the other >notes/rests have been held their full duration. You >can't in general see at a glance that, for example, a >particular note starts at the beginning of beat 3.
Sure you can. You look at the whole measure. Reading music note by note is not a good idea. You scan the whole measure - or maybe even two measures. That way, you see the location of the note within the context of the measure. You see the barlines that tell you where the 1-beats begin each measure, then you see the pattern of notes and rests that define not only the duration of each note, but where it comes relative to the beats in the measure. A whole set of conventions regulating the use of bars, dots and ties has sprung up to ensure the greatest clarity and transparency in rhythmic notation for the sight-reading musician. It is quite possible to write rhythms in a manner which is logically accurate, but which is unclear and confusing to the sight reader.
The alternative would be to "code" each note with not only pitch and duration, but absolute (in the song) or relative (in the measure) information. Computers need this kind of information, but humans can deduce very quickly from context.
Giving a sight reader yet another piece of visual information to decode may not be an improvement. Generally the idea is to simplify as much as possible and to reduce visual clutter, sometimes by using shorthand (using staccato quarter notes, for instance, instead of eighth notes with their added flags and beams).
>This means that if you hold exactly one note/rest an >incorrect duration, every other note that follows will >start at the wrong time.
I used to play in a dance band with a saxophonist who actually functioned this way. If the drum solo went four extra measures, everyone else noticed and laid out another four before going on to the next thing. Not Jim - he'd be counting rigidly and come in all by himself while the rest of the band gave him queer looks.
The fact is, even if you coded each note for location, you's still get out of time if you made a mistake. If your internal counter gets off, you can't hear which beat or bar is being played, so knowing where a note belongs does you no good - you still don't know where to place it in the flowing stream of music going by.
The reading/performing musician has to count beats and bars internally. When he/she fluffs a note or otherwise gets off track, the first thing s/he does is to plug back into the flow and know which bar and which beat is being played. Once back on stride, s/he can come back in, in synch with the music. It matters not one whit whether the placement of the notes is shown by context, as with standard notation, or by some kind of individual locator for each note.
