Xenok is correct that the time signature isn't determined by how the beats break down in a certain measure. The score he linked to is very indicative of many 6/8 songs so it shouldn't be looked at as an exception. It is much less common for music to switch time signatures every measure actually. It's *usually* pretty obvious whether something is 6/8 or 3/4 based on the emphasis patterns/style of the music if you have the ear for it.
Xenok wrote:I would also add it's "musically wrong" to say that America is mixed between 6/8 and 3/4. Actually, the song is only composed in 6/8 but composed with notes that sometime could tend to look like 3/4. We can see this in this music sheet for example: https://s3.amazonaws.com/static.musesco ... core_0.png
But well I think it's not a problem in the post to show the difference between 6/8 and 3/4 since it sound like a 3/4, but I think it's a good think to make things more precise!
Sorry for being annoying...
You're about half right. Time signature as a whole along with tempo marking (i.e., BPM) typically is what determines how many metronome hits are in a measure. 6/8 is almost exclusively counted in 2 and then further subdivided as triplets (i.e., tri-ple-let tri-ple-let) even in measures consisting of 3 quarter notes. 3/4 on the other hand is either counted in 3 or in 1 depending on the tempo marking (i.e. waltz is in 1 typically). There are a variety of ways that the tempo marking could be formatted to include this information (i.e., the tempo marking might be "fast waltz").
Kagetsu wrote:the proposal doesn't take care of the main thing it should be addressing, the metronome hits. a lot of those would be left omitted with this proposal (the whole purpose of the upper number is to denote how many times the metronome hits within a certain measure, as far as my understanding goes, please correct me if i'm wrong)
If osu! properly took timing into account then 6/8 would look like 2/4 but when you hold down the control key instead of hearing 1/2 snaps your would hear 1/3 snaps. 3/4 would need the option to specify whether it should be counted in 1 or in 3 with the former subdividing by 3 and the latter subdividing by 2.
Edit: I misinterpreted the mixed measure as not being something taken directly from a score (it does seem to show up on most scores for America actually). It must not be that common in concert band or symphony orchestra as I was unfamiliar with it but I was always too lazy to do pit orchestra when I had the chance in high school so maybe it shows up more often there.