Will there come a time when every melodic combination of 5 notes will have been used to start a tune?

You have to factor in rhythm, too. You can have eighth notes, quarter notes, and so on. Each of those adds another potential variant – and raises the potential number of possibilities by a massive number.

So… yes, there probably is an upper limit, it probably can be reached.

There are so many more dynamics to music than just the ones you’ve mentioned. I think you’re over-simplifying. One example is that you haven’t accounted for harmony. One note can be played, but backed with many other notes, giving it a totally different feel that you may even think it’s a different melody from just one listen. Even lyrics can play a part. I mean, some people may not even recognize that Twinkle, Twinkle, Little Star and the ABCs song use the same melody!

Theoretically, no, there is no limit to the amount of differences in music. That’s because Hertz is measured with real numbers, which are not countable. What I mean is that you can just keep changing Hertz (440.01, 440.001, 440.0001, etc.).
Technically, yes, there is, because we can’t tell the difference between 440.001 and 440.0001. But again, this finite number is huge, even if we are using those same boring four chords. I once saw a YouTube video on someone who estimated this number somehow

I think they reached them by the mid-80’s. That’s why American music has stagnated so.

A lot of the hit music that humans have generated is pure genius. There is no way to get around that. Today’s computers generating hit music? HA! Forgetaboutit!

Like original thoughts, music is infinite. There are infinite keys. The basic 42 keys can be modified by adding sharps and flats like A#### or Cbbb.

You’ve 5 basic rests but of course they can be modified

Infinitely variable volume levels.

Then there multiple time signatures (basic 4/4. ¾, 6/8) plus more that can be modified.
You can have one instrument playing in A flat miner in 4/4 time, another playing in A sharp major in 6/8 time while the sax is blowing his nose, etc.

Also different lengths of rests the basic are whole, half, quarter, eighth, sixteenth.

Also style: perhaps a slightly rushed rap the beat or a funky laid-back jazz beat etc.

If you need more proof that musical combinations are infinite then just listen to a couple old Frank Zappa albums.

@gondwanalon Infinite keys? Basic 42 keys? 5 basic rests? What?
The key of “A####” is equivalent to the key of uhhh… F. It’s also equivalent to complete nonsense. In any case, you may not even be able to recognize that a song is played in a different key unless you had very “seasoned” ears, like perfect pitch. What I mean to say is that the keys are isomorphic to each other.

Time signatures are definitely another missed dynamic, though.

@dxs Sorry I wasn’t a music major in college. What I was trying to say with the weird keys is similar to Chinese music taken to the extreme level. Like someone sining off key. Of course I wouldn’t consider that music. HA!

Don’t forget that microtonal instruments are a thing now also.

@ARE_you_kidding_me That’s fantastic! Talk about thinking outside the box! Frank would have liked this guy!