Music notation question

Trying to relearn the piano again after 10 years without playing - I can still basically read music but am occasionally running into things that trip me up.

In the pic below - can someone explain what’s going on with the triple crossed minims in the 4th from last bar and the unconnected triple cross between the two C’s in the next bar?

http://uploads.tapatalk-cdn.com/20160216/55656a89d9ce455ca6233993cab9e11b.jpg

Tremolo. Rapid oscillations between the indicated pitches.

Thank you! That’s what I was thinking but I couldn’t summon the word and it’s surprisingly difficult to Google it without it. (I kept thinking trill which is almost but not quite the same thing and didn’t bring me to any notation like the above)

That’s musical notation for “play a shitload of these two notes, oscillating between them as rapidly as you can make your hands move”.

Seriously. There’s a name for it, too, I just can’t come up with it… not trill, dammit…

Moderator Action

Since this involves music theory, let’s move it over to the cafe.

Moving thread from General Questions to Cafe Society.

Correct, but I do want to add that, depending on the age of the piece, some people will insist that three lines means you must play them as demisemiquavers (aka 32nd notes). The older the piece, the more they insist.

I usually just play them around that fast, and play with it musically. Usually I “finger pedal” them a bit, making them sound more like a single continuous note. (Finger pedaling means holding the notes down longer than you normally would, letting them overlap. How long depends on your intention–in the first movement of the Moonlight sonata, I hold them down until I need to resound the note or move my hand.)

Those people are incorrect.

It’s long since been standardized that you only play 32nd note alterations like that literally in time when they’re actually written-out the long way, and not the abbreviated way.

And as it is, the older the piece, actually the more likely the composer was if anything much less tied to the literalness of the notation in the first place.

Well, some musical sources do agree with BigT, like this encyclopedia of music from 1910. I can’t say I know of the history of tremolo notation enough to comment definitively, but I am familiar with this interpretation of tremolo markings. For the music I play, tremolo is not so literally tied to note values.