As you have already noticed, 3D FDM printers, like the Cube3, produce a variety of sounds. Paying close attention to those sounds is more important than might be first apparent.
The Cube3 and all printers of its type use stepper motors to move along the X, Y and Z axes and to control the flow of filament. More often than not, more than one stepper motor will be working at any given time so the sum total of the frequencies can produce some very elaborate sound combinations.
We Can Learn What the Sounds Mean
If we learn to listen closely, it becomes easy to tell if a 3D printer is busy laying down a circle or a rectangle as they produce quite different sounds. With experience, we sometimes don't even have to see the printer to know if a particular design is printing as it should. The more we print with attention to sounds, the more we are able to monitor the progress of a printer with more than simply sight.
Some Sounds Alert us to the Progress and Order of Printed Features
Let's say that we have designed a table with four legs and are printing it upside down. When the top is being printed the sounds signaling the printing of the table edges will be quite different from the sounds of the fill material. And, the sounds of the first and last several 'surface' layers will be quite different from that of the 'fill pattern' sandwiched between those layers.
But, the real change in sounds will come when the top of the table is completed. The sound will abruptly change and something best described as 'screeching' might begin to be noticed as the print jet rapidly crosses over empty space from one leg to another. Again, this is a common characteristic of stepper motors along with the belts, etc. used to move the print jet. And, while it might seem to be due to a z-axis change, it's most likely a rapid return to an X/Y starting point. (Although it may be compounded by a slight lowering of the print table to keep the print jet from hit obstacles.)
Extrusion Sounds are the Most Critical to Learn
The sweetest sound that any 3D printer can make is when the filament is being continuously extruded. Generally, we hear this when the printer is laying down the border of our object. If the base of our object is a large circle, the sound from the extrusion system will be very smooth, with the gear pushing the filament forward in one constant stream. We'll call this the 'Free Forward Flow' sound.
The LEAST sweet sound that any 3D printer can make is that sickening repeated click that alerts us to the fact that the gear cannot push the filament forward. The quicker we respond to that sound, the more likely we are to be able to address the issues causing it. We'll call this the 'Obstructed Flow' sound.
In between, these two sounds we have some equally interesting sounds as the extrusion system periodically reverses direction. In the case of our table, it will be pushing the filament forward as it lays down a layer for each leg. But, it will reverse itself and pull the filament back a bit to keep it from dripping as it moves across the empty space from leg to leg. I think it is critical, with the Cube3, for us to keep our senses sharp to see if there is any correlation between a lot of reverse extrusion activity and clogging in our designs.
One of the things I am interested in studying is how the various fill choices might affect extrusion reversals to the point where one or the other choice might induce a clog?
Right now, I don't know. But, I do know that listening to the printers as these fill type experiments are conducted will be crucial to understanding the actions required to draw them. I have a suspicion that 'hollow'+'lines' might sound quite different from 'solid'+'diamonds' and that, in fact, one or the other choice might help us complete more print jobs. While this remains to be seen, it will be fun listening for the differences. :)