"SD card reader" reads the file but with square symbols

I´m using this SD card reader

with the Arduino Mega 2560.

I´m trying to play some .wav files, I loaded two files for testing, "1.wav" and "2.wav", and this is what I get in the serial print:

As you can see, it can reads the folders name but the files names are shown with those symbols, I tried with other file extensions, and othe names for the files but I get the same result. I also tried with another SD card.
As it can´t read rhe file name, it can´t play it, I guess.

Any idea what could be the problem?

That is a 3.3V module and you use a 5V Arduino board.
It has an 3.3V regulator on the module, but the Arduino SPI are 5V signals.
There are similar modules with an extra level shifter chip.

If I use a voltage divider with resistors, that would solve the problem?

like this one

It didn´t work.

That schematic might work, but it is a little tricky.
The MISO output is a 3.3V signal, the 5V Arduino might accept that or not. In theory it is about on the border whether is works or not. In real life it just works.

Which Arduino IDE version do you use ? Version 1.0.6 and 1.5.7 BETA are the newest and are okay.
Perhaps the sd card itself is not very compatible.

The SD card is FAT16, everything is okay, but not the file names.
Perhaps the file names have special character encoding, or it is not a very good FAT16.
Could you check the SD card filesystem on the computer, to see if the filesystem is broken.
Create files with simple names like TEST1.TXT and TEST2.TXT, are those names okay ?

I feel so dumb, but I finally found the solution, it was quite simple.

I´m using a desktop computer with the arduino, it has no SD card reader so I transfer the files from the pc to dropbox, and then to a tablet where I load the files to the SD card. That is when the character encoding changes.
I tried this with a laptop that has an SD reader and worked perfect.

Thanks for the help and your time.

I'm glad it is working.
You don't have to feel like that, it could easily happen to all of us. It is the kind of things that this forum is also for.