Hello Matteo–
This is a somewhat difficult question to answer because 1) every instrument, even if supposedly identical, plays a bit differently, 2) instruments made from different materials (plastic/resin, soft woods like maple, hard woods like palisander or ebony) produce slightly different basic tone color, and 3) every player develops his/her own taste in sound.
I have a number of recorders–several of them altos. Of the altos, my favorites are a Mollenhauer palisander and a Moeck olive wood which I like because of the complexity of their tone color. As one of my backup instruments, I have a Zen-On plastic which plays well enough to satisfy me when I play it–although the tone color in not as complicated as I like. As another backup instrument, I have an older Aura (AAFAB) pear wood which I don’t play very much anymore because I find that the soft pear wood, while it sounds very pleasant, doesn’t produce as strong a sound as I desire. Please understand that this is my taste–not the same as better or worse, and definitely not the same as some other person’s idea of better or worse.
I have read articles that say that the wood itself doesn’t affect or change the sound of the recorder. This is true–IF you are thinking of the wood (or plastic) vibrating like the body of a violin or guitar and contributing to the sound (which, in an instrument as solid as a recorder, it can not do). However, the surface of the wood or plastic on the inside of the instrument varies a great deal depending on how smooth it can be made–and, because some woods have a more open pore structure, this does affect the timbre.
So, since I think you say that you are a newcomer to playing the recorder, I suggest that you play your Yamaha YRA314B for a while longer until you have developed your own likes and dislikes in recorder sound. It is a decent instrument–especially considering how little it costs. In the meantime, listen to recordings, go to concerts, watch You Tube videos, and read as much as you can about the different woods. Also, save your money so that you can get the recorder “of your dreams” when the time is right. Saving that money is easy if, at the end of each day, you put all of the coins you find in your pocket into a jar labeled “recorder money.” Then, if possible, try recorders before you decide which one to buy.
I hope that this helps.
–Dick–