We own computers in different places (maybe one at home and another at work) and we want to hear the same music wherever we are, without having to move and download it every time "> Resilio Sync, available free for both Window and Mac. 
With Resilio Sync we can choose to share the Music folder of our computer by clicking on the top left corner on Add folder -> Standard folder and specifying the path of the music folder; once added to the program folder, we right-click on it and use the Share item.
In doing so we will get a unique code to access it from any other PC; after adding the folder and sharing, simply go to the new computer, install Resilio Sync and insert, at the right time, the sharing code obtained for our music folder, by clicking on the top left corner on Add folder and using the voice Enter a key or link .
The program will automatically use P2P to keep the two folders synchronized, taking care to update any changes made in real time. The sharing system is very secure: all data travel encrypted and only those who know the unique code can access the folder (we can still set a block for new additions, so as to monitor any access).
With the Free version we will have limitations on the options that we can activate for each share, but it is more than enough to be able to synchronize the music on two or more computers together.
We deepened the topic in our dedicated guide, available here -> Resilio Sync synchronizes folders between PC and mobile phone in P2P .
Syncthing
If we are looking for something free and open source to be able to synchronize music between two or more computers, we can try Syncthing.
In a very similar way to Resilio Sync, we can share the Music folder, by clicking on Add Folder and indicating the path of the same on our first PC; then simply install Syncthing on the second PC, obtain its ID code from the top right menu Actions -> Show ID, go to the first computer and click Add Remote Device . Now paste the ID code obtained and, in the Shares tab, make sure to tick the Music folder.
Warning windows will appear on the new PC, where we will have to confirm the connection and sharing of the folder.
From now on our music folder will be synchronized between our PCs completely automatically and without limitations (there is no license fee or no subscription to unlock the advanced functions).
Google Play Music for Chrome
A good alternative to the P2P services mentioned so far is Google Play Music, which offers an extension for Google Chrome to upload your music to a personal cloud space (up to 50, 000 songs), so that you can listen to them on any other computer.
In order to do this, we download Google Chrome on our computer (Windows or Mac), then add the Google Play Music app for Chrome. After adding the app, we open the address play.google.com/music, log in with our Google account, enter the requested data (if we have not already done so, you will be asked to add a method of payment to ascertain our nationality), then click on the menu with the three horizontal dashes at the top left and click Upload music .
We can drag the songs and folders into this window or use the Select button on your computer to add the whole Music folder. The loading of the songs will start now, which can take some time (depends on our connection).
At the end of the upload, we will be able to listen to our songs on any other PC, we will only have to access the page //play.google.com/music and authenticate with the same account used for adding the files. Obviously, there is no continuous synchronization as with the other solutions, but it is currently one of the best methods to carry the music behind even when we use another computer.
Conclusions
As we have seen, we can use different programs to be able to synchronize the music between two or more PCs together, without having to bother with keys or external disks. If we want to find other services or similar programs, we invite you to read our guide to Share music online by uploading mp3s from your pc to listen to them via the web .As a first alternative to these methods we certainly find the classic cloud services; if we don't know which one to choose for the purpose, we can also read our Free Cloud Drive comparison to save files online .
Another valid alternative, if we use iTunes to manage our music, plans to copy the iTunes library and move it to another computer, so as to be able to take all the songs downloaded from the store and added to the library.
