Singalong - A new invention

Can we categorize all music lovers as only people who like listening to music?

There are quite a few who enjoy singing and who are passionate about it. Why haven't any device been invented for those people to let them sing aloud without disturbing others? (Pardon me if there is such a device but I've not heard of one)

It becomes all the more useful if the person is not a great singer but is passionate about singing and enjoying (A few nuts like me!)

A device, which can prevent spilling of voice and ensure that only the singer, listens to his own voice. (Saving others from this punishment ;-))

Wondering how difficult it is to formulate such a device and how would it be designed? How would a person look wearing such a device if it were to have tubes connecting from the mouth to the ears? A look of a war pilot wearing a mask may be...

On a serious note what other functions could this new device incorporate?

1) It could have a filter to allow the user to listen to only the voice of the singers sans music or only the karoke sans voice.

2) It could allow the user to mask out the original male or female voice and add in their voice with the music and record the same.

3) It could have functions that allow the user to compose own music by providing the sounds of different instruments, which can be customized, by the user to suit his needs.

A device with all these functions could make music more integral and provide exciting options and enriching experience.

Pose in your views on the feasibility of developing any such device and any other funny notion that comes to your mind on thinking about this device.

P.S: I am in a crazy mood and all these thoughts have poured from a crazy jobless mind.

P.P.S: If a few years later Sony or Apple or any other company comes with such a device, I can claim ownership to the idea through this blog ;-)