Nintendo 3DS Sound is a built-in application on the Nintendo 3DS. Like Nintendo DSi Sound, you can record and play sounds with the microphone. But, on Nintendo 3DS Sound, you can listen to mp3 type songs from your SD Card. In a way, it is similar to Nintendo DSi Sound.
The Main Screen is slightly different to the one of the previous installment of sound. Instead of just 1 bird, there is now 3 birds and this is also now your song page rather than having a separate song page and a main screen. The settings have also been put onto the recording screen.
The Recording Screen is the same to the one on the DSi except on settings you can view usage tips like on the 3DS camera. Usage tips is a feature where you can review previous tips the bird has already explained.