It might not be totally clear from the video but the glass is only to contain the sand. The piezo microphone is not like a condenser or dynamic microphone, there’s no *ting!* recorded, only the grains of sand rubbing against the piezo are recorded. I used a glass just because it’s transparent, I could have used a paper cup or a wooden box and the sound would have been the same (but visually less interesting because you couldn’t see the sand moving).

When I’m playing the groove at the beach it’s not my flesh hitting the sand, I taped the piezo to my fingers, again, it’s the sand hitting against the piezo transducers. I could have used gloves and the sounds would have been the same.

Ultimately this video is not to make sand sound like a grand piano or a guitar, it’s a sound design experiment and it might sound nice or not depending on personal taste.

Have you ever heard of booming sands? Those masses of sand moving and producing a loud tone? Some people that have heard them say that they sound pretty interesting, even if it’s just sand moving against sand. It’s one of those fascinating mistery of nature!
Peace.

The sound is: sand bouncing off of the material of the microphone, or rubbing against it. Not the sound of sand. You are using 2 objects to facilitate the sounds. Sand + Object = sound of sand and that object.

Your hands pounding sand like a drum is not the sound of sand, it’s the sound of your hands, your flesh, hitting sand.

Sand is hitting the glass, *ting!* : you would probably not get the same tone from sand hitting other grains of sand.

So, those are really nice samples of sand hitting a contact microphone or a glass, etc., but it’s not 100% the sound of sand, alone… which, like I said above is pretty limited in range.

Sand hitting the microphone. Sand hitting the glass. Without an object for the sand to hit and make different sounds, he’d only have the sound of sand hitting sand which is pretty boring.