Ok, i might be able to help with this. I'm an artists and I discovered the existence of this technology a few years ago. I wanted to make some art Installation with it and started experimenting.

The problem is: in a speaker, the vibration (just like what tass would produce) is basically just already "stuck" to the perfectly shaped and perfectly resonating surface ... And that's what we call a speaker. The perfect shape for sound into air is somewhat like a cone... Think megaphones etc. We all learn this as kids when screaming into various tubes and stuff. The perfect surface to resonate would be something thin and flexible but also not to thin because then it just wobbles away. So that's why you have these cone shaped cardboard things in your speaker. A speaker is basically a TASS that comes with its own built in perfect resonating surface.

You can of course improve this technology a bit with as was mentioned buit in equalizers to make up for "sub perfect" resonating surfaces that are too rigid or not cone shaped at all. But the principle will remain the same. There is nothing one can improve about how sound is transported through air. It's just how it works. And yes you can use almost any surface to vibrate it and it will transport these vibrations into the air. Just like you can hear loud music outside of a car. The whole care becomes the resonating surface that vibrates the air around you to reach your ears.

But all the comments that say: yeah it works but it sound funky are correct. Because any surface that is not cone shaped and not of a flexible yet rigid enough material will sound less nice as what we have in speakers.

The basic idea of an actuator is very old. Is a bit how old gramophones created their sound. The fact that we still went through all the trouble of inventing the speaker still speaks for itself.

Edit: some spelling (I'm on mobile sorry for format)