I hope you don’t mind if I respond to your post.

We used subwoofers to enhance the effect you mention as part of the project at Whitefileds school for the disabled. It’s a great method, but has some limitiations.

The problem is that sound is made up of lots of frequencies – it’s hard to understand this if you’re not experiencing them, and, unlike fundamental vibrations, you can’t detect them if there’s something wrong with your hearing. Also, you can’t get this information from lip reading or lip-reading systems, and you’d need training to get the information from a frequency plot. It’s a significant problem. That’s why we tried this method, and it seems to be a good start.

Thanks for your interest.

Cheers,

Mick