4 ms·
Oh you could make noise dampening and cancelling headphones for MRI with nonmagnetic piezo transducers. Ear canal earphones would help with it too by cutting th
by AstralStorm 4y ago
Oh you could make noise dampening and cancelling headphones for MRI with nonmagnetic piezo transducers.
Ear canal earphones would help with it too by cutting the noise some 30 dB.
The problem is that the noise made by the machine is loud sounds comparable to an explosion or a gunshot. You can reduce it but never fully cancel it, and it's rather startling.
- ace2358 4y agoThere are styles of headphones that are like an ear plug (to reduce noise by say 20db) that have a small tube running to the driver that is a long distance away. They’re these clear tubes with a coil you see on security guards and what not. The actual driver is somewhere else. This could also be used. I think some in ear monitors are like to too.
- squeaky-clean 4y agoWhen I was looking this is exactly how MRI headphones worked. Just with a much longer tube
- squeaky-clean 4y agoNoise dampening? Yeah plenty exist. There's a hard limit of about 30db reduction passively unless you also plug your mouth, nostrils, and wear a helmet around your skull. But noise reduction/dampening does not mean the same thing as active noise canceling. For ANC you need a microphone very close to the ear and some sort of chip to process that and apply it inversely to the speaker. There would just be too much delay if the sound waves have to make a round trip more than a few mm
- ta988 4y agoAnd you will have a phase problem because of the delay of transmission. And the phase of the noise is not predictable that well (the RF that cause it is really precise, but the physical movement of the coils and everything around them is not).