Re:Brain on Psychedelics
by squeaky-clean on Thursday October 06, 2022 @12:59PM
(#33110863)
It's *VERY* loud. You can't wear conventional headphones, you'll need non-magnetic headphones that are made specifically to be used during MRI scans. That means no active noise canceling features. The MRI is loud enough to be heard through the passive attenuation of headphones or earplugs, so you'll still hear the mechanical beat of the MRI underneath any music.
[ Parent
| on HN ]
Re:Brain on Psychedelics
by AstralStorm on Thursday October 06, 2022 @03:07PM
(#33112594)
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.
There 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.
Re:Brain on Psychedelics
by squeaky-clean on Thursday October 06, 2022 @07:37PM
(#33115583)
When I was looking this is exactly how MRI headphones worked. Just with a much longer tube
Re:Brain on Psychedelics
by squeaky-clean on Thursday October 06, 2022 @07:50PM
(#33115697)
Noise 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
And 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).
I honestly don’t think it would be that bad. Let’s say your actually only in the machine for an hour or so during the height of your trip. To me, an MRI scan sounds almost like a deep house or techno beat. It might even be enjoyable. The worst MRI scans are ones done with contrast - having a thick needle in your arm really ruins the MRI experience for me.
Re:Brain on Psychedelics
by archibaldJ on Friday October 07, 2022 @12:17AM
(#33117370)
can we design MRI scan with a programmed physical (movnig) noise absorbing panels so the sound actually becomes rhythmic or even jazz like: https://www.youtube.com/watch?v=WqpEQWRcQcw