Re: The MRI and Looping: For Ambient & Experimental Music?

["Kris Hartung" <khartung@cableone.net>]

FYI: from http://ucdirc.ucdavis.edu/facilities/index.php (see excerpt below). This machine looks exactly like the one I was in. Article discusses audio capturing techniques.

 

This URL has a sound clip of the MRI scan: http://www.cis.rit.edu/htbooks/mri/chap-13/chap-13.htm

 

Direct Link to wav file: http://www.cis.rit.edu/htbooks/mri/chap-13/sounds/se-1.wav (it is only one of many of the sounds...probably the most uninspiring in my opinion).  There must be more of these on the web somewhere.

 

Kris

Auditory System: Auditory stimuli are presented during scanning via a high-fidelity system designed for the MR environment (MR confon GmbH, 39118 Magdeburg, Germany). The headphones contain electrostatic transducers for a broad, flat frequency response and construction-grade Peltor earmuffs for passive damping of gradient noise. By using electrostatic rather than pneumatic transduction, this system produces sound quality comparable to a home stereo, with 88dB signal-to-noise ratio (SNR) and high channel separation. During a functional MRI scanning session, sounds can be presented at detection-threshold levels between "sparse" acquisitions or at conversational levels (approx. 75-80 dB) during continuous scanning. Active Noise Cancellation (ANC) in the headphones will further reduce the gradient noise and create a quieter environment for subjects. ANC is under final pre-release testing at MR-Confon, and the UC Davis IRC will be one of the first centers to use ANC in fMRI research. For communication from the subject, the subject's voice is transmitted to the scan operator via Phone-OR, an MR-compatible, optical microphone mounted on the headphones (Magmedix, Inc., Fitchburg, MA, 01420). This microphone system suppresses gradient noise from the transmitted audio signal, using both simple subtraction and advanced algorithms based on speech-recognition. Combined with the MR confon system, extremely clear bidirectional (subject to/from operator) communication is possible during scanning to provide excellent audio SNR for voice-key applications.

 

----- Original Message -----

From: "Legion" <legion@helpwantedproductions.com>

To: <Loopers-Delight@loopers-delight.com>

Sent: Wednesday, December 07, 2005 9:05 PM

Subject: RE: The MRI and Looping: For Ambient & Experimental Music?

> 
> Ok I have only read some of this thread but FWIW two years 
ago I underwent
> some back surgery and had a few MRIs. I was able to 
record one of them on
> a small handheld mini cassette which the 
technician graciously allowed to
> sit on his desk outside the actual room 
of the MRI. He DID look at me
> rather funny when I asked him if I could 
record the sounds but after a
> brief discussion he agreed. I suppose they 
see weirder folks.
> 
> So, the point is if you don't ask you can't 
get it. I have been working
> with the source material I got for some time 
now and I have to agree with
> all the comments of how it is rhythmical, 
ambient, industrial, etc. In my
> experience in environmental sound there 
is nothing quite like it. 
> 
> FWIW I am only familiar with the 
enclosed MRIs. there are not "open" MRIs
> which I would imagine sound 
quite different.
> 
> D_
> 
> 
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