Re: high quality sound system for fMRI

[Pawel Kusmierek <p.kusmierek@xxxxxxxxxxxxx>]

tnt@physiol.ox.ac.uk said:

> I came across another electro-static system with CE marking and a good
> frequency response from a group in Germany. It is a spin-off from an audio
> lab and they seem very competent. Their web site is
> http://www.mr-confon.de
> .

As far as I remeber, this group (Prof. Scheich's group in Magdeburg) used
dynamic headphones with magnets removed. Instead, the scanners's magnetic
field interacted with coils.  This was done (AFAIR) in cooperation with
Sennheiser, one of the world's leading manufacturers of headphones.

See:
1: Med Phys. 1998 Oct;25(10):2068-70.

Electrodynamic headphones and woofers for application in magnetic resonance
imaging scanners.

Baumgart F, Kaulisch T, Tempelmann C, Gaschler-Markefski B, Tegeler C,
Schindler
F, Stiller D, Scheich H.

Leibniz-Institute for Neurobiology (IfN), Magdeburg, Germany.
baumgart@ifn-magdeburg.de

Electrodynamic speakers compatible with (functional) magnetic resonance
imaging
(MRI) are described. The speakers magnets are removed, their function is
replaced by the scanner's magnetic field, resulting in an uncommon but
efficient
operation. The method can be used with headphones as well as woofers.
Functional
MRI is not associated with any known biological risks, but as a method for
visualization of task-specific activation of brain regions it is undesirably
noisy. Thus, it requires both noise protection and efficient sound
transmission
systems for delivering acoustic stimuli to subjects. Woofers could
possibly be
used in active noise-control systems. The speakers described in this paper
can
be used for either task.

PMID: 9800716 [PubMed - indexed for MEDLINE]


Pawel

--
Pawel Kusmierek
Nencki Institute of Experimental Biology
ul. Pasteura 3
02-093 Warsaw, Poland
phone: (+48 22) 659 85 71 ext. 388 or 379
fax: (+48 22) 822 53 42
email: p.kusmierek@nencki.gov.pl, pq@gazeta.pl