Subject: Re: high quality sound system for fMRI From: Pawel Kusmierek <p.kusmierek(at)NENCKI.GOV.PL> Date: Thu, 21 Aug 2003 22:38:03 +0200tnt(at)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(at)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(at)nencki.gov.pl, pq(at)gazeta.pl