The excellent Out-law site reports on a recent European Decision that Tarzan’s distinctive yell cannot be registered as a trade mark because it is almost impossible to represent graphically. Sounds can be registered as trade marks, but the ruling could limit that to sounds that can be written in standard musical notation. http://www.out-law.com/page-8587 . The mark was submitted as a spectrogram – a graphic representation of Tarzan’s yell – the “aaaahh-ah-ah-aaaaaah-ah-ah-ahhh” (or something like that) with a description of the mark in the application as consisting of ‘five distinct phrases namely sustain, followed by ululation, followed by sustain but at a higher frequency followed by ululation followed by sustain at the starting frequency”. But the OHIM (Office for the Harmonisation of the Internal Market, Trade Marks and Designs) was having none of saying the graphic submitted could not be recognised “from the image as filed whether the sound phenomena depicted is a human voice or something else” … “nobody would be able to hum the Tarzan yell from the spectrogram and nobody reads spectograms for entertainment”. A new application has been filed and the OHIM have issued a release saying that although the sonogram was refused registration, a musical notation of the yell, applied for at the same time has been registered, and an application is pending for the sound represented by a sonogram and an MP3 file (a possibility since 2005).
See also the case of Shield Mark BV v Kist
http://www.out-law.com/page-4110 (European Court of Justice) where a sound which could be graphically portrayed (as a series of notes) was allowed .In the Sieckman case a smell could not be registered, even when it could be reduced to a chemical formula. See Sieckmann v. Deutsches Patent- und Markenamt (C273/00)