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	title        = {Effect of the Double-Filtering effect on Automatic Voice Comparison},
	abstract     = {In forensic casework today it is not uncommon to receive material recorded with mobile phones or other handheld recording devices. From experience we know most people do not treat recordings with as much care as a person well versed in audio technology. Especially given the varying circumstances under which the material can be recorded. Thus it is important we learn more about what sort of acoustic effects take place under particular conditions and how these effects can influence Automatic Voice Comparison (AVC). The current study aims at evaluating the effects of recording material consisting of what could be described as ‘doublefiltered’ sound, henceforth referred to as DF, e.g. when a phone call is recorded using a handheld recorder placed in the vicinity of the mobile device. This filtering effect constitutes sound transmitted via GSM communication (1st filter) which then passes an indeterminable distance through the air before being captured by another recording device, such as a mobile phone or handheld recorder’s microphone (2nd filter). This effect
affects the energy in the signal. The energy decreases in both the low and the high frequencies, while the middle frequencies are boosted.
In this study we have used a database consisting of 150 female speakers of Swedish, all students of speech and language pathology. The recordings were made in a sound treated recording booth using a setup of one computer equipped with an internal MAudio soundcard and a high quality headset microphone. Each recording consists of solicited spontaneous speech together with read speech material (Swedish standard reading passage called ‘Ett svårt fall’). Each speaker is informed and encouraged to finish the task at their own pace. Mean duration of the full recording among the speakers was 69.3 seconds (std 16 seconds).},
	booktitle    = {Proceedings of IAFPA 2014. International Association for Forensic Phonetics and Acoustics Annual Conference 31 August - 3 September 2014},
	author       = {Lindh, Jonas and Åkesson, Joel},
	year         = {2014},
	pages        = {2},