ðɪ ˈɪʃuːz ɑːɹ ɪfˈɛktɪvli dˈʌbəld wɛn ɪɾ ɪz nˈɛsᵻsɚɹi tə tˈeɪk ˌɪntʊ kənsˌɪdɚɹˈeɪʃən ðə pˌɑːsəbˈɪlᵻɾi əvən ˈɑːbstəkəl əbˌʌv ðə dɪvˈaɪs, æz wˈɛl æz ðə wˈʌnz ðˌɐɾɪt mˈʌst tɹɐvˈɜːs bᵻlˈoʊ.
The issues are effectively doubled when it is necessary to take into consideration the possibility of an obstacle above the device, as well as the ones that it must traverse below.