59 The effects of audio exposure to goat kids’ relative intensity ratios of harmonics from birth to weaning

This study evaluated the effects of exposure to sound stimuli on goat kids’ relative intensity ratios (RIR) of harmonics one through five from d 0 to d 49 of growth. RIR are the ratio between a harmonic and the first harmonic. Day zero boer kids were randomly assigned to three treatment groups: treatment 1 (n=5) was only exposed to a single human voice recording, treatment 2 (n=4) was exposed to their boer dams, and treatment 3 (n=4) was exposed to no vocalizations. Each group was housed in pens (2.44 x 3.05 m) and received the same diets, which met or exceeded NRC requirements. The kids were isolated in their respective pens 1x/wk for 7 wk for 120 to 1000 s to obtain vocalization recordings. The kid’s vocalizations were collected via a Blue Snowball iCE condenser microphone and laptop. VoceVista Video software was utilized to analyze the relative intensities (dB) of the first five harmonics. Results indicate there is no difference in average RIR between the human and treatment 1 of the second, third, and the fifth harmonics. Kids raised next to the dams had significantly lower average (P < 0.05) RIR for all of the harmonics. No significant difference was noted between the average RIR of harmonics three, four, and five of treatment 3 and the human recording. No difference in the RIR of second, third, and fifth harmonics suggest that a goat kid exposed to only human vocalization exhibits a human-like tone in relation to these harmonics within the first 7 wks. A difference in treatment two from the average RIR of the dams and no difference between treatments one and three compared to the human recording indicate that exposure to vocalizations during growth does have an effect on seven-week-old kid harmonic intensities.

Prototipe Hydrophone untuk Komunikasi Bawah Air

ABSTRAKDalam pencarian suatu obyek di bawah air dibutuhkan metode khusus yang digunakan dengan suara (gelombang akustik), dikarenakan suara dapat merambat dalam jarak jauh pada air. Frekuensi yang dapat diterima oleh SONAR bergantung pada alat penerima yang mengubah suara menjadi sinyal elektrik agar dapat mendeteksi frekuensi, alat penerima ini dinamakan hydrophone. Dalam penelitian ini dibuat perancangan prototipe hydrophone, yang tersusun dari transducer (akustik-elektrik) dan penguat. Berdasarkan perancangan yang telah dibuat prototipe hydrophone mampu menerima (menangkap) gelombang akustik pada range frekuensi 100 Hz – 60 kHz, dengan menggunakan transducer berupa condenser microphone yang diselimuti oleh bahan karet tipis. Prototipe hydrophone tanpa pelindung anti air, dengan pelindung anti air, dan di dalam air dapat menerima (menangkap) gelombang akustik.Kata Kunci: SONAR, hydrophone, transducer ABSTRACTIn finding an object beneath the water there has to be a specific method used sound (accoustic wave) in keeping with it can apread in long distance in the depth of water. The frequency which can be detected by sonar system, counts on the receiver which converts sound to electric signal so that the frequency can be detected and it is called hydrophone. In this research, there is hydrophone prototype which piled up by tranducer and amplifier. Based on the trial, hydrophone prototype can detect accoustic wave in range 100 Hz-60 kHz with the condensor microphone as a transducer covered of thin rubber material. Besides, hydrophone prototype with or without water resistor is still capable to detect acoustic wave. Keywords: SONAR, hydrophone, transducer