This research aims to determine the role of the Sound System in the liturgy of Sunday services at church. The sound system in a church is an electronic device that is used to amplify and regulate sound so that it can be heard clearly by the congregation. The method used in this research is descriptive qualitative method. The stages of research implementation were carried out through observation, application, interviews and documentation. The object of this research was carried out at the HKI Perumnas Pagar Beringin Sipoholon, North Tapanuli church. In the research process, the author carried out research on the sound system in the church for 3 months, namely from June to September 2024. The stages carried out by the researcher to regulate the role of the Sound System so that it functions according to its use are: recognizing the devices in the Sound System, finding problems with the Sound System , organizing and arranging the Sound System according to its role. The results of this research show that the implementation of the use of the Sound System at the HKI Perumnas Pagar Beringin Sipoholon North Tapanuli church is functioning and can be heard clearly and well, where previously the sound system often occurred storing or buzzing. Based on this research, the author suggests that sound system operators in churches prepare sound system equipment before the Sunday worship program begins.

The purpose of this study is to develop the song "Haholongan Na Badia" in the Saxophone Quartet. The motif in this song still uses the original melody of the song but there is a slight change in tempo and. It aims to be more wise and pleasant to listen to and adjust to the conditions of worship. This study uses qualitative research, namely by describing the Song Arrangement in the Ende Book No. 212 "Haholongan Na Badia" in the Saxophone Quartet at Sunday Worship at HKBP Pardomuan This research was carried out in July - August 2024. By observing, literature and with several sources related to saxophone instruments and the HKBP Pardomuan Church in writing and unwritten. The result of this research is that the Song in the Ende Book No.212 "Haholongan Na Badia" is a very wise song and has a meaning and message in its verses This form of arrangement is a new concept and presentation of the song Tu Jolom O Debatang Ku in the form of a saxophone quartet arrangement. This thesis discusses the presentation, arrangement process of the Saxophone Quartet in the song of the book Ende No. 212 "Haholongan na badia" in accompanying Sunday worship at HKBP Pardomuan. For the rhythm sign, the author uses the 3/4 rhythm which is in the original score of the 4/4 song and the basic note Bb = do and with the tempo of Adagio MM 70.