וּשְׁבַנְיָ֡הוּ וְיֽוֹשָׁפָ֡ט וּנְתַנְאֵ֡ל וַעֲמָשַׂ֡י וּ֠זְכַרְיָהוּ וּבְנָיָ֤הוּ וֶֽאֱלִיעֶ֙זֶר֙ הַכֹּ֣הֲנִ֔ים מחצצרים [מַחְצְרִים֙] בַּחֲצֹ֣צְר֔וֹת לִפְנֵ֖י אֲר֣וֹן הָֽאֱלֹהִ֑ים וְעֹבֵ֤ד אֱדֹם֙ וִֽיחִיָּ֔ה שֹׁעֲרִ֖ים לָאָרֽוֹן׃
And Shebaniah, and Joshaphat, and Nethanel, and Amasai, and Zechariah, and Benaiah, and Eliezer, the priests, did blow with the trumpets before the ark of God; and Obed-edom and Jehiah were doorkeepers for the ark.
Radak on I Chronicles
sounding the trumpets Heb. מַחְצְצרִים. It is written with a double “zaddi”; the first is pronounced, and the second is not pronounced. Likewise יִשָּׂשׂכָר, the first “sin” is pronounced, and the second is not pronounced; and so, (Gen. 4:18): “וּמְחִיּיָאֵל יָלַד אֶת מְתוּשָׁאֵל” and so “יִרְאִיָּיה בֶּן שֶׁלֶמְיָה,” (Jer. 37:13), the first [letter] is pronounced, and the second one is not pronounced.
Radak on I Chronicles
gate sentries for the Ark i.e., although they were gate sentries, they were singers as well.