פירוש על דברי הימים א 15:24

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.

gate sentries for the Ark i.e., although they were gate sentries, they were singers as well.