Why is it der Synthesizer?

Synthesizer ends in -er, and most nouns ending in -er are masculine: in a German dictionary, 86% of them take der.

All nouns ending in -er
Sense 1
der

Meaning

[1] Musical instrument that generates tones electronically by sound synthesis

[1] Musikinstrument, das auf elektronischem Weg per Klangsynthese Töne erzeugt

Examples

[1] The synthesizer has two VCOs and an analog filtere

[1] Der Synthesizer hat zwei VCOs und ein analoges Filter.

[1] The TTS program is a synthesizer for creating human language

[1] Das TTS-Programm ist ein Synthesizer zur Erzeugung menschlicher Sprache.

Declension

1 Singular Plural
Nominativ der Synthesizer die Synthesizer
Genitiv des Synthesizers der Synthesizer
Dativ dem Synthesizer den Synthesizern
Akkusativ den Synthesizer die Synthesizer

Pronunciation

Dictionary entries include material from Wiktionary. Wiktionary