。
By using four kinds of metal, it suppresses specific resonance.
Literal
4-kinds [attributive-の] metal [object-を] use [by-ことで] specific [attributive-の] resonance [object-を] suppresses-[polite-ます].
Technical product description. ~ことで ('by doing X, by means of X') is the means/method construction — literally 'in the matter of doing X.' 共振 ('resonance') is a physics/engineering term. 抑える ('to suppress, to hold down') is used for reducing vibrations, sounds, prices, or emotions. Likely from a description of a musical instrument, speaker, or mechanical device.