Unacoustic

The application of staccato chords has to be strictly limited in unacoustic places, but in resonant buildings, staccato chords, used judiciously, have a very fine effect, as they evoke the echoes from the building in a more effective way than a long sustained chord, however promptly released.

Source: wiktionary

This unacoustic vastness swallows the earth sounds and produces the effect of silence upon the soul.

Source: wiktionary

Few are like the Scottish fiddle-maker Amaryllis once met who had spent a cheerful life making violins out of oak (an impossibly unacoustic wood) on the happy premise that birds sing more beautifully in oak trees.

Source: wiktionary

No wonder, for the pulpit had been placed in exactly the most inaudible situation, and the Hall, however well calculated for purposes of feeding, and holding examinations, was a most unacoustic place to speak in.

Source: wiktionary