The phrase "as a murmur" is correct and usable in written English.
It can be used to describe something that is spoken softly or quietly, often in a way that is not meant to be heard clearly.
Example: "She spoke as a murmur, barely audible over the sound of the crowd."
Alternatives: "in a whisper" or "in a soft voice".
The indiscriminate noise of the other patrons registered as a murmur.
Schubert's Sonata in G begins with a beautiful, sleepy, not immediately gripping theme — not so much a melody as a murmur of chords.
"The grants disappeared without so much as a murmur – that's already affected education because people from other social strata can't enter it, for that dynamic mix".
By Alex Ross Schubert's Sonata in G begins with a beautiful, sleepy, not immediately gripping theme — not so much a melody as a murmur of chords.
In the event, Mr Macgregor went ahead and showed it without so much as a murmur of protest (it has been on display in the British Museum for years).
As a murmur swept through a hearing room packed with gay rights leaders, Admiral Mullen said it was his personal belief that "allowing gays and lesbians to serve openly would be the right thing to do".
The armistice is no surprise to Flynt, who believes the nasty rhetoric could remain at a murmur as long as the football teams beat each other regularly.
"Bumps in the road?" Mr. Romney asked, as a grumbling murmur rippled through the crowd.
Usually, Mr. Caymmi's vocals slid in behind Mr. Santiago's as a murmuring commentary emanating from a deeper place, as if the unconscious mind were quietly announcing itself in the background.
Much of Selena's music forms similar tensions, [such as "Amor Prohibido"], in which the dominant precepts are fashioned as a murmuring, a catty whispering that achieves a certain primacy as a hegemonic disclosure.
It begins as barely a murmur, and after the elements of its slow, simple theme gradually coalesce, the work goes into a holding pattern, repeating its materials with little development.
