low-pitched 
adjective
1(Of a sound) deep or relatively quiet: the fin whale uses a low-pitched call...
- Our evolutionary fear of certain sounds, such as low-pitched sounds indicating aggression or high-pitched screeches indicating alarm-calls, has been with us for thousands of years.
- They point to research showing that manatees cannot hear the low-pitched sound of slow-moving boats and thus avoid approaching vessels.
- One was a high-pitched sound that resembled a doorbell while the other was a low-pitched sound that gradually increased in pitch.
2(Of a roof) having only a slight slope.The roof is low-pitched and small dormer windows are sometimes used....
- The low-pitched roof form was sufficiently high to enable the inclusion of a first-floor cooking school, which overlooks the centre spine.
- Both buildings have low-pitched roofs and overhanging eaves supported by brackets that are typical of the style.