subbase / subbass [ˈsʌbeis]
subbase – n. – 1. Architecture the lowest, horizontal part of a divided base; 2. a platform under machinery; 3. in engineering, a layer underneath the base layer of a road; 4. a secondary station
subbass – n. – 1. Music a deep sounding stop in a pipe organ; 2. a very low frequency in dance music