I used to use an app called dB Volume. I found it worker better for me as it has a "slow response" option, so your dB readings are constant instead of jumping around.
Hopefully your centre is ok and its just a measurement issue, because as taibanl says, the centre should be louder than your doors.
Turbo Dynamics Hybrid Turbos, Wagner Intercooler, DPF Delete Pipe with Sports Cat, Ecotune custom map ~ 422bhp & 618ft.lbs
Ohlins R&T with custom Swift rears