I have had a few different setups over the years but one thing seems to
always stay consistent: I've always had to boost the bass on my head unit
in order to get decent output from my subwoofers. Right now I have a
Pioneer DEH-P2600 which has 2.2V preouts hooked up to a DEI D1200.1 amp
and a pair of Infinity Reference subs. I need to have the 40 hz region
EQ on my HU maxed out at +12 dB or otherwise I can't even tell I have subs.

I've had other setups with completely different components and I have the
same result. A lack of bass without any boost. I keep reading about
other folks who get sufficient bass output while everything is
flat so I don't understand why my systems require a big boost.

Can someone suggest why this may be the case? I plan on getting a more
expensive subwoofer in the near future and I don't want to be pushing it
unnecessarily if I can help it.

Thanks,
George