Sundown 3000d vs. XXColossus 3200d

what size alt you have? You might not have enough power to run at.5

Subsonic filter perhaps?

voltage drop...

Those XXV Colossus are no joke . That's why u shouldn't belive everything you hear, but now you know the real truth

the hifonics is nice and does abit over rated.. but so does the SD they are capible of doing 3500+ @1ohm with 14 volts.. your seeing a small efficency drop going from 2 to .5 with the SD.. frequency response won't change between the 2 amps.. im 99.9999% positive you just need to properly set the gains... honestly i don't know hwy you sold the hifonics there great amps..

check you CDC players settings, turn the SSf on the SD all the way down turn the HP all the way up and make usre your wiring is correct, make sure you didn't wire a coil out of phase etc.. chanes are you won't hear any difference between the 2 amps..

It could be many things, if you want to email me every spec of your setup I can check it over..Sounds like a voltage drop though. The 3000 is a beast.. you should get better results.