Last month I installed my Pioneer AVH-X4600BT and the Alpine KTP-455u, but didnt have time to install the Polks till this past weekend. I was pleasantly surprised how loud the stock speakers got compared to them just running off my old HU (Pioneer AVH-3200BT). At around 10-12 the volume matched what the old HU was doing at like 20. But now, after installing the Polks, the volume profile is back to the way it was where 18-20 is 'loud' compared to 10.
Im positive I didn't miss-install the speakers. Hard to do when you have plug and play adapters. Reading around I believe this is due to the efficiency of the Polks vs the Stockers... Stock speakers have to be more efficient at low power so when they were amped they became much louder. But since the Polks handle more power, the must be a bit less efficient so they need more 'power/volume' to get the same output?
Does this sound right?
Also I was excited to finally use my headunits "AUTO EQ" to tune everything after I got the Polks installed. Come to find out that since I have the AutoBypass module installed, this feature is not available. So now I have to rewire with a flip switch or something to be able to use both. A lot of work for a one time thing lol.
And finally... Make sure when you install new speakers you turn off all the gimping you had to do to make the stock speakers not bitch and moan at you. I was all
after installing the Polks... until I realized I had them highpassed at 125... dropping that down to 80 finally made them sound good.