system evaulation and questions

The rms rating that I quoted you was straight from Crutchfield's website and is 2 - 35 watts rms at 4 ohms each speaker. Typically your standard car speaker is a 4 ohm speaker, so unless you are running your speakers in paralell or series, ohms mean very little until you get to a subwoofer and your amplifier specs. Ensure that when purchasing your amplifer you concentrate on the rms rating not peak power. Amplifiers are rated Peak Power first and then RMS or nominal rating for a 2 OHM Load and then for a 4 OHM Load. Example: Amplifier #1 is rated as 200 Watts Peak and 50 Watts RMS X 2 into 2 Ohms and 35 Watts RMS X 2 into 4 Ohm's. Amplifier #2 is a 4 channel amplifier rated at 400 Watts Peak and 50 Watts X 4 into 2 Ohm's and 25 Watts X 4 into 4 Ohm's. This is very typical of the market, so once again make sure that you read the RMS RATING per channel at whatever Ohm load that you are wanting to push the amp at.

The BASS Blockers will be rated in Hertz, for instance, your Polk 4x6's can only handle a frequency response of 95-21,000 Hz, so if your HU does not have a HPF (High Pass Filter) you will want to install a pair of Bass Blockers rated at 100Hz or higher (200Hz, 300Hz, etc...) and let your Sub take care of the Bass for you. You will not get much bass out of your 4 inch speakers or those 4x6's so you will need to cut out the lower Hertz freq's so as not to blow them. You can locate 200Hz Bass Blockers at either Best Buy, Circuit City or any local Audio shop. But, because you are planning to have a two amp system you may be able to buy an amp with a built in crossover and that will allow you to do basically the same thing as I described above.

Regarding your sub, remember Peak Power means nothing and this also equates to your speakers as well. Is that a 400 Watt RMS sub or is that a 400 Watt Peak Power Sub? If you have a 400 Watt RMS sub then I would find a mono amp with close to the same rms rating as my sub. 400 Watt RMS Subwoofer and a 400 Watt RMS Mono Amp. Don't forget that you have 4 Polk's in your Jeep that are possibly going to be killed by the sub. I would recommend you posting a second question asking for some advice on Subwoofer and amplifer selection. Some of these guys really know their stuff.

Hope this helps. If not let me know and I'll try to find you an answer.

Regards,

Razorbacx