Amp and Component Crossovers redundant or competing?

brucem206

I've just begun an upgrade to my 2008 F150 screw. I've got a Kenwood 6170 HU and just installed MM6501s in the front doors. I have a Alpine PDX-5 inbound next week and it will be the next install. If the bass is good I might stick there but I'm probably on the path to include an under rear seat sub and mids in the back doors.

I get the concept of signal separation but I am not clear how to best set it up. Doesn't the HU EQ start the separation and deliver it to the amp via the preamp outs? Then the amp takes those three signals and has a crossover for each that can be tweaked before going to (as in the case of the fronts) the speaker's crossovers and ultimately to the tweeter and mid-bass speakers of the MM6501s? Are these 3 crossovers redundant or competing? I assume the EQ in the HU is for fine tuning but the amp and speaker crossovers are or will be buried behind panels and seats and generally set and forgotten. Any setup suggestions for those two crossovers?

Also, any suggestions for the back door mids?

arun1963

You can do without the rears. Honestly, you don't need them. The sub though is a good idea. It will give you coverage over the two lowest octaves that your mids would miss. You're using your subs to complete the sound not overpower it.

Googling

Kenwood 6170 HU

Yields little. A typical hu would let you set the xover between the sub and the mid. That is the point where the sub cuts off and the mid takes over. The better hu will let you control how steep that cut off is.

The signal that goes from your hu to the MM's crossover is now carrying information from 60hz (assuming thats where you set the sub/mid xover) to 20 hz. Since neither the mid nor the tweet can play this entire range, you have the passive crossover in the path that splits this signal between the mid and the tweets. Most passive xovers split the signal to the mids and tweets between 2-3khz. So with a xover of 60hz at your hu and a 2khz at the passive, the sub would play 20-60hz, the mid 60-2khz and the tweets would play everything above 2khz.

A car is also the worst environment for reproducing audio signals. The speakers are at different distances from you hence different arrival times, they are at different axis relative to your ear thereby affecting the frequency response of each speaker, then you have to factor in the pure noise element while on the move and the fact that there are tons of reflective surfaces. All-in-all, what your ears receive and what your brain processes, is a jumble of sounds called music. Of course this is one extreme view. 99% of the folks aren't really fussed on the quality of sound as long as its loud enough, when they want it to be loud.

To correct for the above you need a ton of DSP. Via your hu or a processor.
Correcting for most of the things above will let you experience sound that's close to a decent home 2ch setup. Then again 99% of people are not that OCD and just want crankable sound driving back and forth from work.

Hope this sets things up for you. Btw welcome to CP.

brucem206

Arun:

Thank you for you reply re: the HU. I was thinking I could skip the back door mids.

Any thoughts regarding the seemingly duplicate amp and speaker crossovers? How do you recommend each be configured?

arun1963

Just set the sub/mid xover at your hu and bypass all crossovers at the amp. The passive cross over on the MM's will split the signal between the mids and tweets.