question on crossover settings for polk amp

[trojannemo]

hey guys.

here's the setup

- Kenwood KDC-MP238 head-unit
- Polk DB351 3.5" in front doors
- Polk DB521 5.25" in front doors
- Polk DB521 5.25" in rear doors
- Polk DB691 6x9" in rear deck
- Polk PA200.4 amp

- amp is wired using 8ga power and ground. all speakers are wired individually using oxygen-free copper 16ga wires with gold-plated connectors at the speakers. running streetwires/kicker (front/rear) gold plated RCA cables from the kenwood to the amp.

so i think this is the best installation i've ever done!

now i have a question for you guys. i'll be tuning the system tomorrow morning. i dont know what i should set the crossover settings for.

I have the following options:

HPF - Flat - LPF

according to the manual:

HPF - attenuates low frequencies and is used with mid-range speakers and tweeters. i think this is the setting i should use, am i right?

Flat - does not attenuate, for full range speaker systems. is this intended for the component speakers that i've heard of yet never seen?:o

LPF - attenuates high frequencies and is used for subwoofers. i'm pretty sure it's not this one.


so essentially i'm undecided between HPF and FLAT. i think based on the manual i should use HPF, as its designed for "mid-range" speakers and on the speaker manuals, all my speakers are designated "mid-range/woofers" by Polk.

any other input or suggestion on the matter greatly appreciated.

[arun1963]

1. You have four sets of speakers. Am not clear what is running of the amp and what is running of the HU.

2. For cross over use the HPF setting. I think with your HU you cant select the xover frequency or the slope. So the crosover at the HU is set at one frequency (prob 80hz). Setting the HPF will feed only 80hz and above to the selected speakers.

IMHO you have too many speakers. As and when you are ready to upgrade the sound, you could work on the following sequence:

1. Components up front, 6x9 at the back connected to the 4ch amp
2. Ditch the 6x9, add a sub and mono amp to drive the sub.
3. Bi amp the comp's and change the HU to one that offers tuning options.

SQ is a long journey so enjoy the ride.

[MacLeod]

Yeah, Im gonna agree with Arun on this one. Youve got way too many speakers to be anything but loud. Having 8 speakers playing at the same time means youre going to have the same frequencies hitting your ears at different times which means cancellation and phase issues.

If it were me, Id go with 6x9's in the rear and 5.25's up front.

[trojannemo]

i dont understand this issue with "too many speakers"

i come from a 2006 Nissan Maxima with a BOSE sound system, which came stock with 8 speakers, similar setup as the one i have now. that sounded great and also loud, not just loud.

this car i got it with one working 3.5" and one working 6x9", and a fm/am radio with missing knobs.

so my first thought was to put a CD player and then i put four speakers to work. then i realized the car came prepared to have 8 speakers installed, and since the maxima had them, i went and got all Polk speakers at CircuitCity since they were going out of business.

then i posted here because i hooked up those 8 speakers to the HU alone, and i couldn't go anywhere with the volume before the speakers started crackling. in here you guys told me that i was running too many speakers off the HU, and to unplug 4 and leave 4 on until i could get a 4 channel amplifier that runs stable at 2-ohm, and then recommended to me the same amp that i just got now.

so now i have all 8 speakers running from the 4-channel Polk amp, effectively running each channel at 2-ohm load, which it can handle efficiently according to its specs.

i did all the testing already, and found that HPF gave me the best sound. i have the HU set to +2 bass, 0 mid, -1 treble, bass boost level 1 (out of 2) and +8 db on the rear channel bass signal set on the amplifier. with these settings i can go up to volume 26 (i.e. 3/4 of the hu volume as i was told) and get almost 0% distortion. at the regular volume i listen to, 20-22 i get 0% distortion and it sounds great (to me).

eventually i will put a sub and amp and return all the bass boosting settings back to normal, but i plan on keeping the 6x9s also to drive more power on the higher frequencies...


can someone explain the whole idea of phase issues and cancellation?

if there is anything to do to improve sound while keeping the speakers, let me know, but after all the money and time spent on this, they're not going anywhere


EDIT: i just did some research on the concept of "out of phase" polarity on speakers, and all my 8 speakers are in phase. i know because as i said above, i did this install right and all the polarities are matched exactly. is this the issue you were talking about?

[arun1963]

chill bro. Advise ure getting is from a sq boss and an sq wannabe.

at the end of the day its about what you like listenening to. If you like the sound from 8 speakers cool scene.

Its like two guys like whiskey, one likes bourbon one likes single malt. So who likes the better stuff?

Ans: After 3 drinks you wont know the difference, IE like whiskey, music is highly personal. Enjoy the journey...............

[MacLeod]

Your CD was recorded on 2 channels. A left and a right. Your system has 4 speakers per side all different distances from your ears. So when you have 4 speakers at different distances playing the same frequencies, theyll be hitting your ears at different times and running over each other.

A sound wave is nothing more than turbulence - a vibration in the air just like a ripple is a vibration in the water.

Think of it like this - youre at a pond that is still. Throw a rock in and watch the ripples. Now throw 4 rocks in and watch the ripples collide with each other and distort and/or outright cancel each other out. This is the same thing that is happening in your car.

Also, since the speakers are all different sizes and are at different spots in your car, their outputs are going to be different so you have the same frequencies coming from 4 different speakers but at different output levels and this will smear detail.

Stereo sound works best with 2 channels. A left speaker and a right speaker. The more speakers you throw into this mix, the more trouble youre going to run into.

[trojannemo]

thanks for the clarification. though now you've made me feel like i wasted a bit of money on getting those speakers!

so you're saying that having only 4 speakers (let's say 5.25" in the front doors, 6x9" in the rear deck) would sound clearer than all 8 speakers together? i assume even with 4 speakers it's good to keep the amplifier?

EDIT: i apologize if i have sounded like an ******* in the previous posts. i assure you it was not intentional and I really am interested in learning about all of this.

[MacLeod]

Ideally youd only want the front speakers.

However that is only if youre after the best sq and imaging you can get. If youre just wanting some good tunes to listen to while you drive to work or whatever then dont sweat it. It might not be the most accurate reproduction of music but itll still sound pretty good. ;)

[trojannemo]

thanks for the info.

i'll be listening closely and see what works best for me. so far my inexperienced ear isnt complaining from the louder, clearer (when loud) sound i'm getting. i also noticed i'm getting significant bass even though i dont have a bass system (yet!):D