Crossover settings for Polk SR6500 + Polk SR104

[GelatinousFury]

I'm preparing for an install coming up during Christmas break which will include Polk SR6500's up front (no rear fill speakers) and 1 10" SR104 subwoofer. The SR6500's will be powered by an Alpine PDX 2.150 and the SR104 will be powered by an Alpine PDX 1.600.

Now, I will be running the Alpine H701 processor for EQ/time alignment purposes but will be using the SR6500's passive crossovers as well. Again, SR6500's will have their own passive crossover while the SR104 will be controlled by the crossover in the Alpine H701.

Can anyone help me out with some good starting crossover points for the SR6500's and the SR104? I know the Polk passive crossovers will split the frequencies up between the midbass/tweeter but won't I still have to apply some kind of high or low-pass setting so that they won't play any incredibly low or incredibly high frequencies? And for the SR104, should I keep the low-pass set to 60Hz or so with a steep slope?

I guess in all of car audio this is the part I know the least about, and it's probably what I need to know the most about.

Thanks for any help!

[Thom]

60 might work for the sub, and you could try 80 for the components. You'll be able to try some different settings with the 701 and switch between them. Try a 60 Hz lowpass for the woofer and 80 Hz for the mids. Then move them up and down a bit and change the slope. When you get to a point that you think sounds best, save it. Then keep making changes and if you find something that you think sounds better, save that to a different preset. Then compare the two (or more) saved settings to see what you like better.

[MacLeod]

For my daily driving and heavy metal listening, I found that 63 Hz @ 24 db for the sub and 63 Hz @24 db for the mids works best.

For my SQ setting, which has a lot of stand up bass that can be very boomy and pull to the rear, I have the sub at 40 @ 30 db and the mid at 50 Hz @ 24 db.

[GelatinousFury]

I don't want boomy bass, as that can easily overpower fast percussion-heavy music like metal (what I mainly listen to). I guess I'll start out with:

1. SR104: Low-pass set at 63Hz/24dB on the Alpine PXA-H701

2. SR6500: High-pass set at 63Hz/24dB on the Alpine PDX 2.150 which then feeds that signal into the Polk SR6500 passive crossovers

(tweak from there as desired)

Thanks for the help everyone. I'm going to use the H701 to achieve a relatively flat frequency response in my vehicle and then, again, tweak from there as desired. Didn't have much of a clue on crossover settings though :)

[MacLeod]

I wouldnt shoot for a flat setting, those almost always sound like total ass.

First thing I do is set the gains. Generally I set them all the same, about 25% or the 9:00 position.

Then I go into the crossover setting of the 701 and set the crossover points. Then using a SPL meter, run some pink noise thru each individual channel and adjust the levels til theyre the same.

Next up, start off by playing some pink noise thru there and then adjusting all the peaks out of the curve. Then once you got everything relatively together, then get the left and right sides together.

After you have them level matched, crank up some music and adjust the sub level til it blends well. Then after you have all that, then start on the fine tuning.

This is of course assuming you have access to either an RTA or a SPL meter and filtered 1/3 octave pink noise tracks.

[GelatinousFury]

I wouldnt shoot for a flat setting, those almost always sound like total ass.

First thing I do is set the gains. Generally I set them all the same, about 25% or the 9:00 position.

Then I go into the crossover setting of the 701 and set the crossover points. Then using a SPL meter, run some pink noise thru each individual channel and adjust the levels til theyre the same.

Next up, start off by playing some pink noise thru there and then adjusting all the peaks out of the curve. Then once you got everything relatively together, then get the left and right sides together.

After you have them level matched, crank up some music and adjust the sub level til it blends well. Then after you have all that, then start on the fine tuning.

This is of course assuming you have access to either an RTA or a SPL meter and filtered 1/3 octave pink noise tracks.

Nice...got it.

I know about level matching because I've done that in my home theater with my Radioshack dB meter. I have TrueRTA (1/24 octave resolution) but have not gotten around to using that yet. I'll probably just use the Radioshack meter calibration file and run that into TrueRTA and follow your guidelines that you just posted.

When (if at all) do you adjust the gain settings from the original 25%? I assume I'll be adjusting the levels with the H701. I only ask because I had planned on using the voltage formula SQRT(Watts x Ohms) and setting those voltage values with my multimeter:

PDX 2.150: SQRT(130 watts x 4 ohms) = 22.8V

PDX 1.600: SQRT(600 watts x 2 ohms) = 34.64V

The only thing I wandered about was if the 2 ohms was correct or not since the PDX amps have regulated power supplies...

[MacLeod]

That would be fine. I dont have the smarts or the multimeter to set my gains by voltage so I just drop em down to the 9:00 position which is pretty much guaranteed not to clip and then adjust the levels thru the 701.

Its up to you tho. If you set them by voltage then youre guaranteed of not clipping them anyway so that would work just fine.

That Radio Shack meter is a fine tool and all you really need. Just get you a test CD that has filtered pink noise at 1/3 octave intervals. Play each one and hold the meter where your head would be and pointing straight ahead. Write down each reading for each frequency and then go back and smooth out any peaks or dips.

After youve done that, go to left only and right only. Hold the meter where your head would be and pointing slightly to the left or right. Play the left then fade to the right and point the meter slightly to the right. Then go into the l or r EQ on the 701 and adjust them til theyre within 2 db of each other.

You can get a disc here

http://www.rainfall.com/cdroms/pink_noise.htm