With election day being a state holiday (hooray being a state employee), I was finally able to empty the boxes in my basement and get them into my car. Here is what my system finally ended up as:

Deck:
Pioneer Premier DEH-980BT

Speakers:
Front Speakers:
Alpine Type-R SPR-17LS 6-1/2" Component 2-Way Speaker Set
Rear Speakers:
Pioneer TS-A1681R 6½" 4-Way Speaker with 260 Watts Max.Power
Subs:
2x JL Audio 12W3V2

Amps:
Front:
Rockford Fosgate P325.2
Sub:
Alpine MRP-M650

I used about 10 rolls of Dynamat as well... Vibrations drive me nuts.
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My problem now becomes tuning. I have a decent ear, I can tell what sounds good and not, but this system is a lot more than I've had previous. Where is a good place to start? I figured the first and most important thing I should do is properly set the gains on both amplifiers. I don't have a oscilloscope available to me, so I will be setting them with a digital multi-meter.

The deck I have has the built in HPF and LPF for the front, rear, and subs. I understand what those do, and how I should tune them, however, I do not understand the "Filter Attenuation Slope" The Deck has several options, -18, -12, -6 dB/oct. Can someone explain what these do, and how they should be set?

Are there any other hints, tips, techniques, etc, that would help make the system sound as good as possible?

As always, Thanks in advance

 

The "slope" is the rate of attenuation per octave beyond the crossover (filter) point. Say your subwoofer crossover (actually low-pass filter) is set for 80Hz, "-18". This means the at one octave beyond the 80Hz crossover point, which is 160Hz, the output will be -18dB. This is also referred to as a "third-order" filter, where "-12" would be second order (less aggressive attenuation than third-order).

In your situation, where you're concerned with setting the crossover point between your subs and components, higher-order slopes will provide the best performance, regardless of the frequency you choose, so I suggest using "-18" if that's the highest choice you have.

As for the frequency, it'll likely be best using the same crossover point (not under nor overlapped), which can best be determined by the low frequency limit of your front components. You may also be limited by the frequencies offered by your HU, and I don't know what choices you have since you didn't mention them. 80Hz is a common crossover point, and I'm sure your front speakers would perform well at that, but if you have a 60Hz choice, that might be preferable,

Concerning tips, that's one reason I mentioned 60Hz being preferable to 80Hz. For SQ, you don't want to be able to "localize" the subs (easily determine their location), and it's often possible to make it seem as if they're located in front. One way to accomplish this is by using lower crossover points and greater attenuation rates.

Good luck with the system, it's got potential.

 

Sorry for not mentioning the frequencies, I had been typing for a while...The Sub cut off frequencies (LPF)are as follows: 50, 63, 80, 100, 125, 160, 200 (Hz)

With slopes: –18, –12, –6 (dB/oct.)

Front and rear HPF's are as follows:
Frequencies:
50, 63, 80, 100, 125, 160, 200 (Hz)
With available attenuation slopes of:
-12, -6, 0 (pass) dB/otc.


Reading through the manual of the deck, I found this little blurb: (yes I actually read the manual...) I'm not sure what it means exactly...

"When slope of subwoofer and high pass filter are
–12dB, and same cut-off frequency, the phase is
reversed 180 degrees at the cut-off frequency. In
this case, reversing the phase assures improved
sound continuity."


The Frequency response on the front speakers is 35Hz - 30kHz so I can pretty much pick any available x-over point and go from there, should I still be looking ~60Hz?

 

I understand the speaker's spec sheet stated 35Hz as their low-end response, but that's very misleading, because they didn't supply a tolerance, such as "+/-3dB". Generally speaking, the higher your crossover point, the more power your components can handle and still produce clean output, up to a point.

In this situation, I'd use 63Hz, -18 for the sub settings (this being the low-pass filter), and 63Hz, -12 for the components high-pass filter. Once set that way, and after you've adjusted your gain structure, disconnect the subs and listen to your components. When you turn it up loud, listen to ensure the woofers aren't distorting, that they're producing output that sounds good to you. If that's the case, fine, no need to change anything. If they distort much, and/or sound like they're trying to produce bass that might damage them, then try changing the crossover point for both high & low to 80Hz, using the same -18 and -12 slopes as previously specified.

One setting or the other (63 or 80Hz) will be fine for your system. Using 63Hz, if your front speakers can handle it (probably), would be the best from an SQ perspective, but you'd likely be pleased with 80Hz too. Anything higher than 80Hz and it'll be obnoxiously obvious where the subs are located.

 

nodsetse,

Thanks a lot. Between you and Google, I've got the best sounding car I've ever had...

I ended up having to use 80Hz (with -18, -12 slopes) to get the volume without distortion. The components starting distorting around 1/3 volume with the x-over at 63hz, depending on the song. I listen to tons of music, from Jazz to "kill your parents" hard rock and it can change at any moment, so moving the x-over up to 80Hz gave me better sound all around...

All I need now is a few more rolls of Dynamat to help a few 'new vibrations' and I'll be a really happy camper.

 

Very cool, congrats on the tuning and glad I could assist. :D

There's one additional tip I can offer. From your earlier description, it sounds as if your head unit has a phase reverse setting for your subs. If so, I suggest you try both settings (in & out of phase, or 0 and 180 degrees, however it's stated), so you can determine which provides the bass response you prefer most. There will be a difference in sound that you can notice between the two settings, but neither is necessarily right or wrong, it's simply a matter of which you like most.

 

this is awesome info, im gettin this head unit soon too. how much and where did you get yours from zero? and sry to bring this back from the dead. less than a month though.