Crossover point for door speakers & sub

[C6H12O6]

I'm having issues with my current stereo set-up.

Here's what I have:
Alpine 9831 CD head unit
Alpine V12 4ch. amp
Infinity 6.5" Kappas in front
Infinity 6.5" Reference in rear
iPod interface

The problem:
The speakers in the door are so buzzy with any amount of bass, it really sounds like crap. I have played with the HPF on my head unit and currently have the door speakers only running above 80Hz, but even that is too much bass for the speakers. I plan on putting in some sort of sound deadener when I clean/lube the window tracks to help with the vibration. I can hear parts of the door buzzing from the outside and I can feel the door trim panel vibrating along the edges. Not good.

My questions:
1. How much can I expect the Dynamat to clean this sound up? I guess I really want to know is whether the mat will kill enough of the errant vibration to allow more bass through the door speakers without turning into a resonant glob of mush.

2. For the guys and girls out there with amp powered door speakers and a sub, are you running full range signals through the door speaker with the sub? If not, which I wouldn't think you would be, what crossover points are you using in your cruiser? I know it will be quite a bit of personal preference and speaker specific info, I'm just looking for some ideas of what other people have made sound good. I'm sick of $1000+ of equipment sounding about like my wife's stock Accord.

I plan on adding a sub as soon as I figure out what I'm doing in the rear for a drawer system. I like the looks of the internal tire carrier slee has on his web page, and that wouldn't really jive with the drawer I was planning on building with a sub tucked away.

Sorry for the longwinded post. I was not blessed with brevity. I think it all goes back to my grandfather. Right after the war, he...

Sorry.
Steve

 

[El Perro Grande]

Gosh I really dunno what to say. I do have the full spectrum coming from the front doors, but I've jammed in a Boston Acoustics Pro 6.53 system (3 way seperates).

I used to have the Infinity Kappas in the front though, and they handled the 80 cutoff just fine. What's the next step up on your head unit? 120 or something? That's a little high unless you are going to get some midbass speakers. I don't think you want to have your sub cranking out 120.

I dunno, the Kappas should be handling the 80 just fine. I say make sure everything's hooked up right, secure the door the best you can, put in the dynamat and a sub and see how you like it.

Sorry... not much help.

 

[Bruneti]

Is it the door panel vibrating, or the speaker distorting? If I assume that it's the speaker, then something doesn't sound right. Those should play full range at lower volumes without distortion. At louder volumes, 80 Hz may be a little low of a cutoff. Try 120 Hz highpass, and when you add your sub make it 80 Hz lowpass. Also, make absolutely sure that your speakers are properly installed and wired. Loosen all the speaker mounting screws and ensure that you re-tighten them equally. I've never installed Kappas, so I don't know how rigid their basket and frame are. Also make sure on your head unit that any "loud" or bass boost type functions are turned off. Start with your bass eq setting flat (no bass boost) until you're sure everything is working correctly.

 

[C6H12O6]

Yeah, all good advice. I triple checked the goofy Infinity crossover box to make sure I wasn't wiring it out of phase, so I'm reasonably certain it's wired correctly. I'll have to check the wiring at the amp again. Maybe I reversed it there. Dunno. I do remember doing a particularly bad job of soldering with a crappy, cold soldering gun on the PS (worse side). I cleaned the tip off really well and let it heat up a little better for the DS, but I can't imagine a sloppy soldering job making this much difference.

As far as whether it is the speaker distorting or the door vibrating, I can't really tell. It sounds like it's the speaker sounding almost blown as I drive around, but when I stop the truck and put my head right by the speaker, it sounds ok and I can hear the inside of the door vibrating. The weird thing is that I would swear that the PS speaker is not nearly as loud as the DS speaker. Only in front though ~ the rears sound even, near as I can tell.

And yes, I have it at 80 right now. The next step up for the HPF is 120Hz. A little high for me unless I run something else for the mids, which I don't think I should have to. Wouldn't I have a decent sized gap if I ran the HPF at 120 and cut the sub off at 80? I need to go do some homework. I was mostly just curious what other people were running.

 

[PKP80]

Here goes,

I have a similar setup
Audiobahn 6.75 front and 5.25 rear. I have a relatively high power Fosgate giving about 100 per speaker. My fronts have a custom enclosure, but rears do not

What I did for the rear was first made a mounting plate out of 1/2" MDF to use as a median btwn the door and speaker. This did an excellent job of isolating the front of the speaker from the rear which if not done correctly will cause the speaker to "huff" and bottom out. this will cause all kinds of unneccessary cone movement and vibration. (if you've ever see a subwoofer work in free air no box no baffle, or in a box that has too much volume, similar effect, no bass is produced, you just see the cone of the woofer moving rapidly to it's max).

What speaker gauge are you running to the speakers? I wouldn't be using the stock 18gauge or whatever comes with the truck. I have 12gauge in the front and 14 in the rear.

I would also dynomat, even though I didn't, I am thinking about doing it because it really kills 90% of all vibration, it's real nice.

So to recap:
-make sure the speaker is sealed and isolated front to back
-the mount is very solid and even between the speaker and the car door (which will also contribute to the isolation fact, you wont have proper seperation if the speaker is on an un even surface)
-Speaker gauge
-Dynomat

IF non of that helps I would test the speak out on a seperate baffle board just outside the car, it might just be F*(&ed up to start with.

Best of luck and let us know what it turns out to be.

Sam

 

[ginericLC]

I'd look at the mounting first and then move towards wiring. Reversed wiring could cause this but if you were careful that probably isn't that. I did have a problem with one of my front door speakers. The tabs were close enough to the door panel that when the bass would hit really hard that the tabs would touch the door sheet metal. I took it apart and rebent the tabs and coated them with liquid electrical tape. All has been fine now for 2 years.

 

[C6H12O6]

More good ideas. I was a little suspect of the mount up front. It didn't seem very secure or sealed off at all. I doubt I have room for 1/2" MDF, but I bet I could find something online somewhere that is designed to address just this problem. I'll look into it. I wonder if running a bead of silicone under the speaker would help to seal it off, or cause more problems? Oh boy, more homework!

I have 12 ga. to all the speakers from the amp, and the amp wiring is pretty rock solid, so no issues there. I'll start with Dynamat and a good seal for the speaker and go from there.

Thanks,
Steve

 

[chip7238]

I agree with the above - check the mounting.

I have 5.25" Kappas, and have the HPF set at 50 Hz - No distortion here!

 

[ed97fzj80]

I'm getting in late here, but it does sound more like the problem is in the structure around the speaker than in the speaker itself. IMO you're on the right track with getting a good solid structure to hold the speaker, and then work on getting everything damped to cut out the resonant vibrations. I don't know the specs on your speakers, but you should be safe with the crossover set to the speaker's F3 or higher.

 

[Arleaux]

My cutoffs are as follows
60hz front
100hz rear

65w / channel, with none of the problems you describe.
Gotta go w/ the mounting opinion.

 

[Arleaux]

Forgot to mention that I am running the same speakers (kappas) as well.

 

[CreeperSleeper]

Will Dynomat help? In my experience, yes.

What cutoff- for the rear I would do 100Hz.

 

[Erratic]

Will Dynomat help? In my experience, yes.

What cutoff- for the rear I would do 100Hz.

You should be able to run close to full range on those without distortion. I second, or third, or whatever by now the dynamat thing. It makes a huge difference. Perhaps a piece of 1/4" plywood with some dynamat over it. I prefer to use plywood or abs plastic in the door because of the amount of moisture in a door. MDF tends to absorb moisture and will expand. I had one instance where a really high end woofer was mounted to a 1/2" mdf panel and the screws went into the metal. The wood expanded and destroyed the basket of the speaker since the screws held it in place and the mdf expanded in between. Just something to look out for. Dynamat and tune this thing and you'll be pleased. Thats nice equipment.