HELP! Subs dont sound right

 

Bronze Member
Username: Eric77

Post Number: 29
Registered: Nov-04
I got my subs installed today and they sound really good at low to medium volume, but when I turn them up they sound like they are kind of rattling almost and they are a little boomy. They also dont even sound decent when you are in the backseat. I had a guy at a local car audio shop set the gain and crossover and bass boost since I have no idea how it works.
BTW, I have two diamond m6mkII 10d4's wired to 1 ohm on a nine.1 and I have the pioneer deh-6300 head unit. Also, these subs are rated 800 rms each by diamond, but I cant even come close to turn it up all the way on a lot of songs. The amp is no more than 1500 in my car and the subs are 800 rms and I am running each in a sealed enclosure that is .85 ft3 ( .05 larger than what winisd recommended), so I thought I would be able to turn it up pretty loud without a problem.
IS any of this normal?

Thanks.
Eric
 

Silver Member
Username: Zacdavis~

Post Number: 350
Registered: Sep-04
sounds like you might want to turn the subsonic filter up some. also, subs move further in sealed enclosures, maybe in the future you could try a ported box. remember some songs have too low of bass for some subs in certain applications, thats why i recomended using the subsonic filter up to least 28 to 35 hz for those tens in that sealed box.
btw, diamond kicks azz:-)
 

Bronze Member
Username: Eric77

Post Number: 30
Registered: Nov-04
I thought the subsonic filter was just for ported boxes?
I considered doing a ported box, but diamond recommends a sealed enclosure for those subs and I plugged the specs into some other program that said the subs would do best in a sealed enclosure. Someone told me I may have screwed up my speaker wiring so I think I may try that. Also, Im thinking about adding polyfill/pillow stuffing just to see what happens.
 

Silver Member
Username: Zacdavis~

Post Number: 351
Registered: Sep-04
you dont want to add poly fill, your already over the recomended volume.
the subsonic filter is alot like a high pass filter. what ever frequency its set at is where the bass only goes down to.
so if it were set at 29hz, then only bass that is 30hz and higher will play through to your subs.
subsonic filters are meant to keep subs from over excursion in most cases.
as far as your wiring that may be a problem, you could possibly have to low of an ohm load and thus creating amplifier distortion of some sort.
check your impedence at the box terminals using a volt meter set at res/ohm.
thats about as much as i can think of at 4 in the morn
 

Bronze Member
Username: Eric77

Post Number: 31
Registered: Nov-04
Thanks for all the help. Someone on another forum highly recommended rewiring and checking each coil off a 9v or less battery. Have you ever heard of doing this? I dont have any terminals on the box. I just ran the wire into one chamber then over to the other chamber. Should I buy a couple of terminals to install on the box?
Tomorrow morning I'll try and set the subsonic filter and then if that doesnt work i'll rewire.
 

Bronze Member
Username: Addicted2bass

Miami, FLORIDA USA

Post Number: 80
Registered: Nov-04
One thing that might be causing it, is you did not break the subs in yet.
 

Bronze Member
Username: Eric77

Post Number: 32
Registered: Nov-04
It could be that they arent broken in. Afterall they only have about 3 hrs of playing time. Im gonna try and keep the volume down a little bit for a while.
BTW, I just hooked up my sub wires to a d battery and they hit in unison. Then i checked the phase and saw that the guy had it at 180 degrees so i turned it all the way back down to zero. Then I turned the subsonic filter on and put it 29. The gain was a tiny bit past half way so I turned it to exactly half way. The bass boost was pretty low (less than 1/4 turn) so I just left it. I played breathe on it and sounded really good from the drivers seat. I didnt have a chance to try any other songs out cuz my mom got mad. lol. Ill repost once I try my other cds and let you know if I still have a problem. Thanks for the help.
Eric
 

Silver Member
Username: Zacdavis~

Post Number: 352
Registered: Sep-04
:-) glad to see your learning how to work on your own stuff, good job.
btw, it has nothing to do with breaking in your subs, it would be the exact opposite, when a sub is new it is a little bit stiffer than an older one, the older one would be more likely to bottom out if either were goin to.
l8a eric
 

Bronze Member
Username: Eric77

Post Number: 33
Registered: Nov-04
Are there any in depth tutorials that you know of where I could really learn about all the adjustments on my amp?
I actaully built and installed my entire system on my own. I am reallty proud of this because about a month ago I knew NOTHING about car audio. A couple of my friends even gave me sh*t for not getting it professionally installed or getting a prefab box.Thanks again.
Eric
 

Bronze Member
Username: Addicted2bass

Miami, FLORIDA USA

Post Number: 92
Registered: Nov-04
www.bcae1.com

it teaches you alot about car audio
 

Silver Member
Username: Zacdavis~

Post Number: 354
Registered: Sep-04
thats kick azz eric, here is a link with quite a bit of interesting info,
http://www.the12volt.com
 

Bronze Member
Username: Eric77

Post Number: 34
Registered: Nov-04
I spent some more time tweaking with everything and I discovered that my amp placement was creating a lot of the problems. I had my amp on top of the box screwed down tight on top of a piece of edead, and a lot of the rattles that I thought were the sub were actually the amp. I took 2 pieces of styrofoam that came in my sub boxes, taped the edges together then taped them down on top of the box. Then I had to wrap the styrofoam in duct tape so it wouldnt break into little pieces or squeak. Finally, I screwed my amp down on top of this. I cranked the volume way up and it sounded great. I tried a lot of cd's and really had no problems. Hopefully the problem is solved. I'll try and get some pics up by tomorrow so you can see what Im talking about.
I also, used some edead v1 on my cargo door to reduce the vibrating and improve the sound. Just one layer made a huge difference. My subs are rear fireing in a jeep and you can really tell the bass is just bouncing off the trunk door. I couldnt really use too much because I bought it for my friend to do his trunk, but I figured I might as well use some. I think I am going to buy the 120 sq ft of edead off ebay and split it with another friend.
Does anyone else have a problem with their rearview mirror vibrating so much it faces straight down? Every time I turn it up the mirror becomes worthless. lol.
When I get a chance Im gonna put some mdf in the box to reduce volume and add some polyfill or i might add polyfill first then add mdf if its needed.
I would like to seal the hole where my speaker wire come up but all i can think of that would do it is silicone which I heard is harmful to the speaker. What should I do?
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2807
Registered: May-04
You definately need to seal up the wire hole, use silicone. Silicone can damage surround when it cures (mainly foam surrounds), so the best thing to do is remove the sub and seal it up, and reinstall after it cures.
 

Bronze Member
Username: Help_2

Post Number: 41
Registered: Dec-04
The fumes from silicone are harmful, yes.
Especially to foam.
It also leaves sort of a residue on stuff, and
stinks up your car for a while.
If you seal up anything using silicone, you
should let it dry in your garage or something before putting the subs back in, and into your car.

I find its easier to use 2x4 chunks as opposed
to MDF for reducing box volume, but thats me.
Also, adding polyfill will "increase" box volume..
You probably knew that, but its not clear in what
you wrote, so...


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