Is my sub overpowered?

 

New member
Username: Bigboat

Post Number: 5
Registered: Mar-05
so i just got a JL 12w3v2 and a fosgate amp. Im running the 300w rms to the sub and it seems like under a lot of the bass the sub moves to much and buzzes. Is this normal with the gain probably 1/3 of the way up. It just doesnt seem right with the power im sending to the sub.
 

Gold Member
Username: Taylor17

Kopperl, Texas

Post Number: 1414
Registered: Jan-05
No, I've seen a w3 taking a 500 watt Kicker amp with no problem. What size box is it in, and are you running it at the right ohms?
 

New member
Username: Bigboat

Post Number: 6
Registered: Mar-05
and the sub is in a sealed box if that matters
 

New member
Username: Bigboat

Post Number: 7
Registered: Mar-05
the box are the same dimensions from jl's website, 1.25cuft. Should be running at two ohms according to the wiring diagram. its the 4ohm dvc stable at 2 ohms so i dont think thats it.
 

Silver Member
Username: Theelfkeeper

Stockbridge, GA USA

Post Number: 305
Registered: Feb-05
double check your wireing, grounds, turn the gain down while playing and see if it goes away. is the amp wireing sufficient for the power its pulling??
 

New member
Username: Bigboat

Post Number: 8
Registered: Mar-05
ok well it still buzzes with the gain all the way down. Im running a 4 gauge wire to the amp and for the ground. Could a bad ground cause this, i think the bolt was rather small at where it was grounded.
but the sub should be able to handle the power when the gain is like half way up right?
 

New member
Username: Bigboat

Post Number: 9
Registered: Mar-05
i dont have any way to check the volts, but the gauge on the dash says its a little less that 14 volts
 

Gold Member
Username: Taylor17

Kopperl, Texas

Post Number: 1422
Registered: Jan-05
The buzzing sounds like a ground problem, play around with that and see if it stops.
 

New member
Username: Bigboat

Post Number: 10
Registered: Mar-05
alright ill work on it. i think im just going to drill a new hole in the body
 

Bronze Member
Username: Bigboat

Post Number: 11
Registered: Mar-05
ok well i made a new ground with a 3/8" bolt. it helped a little, and then i dropped the gain a little and turned the crossover on the amp up so it wouldnt play the really low notes. its a little better but still seems a little buzzy, could it be anything else?
 

Gold Member
Username: Taylor17

Kopperl, Texas

Post Number: 1429
Registered: Jan-05
What size ground wire are you using? Some times if the ground isn't big enough it can cause funny sound's.:-)
 

Gold Member
Username: Carguy

Post Number: 2399
Registered: Nov-04
When you say buzzing sound, at what point does it occur? All the time or only at high volume?
Is the buzzing coming from the sub or speakers?
 

Bronze Member
Username: Minime

Portland, OR

Post Number: 38
Registered: Mar-05
Is the power wire to the batt anywhere near the RCA's?
 

Bronze Member
Username: Bigboat

Post Number: 12
Registered: Mar-05
ok well the ground is a 4 gauge wire thats probably 3 feet long, and the rca cables dont get near the power cord until like a foot away from the amp.
also the buzzing just occurs at high volumes, it seems like the note is like to low or somthing for the sub to play. It definetally the sub though, i can stand there and watch it happen.
 

Silver Member
Username: Fishy

Tamarac Ft.Laud, FL USA

Post Number: 987
Registered: Sep-04
Is that RF a monoblock?

There's not too many two channel amps stable at 2 ohm bridged. Wired in that fashion the thing would be attempting to produce four times the rated power at 4 ohm stereo(8 ohm bridged). You could be supplying a bit too much power with a bit too much distortion with a two channel setup.

-Fishy
 

Bronze Member
Username: Bigboat

Post Number: 13
Registered: Mar-05
Well im pretty sure its a mono amp, its a p3001. if there were 2 inputs for speaker wires would that make it a 2 channel amp. but if not im pretty sure that its a monoblock. Im starting to wonder if i got the wrong sub and i wired it to a 1 ohm load, would that cause a problem?
 

Silver Member
Username: Fishy

Tamarac Ft.Laud, FL USA

Post Number: 988
Registered: Sep-04
Is it a 12w3v2d2 or 12w3v2d4?

The d2 has dual 2 ohm vc's(4 or 1 ohm operation) and the d4 has dual 4'(8 or 2 ohm operation).

If this is your amp:

http://www.rockfordfosgate.com/products/ez2rockford/ModelInfo/ModelInfo.asp?Item Key=10063526&CategoryDesc=Punch%20Amplifiers

then you'd want the d4 model.

I noticed that the amp has a bass boost feature. Run that thing flat, i.e. turn it all the way off to 0dB boost. In a sealed box you could be very well over driving that thing. If you want more output(3 dB+) a ported enclosure per JL's specs would be a better choice as the sub's cone is damped(barely moves) at the box's tuning frequncy with most of the output coming from the port.

IMHO bass boost suxxorz if SQ is of much concern.

-Fishy
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 3723
Registered: May-04
Ground wire shouldn't be 3 foot long. Around 18" or less is optimal, basically, make it as short as possible. It may help with the noise, at least to an extent. And typically that sub will reach it's potential around 300 watts RMS, it may be distorting or similar. The crossover on that amp should be only LPF and not HPF, you don't need a subsonic filter on a sealed box sub.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 3724
Registered: May-04
If you really want to control that sub and keep it from overexcursion, then a ported box is the way to go IMO. Tune it low and you won't have much trouble with overexcursion as long as you don't drop below tuning. By your description and watching the sub, it seems that the sub itself is making the noise by it's own means via overexcursion, possibly at resonance of the system, which is a point where overexcursion is easily reached.
 

Bronze Member
Username: Bigboat

Post Number: 14
Registered: Mar-05
well the amp had either a lpf or hpf. when it was on lpf it buzzed more, so i just used the lpf from the head unit and set it at 80hz and the rose of the bottum of that a little on the amp, it worked a little i guess. So basically the buzzing sound is just the sub distorting because its to loud?
and the ground is probably like 2 feet long max i think, but i cant make it any shorter.
 

Bronze Member
Username: Bigboat

Post Number: 15
Registered: Mar-05
ok so yeah when i tested it the bass boost was all the way up, so fishy ur saying just turn that all the way down and adjust the gain from their. ok that was probably the problem then. and yeah that is my amp, and im sure i bought the D4 version of my sub i just wasnt sure if thats what came in. ok Another question, the buzzing sound is harmful to the sub right?
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 3726
Registered: May-04
The buzzing sound could be the sub distorting, but I can only go so far off of a forum, as you know I'm sure. Anyway, it sounds as if you have a problem with overexcursion at lower frequencies, what type of music are you listening to when you notice this buzz the most? If possible, try and name a specific song that many are familiar with, that way we know roundabout how low the song gets.
 

Silver Member
Username: Fishy

Tamarac Ft.Laud, FL USA

Post Number: 991
Registered: Sep-04
Yeah with the bass boost off you should be able to run the gains a bit higher and it'll probably sound a lot better too.

There's no problem adding a touch of bass boost. Just don't go crazy with the thing.

:-)

-Fishy
 

Bronze Member
Username: Bigboat

Post Number: 16
Registered: Mar-05
well the song i was testing it with was some "Ultimate bass test" a friend of mine got off of kazaa, but it also does it on Never Enough by Eminem, specifically the low part of the beat.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 3730
Registered: May-04
The bass boost is the most likely culprit, and easily fixed :-). Easy problems there, you strain both the amp and the sub with excessive bass boost.
 

Bronze Member
Username: Bigboat

Post Number: 17
Registered: Mar-05
well i turned the bass boost all the way down, it still buzzed a little. could the head unit be causing it. I have an alpine cda-9830... i was running it with the sub volume all the way up and the media xpander on, should those be down/off?
 

Silver Member
Username: Fishy

Tamarac Ft.Laud, FL USA

Post Number: 995
Registered: Sep-04
Turn off all the bells and whistles(except the LP xover of course) and try again, but I think your sub may be having problems.

You buy it new?

-Fishy
 

Silver Member
Username: Fishy

Tamarac Ft.Laud, FL USA

Post Number: 996
Registered: Sep-04
Oh and I know this may sound like a stupid question, but are you absolutely positive its the sub that making the noise and not a vibrating panel or something?

Have you tried it outside the vehicle?

-Fishy
 

Bronze Member
Username: Bigboat

Post Number: 19
Registered: Mar-05
im 99% positive its the sub, theres no way a panal would rattle that loud. but yeah ill go try it with everything off and see wat happens
 

Bronze Member
Username: Bigboat

Post Number: 20
Registered: Mar-05
alright well with equalizer and everything off the buzz is gone, but theres no real bass left in songs. i dunno i guess i can just live with it. It just seems like the sub cant handle wat it should be able to.
 

Silver Member
Username: Fishy

Tamarac Ft.Laud, FL USA

Post Number: 998
Registered: Sep-04
Ok turn the gains up a tad and then gradually turn up the bass boost up on one of your "louder" tracks til it starts sounding bad then back it off a bit.

If you've got room, go ported and you'll get a "natural" bass boost that'll sound a whole lot better.

-Fishy
 

Silver Member
Username: Fishy

Tamarac Ft.Laud, FL USA

Post Number: 999
Registered: Sep-04
Actually you may be better off trying to get better output with the gains alone. Set your h/u at about 2/3rds volume on your loudest track and with EVERYTHING flat increase gain til it gets nasty then back it off some. You can then mess with your EQ and the bass boost, but do so in moderation and remember when using the EQ its easier to cut an unwanted frequency than it is to boost a missing one. If you want more bass I wouldn't recommend using an EQ for that. You'll usually end up with something worse than you started with.

-Fishy
 

Bronze Member
Username: Bigboat

Post Number: 21
Registered: Mar-05
ok well thanks for the help guys, that clears it up more or less.
 

Silver Member
Username: Rzarector

Coquitlam, Bc Canada

Post Number: 289
Registered: Dec-04
is it possible he fried a coil and thats what the sound is
 

Bronze Member
Username: Bigboat

Post Number: 22
Registered: Mar-05
well the sub still works though.... wouldnt that ruin the sub?
 

Anonymous
 
Ran across this post and thought I'd throw in my 2 cents. If you're getting a buzz from a sealed box, make doubley sure that the box is completely sealed. Any little leak will cause a small buzz at volume. Might not be it, but I've seen it twice.
« Previous Thread Next Thread »



Main Forums

Today's Posts

Forum Help

Follow Us