Subwoofer difficulties

[Maseman47]

Well, hello everybody! I just joined today, was hoping to get some help with a problem I have had for at least a year and a half. Before I start, I am a residential and industrial electrician by trades, with an automotive degree and tons of other certs. Been doin audio stuff since college ( 3 or 4 years) and know alot more then the average audio guy, but still far from an expert (just so you guys know I ain't a total noob) I have searched all over but have not been able to find any kind of helpful info. I have a power acoustik mofo 12 inch sub, a power acoustik 4000 watt D amplifier. My subwoofer is at one ohm resistance, I also have two 35AH 12 volt batteries in parallel as well as a 2 farad cap as the batteries are gel type. Now I have set the gain to the best of my knowledge, have the subsonic filter set to one half an octave below the port frequency, have the LPF filter set to around 100Hz and do not use the bass boost. I have 4 gauge power and ground wire, with a chassis and battery ground. I have added a much larger gauge wire from the alt, tho I dont know what gauge as it came off of a welder. There is a smell coming from the sub, however, it is not a burning smell. It just smells like a new subwoofer smell, just stronger. The sub does not feel scratchy when moved by hand, the dust cap gets warm but not hot and has been doing this for a year and a half, maybe more. I recently found out that my box is .4 cubic feet smaller then recommended, only has one port instead of the reccomened 2 and the HZ of the sub is 36, while my port is 32. I have been pulling my hair out for almost three weeks, and am at wits end! I apologize for all of the information at once, I think too much! If anyone can help, it would be much appreciated!

Also, I was wondering, does it matter what voltage the cap is set to? It maxes out at 16 volts, I have it set to about 15.4 as the voltage drops under 13.5 if set any lower

[boomintahoe]

Sounds like your overpowering the sub....which explains the hot dustcap. Ditch the cap. As long as you have multiple batteries your ok.

for a 4k amp I would have used at least 1/0 wiring, for power/ground. Since that is a crappy brand, I sincerely doubt it does 4k watts. The 4 gauge your using might be choking it. Have you ever felt your power wire during testing/troubleshooting see if it gets warm besides your sub? If so, change the wiring to 1/0 gauge.

[whazoo84]

Well, hello everybody! I just joined today, was hoping to get some help with a problem I have had for at least a year and a half. Before I start, I am a residential and industrial electrician by trades, with an automotive degree and tons of other certs. Been doin audio stuff since college ( 3 or 4 years) and know alot more then the average audio guy, but still far from an expert (just so you guys know I ain't a total noob) I have searched all over but have not been able to find any kind of helpful info. I have a power acoustik mofo 12 inch sub, a power acoustik 4000 watt D amplifier. My subwoofer is at one ohm resistance, I also have two 35AH 12 volt batteries in parallel as well as a 2 farad cap as the batteries are gel type. Now I have set the gain to the best of my knowledge, have the subsonic filter set to one half an octave below the port frequency, have the LPF filter set to around 100Hz and do not use the bass boost. I have 4 gauge power and ground wire, with a chassis and battery ground. I have added a much larger gauge wire from the alt, tho I dont know what gauge as it came off of a welder. There is a smell coming from the sub, however, it is not a burning smell. It just smells like a new subwoofer smell, just stronger. The sub does not feel scratchy when moved by hand, the dust cap gets warm but not hot and has been doing this for a year and a half, maybe more. I recently found out that my box is .4 cubic feet smaller then recommended, only has one port instead of the reccomened 2 and the HZ of the sub is 36, while my port is 32. I have been pulling my hair out for almost three weeks, and am at wits end! I apologize for all of the information at once, I think too much! If anyone can help, it would be much appreciated!

Also, I was wondering, does it matter what voltage the cap is set to? It maxes out at 16 volts, I have it set to about 15.4 as the voltage drops under 13.5 if set any lower

Yeah that box is all sorts of wrong, if that's actually true what you're saying.

Another thing is Power Acoustik isn't a good brand in any way. Deffo doesn't do 4k, probaby 2k peak. Another thing is Power Acoustik amplifiers share a similarity to Hifonics: They love to distort! The sub may be getting hot from a couple factors here:

Wrong box could be fucking with the mechanicals of the subwoofer, might be constricting it too much or too little. Could also be restricting the air that's getting to the voice coil.

The other thing here is the power getting to the amp. Even though you're using 4AWG which shouldn't be *too bad*, it's not good for the amp, get some Sky High 0 gauge and you'll have a better day. Also if you have CCA wire, not OFC, then you're really choking the amp. In terms of voltage drop from the cable, that is.

The other thing is the amp isn't that great, they use high gain on the chips inside to get the best rating out of it possible, like they really push their chips. Hence why Rockford can take lots of abuse and last through it, meanwhile one day of abuse on a Hifonics = blown fets.

So yeah, if I were you I'd do an overhaul consisting of this:

New wiring, 0 gauge OFC or at least CCA from a good brand like Sky High.

Make a new box, have a professional evaluate the box before you make it, because sometimes manufacturer recommended specs aren't that great for the woofer.

Get a better amplifier that's of good quality, not such high wattage. If you're really trying to run the woofer at the MAX wattage, you're asking for problems and smoked cones. Get a 1500W Rockford or Alpine amp that'll put out some really clean wattage. I got a buddy running 2 12" alpine type R's in a sealed box on a 1200W alpine amp, this shit can be heard for blocks because of the good box, amplifier, and wiring all around.

What about your mids? You got an amp running those or are they running off of the head unit? If they're running off of the unit, then they're suffering, BADLY.

Stock door speakers? If so, get them the fuck out unless they're like my car, using Monsoon Audio speakers stock (which sound fucking amazing, considering before Monsoon audio was bought, they made planar magnetic speakers.)

Basically, can you give us some more info on your system. If you've done everything like door speakers and are making sure they're not suffering, then just upgrade your wiring, box, and amp and you'll be good to go.

[Maseman47]

Well, I've got a kennwood deck and 4 channel amp powering all Pioneer speakers. The wire doesn't get hot at all, and from testing the RMS (fluke amp clamp and klein meter) its only around 1000watts and no visible distortion on an oscope. Its my understanding that a cap should be used with gel batteries, as they are not designed for mass amounts of current draw.I know I would be better off with a new one, but I've got too many more important things to spend any money on it. I will look into the box definitely. Do the number of ports matter even though it is tuned to the correct Hz?

[DLHgn]

Well, I've got a kennwood deck and 4 channel amp powering all Pioneer speakers. The wire doesn't get hot at all, and from testing the RMS (fluke amp clamp and klein meter) its only around 1000watts and no visible distortion on an oscope. Its my understanding that a cap should be used with gel batteries, as they are not designed for mass amounts of current draw.I know I would be better off with a new one, but I've got too many more important things to spend any money on it. I will look into the box definitely. Do the number of ports matter even though it is tuned to the correct Hz?

I wouldn't say that the number of ports matter but the port area does. If you don't have enough port area you can start running into port noise and compression which will limit your output.

[notorious97200]

Keep all your amps, you don't need to change.

You can take your cap out, you'll have a better voltage ! Your amplifiers will love that move.

Did you try to lower the gain on your bass amp ? It may help a lot, since you seem to really overpower the sub. I know those subs don't like too much power.

As DLHgn said, port area is an important factor for a box. Gotta check the box.

[Jessica]

I won't recommend brands. as far as your power wire, if you have the degrees you say, you should know the power handling of 4ga wire in a DC circuit. I won't say more about that.

As far as a stinky sub, one of two things, it's just a stinky sub, or you are clipping or overpowering and getting the coils hot.

You are fine using a cap, just wire it as close to the amp as you can, like within 6" for the best results.

[Maseman47]

According to a chart found on crutchfield, and from what I understand, 4 gauge should be able to handle 120-130 amps. I'll try and get ahold of some 0 gauge, but the wire I have is OHC (least thats what they told me when I bought it) I've played with all the gains, filters,and head unit settings. I do use the remote bass knob, is that a problem there?

[Jessica]

well, your amp is fused for 120amps. so the power wire should be fine. thats why i didnt say much about it.

which mofo 12 do you have? it looks like there are about 50 different variants of it.