Printer Friendly Forum Posts - One sub moving more then other

I have 2 Orion 12" subs, they are 200W rms. They are running off a Memphis 250W class D amp. One of my subs is not moving as much as the other, I can tell just by looking at it that its not working as much as the other. What in the world could be causing this? I dont recall it being like that when I had them hooked up to my power acoustik amp. The subs are only a few months old and I have not been abusing them, so I dont think they are the problem.

-------------

One sub probally came unhooked. Pull em outta the box and check. Also check polarities on the subs and the wires going from the sub box to the amp.

-------------
double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

Is the box single or dual chamber?

Its a dual chamber box. Im faily sure a wire didnt come lose becasue the sub still works, its just not working on the same level as the other one. Not to mention I soldered the wires on,so they arent goin anywhere.

-------------

Sounds like a weak voice coil or blown sub... Also, verify your connection is not lose.

Are they both fully broke in? I have experienced this a few times til they are fully broke in.

Something I always do is make the sub wires exactly the same length and roll up a little if one is too long. That way they the signal/current has the same distance to travel to each sub.

-------------
BOOM, BOOM, BOOM BOOM....

I'll make sure when I get home today that a wire isn't lose. The subs are about 2 months old, so I can return the one to the shop if it is infact a problem with the speaker itself.

-------------

how are you running them? bridged into the same channel of the amp or to 2 diffrent channels. maybe your gain's are diffrent if running seprate channels

-------------
2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place

Might be out of phase check the wiring, also check your deck. If there bridged, check your gains.

Test 1 sub at a time in the same box/chamber and with the same wire, and the same test tone, , if theres a difference then its the sub, , , if they both work fine then look elsewhere, , do a process of elimination. To do that you must do each test equally to make them accurate.

-------------
2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.

air leak? dont forget about that. but as 94 legend said they might be outta phase. reverse the polarity on one sub, see if it makes a diff.

-------------
1990 Honda Civic HB:
Clarion DXZ545MP H.U.
2- 6.5" Power Acoustik interiors
Diamond Audio 600.1 amp
Diamond Audio 15" M6MKII
Pyramid PB881X 4 CH. Amp

Yeah, we really need to know how they're hooked up to the amp...check gain settings.

Also, use a DMM to actually check what ohms the subs are...I wouldn't be surprised if they accidently sold you a 4 and an 8 ohm insted of 2 4's or 8's. It might have been an error at the factory as well.

Check for an air leak.

Also, the easiest thing to do would be swich the wiring. If you do this and the same sub is not moving as much...then you KNOW it's a problem with the driver itself or the enclosure.

I have run into the same problem in past, I was running 2 DVC subs. What happened is one of the Voice coils on one of the subs blew/malfunctioned which caused the impedence to change. So one sub was running with a 2 ohm load and one was running with a 4 ohm load. Which in turn would cause one sub to get less power.
Possibly this is what is happening. Swap your subs and see if the problem shows up with sub or the lead that feeds it.

Each sub is 4 Ohm, DVC. They are running off 2 seperate channels. The amp is a class D if that makes a differance. Their is one more thing I forgot. Some water got into the side of the box that the less-moving sub is in. This was right after I installed everything. The inside of the box was damp and had some mildew on the bottom. Their was a small amount of moisture on the magnet of the sub. Only the bottom of the box got wet, and not enough to warp the MDF or anything. The culprit (a small hole in thte side of the trunk) has since been fixed with fiberglass and I made sure the sub and box were completly dry and mildew free before putting everything back together. I should also mention that this happend about 2 months ago, and I just recently noticed the sub not moving as much.

-------------

flip the channels, , see what happends. This honestly should only take 5 min to diagnose

-------------
2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.

If you are using a mono class D amp, and if I haven't missed something along the way...it's a one-channel amp. You would be using two sets of terminals that are paralleled inside the amp, making a 1 ohm load on the amp (if you have also paralleled the coils of the 4-ohm DVC's). Is that what you wanted to do?

-------------
Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

pimpincavy wrote:

Each sub is 4 Ohm, DVC. They are running off 2 seperate channels.

We need to know exactly how the speakers are hooked up before we can tell you anything. First of all, there isn't two seperate channels on that amp...second of all, how do you have each voice coil hooked up in relation to the one channel on the amp.

Finally, did you swap channels on the subs? simply swap the wiring from one sub to the other and see if the same sub is effected.

This is really all you have to do to figure out where the problem lies..like dude said...should take 5 min...

djmoose, you just reiterated what I said about it being one channel...and then you asked if he swapped channels (???). What good will it do to switch the wires from the amp when they all originate from the same place, guys?

-------------
Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Yes it is a mono amp. On each side of the sub their is a + and a -, I wired these together, + to +, - to - on each sub. This is what the guy at the shop told me to do. I think I will actually have time to do some testing today (been EXTREMLY busy lately)

-------------

stevdart wrote:

djmoose, you just reiterated what I said about it being one channel...and then you asked if he swapped channels (???). What good will it do to switch the wires from the amp when they all originate from the same place, guys?

My bad on that...I wasn't thinking....however, now that I am...I guess that there COULD be a bad speaker wire maybe? Since it was working fine before...maybe dude screwed something down and damaged a speaker wire? Maybe one of the connections on a particular voice coil came off?

There are several suspect causes at this point. Two months ago I thought it was unusual for the enclosure to have standing water in it from a leak in the trunk. The leak was on the side where there now is a problem. Could be damage to the speaker from moisture, or it could be damage to the enclosure from the same moisture saturating the box and then drying out, leaving the wood split somewhere.

I also wonder about the load on the amp. pimpincavy doesn't say here what amp it is, but I doubt it is an amp capable of sustaining a 1 ohm load...which is what the subs' wiring was putting on it. The subs are 200 RMS, so damage by overpowering might be the culprit, too.

-------------
Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

i'd say, take both subs out of the box, use a dmm and check the resistance on each vc. make sure they read at 4. if they do, replace the wires going to the subs and amp. then inspect the box thoroughly, make sure there isnt an air leak or even worse, a big hole or crack. if all is well, when u re-install the sub, make sure that u tighten the screws enough so no air gets out through the top. if that doesnt help any, well... throw it all out a window, and get new stuff. lol

-------------
1990 Honda Civic HB:
Clarion DXZ545MP H.U.
2- 6.5" Power Acoustik interiors
Diamond Audio 600.1 amp
Diamond Audio 15" M6MKII
Pyramid PB881X 4 CH. Amp

Ok. Their was NOT standing water in the trunk or box. Only a small amount of water that should neither have damaged the sub or box. Here is a link to my amp which I HAVE mentioned multiple times already.https://www.memphiscaraudio.com/products/details.asp?id=23
I also dont think im running at 1ohm, unless im mistaken. I have had no problem with either of the amps ive had hooked up. The other one was a power acoustik, and both were 2 ohm stable.

-------------

u know, i just went back and re-read what you said pimpincavy, and i thought of something else. you might want to check your RCA's. if they are wired to seperate channels, they are gettin different signals. check your rca's. it might be a really simple fix.

-------------
1990 Honda Civic HB:
Clarion DXZ545MP H.U.
2- 6.5" Power Acoustik interiors
Diamond Audio 600.1 amp
Diamond Audio 15" M6MKII
Pyramid PB881X 4 CH. Amp

Pimpincavy, sounds like you're a little tight there...take a breath. If you linked to info about the amp in this thread before, I missed it. Anyway, you tell me what ohm load the amp is getting: mono amp, two 4 ohm DVC speakers, all parallel wiring, one sub at 2 ohm hooked to a set of terminals, and the other sub hooked to the other set. 2 ohm + 2 ohm paralleled at the amp = 1 ohm.

Look at each set of voice coils. 4 and 4. Parallel them together you get 2 ohm. Whether you connect the subs together in parallel (1 ohm), or connect each sub to a set of terminals on that one-channel amp you still get a 1 ohm load.

What's not right here?

-------------
Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Stupid DVC subs. The shop I bought it from said I would have no problem running them just like they are with my power acoustik amp (this was before I bought the memphis). I know how ohms work, but I did not realize that dual voice coils effected them that way. Perhaps I should return the subs for SVC versions? I dont have money for a new amp right now, but I havent had a problem with my memphis and as far as I can tell its not a 1ohm stable amp. Its been raining for the last two straight days and I have not had time to do any of the things you guys have suggested. What I really need is a bigger amp, but that means a bigger alternator and I dont have the money for that sort of thing. So unless its a cheap fix I will have to wait untill i get a little cash saved up.

-------------