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I'm looking at the Kicker CVR 15 dual voice coil 4 ohm sub. Could that sub be ran at 2 ohms? Because I would like to run an amp at 2 ohms bridged.

I'm green at car audio, i'm trying to learn.

 
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As long as the amp can handle it, absolutely!

 
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absolutely not. theres a reason its called a 4Ohm sub not a 2Ohm sub.

 
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lol. a 4ohm DVC sub wired in parallel = a 2ohm load.

To the OP:
Do it. Wire the subs in a parallel circuit

 
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Alright. Thanks for the help.

To envy,

Why would you not recommend wireing them paralled and make it a 2 ohm load?

 
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Dude, no offense - but please get some basic electrical theory/knowledge before you post something that blatantly WRONG.

2-4ohm voice coils only leave you with two options. Either a 2 ohm load with the VC's in parallel (exactly how mine is set up right now).

Or wired with the VC's in series for an 8ohm load, which is nice if you are running multiple subs on the same circuit (2 subs for 4 ohm load, 4 subs for 2ohm load, etc.)

I also have a dual 2 ohm sub with the VC's wired in series. That DOES give you a total DC impedance of 4 ohms creating a '4ohm sub'.

To OP: why are you set on using a 15? 12's move a lot faster and a well set up single 12" sub (or a pair of 12's if you really wanna compress some airspace) can KILL in a coupe or hatchback. Just personal preference, but I tend to find 15's sloppy, sluggish, and usually a huge watt-waster in autos SQ-wise.

 
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my bad big time. i didnt read that it said dual voice coil.

 
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it's not the sub you have to worry about, it's your amp. can your amp handle a 2 ohm load?

 
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if you bridge a 4ohm amp (make 2 channels become 1) it puts out a 2ohm load.

Correct me if i'm wrong.

 
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YOU'RE WRONG! just kidding.

the subs are the load. an amp is a source, it does not put out a load. you're thinking of it backwards. there aren't 4 ohm amps and 2 ohm amps. amps don't have an impedence for the sake of our comparison. you have to think of them as being 4 ohm stable or 2 ohm stable (or whatever yours is). at a given voltage, an amp can supply a given current. so if the resitance is cut in half, by Ohm's Law, the current will have to double in order to maintain the voltage. if the amp is not capable of sustaining this current, it will become unstable, overheat or be damaged. does that make sense?

 
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i loled^

 
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Sorry this got kinda long, but hopefully it's worth the read. Free headache!

I'll try to keep this relatively simple while attempting to help:

Audio is truly electro-mechanical, but let's talk strictly about the electrical side of things first...

The amp does not 'put out' a '2ohm', '4ohm', etc. load ever. The term 'load' refers to the resistance (in this case the voice coils) to the flow of electricity in a given circuit.

The output transistors in a solid-state amp are actually supplying the voltage/current to your speakers. The power supply is what supplies voltage to the 'rails' that components in your amplifier draw from. I mention this because a given power supply can only provide a given amount of voltage and current before it starts to get unstable and shut down/burn up/other unpleasant things.

When a designer makes an amp circuit, it is calibrated to operate at a given impedance. This way the components necessary for the amp to operate at a given wattage without overheating or going into oscillatory convulsions, etc. can be reliably mapped out.

Most car audio speakers are 4 ohms, whereas most home audio components are 8 ohms (sometimes 6). I'll try to stay outta that for now, you'll probably understand more in a moment.

In a perfect world, if you exactly halve the impedance -resistance to current flow- (e.g. going from a 4ohm speaker to 2 ohm) speaker in a given circuit (amp output), then the result would be exactly double the current flow (in this case expressed as watts). Usually in the real world the amp's power will not completely double with each halving of the impedance due to losses with the components of the amp and that is completely normal.

This does come at a cost, however. Since those same output transistors in the amp are now passing twice the current, they will run much hotter. They will also draw much more current from the power supply making it run hotter as well and and potentially not be able to supply all the components with enough voltage and current in the amplifier when really getting hammered on (e.g. a big bass hit in a sub amp).

Some amplifiers are designed to happily run at a load as low as 1ohm, while others may jump off a cliff at anything below 3.6ohms DCR (d.c. resistance).

That 'load' on the amplifier's outputs is what keeps it stable, cool, and happy by not allowing the output transistors to attempt passing more current than the amps components were designed to handle.

Bridging: when you 'bridge' across two channels of an amplifier, you essentially are getting the power of both channels combined. When you do this the amplifier 'sees' half the impedance it would if run in 'normal' configuration. Basically this means that if your 2-channel amp can handle a 2ohm load per channel in stereo, it will need a 4ohm or greater load when running bridged mono to stay stable and not overheat or worse.

Additional fun:
In the early days of 'modern' soundoffs the governing bodies went strictly by what an amp was rated at wattage-wise at a 4 ohm load, hence the dawn of 'high-current' amps that only made 25 watts per channel at 4ohms, but would go ballistic when the impedance dropped. That is why those ancient HCCA Orion amps (among others) were gigantic for 'tiny' wattage ratings the carried. The power supplies were massive, along with the giant heatsinks and output transistors needed to handle the heat generated by passing all that current.

Even more fun:
Impedance varies wildly with frequency, speaker type, and the load that the air itself places on the speaker diaphragm. Normally it is highest right at the free-air resonance frequency of a given driver and lowest just above there. This can be exploited to great effect in a well-designed system, although YMMV so don't blame me if your amp blows up...

.e.g. I am using a 4-channel amp that can handle 2ohms per channel and/or 4 ohms bridged across 2 of the channels. (I'll leave my van's system out of this because it is much more complex and give me a headache to think about)

The components are quite simple:
One headunit, no outboard eq or processor, one relatively small 4-channel amp, one cap, five drivers. Lots of OFC wire and a fair bit of damping material.

Front stage: One pair of Boston Acoustics 6.5Pro components. They use a pretty robust diecast frame woofer (that I'm running as a mid-bass driver) with a voicecoil rated at 3ohms DCR each and a 4ohm tweeter and a nicely engineered separate crossover network.. in reality my tweeters are really setup up at around a 10 ohm effective DCR load on the amp to get a nice, flat, not-harsh-to-my-ears-at-high-volumes frequency response curve.

The sub: One 4ohm DVC old-school RF HX2 with diecast frame and thick, stiff, and well damped paper cone. It is wired at a 2 ohm load with the voice coils in parallel. This is exactly half of what the manufacturer of my amp endorses, voiding my warranty and not guaranteed to work at all.

The trickery:
When you put a sub into an enclosure and play actual music - throw DCR out the window for the most part. As long as they particular combination you have assembled has a high enough impedance to keep the amp from shutting itself off in 'protect' mode or overheating whiel in use, you are essentially good to go. Remember you probably are cutting some lifespan off your amp, but the factory knows what I'm doing and will fix it for a whopping $113.00 if I do blow it up. Good airflow and/or a fan are recommended, and not all amps can do this. Part of that equation is simply the tolerances of the parts on the assembly line - I have seen other folks with the same amp do what I'm doing successfully while other amps of the same model & year will immediately shutdown into protect mode (although I did the same thing on a version of this amp made in 1998 with almost identical circuitry design and still have it).

Another part of this is that since I am only running half of the output transistors beyond specification, the power supply's life is much easier and probably thinks the amp is running at 4x2ohms or 2x4ohms, etc. I am also using a very steep 24dB/octave slope crossover at 80Hz on the front speakers to free up additional overhead for the power supply, while sticking to a more traditional 12dB/octave slope on the sub - set to either 63Hx or 80Hz depending on source material I'm playing. 24dB/octave on the sub is very clean, but I like the overall sound better with 12dB/octave with limited overall system power and cone area in this system (whereas my van uses brute force+lots of cone area).

I don't have any elaborate testing equipment at my disposal these days, but I'm putting out at least 260+ watts continuous to the single 12" sub, and around 92watts or so to each front channel from an amp rated at 4x100watts@2ohms. It never has never blown a fuse or shut down.

Anyhow, have fun and don't blow anything up!

 
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^^^mine was shorter!

 
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Quite true!

Maybe someone will find mine useful somehow, if they can get thru it without falling alseep.

 
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Alright. I'm having a hard time figuring out what to do. I haven't bought anything yet. But, I might be buying 2 Kicker 15 comp cvr's off of a guy.

I was looking at the Kicker 800.2 amp, but it only goes to 4 ohms bridged. So, basically I need am amp that can do 2 ohms bridged. Is that hard to find?

I'm very green at car audio, and I don't wanna buy the wrong things and be dissapointed.

Edit. I'm looking into a Memphis 500 watt amp it is its 2ohm stable when its bridged. Should I be able to push the subs good with that?

 
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Alright I made a retarded impression on this thread already, but ill try to help here.


Personally I would go for a Class D mono amp for a sub. Not a two channel. Monos can be cheaper, are more efficient, and will send less distortion to your subs. Most Class D amps are stable to 2-Ohms with a few to 1 ohms. If you wire 2 seperate 2ohm dvc subs in parrallel, you will put a 2ohm load on a bridged amp. a 4ohm dvc sub can only be wired to 4ohms or 1 ohm, depending if its even or odd.


So for your question: get two kicker DVC 2 ohm subs, wire them off one bridged wire from a mono amp, and youll have a 2ohm load on the amp.

 
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Also- DO NOT PAY ATTTENTION TO 5MAXX RATINGS. only to RMS 75%-100%ATINGS! match the RMS ratings from 7070% of the subs max value\\

EDIT : only pay attention to RMS ratings, and match the amp to the sub.

 
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lol i use a wrong word and look what i start, i meant to say it can handle, not put out. lol ;D

and i guess i got it backwards. oops. So if your amp can handle 100Wx2 @ 4ohms, it can handle 200Wx1 @8ohms? I got it the other way around. I guess it's a good thing i've never bridged an amp lol ;D

 
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when you bridge an amp, you lower its impedence. so it acutally by 200x1 @ 2ohms

but this of couse depends on the wiring of the subs. this is just the most likely outcome.

 
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You're getting there, but bridging the amp DOES NOT change the AMPS's imedance. Impedance is provided by the speakers for out purposes here, NOT by the amp. Bridging the amp DOES change the way the AMP 'Sees' the load - it effectively sees one half of the impedance it would in non-bridged mode.

That is why many amps that run fine at a 2 ohm load per channel need a 4 ohm load when bridged or they will overheat from trying to pass too much current and other bad things.

I will add... the voice coils in the speakers don't care if the amp is bridged or not and their DC impedance of each coil does not change no matter how you wire them up.

The way you wire that dual voice coil speaker DOES change what the amp sees: if you wire them up in parallel it lowers the impedance of one coil to half of its numerical value (2-4ohm coils in parallel = total impedance of 2 ohms load on the amp),

If you wire the coils in series you will double the numerical value of one coil (2-4ohm voice coils in series- 8 ohm load on the amp). If you set up a pair of dvc 4 ohm drivers wired like this and then wire the two speakers in parallel, the amp will 'see' a load of 4 ohm (half of the 8 ohms total impedance per dvc speaker).

Make sense to you now?

Have a great weekend folks!

 
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Your scenario is correct, but I personally usually try to avoid 8 ohm loads in cars

 
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the way that i like to see it is:

the less wires the electircity has to travel through, the lower the impedence. The lower the impdenence, the more power available.
ie: instead of running 2 subs off one amp that has two sets of terminals, run both subs from ONE set of terminals on one amp.

however this is just a general rule.

 
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nope, still not quite right, basically. for most electrical rules, wires have zero resistance/impedance. they aren't even factored into ohms law. and your scenario doesn't hold up for mono amps. in mono, you only have one set of terminals, yet you can run a 4 ohm or 2 ohm load (as long as the amp can handle it) depending on how you wire the subs. the load depends on the impedance of the speakers, not the wires or the amp. if you have a 4 ohm speaker versus 2-4ohm speakers, in parallel, the 2 speakers will have a lower impedance, yet there's more "wires." if you wire them in series, you now have a 8 ohm load for the same amount of "wires". for all intents and purposes, amps do not have impedance. only the speakers to.

 
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Yeah, i know, 8ohms is for home audio and such. I was just giving an example. lol =]

back to the OP: As long as your amp can handle a 2ohm load, then wire the DVC subs in parallel and you're good to go. For this, try and get a mono d-class amp. Don't worry about doing the whole bridging, unless you already have the amp?

 
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I suck at putting my thoughts into words. my mono amp has two sets of terminals. so FOR ME, if i ran wires from each of those to a SVC sub, each terminal would see 4Omhs. For my setup this is a lot of wires. I am now running 2 DVC subs wired in parallel to each other. They are bridged off one terminal, making the amp see 2Ohms. So for me, by eliminating the second set of wires and adding a set of voice coils, i lowerd the speakers impedence and upped the amps power. The same is true for my 4Ch amp. Instead of running two speakers off each terminal for a certified 70RMS at 4ohms, I bridge 2 channels together and wired the speakers in parallel to lower impedence to 2ohms, thereby giving me 200RMS to split between the two.

So in both instances, I elimanted a set of wires as I wired the speakers in parallel, hereby allowing my amp to pass more power through. So for me, the less wires, the more power. Although not theoretically correct.

 
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Thanks for the help!

ALright here is a sub/amp combo I'm looking at, someone is selling.

2 -12in DB Drive speed series subs
powered by an MTX thunder 1200 watt mono block. Should this be good?

The MTX is suppose to be 1 ohm stable.

 
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Also Important question from me!

The db's have a 50 oz. magnet, is that a good size?

 
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ha thats a good size. its pretty big. whats the rms rating on the amp?

 
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I bought the system I mentioned above. The amp will be running 600 through each sub. That's unbridged. I'm not sure if the guy who had them set them at 4 ohm or 2 ohm. I got a 4 gauge amp wire. Should that be suffiecient? I got some rockford fosgate RCA outputs.

 
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Magnet size & type, moving mass, cone suspension stiffness, voice coil winding width, is all a balancing act. A light cone is efficient and easy to move, but can easily flex & distort at high volumes in addition to not being very well damped. A light cone can usually be controlled by a fairly light/weak magnet. A heavy cone will be well damped and potentially quite stiff at high volumes but will need a stronger magnetic field to control properly and will usually tend to suck up more power.

50oz is not very big on a 12" driver if they are ceramic magnets (neodymium is a different story). The ceramic magnets on my 12's are 102oz each and they handle 500WRMS per driver. I would also not consider these magnets 'large' for a 12" driver, just adequate