Alright I got the subs... here is a picture of one

http://members.aol.com/speednsound007/sub.jpg

here's the box

http://members.aol.com/speednsound007/box.jpg

the info
GT102D Grand Touring Automotive Speaker

Impedance Dual-4 ohm
Series-8 ohm
Parallel-2 ohm

Magnet Weight 40oz w/2” Dual Voice Coil

Nominal power rating 130 watts
Peak Power 260 watts

Sensitivity 94 db


and a picture of the way the subs are wired in the box is

http://members.aol.com/speednsound007/subwiring.jpg

is the wiring correct for the subs? this is how it came. What kind of wiring is this/the ohms? How many watts of a sub am I looking at and at what ohms? Any other info is appreciated! thanks,

PJ

 

The entire setup is wired for a 4-ohm load for the amp. Get an amp that puts out about 300-350 watts into a 4-ohm load (such as a two-channel amp bridged mono).

 

is it good wired in 4 ohms? What exactly is the "Dual" wiring method that it says is the 4 ohm setup? is this the best for DVC's or something? If my amp handle's a lower load (2) should i wire it like that instead? Some of the subs ratings don't say what they are at 4 only 2...whats the conversion to get from 2 to 4?

thanks,
PJ


btw-they ARE NOT stolen!

 

Don't think you can get to 2 ohms with a pair of dual voice cail (4ohms per coil) subs. But you could go to 1 ohm. i really wouldn't recommend it. Don't think you'll find an amp that can hand'l it. If they were single voice coil you could wire them parallel and get a 2 ohm load. But they aren't so you can't.

 

Hey, Speed.... No offense was intended, I just felt the need to spew verbally, lecture in general terms to the world at large...

You should be able to wire the dual voice coils in series, so that each individual woofer by itself is 8 ohms, then wire the two 8 ohm wired woofers together, in parallel, for a final 4 ohm load. Any normal amp can do that just fine... run a mono signal, if you can.

And by the way, (lets use 400 watts just for fun) 400 watts is 400 watts, whether it's 400 watts into 4 ohms, or 400 watts into 1 ohm. In your situation, going 1 ohm doesn't buy you anything.

 

then how come this is on crutchfield?

Q: What is a "high-current" amplifier?

A: A "high-current" amplifier is capable of passing high current into very low impedances without overheating or shutting down. In a perfect world with a perfect amplifier, power output would double every time the impedance was halved. For example, an amplifier rated at 50 watts RMS x 2 channels into 4 ohms would produce 100 watts by 2 into 2 ohms. Unfortunately, this is not a perfect world, and most amplifiers can't do that.

am I just misunderstanding this? I thought the lower ohms you ran your system at the more power you got out of it. I was told that mine is wired for 4 ohms, is this the best for the DVC's?

Q: What's the difference between "parallel" and "series" wiring?
You can run more than one speaker from a single amp channel by wiring the speakers in series or in parallel. Series wiring will raise the load (resistance) that your amp sees, and parallel wiring will lower it. Be certain your amp is 2-ohm stable before wiring speakers in parallel.


A: When you wire a pair of speakers in parallel, you connect the positive (+) leads of both speakers to the amp's positive (+) terminal, and the negative (-) leads of both speakers to the amp's negative (-) terminal.

If you parallel wire two 4-ohm speakers, the amp sees a 2-ohm load. This lower ohm load (lower resistance) pulls more power from the amp and causes the amp to run hotter. Amps that can handle this additional heat build-up are considered 2-ohm stable.

Series wiring works the same way as flashlight batteries; the positive end of one speaker is connected to the negative end of the other speaker. Wire from the positive terminal of the amplifier to the positive terminal of one speaker. Then wire from the negative terminal of the first speaker to the positive terminal of the second speaker. Finally, run a wire from the negative terminal of the second speaker to the negative terminal of the amplifier.

If you series-wire two 4-ohm speakers, the amp will see an 8-ohm load. This higher ohm load (higher resistance) inhibits the flow of current out of the amp. You get less power, but the amp runs cooler and is more stable.

More from Crutchfield...So since my subs are wired for 4 ohms (if this is true, but not doubting Micah who told me I just don't understand myself) IF I run them wiring from amp to subs in parallel, then will I gte more power out of ym amp like it says? (twice the power, 2 ohm load).

thanks, i know I need a lot of help...I am just gettign confused with the DVC's and what everyone is telling me here.

PJ

 

There aren't many amps that can handle a 1-ohm load bridged mono (and they are quite expensive), so you are better off keeping the 4-ohm load and choosing one of the many 2-channel amps and bridging it mono to run the setup. Running an amp bridged mono into 4 ohms is the same thing as running it in 2-ohm stereo, so you'll get the same amount of power either way.

 

I thought that you could only bridge into one sub?

PJ

 

To answer your last question first, No. For example, I just picked up my last two subs(I now have 3 DA MD12.8 drivers, dual 4 ohm voice coils), and my MTX 1000D mono amplifier. In 2-3 weeks when I finish epoxying and molding my box and then securing it to my rear deck I will have three speakers and a total of 6 coils bridged to one channel at 2.6 ohms. This is because I will series wire the two coils in each sub for an 8 ohm load, then parallel wire the 3 speakers. 8/3=2.666 ohms. Or more correctly 1/(1/8+1/8+1/8) - - - this is for parallel wiring.
When you wire in series the impedance is additive (4+4=8) and the voltage is constant. In parallel wiring the voltage goes up which is generally where you get more heat and why most amps can't reun efficiently or at all at low impedance. Most home receivers recommend no lower than 6 ohms per speaker. Remember the quote, "In a perfect world." This is not a perfect world and their are no 100% efficient designs that I know of, amplifiers included. A few years ago there were many amp manufacturers building car amps designed for low impedance. This was due to a "loophole" in competition rules which used amplifier power into 4 ohms as a base for classes. I think the rule has been modified to include total number of woofers. I have never competed so I don't know all the details.

 

The amp doesn't care how many speakers are wired to it, only that the load isn't too low.

 

Sorry if we're causing confusion...

My earlier statement, 400 watts at 1 ohm is the same as 400 watts at 4 ohms means that if you have an amp that can put out 400 watts into 1 ohm, it's still 400 watts. You don't get any more sound if you're delivering 400 watts to the speakers wired at 1 ohm, vs. delivering 400 watts to the speakers wired at 4 ohms. The difference is, the 400 watt into 1 ohm amp may be labeled as 100 watts into 4 ohms, but it's capable of producing 200 watts into 2 ohms, and 400 into 1 ohm. (That's kinda where Crutchfield was going). So, if you already had THAT fictitious amp, go ahead and wire into 1 ohm. But, here's the catch.... That amp would cost more, probably quite a bit more, than a 400 watts into 4 ohm amp. Also, those amps are generally designed and sold with fanatics in mind, so it might require a fan, a new alternator, and other special installation considerations too.

For example (forgive me, I'm using very rough estimations of prices here) Soundstream used to have an amp with some laughably low power rating, something like 25 watts per channel, and it costed something like $900 dollars. Why? because it was 25 watts into 4 ohms, 50 into 2 ohms, 100 into 1 ohm, 200 into half an ohm, and 400 into a quarter ohm. So no, it wasn't really a 25 watt per channel amp, it was a huge beast of an amp for special purposes. So like jmax said, in the old days, you could enter a contest for 25 watts and under, connect 8 pairs of subs to that amp, add a second and third alternator, and yeah, you'd win that 25 watts and under contest pretty easily

in your case, you have two dual voice coils that can be wired either for 16 ohms, 4 ohms, or 1 ohm. Amps that drive 1 ohm safely cost lots of money, so to find one that can effectively produce 400 watts into 1 ohm, you would probably spend more money than finding one that effectively produces 400 watts into 4 ohms.

And if you're not confused enough... sighhh... check carefully before you buy... many amps nowadays are 2 ohm stable, and their advertised power ratings are into 2 ohms, not 4. :-) (Rockford Fosgate is one that still does this, I think).

 

Those soundstream amps, like the Picasso 4X25 are still sold. You can get some pretty good deals on amps that are still new in the box. Let me know If you want one but can't find it.

 

Plus, Soundstreams are WAY underrated, so they definetly put out a lot of power.

 

completely... Now, you said my subs are setup to run at 4ohms as it is, how would I change their wiring to run at 2 ohms? Or...do I leave it as it is no matter what and the wiring form the amp to the sub is what determines the ohms that are being pulled form the amp?

PJ

 

completely... Now, you said my subs are setup to run at 4ohms as it is, how would I change their wiring to run at 2 ohms? Or...do I leave it as it is no matter what and the wiring form the amp to the sub is what determines the ohms that are being pulled form the amp?

PJ

ps-thanks a lot guys

 

get a good stereo amp that puts out 75-100 watts per channel, and bridge it. You can get a better amp for the same money (as compared to a 4 channel), with better damping at the 4 ohm load.

 

so my subs are wired for 4 ohms correct? Now, how do I wire them to an amp so that the amp still sees 4 ohms? Bridge a two channel...by connecting into the positive terminal form one channel, and the negative terminal from the other channel correct? Then what do I do? btw, take the ---x1 power rating from a 2 channel amp and thats what it puts out bridged correct?

PJ

 

Read the manual for your particular amp to see how to bridge it correctly. Don't believe the "rated" power specs. They are pretty much always inaccurate.

 

does anyone know for sure what ohms my subs are setup to run at right now? If they are set for 4 ohms how do I wire from a 2 channel bridged amp to the subs so that the amp still sees 4 ohms? The DVC'S are confusing me with the wiring. I was looking at 300watt bridged amps, this should be more then enough power right?

PJ

 

Yes, that's enough power. Like I said, read the manual for the amp. Different amps work differently.

 

I think I remember seing each individual speaker wired in series. This gives you two 8 ohm speakers. Now connect both speakers positives together and run that connected pair to the amp - connect to the positive bridged output connection(check your amp manual to be sure). Now do the same thing with the two seperate negatives. You are showing a 4 ohm load as far as the speakers go but the amp does see it as 2 ohms. It puts out it's rated output at 2 ohm stereo. This is generally higher than the 4 ohm stereo output. And double this power to figure out the total amp output to the pair of speakers. Or you can figure that each speaker is seeing the 2 ohm stereo output.

 

Do you mean that the amp will see the 4 ohms? because...most amps won't take 2 ohms while being bridged. A lot of the 2 ohm stable amps I was looking at minimum impedence was 4ohms while being bridged.

PJ

 

The amp does sees it as two seperate 2 ohm speakers which are receiving the same signal. So if the amp is 2 ohm stereo stable it will be okay. It would need to be 1 ohm stereo stable if you had a 2 ohm load connected to the bridged outputs. But that is not what you have. The majority of car audio amps are 2 ohm stable.

 

gotcha man, thanks

 

You can go to 2 ohms by wiring parallel. As in the description from Crutchfield above. If you do that try to get a 2 channel amp that is 2 ohm stereo rated near the RMS power of the subs.