You should have an option for a 120a alternator for you. If you have an autozone there are two options available. One is the Duralast Gold, and the other is the Duralast Import. Both are 120A and should push the amp. You are going to want a better amplifier though. The one you are looking at is good enough for one subwoofer, but you are running two. You need 1200 RMS. Also, avoid adding the capacitor. It will do nothing for you. The optima is a good choice though. Perhaps you need to look into a Stinger or XS Power (preferably XS Power) instead of the optima. They work out better in an audio setup.

 

Your 1998 1.8t alternator is probably a 90a unit. Swapping that out with a 120a alternator and upgrading "the big three" will help.

http://www.passatworld.com/forums/6...om/forums/61-b5-information-base/209218-updating-electrical-system-big-3-a.html

 

Thanks for the tips. A 98 Audi A4/A6 will have the same alternator as the 98 Passat? I may end up picking one up online.

 

Other question. If I get another amp same make and model....is a 120A alternator going to be able to handle that?

 

You would be better off running a single amp pushing 1200 rms, but I suppose it could work for you. I had no problems running 1200 rms on an upgraded 120A alternator and a good battery without doing the big three. Its a good idea to do the big 3, but I have never needed it under 1500 watts rms with a good charging system. Depending on what you are paying, I might look into something other than Directed. They are great with alarm systems, but I have never heard of them for audio. I tried looking up your product specs and can only come up with product discontinued. If you are on a tight budget you might want to look into JBL or Rockford p series. Avoid the r series. Good luck on the install. Youtube a video of it rocking if you can. I would love to see what directed can do for car audio.

 

Buddy of mine gave me a good deal on the equipment he wasn't using. According to him...it feels like someone's punching you in the back of the head and you can feel the air moving in the car. Guess I'll see what they do when I get it all hooked up. Sure, can record a video. Not sure when I'll have it all wired up...maybe this weekend.

 

Well I've got everything wired in...but I'm confused about the subwoofer setup. The amp is a Class D mono (Directed D1200)...but it has 2 speaker channels?

Directed D1200 (dei-d1200) 1200W Max, Class D Monoblock Amplifier

Then I have a friend who's wired a few systems before telling me that the negative of sub 1 may need to be wired to the positive of sub 2?

I'm so confused and I don't want to wire it wrong and then screw something up. The wiring diagrams from show wiring the negative of sub 1 to the negative of sub 2.

The subs are 4 ohm dual voice coil if that helps.

Directed SX12D4 (dei-sx12d4) Dual 4 ohms 12" Subwoofer

 

If you wire neg to neg, and pos to pos it will be in parallel which will net you 2 ohms. If you wire them in series which is one wire goes from neg of the first sub to pos of the second sub and then the pos from first to amp and neg of the second to amp you will be running at 8 ohms.

As for the speaker terminals it should tell you in the manual.

 

If you wire neg to neg, and pos to pos it will be in parallel which will net you 8 ohms. If you wire them in series which is one wire goes from neg of the first sub to pos of the second sub and then the pos from first to amp and neg of the second to amp you will be running at 2ohms.

As for the speaker terminals it should tell you in the manual.

Thanks for the helpful info. The amp calls for 1-4 ohms only...and I managed to find the manual online. Says the amp is wired parallel internally and the diagram shows for 2 subs to hook the positive/negative to one...and the other sub to the other positive/negative.

Pg 11: http://www.directeddealers.com/manuals/og/directed_audio/G45095.100.105.110_12-04.pdf

Sound right?

 

Oh your subs are DVC 4ohm. Ok so you'd want to do it like this to wire it into 1ohm (if going for max current).

Looking at your manual if you want to wire it for 1ohm opperation you want to wire them together like the picture above, and then wire them to the amp as a single sub, so you'd wire the 2 wires to the left terminal on the amp.

Page 13 http://www.directed.com/guides/manuals/og/viper_audio/G600_1_d1200_1.pdf

 

Edit: So main difference between series and parallel is acoustic output from what I'm understanding so I want to go with parallel wiring. So the question boils down to 1 ohm or 2 ohm operation? 1 ohm will have higher acoustic output?

 

From what I'm reading online dual 4 ohm voice coil can only be wired for 1, 4, or 16 ohm configuration and Class D amps are designed for lowest impedance. So parallel wiring, for 1 ohm. So my last question is both subs have to be wired to 1 stereo output on the amp and the 2nd stereo output isn't used?

Also reading in the manual it shows that amp will supply 600w RMS with 1 ohm application? So a larger amp isn't necessary since both subs want 600w RMS? This was a question that came up earlier in the thread.

Pg 21: http://www.directeddealers.com/manuals/og/directed_audio/G45095.100.105.110_12-04.pdf

 

So my last question is both subs have to be wired to 1 stereo output on the amp and the 2nd stereo output isn't used?

The dual + and -- sub-out terminals of the D600/D800/D1200/D2400 are paralleled internally

It's a mono amp. There is only one channel of amplification. Both those sets of outputs are the same set. It's really one set of outputs with an extra set of screws to connect more wires.

You can run one speaker (wired for 2 ohms) off of the first set of terminals and the other speaker (wired for 2 ohms) off of the second set of terminals and you'd be presenting the amp with a 1 ohm load.

Or you can just use one set of terminals and run a single pair of wires from the amp to the cabinet. Wire the speakers in parallel at the cabinet and you're presenting the amp with a 1 ohm load.

 

That model speaker has two voice coils. The coils are 4 ohm impedance, each. You can wire these two coils in series which would give you a 8 ohm total impedance for that speaker. You can also wire them in parallel which would give you a 2 ohm total impedance for that speaker.

With those speakers wired for 2 ohms, if you wired both speakers together in parallel, you'd be presenting roughly 1 ohm impedance to the amp.

That amp can drive a 1 ohm load at 600w rms. Those speakers can handle 600w rms EACH. In other words you really need an amp able to drive a 1 ohm load at 1200w rms.

As long as you're careful and don't run anything past its capacity, it'll make lots of boom, boom, boom noise. If you crank up beyond what that setup can handle, you'll be burning up amps or speakers. Clean sounding bass is what you want to hear. If it's breaking up and distorting, something is being overdriven. If you push a system beyond its capacity, too little wattage can destroy things as easily as too much.

 

Perfect explanation thanks Steve. I'll wire it up using 1 terminal. I still don't understand why I need the 1200RMS amp though. From what I'm reading if you wire in parallel the current sent through the system doesn't have to be divided. So doesn't that mean because the amp is pushing 600w that each sub is also getting 600w?

Parallel wiring is best used for a larger audio system. Since all of the speakers are wired to operate on the same voltage level, the current sent through the wiring does not have to be divided among the various speakers. This allows for the utilization of more speakers in the audio system.

 

I don't know where that quote came from but it's not true.

You only NEED a 1200w rms amp if you want to get the full potential out of that pair of speakers. They will work fine being driven with 600w, just not as loud. I don't know how loud the rest of your system is. For all I know, even 600w of sub will be too much and overpowering the rest of the system.

That amp can provide 600w rms at 1 ohm impedance. Each speaker will consume half the available power (300w). Those speakers are rated to take up to 600w rms EACH. So to drive both of them to the maximum would require 1200w rms of power.

 

Here, think of it this way.
The amplifier is a gallon of water.
The two subs are a gallon of water each.
Dump the amp (gallon of water) evenly into the 2 subs (gallon each = 2 gallons of total capacity)
You would need a 2 gallon amp (1200 watts) to fill up the subs.

 

Guys he has a 1200w amp at 1ohm, he has the D1200 not the D600. So at 1 ohm it is rated for 1200w. That manual covered both models.

Either way 600w honestly would of been plenty loud. Doubling power will net you something like 3 dB in higher output and unless you are going to dB drag events it would likely be way too loud for sustained listening at high volumes even with 600w.

 

According to the specs on the Sonic Electronix web page, the amp is rated at 600w rms, 1200w peak. The speakers are rated 600w rms, 1200w peak (each). So a pair of them could handle 1200w rms, 2400w peak.

 

Well the manual states 1200w RMS at 1ohm load. Wouldn't be the first time I've found wrong specs on Sonic's page.

 

The manual linked in post #10 is for a different amp. (Viper D1200.1)

The manual for this Directed Audio D1200 amp can be found here... http://www.google.com/url?q=http://...ed=0CEUQFjAL&sig2=yHzvMmo4u6yE0DGKMsd94A&usg=AFQjCNHpnUd1Tg6y1l91UYRvwKISKjfylg

 

Hmm strange, Viper is of course owned by Directed so I'd be surprised if there is actually any difference at all between those two amps, what does appear to be different is the standard they used for measurement. But regardless of all this what I said a couple posts back is still true, even at 600 watts this will be way louder than your ears can handle. Unless of course you're trying to win some dB comps in which case I think you may have chosen the wrong approach on the equipment all together.

Also there is a lot more to power handling when designing a sub setup. If you ran those at 1200w and built an enclosure tuned to something different then what they rated the sub to there is a chance you could be overdriving the sub even though they are rated to handle that power. Enclosure design affects things like this which is why enclosure programs show the estimated xmax curve across the range of frequencies to aide in the design of the enclosure. All I'm saying is the specs aren't always the ideal setup especially when it comes to power, the only way you will damage anything is if you set it up wrong and are clipping the amplifier which could damage your sub's or the amp. Look online to find how to properly set gains to avoid clipping.