gfeller2006

I know there are a few car audio god's in here so I would like to inquire for some help.

I recently had a JL 10W0 quit on me. I was running it in a SubThump stealth box and being pushed by a Rockford P300-1 amp. It sounded great to me.

I left the subthump box and Rockford P300-1 alone and replaced the sub with a Rockford P3 10D4 and wired it in parallel to 2 ohms.

On very hard hitting songs or when I turn the volume on the head unit up pretty high, the sub will start to cut in and out.... Its really frustrating since I was expecting even a better sound from the new sub compared to the old.


Any insight would be much appreciated. PS. The bass boost and gain on the amp are up about halfway. The frequency is set to about 80 hz.

Thanks in advance

Black_Z28

iTrader: (1)

Just setting your gain to a random setting is not the way to go. There are certain levels you want to set it it. And it depends on your voltage output from your HU, as well as a few other perimeters.

Here is a link to sound settings for you to play while checking voltage.

Link

And here is the link to figure out what voltage your outputs should be putting out.

Link

Basically, you need to unhook all speakers from the sound source. Turn down the gain and bass boost to 0. Set the High, mid, low to 0 on the HU. Turn it up to about 3/4 volume, or the loudest you'd ever listen to music at. Then, play that CD, if you're just powering the sub, then all you need is the 50hz track. Then, hook up a volt meter to the +/- and turn the gain up to the put that is listed on the graph. And you're done.

gfeller2006

The Spreadsheet was extremely helpful! Thanks, I stand corrected, the amp is actually a P200-2. I have it bridged. Following the spreadsheet it is no longer cutting out. It doesn't thump as hard as I would think a P3 would but I havei t extremely underpowered don't I? That sucks, amps are so damned expensive.

gfeller2006

For that P200-2 amp I looked up the specs and it looks like this.

Rated Power
(RMS Continuous Power) 50 Watts x 2 @ 4-Ohms
100 Watts x 2 @ 2-Ohms
200 Watts x 1 @ 4-Ohms Bridged


I have it bridged at 2 ohms which it doesn't even list. Do I need to rewire for 4 ohms until I can afford a bigger amp?

SparksAI

Yeah you will need to go 4 Ohms until you can get one that is 2 Ohm stable at 1 channel.

gfeller2006

It is playing at 2 ohm's right now. Will this damage anything? Or I guess why is it playing alright at 2 ohm's?

Black_Z28

iTrader: (1)

You'll damage the amp if you're running a 2 ohm draw, and it's safe to just a 4 ohm draw while being bridged.

And yes, that amp is way underpowered for that sub.

SparksAI

It will play but it is why manufactuers list impedences as 1 Ohm Stable or 2 Ohm Stable. If they are unstable at those Impedences you can do damage by presenting that kind of load to the amp. It usually isn't a problem to go up impedences but going down gets scary.

gfeller2006

That sux, its a DVC 4ohm sub. So theres no way to wire it to 4 ohm's at the amp is there? It will have to be 8 ohm's at the amp and 4 ohm's at the sub in a series?

SparksAI

Yes you can run it at 4 Ohms, follow the second example on this guide.
http://www.stereointegrity.com/docs/DVCwiring.pdf

When you look at that diagram keep in mind that one voice coil is on the left and the other is on the right.


That is why dual voice coils subs are gret, you have a lot of flexibility with them.

gfeller2006

Hmmm, That seems to disagree with this diagram I'm using from Crutchfield's website. This show's 8 ohm load at the amp?

I attached the diagram.

SparksAI

Yes sorry had my mind in 2 Ohm land. You can connect only a single voice coil to run it at a 4 ohm, but you will look at a 3db loss in efficency and reduced performance, I would consider it a limp mode at best.

gfeller2006

In other words I am really wasting my time with this amp... I need to get a decent monoblock amp around 400 watts RMS that is 2 ohm stable correct?

SparksAI

Yeah if that is the sub you want to run it is really time for another amp.

gfeller2006

Anything off of your site you would reccommend for that particular sub?

SparksAI

We have three good ways to go for that sub,

The first is the Precision Power S420.2
http://www.sparksai.com/product-p/s420.2.htm
It produces slightly more power than the 400w RMS that the rockford calls for but they also aren't CEA - 2006 numbers. Since Precision Power aren't Hifonics or some other less than reputable companies you are looking at about 380w true RMS out of these. THey also come with a free amp kit right now.

On the budget side of the house the Jensen Power900
http://www.sparksai.com/Jensen-Power...p/power900.htm
Jensen surprisingliy is CEA-2006 so the numbers they state are the numbers you get. At $89 this amp can pull out 340w RMS. If you add an amp kit or something to take your order over $99 then you get free shipping on it.

For the higher end option the Kicker ZX400.1
http://www.sparksai.com/product-p/zx4001.htm
Kicker are CEA-2006 and this amp will take your Rockford to it's limits at a full 400w RMS

I have several other amps that haven't made their way to the site yet so if you have been looking at another let me know and I will see if I can get ahold of it for you.

gfeller2006

The sub is 400 RMS. Do you think the Jensen at 340 would be that much noticebly less than say the kicker at 400 pushing it?

SparksAI

I think it would be noticeable but I don't think it would make a giant earth shattering difference. The Jensen is a good amp. Any company that is willing to put their stuff up to CEA-2006 should be considered. he price difference is pretty big between the two I know so what i might suggest is just asking if having the extra bump is going to be worth it. If yes then go Kicker, if no then the Jensen might be the way to go.