Trying to find a good amp for my new p3

Jason C Bolt

I have a new Rockford Fosgate P3 D212 sub and am looking to buy an amp for to make it sound as good as possible. I want this thing to pound the highs and lows as good as possible. The subs 1000 watt peak, 500 RMS dual 2 ohm. I'm semi broke so the cheaper the better unless there's a really good one for a little more. Any suggestions?

Im currently running it off of a http://www.savinglots.com/lotprod.asp?item=GM7200F but it is not doin the trick, obviously lol. I used it to power my Polk Momo MM2124 and it worked just fine.

I have my eyes on these 2...

1.http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=20597

2.http://www.homegoodz.com/viewitem.php?IndexID=104285&RefTag=froogle#spec_detail

The box i have it in is http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=21329 Its loud of course but it doesn't go low enough for me. Rockford recommends a box of 25x14x12. I wanna make a new one for it but cant decide on ported or sealed. I'm leaning more towards ported.

Also im a little unclear on the whole 1, 2 and 4ohm thing and how to achieve it. I know the less resistance the better but not sure how to do it with the wiring and all.

Any help would be greatly appreciated. Thanx.

nguyendot

Your amp now is not doing the trick because you are only running 250 watts RMS to it @ 4 ohms (I hope you have it wired into 4 ohms). You should have it wired in series right now - that is + to - and - to + on the voice coils.

Less resistance is not "better". It generally means that more power can be utilized from the amplifier, but not all amps can run those low loads (1 ohm, for example). Also with low resistance you generally lose quality specs, such as dampening (how easily the amplifier can control cone movement), and distortion (how clean the audio is). For a subwoofer the distortion piece is genernally not an issue unless it goes insanely out of spec, which your amp can and probably will do if you drive it too hard. You are severely underpowering your sub right now.

The hifonics brutus is 600wrms, which should be fine for your sub. You will not be driving it at it's full potential (always allow more power for headroom) but it will drive it better than your current amplifier. Be prepared to do the big 3 upgrade as that amp will draw more current than your amplifier now by twofold.


The Rockford amp will not drive your subwoofer as it is not 1 ohm stable. It can work, but you will have to wire your sub at 4 ohms and at that rating you will only be p utting out 250watts rms, which is no improvement from your amplifier right now.

The "ohm thing" is just how much resistance your sub is giving the amp. It's easy to calculate with only 2 coils. If you wire it in parallel, you simply take the Ohms (you have two 2 ohm coils) and divide them. In your case it would be 2Ohms/2coils = 1 ohm. If you wire it in series, you add them together. 2+2=4Ohms. It's easy for 2 coils, or any even amount. This applies if you have 2 subs too.

Here is a picture with an example. The left is wired in series, the right is wired in parallel. Each circle can represent a single voice coil, or subwoofer with one voice coil.



As far as the box goes, it all depends what type of sound you're looking for and what type of music you listen to. Sealed will give a crisper, tighter sound. Ported will generally be louder around the tuning frequency of the subwoofer, but not be as "tight". Your current box is not made specifically for your subwoofer, so your sound will be less than stellar.

P.S. have you checked out ikesound.com? There are a lot of amps with great prices. (no affil)

exalted512

Cheap and needs to be run at 1 ohm, my first thought is Hifonics, go with choice number 1.
-Cody

only126db

exalted512 wrote: »

Cheap and needs to be run at 1 ohm, my first thought is Hifonics, go with choice number 1.
-Cody

X2 Get the Hifonics.

Since you have dual 2ohm vc's you can also run the Hifonics 2ch a/b amps bridged mono and if you ever want to switch out to a larger amp then you will have a 2ch a/b for your front stage instead of having to buy 2 amps later if you do upgrade.

Jason C Bolt

I think im sold on the Hifonics. Not sure if i want the mono or 2 channel... it would be nice to add another someday distant in the future... What kinda of amp would drive the p3 to it full potential? And are you certain ill have to the big 3?? I'm broke and shouldn't even be buying an amp lol. I just got such a deal on the sub i couldn't pass it up.

I also found this amp 1000 rms x 1 bridged it say. What do you think? And the price is great!
http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=20667

nguyendot

Stay away from crunch.

Big 3 are :

Definition: the "Big Three" upgrade means improving the current capacity of three cables: 1) alternator positive to battery positive, 2) battery negative to chassis, and 3) engine ground to chassis. Some people replace the factory wiring; others add additional cables to the factory wiring. This instruction is to add cables to existing OEM wiring.

These are the 3 that you get power from for your entire car.

arun1963

Definition: the "Big Three" upgrade means improving the current capacity of three cables: 1) alternator positive to battery positive, 2) battery negative to chassis, and 3) engine ground to chassis. Some people replace the factory wiring; others add additional cables to the factory wiring. This instruction is to add cables to existing OEM wiring.

nguyendot,

With my car running, my hu tells me its getting 13.6-13.8 volts. Would doing the big 3, bump this upto 14+ volts, so that I'm closer to the pa500.4's 14.4 volt ref level and hence get all the 90watts /ch? IE my setup would play louder and clearer........

nguyendot

Arun1963,

That depends honestly on quite a few things. Theres the amount that your car might be losing already through less than optimal connections. Theres the level that your alternator puts out while running (14.4 usually), the level of your battery (a dying battery will suck power from the system as it will seem to "charge" all the time. There's also how much power your accessories such as A/C and the engine use.

The "Big 3" isn't so much a voltage improvement, but there to ensure that your car can supply an adequate amount of current so the volts do not drop. Voltage drop = higher amp draw and usually poor performance.

The "Big 3" should be the first big update when running high power in a car audio system. Imagine, if your amp uses 4/2/0 gauge wire, what good is it if the ground to the car is only 8 ga? It would be similar to trying to suck water through a water hose (2ga wire typically used on an amp) on one end, with a straw (8ga chassis ground) on the other end. Your straw has a lot of capacity, but it will never be used because the straw is all thats supplying it!

With this upgrade, you will more likely see that your volts drop less while playing loudly, instead of a voltage increase while it's sitting there.

exalted512

It is not uncommon to see a half-volt increase when the big 3 is done.
-Cody

Jason C Bolt

What about equalizers? And and or a infrasonic filter? Nessesary or no? Good kind that's cheapish?

only126db

Jason C Bolt wrote: »

What about equalizers? And and or a infrasonic filter? Nessesary or no? Good kind that's cheapish?

The Crunch amps are pretty solid, they are rated at maximum power, and usually only put out 50% of what is stated, so that one would be 500 x 1 bridged.

I personally have never heard of any problems with the Crunch amps just the power ratings are deceptive.


As for your voltage from doing the big 3, it is quite possible you will see a voltage increase at idle with no music playing, but the important thing is the voltage and amperage increase while you are bumping the system hard, this is where the big 3 will shine, the larger wire creates a path of less resistance, it can be compared to hooking a drinking straw to your water faucet, good luck getting much water from it, but hook up a larger diameter hose and you get plenty of water.

As for eq's that will depend alot on the speakers, vehicle, and installation, I use no equalizers at all, just bass, mid, and treble on my deck.

A subsonic filter will help if you run a ported enclosure, or use subwoofers which cannot handle the power at lower frequencies due to either power or mechanical limitations in it's design.(Hifonics has a built in adjustable sub sonic/infrasonic)

I have NOT done the Big 3 in my truck and I run 2 Hifonics, the ZXI6006 (300x2 @ 2ohm stereo) and the BXI2006D (2000 x 1 @ 1ohm mono) I always keep up on battery maintenance by running a charger to my batt. every so often and making sure my contacts are clean.

The big 3 will help alot if you use many accessories while bumping, I never do.

Jason C Bolt

Thanks for all the Help guyz!!

nguyendot

No problem. I think it's funny we all basically said the same thing 3 times.