Printer Friendly Forum Posts - JL 12W3V2 D2 Amp Help

Hi i have just purchased a used JL 12W3V2 D2 its in a PORTED 2.0 Ft^3 box. the owner said he had a Jl 250/1 runnin it and the sub was not abused. I know it works saw it pounding in his suv. Ok now it says wired in series it acn do 4ohms. So i need a amp that can do about the max 300RMS at 4 ohms? Am i correct? i have no clue ive also read that Jls can take a lot more than they say and some have said that i can put 400WRMS amp to it and illbe fine. Since im kinda new to subs i have no clue what to get. I would like some of your opinions and reccomendations on what amp to purchase please help me it will be greatly appreciated.

My current set up

Deck: ALpine 9831

Components up front: Infinity Perfect Kappa's 6.1

Amp for components: ALPINE MRV T320 80W*2 @4ohms

STOCK rear 6*9

temporary i know my amp can do 240W*1 @ 4ohms so im gonna connect it to that and put components to the deck and DISCONNECT the REAR 6*9's. I sthis a bad choice. I only wanan do this is cuz i want to hear some nice bass! I know this is goign to suck beacuse my components really need an amp so im gonna loose some quality but id rather have the bass from the sub unitl i buy a decent amp for the sub.Any help will be greatly appreciated.

This is where I got information on your sub

Your sub is rated at 300RMS. I would suggest that you get an amp that is rated between 300~500RMS at 4 Ohms.

How much are you looking to spend on an Amp? Answer that, and then we can give you some recommendations.

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Here are a few amps

Kenwood Kac- 7251 150 x 2 You can wire each of the voice coils to this amp individually. This amp is rated at 230w RMS x 2 @ 2Ohm, that should be plenty of power.

Alpine MRV-T420 110 x 2 Again, you can wire each voice coil individually to this amp. It is rated at 170w RMS x 2 @ 2Ohms.

I will look for more amps. I am finding that Mono block amps cost more then there equivolent 2 channel amps.

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Poormanq45 wrote:

This is where I got information on your sub
Your sub is rated at 300RMS. I would suggest that you get an amp that is rated between 300~500RMS at 4 Ohms.
How much are you looking to spend on an Amp? Answer that, and then we can give you some recommendations.

If his sub is rated at 300RMS then he'll probably be fine from 150-300RMS. There's absolutely no reason to push over 300rms to that sub, especially with a ported box. It would be a complete waste of money unless headroom simply gets you off.

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New Project: 2003 Pathfinder

Oh, I'm sorry. It's just that many people keep telling me that it is better to overpower the sub(s) then underpower them.

I never believed that^^^, but I just thought that I would pass on the "concensus" that most people have given me.

ANyway, I will post some more amps between 150~300RMS. Should he try to use a Mono block amp rated at 4 Ohms? Or a multi channel amp that can handle 2 Ohms?

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Hey, no need to be sorry, you're trying to help! :-) Check out https://www.bcae1.com/ for some reasoning on why the underpowering thing isn't a major concern.

I'd probably go with a mono class D subwoofer amp personally. 3 reasons:

1) Running low priced 2-channel amps at 2-ohms is going to increase distortion .. Will it be audible? Who knows, but at 4-ohms mono the distortion will probably be less.

2) Class D amps are more efficient

3) Many class D mono subwoofer amps have a subsonic filter on them, which he will definitely want for a ported box.

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New Project: 2003 Pathfinder

wow thanks for such quick respones.

kfr01: Which amps do you reccomend? My buddy has two of these subs 12w3v2 but the D4 he has givien each of them a PG TANTRUM 300.2 and he is shoving 430W @ 2 ohms to each RMS. this amp can do 300*1 RMS at 4 ohms too i was thinking to go with PG (Phoenix GOld) because they make high quality amps? please give me some reccomendations if you know of better amps. my price rang is max 170US. i just spend 230 CDN on the sub and 300CDN on compoents and then 115 on the amp (I got this amp for cheap Alpine MRV-T320). and then 200 for the install of all these are all in CDN. but i max wanan spend is 170US on a amp for this sub. If you guys will reccomend it i will just use my alpine amp Bridged at 4 ohms to give this sub 220W RMS and power my components with teh deck. any other reccomendations willbe greatly appreciated thanks for your help.

PS here is the SUB INFO FROM JL https://www.jlaudio.com/subwoofers/pdfs/12W3v2_MAN.pdf

For the reasons I stated above, I would look at a mono class d subwoofer amplifier with a subsonic filter.

Search some out and let me know if you're finding anything good. You might have to hit ebay for this. Less than a dollar a watt retail, under $200, is generally tough to do.

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New Project: 2003 Pathfinder

^^^^

That is why I was suggesting that he get a 2 Channel amp. It seems that they are cheaper, Watt for Watt. Albeit, the distortion may be a little higher(50%), I do not think that it would be that noticable.

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I feel the 3 positives I outlined above justify a search for the right class d mono subwoofer amp for him. I mean, why not search for the BEST amp for his needs first? Then give up and compromise if you can't find one?

https://cgi.ebay.com/dll?ViewItem&category=18797&item=5736131147&tc=photo here's one that would work. There are plenty of others.

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New Project: 2003 Pathfinder

wow thanks today i couldnt help it i conneced my components to the deck and set my ALPINE MRV -T320 @ 220RMS*1 @4ohms its a v12 amp. GOD DAmn this JL is killing the civic wow the bass is amazing it is hitting like nutz more than enuff for me but everyone says i can get more outta it. I dont see what woudl be wrong wit ha PG Tantrum 300.2 Brided tat 300/1 @ 4ohms. a Class D is gonna cost me a lot. That octane R amp cant satisygy my needs cuz its a 500 /1 @ 2 ohms i need it to be 500/1 @ 4 ohms also 500RMS to a PORTED box is prob gonna k ill the sub thast what im thinking i dont wanan put more than 400W RMS to it. Im thinking when i can afford it a PG TI 400.2 brided at 400*1 RMS @ 4ohms PG makes killer amps. anywyas thanks for your help im gonna go look up some AMps that KFR01 suggested.

If you do go bridged buy a subsonic in-line filter from harrison labs around 30hz.

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New Project: 2003 Pathfinder

ok what kinda amp cuz brideged are much cheaper how many watts rms should i pump into this sub since its in a 2.1cubcit feet box. Im feeding it roughtly 200RMS now and its banging to my needs but i do want more boom if i can get it.

200-300 is fine. Don't go over 300, there's no need. Also, you probably won't hear much a difference between 200 and 300. You'd need to jump up to 400w (double the power) to increase the SPL by 3db. This subwoofer in a ported box should not be fed 400w continuously. So, with 300w added you'll be getting significantly less than a 3db max SPL gain. You'll barely be able to hear it.

Any bridgeable amp is fine. Get a decent brand that's actually rated correctly, or fairly at least. Alpine is a good choice, if you like that company. You can find the same Xtant 2x50w amp I use bridged to my sub for less than $150 all over ebay. It would serve you very well for the price.

Remember to get that subsonic harrison f-mod filter.

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New Project: 2003 Pathfinder

This amp is better than the PG one you were looking at, and it costs less. You wont get a warranty from this store but you won't get one from ebay either so I guess it dosn't matter to you: https://www.ikesound.com/product-product_id/2401 Oh and make sure to use a subsonic filter on it like kfr01 said.

ok for now can i get some more detail on this sub sonic filteram i am not understanding it my ALPINE amp im gonna use it for a couple months the mrv-t320 2201 @ 4ohm RMS should i slap a filter ont his now ? i think i shoudl cuz you guysing are saying its importnatn please give me a site or somethign to help explain it. I appreciate all your help here thanks.

You'll want to buy these.

Harrison Lab High Pass Filters

Might be one reason just to look for a mono subwoofer amplifier...

Basically ported boxes are tuned to a certain frequency. When music plays below that frequency the subwoofer distorts. This sounds bad. A filter like this will prevent the rca from getting these ultra low frequencies, those below your tuning frequency, so the woofer doesn't distort as much.

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New Project: 2003 Pathfinder

should i be purchasing this thing right now im in CANADA so this may be a problem and also does it need to be connected near amp or near deck i cannot connect this neat my amp its gonna hit something for sure.its very long.

ok i found a ebay link here it is https://cgi.ebay.com/dll?ViewItem&category=14931&item=5726113377&rd=1&ssPageName=WD1V

is this what i need and which HZ i need

ok WHA Ti dont get is in this auction the guy is saying that a High Pass filter BLOCKs low frequencies why would i wand to block low frequencies to the sub doesnt the SUB process the low frequencies isnt that we have subs ? Im sorry if its stupid question but im not understandying why i need a HIGH PASS filter when it says that "The high pass (blocks low frequencies) shown as the red labelled model."..

From what i think in my mind, enven though im probably wrong but this makes sense to me, is that i need a a LOW PASS filter which BLOCKS HIGH FREQUENCIES. sorry if this is all confusing im just stillnot getting why i need a HIGH PASS filter. Maybe you can clarifiy some more.. Sorry for askign stupid questions.

Order the 30hz high pass.

Your subwoofer shouldn't play the ultra low frequencies as it is in a ported box with a high tuning frequency. If it tries, it will introduce more distortion.

You'll ALSO need a low pass crossover, but most 2-channel amplifiers have those.

So.... if you use a 30hz high pass and a 80hz low pass you'll have a ~30 to ~80hz sub bass window. Most of the bass information you want coming from the subwoofer in music is from 30-80hz. Trust me, it will sound better than it would without the f-mod.

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New Project: 2003 Pathfinder

my amplifier has a LP crossover adjustable from 30-400 HZ so i should this one to 80Hz after installing the HP 30HZ . Does this need to be installed NEar the amp or Near the decks preout i? Because if i hve to install near the amp , which i think is what needs to be done, i will run into a problem because their is a plate that tries to hide wiring to the amps and this plate will be in the way if i install this HP near the amp. I want if i can aget a bendable version.

Near the pre-outs is fine. Or you can just get a short length of rce to put between the f-mod and your amp.

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New Project: 2003 Pathfinder

Sorry, no Gumby models available.. so just pick up a pair of short RCA's and install the filter between RCA's.

Ok so even though im not buying a new amp right now i should still purchase this HP Filter 30hz and install it near my amp i have? i dunno maybe i will keep this alpine amp its feeding it 220W Rms and i dont know if i really shoud get a new amp its a V12 and its about 400 dollars to buy it new i got it for 100.....maybe illjust pick up any 100*2 amp for components or so.... any suggestions this amp i have is pusing the sub beyond my needs i think if i were to buy a new amp just for the sub it would be just to show off. i can get another one of these alpine amps cheap aswell 120 bux cdn or so shoudl i do this or invest in a new amp? So i should go ahead and buy this HP filter asAp right ?

I totally agree. There's no need for more watts if you're happy with what you have. Get a good 50x2 amplifier for the components and you'll be set.

Car audio is very hung up on megawatts. The fact is, for daily driving, as long as you find something that meets your needs why waste money on more?

I only run 200w to my sub and never feel like I need more. Power is all personal preference. If your current amp works for you, keep it!

I would definitely pick up the high pass filter. It will make your bass even more clean.

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New Project: 2003 Pathfinder