Explain OHMS to me, would you go from 8ohm to 4ohm? benefits? JL audio

[Mike Hawk]

Hey, Im going to get 2 JL 10w1v2 but cant decide on wether to get 8-ohms or 4-ohms. My amp is the old school fosgate 75.2 but it has some good power, would there be any benefits going up to 4-ohm?, my current subs are 8ohms, i wouldnt want to blow the speakers. thanks

[casperss]

your amp has a OHM stable rating do you know what it is? are you going to bridge or run stereo? these are all big factors that need to be known when chosing the correct speaker OHM rating.

[Mike Hawk]

ok heres what i found , the amp is stable up to 2 ohms making it 75 watts x2 , and it will NOT be bridged. thanx

[casperss]

Ok... i would recomend using the 4 OHM subs. that will keep you in range of what your amp can handle. Thats in a stereo mode 2 channel, If it can be bridged running two 4 ohm subs with both positives hooked together and both negatives hooked together on one channel you will get a 2 ohm load. Honestly bridging makes more power but it also makes more heat in the amp. personaly I think bridging is the way to go but if your amp can't handle it you have no other choice. Most amps will double the power in a bridged mode. if this all is confusing let me know and I will try to better explain it.

[Mike Hawk]

no it makes sense, thanks man. I might as well get the 4 ohm subs to use some amp power ive never tapped before. appreciate your help

[casperss]

No problem...

[fredmr85]

Ok... i would recomend using the 4 OHM subs. that will keep you in range of what your amp can handle. Thats in a stereo mode 2 channel, If it can be bridged running two 4 ohm subs with both positives hooked together and both negatives hooked together on one channel you will get a 2 ohm load. Honestly bridging makes more power but it also makes more heat in the amp. personaly I think bridging is the way to go but if your amp can't handle it you have no other choice. Most amps will double the power in a bridged mode. if this all is confusing let me know and I will try to better explain it.
I think you're a little confused....especially when you talk about bridging.

If the original poster plans on two subs - definitely be sure they are 2 ohm stable (or have dual voice coils of 4 ohms). Your amp may not state it, but I'm sure that amp is capable of being bridged and after a brief search it appears it can be. The power will close to double, but you would only have one output channel and the power would be made at 4 ohms -- so you would have to have a 4 ohm load in that case, not 2 ohms. Bridging does make more power per channel, but may not sound louder overall. (e.x. 2 subs, each with 150 watts will sound louder than 1 sub with 300 watts) Your amp seems to only put out 75wRMS of power tough -- in this case, running 2 subs with only 75wRMS each isn't the best idea -- might as well bridge for now and power ONE sub of 4 ohm impedance. That way you'll at least get 150 watts out of it.

So compared to models you are looking at, the JL Audio 10W1v2-4 (4 ohm version) would be a very good choice -- especially because it is rated around 150 watts, which is about the power it would be seeing.

[Mike Hawk]

ok thanks fredmr, hey i have a question. The power ratings for my punch 75.2 amp are stated below. Now actually before I had 8ohm speakers I had two 12 ohm speakers that i took from one of those JL Powerwedges that come with the three tens in it, my question is, if i was running 2 speakers at 12ohms does that mean i was only getting about 12.5 watts per channel according to the power output below?

Output Power (4 ohms) 37.5W x 2.
Output Power (2 ohms) 75W x 2.
Output Power Bridged(4 ohms) 150W x 1.

[casperss]

Ok ok this is what i would run if it was mine and i wanted two subs.
two dual voice coil 4ohm 10' in a stereo mode (two channel)
each speaker hooking both positive together same with the neg. one on each channel this will make it 2 ohm stereo and according to your specs the amp will take it "Output Power (2 ohms) 75W x 2."

option 2
two single coil 10' 8ohm in a bridged mode (one channel)
hooking positive together and the same on the neg.
this will make a 4ohm load (bridged only)
same power just two different ways to get it.

i prefer the dual voice coil method better cuz if you ever want to sell the subs, the dual 4ohm coils will sell alot easier the single 8ohm subs. Around here anyways.

[fredmr85]

option 2
two single coil 10' 8ohm in a bridged mode (one channel)
hooking positive together and the same on the neg.
this will make a 4ohm load (bridged only)
same power just two different ways to get it.

i prefer the dual voice coil method better cuz if you ever want to sell the subs, the dual 4ohm coils will sell alot easier the single 8ohm subs. Around here anyways.

You're forgetting that you could always wire dual 4 ohm VCs in series then the subs themselves in parallel.

Those are your options if you really want two subs.....not sure why you would -- just going to be a waste of time/space/weight unless you plan on giving them more in the future. Even though 2 subs given the same power as a single sub will provide more sound (thanks to more air movement), there is also a trade off in sensitivity where underpowering a sub may not provide as sensitive of results than if they were receiving power in their recommended range. I don't think this would be much of a problem since you are going for a low power application -- the extreme of my example would be trying to give 800wRMS subs 100 watts RMS (usually not enough to make the sub work properly).

[fredmr85]

...if i was running 2 speakers at 12ohms does that mean i was only getting about 12.5 watts per channel according to the power output below?

Output Power (4 ohms) 37.5W x 2.
Output Power (2 ohms) 75W x 2.
Output Power Bridged(4 ohms) 150W x 1.

yea somewhere around there... did they even reproduce sound?

[Mike Hawk]

ya they actually hit pretty good, i mean my rear view mirror and side mirrors would vibrate pretty hard, so i guess even goin up to 4ohms would be like doubling my previous setup even if it is only 37.5 watts

[casperss]

Question??? i'm not up on the JL products, what is the power handling rating on the subs that you are wanting?

[Mike Hawk]

150w each

[casperss]

that should be a good combination I think anyways. How old is your amp? alot of the old school amps actualy under rated their amps back in the day to get in a lower power class for competitons. so called cheater amps... i have an old Lanzar Opti drive 25.2 that makes a hell of alot more than its rating. It pushed 4 10' 4 ohm lanzar OA series without any problem. My opti 75.2 does even better the metr at my buddies stereo shop showed it making 150.2 at 4 ohms. OLD SCHOOL ROCKS....

[Mike Hawk]

ya man old school stuff is TUFF!, my punch amp i bought around 97 and it has never been a problem, not once, and it has pretty much been used every day since i had it in many different setups, so ya like you said, it must be underated because its pushin more than it wants me to think.

also, the JL tens i bought along with that amp in 97 are the ones i was using until a month ago when the foam around the cones of them finally deteriorated and caused it to fail, but hey i got 10 years out of them.

[casperss]

I bought my Opties in 91 they still work like new. even after the big crash they went thru in 98. they were both ejected from the car. Can't beat good american quality.

[casperss]

Hey how do i put pics in the reply box? I could show you the wrecked Z

[casperss]

http://http://www.ls1.com/forums/attachment.php?attachmentid=14254&d=1189382032

Is this how? I'm not sure...

[Mike Hawk]

i dont know how to do the pictures either, that link just sent me to wikipedia.com haha. Does Lanzar still make stuff or do they go by a different name now? Im sure i saw some lanzar stuff a while back but cant remember

[casperss]

Yea but it is junk.. Pyramid corp. bought them out a few years back. Kove audio is now what the old Lanzar used to be. They make killer stuff.

[casperss]

hey I just posted a new thread on how t place pics in a reply. Maybe somone can teach us. I hope so anyways.