Car Audio System

[Matt2]

ok,

so, right now I have 2 Power Acoustik 12" FUBR-12 subs in the back of my jeep. Each sub is 1800 watts peak, 800 watts RMS

Problem is, only one of them works. The amp Best Buy sold me with the subs (package deal) is only 980 watts 2 channel. So when we were installing the amps we figured out that each one of those subs needs 2 channels to itself (2 voice coils each) and we decided to only hook one sub up instead of trying to bridge it and under power both of them.

So one sub works and the other just sits there waiting for a better amp. Let me tell you, just one of these subs running off a 980 watt amp rocks my car, it's intense.

Now, I'm looking to get an amp that's gonna power both of these subs and the amp I was looking at a Power Acoustik 2400 watt mono channel amp I can get for around $250 online.

2400 watts would definately supply enough juice to both subs, but I was wondering, if the one sub I have working now needed both channels on the amp I have now, can I hook up both subs, a total of 4 wires, to only a single channel amp?

This is my first system, so bear with me!

Thanks.

 

[95SS]

What is the rating of each voice coil?

 

[95SS]

Hold on, you've got a stereo amp pushing one DVC sub, one channel per coil? You don't need a new amp, just some wiring help. Each sub has two sets of terminals, wire each set of terminals to one channel of the amp. This is called parallel, and will drop the load to 1/2 of the rated load per coil. If the sub has 4 or 8 ohm coils, this is fine. If it has 2 ohm coils, don't do this. With 2 ohm coils, run the sub in series, meaning from one coil to the other. You would have speaker cable from one channel of the amp to the + of one coil and the - of the other coil, and a wire between the unused connections. I'll find some pics for you.

pic

 

[Matt2]

each sub has dual 2 ohm voice coils

 

[95SS]

Originally posted by: Matt2
each sub has dual 2 ohm voice coils

Cool, try wiring each sub with coils in series to a seperate channel. This will be a 4 ohm stereo load, easy for the amp. If after this you want more, then buy the new amp. But if one sub is rocking your car, hooking up both should be more than enough, even on the original amp.

 

[Matt2]

Originally posted by: 95SS
Hold on, you've got a stereo amp pushing one DVC sub, one channel per coil? You don't need a new amp, just some wiring help. Each sub has two sets of terminals, wire each set of terminals to one channel of the amp. This is called parallel, and will drop the load to 1/2 of the rated load per coil. If the sub has 4 or 8 ohm coils, this is fine. If it has 2 ohm coils, don't do this. With 2 ohm coils, run the sub in series, meaning from one coil to the other. You would have speaker cable from one channel of the amp to the + of one coil and the - of the other coil, and a wire between the unused connections. I'll find some pics for you.

Ok, that makes a lot of sense, I think I understand now.

HOWEVER,

I'm still gonna need a new amp cause 980 watts is not going to drive both of those 1800 watt speakers. It runs one fine and it sounds excellent, but I can't imagine cutting the power to each of those subs in half. That's why I want to get the 2400 watt amp, that'll be plenty for both subs.

 

[95SS]

Originally posted by: Matt2

Originally posted by: 95SS
Hold on, you've got a stereo amp pushing one DVC sub, one channel per coil? You don't need a new amp, just some wiring help. Each sub has two sets of terminals, wire each set of terminals to one channel of the amp. This is called parallel, and will drop the load to 1/2 of the rated load per coil. If the sub has 4 or 8 ohm coils, this is fine. If it has 2 ohm coils, don't do this. With 2 ohm coils, run the sub in series, meaning from one coil to the other. You would have speaker cable from one channel of the amp to the + of one coil and the - of the other coil, and a wire between the unused connections. I'll find some pics for you.

Ok, that makes a lot of sense, I think I understand now.

HOWEVER,

I'm still gonna need a new amp cause 980 watts is not going to drive both of those 1800 watt speakers. It runs one fine and it sounds excellent, but I can't imagine cutting the power to each of those subs in half. That's why I want to get the 2400 watt amp, that'll be plenty for both subs.

I think you'll be pleasantly surprised with two subs hooked up properly. But what amp did you get when you bought the package?

 

[Matt2]

I dunno, maybe it'll sound better than I'm imagining in my head. The power acoustik tech told me straight up when I was wiring them up that that amp was not power enough to drive both of those subs and they "would sound like sh1t". He really told me that, but I'll try it out in the morning and see what I can come up with.

Edit: It's a Power Acoustik LT980/2

 

[95SS]

Quick rule of thumb for subs :

Double the power = 3db increase
Double the cone area = 6db increase

You'd be increasing your bass output by simply wiring both subs correctly, no more power needed.

And if you had both subs in the enclosure, and they weren't in seperate chambers, then you were getting cancellation from the unused sub, as it was out of phase with the powered sub, and cancelling some output.

 

[0roo0roo]

you think that sub is really using 1000watts? just try hooking both to the single amp. something is wrong if you really need more then 500watts for a sub in a car. if that single sub is using the full 1000watts i think you're playing music to annoy people 5 lanes over.

 

[Matt2]

They're definately not in seperate chambers, so I'll wire them up right tomorrow before work.

Thanks for the insight, I'll let you know how it goes.

 

[95SS]

Cool, good luck. And remember to practice responible listening. :thumbsup:

 

[0roo0roo]

and yes if its not in a separate chamber a dead woofer is like having a flexible cabinet wall. bad

 

[Syringer]

I felt more patriotic reading through this thread..not sure why though.

 

[MikeMike]

Originally posted by: 95SS
Quick rule of thumb for subs :

Double the power = 3db increase
Double the cone area = 6db increase

You'd be increasing your bass output by simply wiring both subs correctly, no more power needed.

And if you had both subs in the enclosure, and they weren't in seperate chambers, then you were getting cancellation from the unused sub, as it was out of phase with the powered sub, and cancelling some output.

6db is doubling the cone and power.

both individually result in 3db unless im greately mistaken.

MIKE

 

[quakefiend420]

Originally posted by: Matt2

Originally posted by: 95SS
Hold on, you've got a stereo amp pushing one DVC sub, one channel per coil? You don't need a new amp, just some wiring help. Each sub has two sets of terminals, wire each set of terminals to one channel of the amp. This is called parallel, and will drop the load to 1/2 of the rated load per coil. If the sub has 4 or 8 ohm coils, this is fine. If it has 2 ohm coils, don't do this. With 2 ohm coils, run the sub in series, meaning from one coil to the other. You would have speaker cable from one channel of the amp to the + of one coil and the - of the other coil, and a wire between the unused connections. I'll find some pics for you.

Ok, that makes a lot of sense, I think I understand now.

HOWEVER,

I'm still gonna need a new amp cause 980 watts is not going to drive both of those 1800 watt speakers. It runs one fine and it sounds excellent, but I can't imagine cutting the power to each of those subs in half. That's why I want to get the 2400 watt amp, that'll be plenty for both subs.

well...kinda...you need to look at your amps power rating at different loads...also is that 980 watts peak or rms out of the amp? if you can run 1 ohm stable on that amp...i would go out on a limb to say you're gona be good to go...like someone else up there said, double the cone area = about 6db...and also like someone else suggested...i would run both subs in a series...

 

[MikeMike]

i doubt his amp is 1 ohm stereo

il draw up a diagram of what he should do...

MIKE

 

[quakefiend420]

Originally posted by: Matt2
I dunno, maybe it'll sound better than I'm imagining in my head. The power acoustik tech told me straight up when I was wiring them up that that amp was not power enough to drive both of those subs and they "would sound like sh1t". He really told me that, but I'll try it out in the morning and see what I can come up with.

Edit: It's a Power Acoustik LT980/2

and tell your "tech" he's an idiot...those subs will sound fine...whenever you are playing at low volumes the sub is getting minimal watts...and it still sounds ok, doenst it?

 

[MikeMike]

http://web.ics.purdue.edu/~mbarnard/sublayout.JPG

that is both vc's in a paralle stereo 4 ohm mode, you will receive about 220 watts to each (the one is currently getting about 280watts).

there we go, sorry about the quality, its an ms paint jobber

MIKE

 

[95SS]

Originally posted by: nourdmrolNMT1

Originally posted by: 95SS
Quick rule of thumb for subs :

Double the power = 3db increase
Double the cone area = 6db increase

You'd be increasing your bass output by simply wiring both subs correctly, no more power needed.

And if you had both subs in the enclosure, and they weren't in seperate chambers, then you were getting cancellation from the unused sub, as it was out of phase with the powered sub, and cancelling some output.

6db is doubling the cone and power.

both individually result in 3db unless im greately mistaken.

MIKE

I thought it was 6db for doubling cone area, provided the same power to each driver. I guess we're both right, since that would double the power over one driver. So it's like

1 driver @ 100w = baseline
1 driver @ 200w = +3db
2 drivers @ 100w total = +3db
2 drivers @ 200w total = +6db

And plus, since I'm wasn't all that awake, I now realize that he was running 2 ohm stereo to 1 driver, albeit ineffciently due to the out of phase driver, and independent input signals, so all things considered, it should sound louder, though not by 3db. Plus the amp will be happier.

PS - your drawing is parallel, that would be a 1 ohm stereo load. He needs series for a 4 ohm stereo load.

 

[MikeMike]

Originally posted by: 95SS

Originally posted by: nourdmrolNMT1

Originally posted by: 95SS
Quick rule of thumb for subs :

Double the power = 3db increase
Double the cone area = 6db increase

You'd be increasing your bass output by simply wiring both subs correctly, no more power needed.

And if you had both subs in the enclosure, and they weren't in seperate chambers, then you were getting cancellation from the unused sub, as it was out of phase with the powered sub, and cancelling some output.

6db is doubling the cone and power.

both individually result in 3db unless im greately mistaken.

MIKE

I thought it was 6db for doubling cone area, provided the same power to each driver. I guess we're both right, since that would double the power over one driver. So it's like

1 driver @ 100w = baseline
1 driver @ 200w = +3db
2 drivers @ 100w total = +3db
2 drivers @ 200w total = +6db

And plus, since I'm wasn't all that awake, I now realize that he was running 2 ohm stereo to 1 driver, albeit ineffciently due to the out of phase driver, and independent input signals, so all things considered, it should sound louder, though not by 3db. Plus the amp will be happier.

PS - your drawing is parallel, that would be a 1 ohm stereo load. He needs series for a 4 ohm stereo load.

it took me three tries and three trains of thought on the pic. i havent slept and have class in 2 hours.

i guess ill try again

MIKE

 

[virtuamike]

Originally posted by: quakefiend420

Originally posted by: Matt2

Originally posted by: 95SS
Hold on, you've got a stereo amp pushing one DVC sub, one channel per coil? You don't need a new amp, just some wiring help. Each sub has two sets of terminals, wire each set of terminals to one channel of the amp. This is called parallel, and will drop the load to 1/2 of the rated load per coil. If the sub has 4 or 8 ohm coils, this is fine. If it has 2 ohm coils, don't do this. With 2 ohm coils, run the sub in series, meaning from one coil to the other. You would have speaker cable from one channel of the amp to the + of one coil and the - of the other coil, and a wire between the unused connections. I'll find some pics for you.

Ok, that makes a lot of sense, I think I understand now.

HOWEVER,

I'm still gonna need a new amp cause 980 watts is not going to drive both of those 1800 watt speakers. It runs one fine and it sounds excellent, but I can't imagine cutting the power to each of those subs in half. That's why I want to get the 2400 watt amp, that'll be plenty for both subs.

well...kinda...you need to look at your amps power rating at different loads...also is that 980 watts peak or rms out of the amp? if you can run 1 ohm stable on that amp...i would go out on a limb to say you're gona be good to go...like someone else up there said, double the cone area = about 6db...and also like someone else suggested...i would run both subs in a series...

Actually what I'd do is wire each VC in series, so each sub is a 4 ohm load. Wire the subs together in parallel to produce a 2 ohm load. After that, do some praying and hope the amp doesn't fry running bridged.

It looks like the amp is rated at 220W RMS x2 @ 4 ohm whereas it'll do 560W x1 RMS @ 4 ohm. In theory since you're dropping to 2 ohm bridged, each sub will be getting more than 280W RMS (meaning bridging your amp will give you more power per sub than running each on a separate channel).

Specs here, looks like someone already tried bridging to 2 ohm

Sorry to burst your bubble, but there is no way your Power Acoustik amp is putting out 980W RMS. But if you like the way it sounds, stick with it.

Me, I went overkill and went with an ID Max and a JBL 1200.1 in my Accord. I have the gain set to 1/4 because any higher and my trunk goes ghetto, haven't gotten around to deadening the car.

Next time, do yourself a favor and don't trust the Best Buy monkeys to do your install.

 

[MikeMike]

Originally posted by: virtuamike

Originally posted by: quakefiend420

Originally posted by: Matt2

Originally posted by: 95SS
Hold on, you've got a stereo amp pushing one DVC sub, one channel per coil? You don't need a new amp, just some wiring help. Each sub has two sets of terminals, wire each set of terminals to one channel of the amp. This is called parallel, and will drop the load to 1/2 of the rated load per coil. If the sub has 4 or 8 ohm coils, this is fine. If it has 2 ohm coils, don't do this. With 2 ohm coils, run the sub in series, meaning from one coil to the other. You would have speaker cable from one channel of the amp to the + of one coil and the - of the other coil, and a wire between the unused connections. I'll find some pics for you.

Ok, that makes a lot of sense, I think I understand now.

HOWEVER,

I'm still gonna need a new amp cause 980 watts is not going to drive both of those 1800 watt speakers. It runs one fine and it sounds excellent, but I can't imagine cutting the power to each of those subs in half. That's why I want to get the 2400 watt amp, that'll be plenty for both subs.

well...kinda...you need to look at your amps power rating at different loads...also is that 980 watts peak or rms out of the amp? if you can run 1 ohm stable on that amp...i would go out on a limb to say you're gona be good to go...like someone else up there said, double the cone area = about 6db...and also like someone else suggested...i would run both subs in a series...

Actually what I'd do is wire each VC in series, so each sub is a 4 ohm load. Wire the subs together in parallel to produce a 2 ohm load. After that, do some praying and hope the amp doesn't fry running bridged.

It looks like the amp is rated at 220W RMS x2 @ 4 ohm whereas it'll do 560W x1 RMS @ 4 ohm. In theory since you're dropping to 2 ohm bridged, each sub will be getting more than 280W RMS (meaning bridging your amp will give you more power per sub than running each on a separate channel).

Specs here, looks like someone already tried bridging to 2 ohm

Sorry to burst your bubble, but there is no way your Power Acoustik amp is putting out 980W RMS. But if you like the way it sounds, stick with it.

Me, I went overkill and went with an ID Max and a JBL 1200.1 in my Accord. I have the gain set to 1/4 because any higher and my trunk goes ghetto, haven't gotten around to deadening the car.

Next time, do yourself a favor and don't trust the Best Buy monkeys to do your install.

just another disclaimer, an amp that is rated for 2 ohm stereo, normally will not be able to handle a 2 ohm bridged load, just because thats theoretically 1 ohm per channel, with impedence probably being higher due to impedence rise at certain frequencies, and with the vc's heating up, and etc.

for full safety, my previous drawing would work.

MIKE

 

[virtuamike]

Originally posted by: nourdmrolNMT1

Originally posted by: virtuamike

Originally posted by: quakefiend420

Originally posted by: Matt2

Originally posted by: 95SS
Hold on, you've got a stereo amp pushing one DVC sub, one channel per coil? You don't need a new amp, just some wiring help. Each sub has two sets of terminals, wire each set of terminals to one channel of the amp. This is called parallel, and will drop the load to 1/2 of the rated load per coil. If the sub has 4 or 8 ohm coils, this is fine. If it has 2 ohm coils, don't do this. With 2 ohm coils, run the sub in series, meaning from one coil to the other. You would have speaker cable from one channel of the amp to the + of one coil and the - of the other coil, and a wire between the unused connections. I'll find some pics for you.

Ok, that makes a lot of sense, I think I understand now.

HOWEVER,

I'm still gonna need a new amp cause 980 watts is not going to drive both of those 1800 watt speakers. It runs one fine and it sounds excellent, but I can't imagine cutting the power to each of those subs in half. That's why I want to get the 2400 watt amp, that'll be plenty for both subs.

well...kinda...you need to look at your amps power rating at different loads...also is that 980 watts peak or rms out of the amp? if you can run 1 ohm stable on that amp...i would go out on a limb to say you're gona be good to go...like someone else up there said, double the cone area = about 6db...and also like someone else suggested...i would run both subs in a series...

Actually what I'd do is wire each VC in series, so each sub is a 4 ohm load. Wire the subs together in parallel to produce a 2 ohm load. After that, do some praying and hope the amp doesn't fry running bridged.

It looks like the amp is rated at 220W RMS x2 @ 4 ohm whereas it'll do 560W x1 RMS @ 4 ohm. In theory since you're dropping to 2 ohm bridged, each sub will be getting more than 280W RMS (meaning bridging your amp will give you more power per sub than running each on a separate channel).

Specs here, looks like someone already tried bridging to 2 ohm

Sorry to burst your bubble, but there is no way your Power Acoustik amp is putting out 980W RMS. But if you like the way it sounds, stick with it.

Me, I went overkill and went with an ID Max and a JBL 1200.1 in my Accord. I have the gain set to 1/4 because any higher and my trunk goes ghetto, haven't gotten around to deadening the car.

Next time, do yourself a favor and don't trust the Best Buy monkeys to do your install.

just another disclaimer, an amp that is rated for 2 ohm stereo, normally will not be able to handle a 2 ohm bridged load, just because thats theoretically 1 ohm per channel, with impedence probably being higher due to impedence rise at certain frequencies, and with the vc's heating up, and etc.

for full safety, my previous drawing would work.

MIKE

Yeah but my diagram is prettier

I'm not saying your way wouldn't work, but basically this is the same concept as overclocking: getting the most out of your equipment. Someone else has already tried and run the amp at 2 ohm bridged. I'd be hesitant to try to drop down to 1 ohm bridged but 2 ohm should be fine. If anything the amp will get hot. If that happens, just let it cool and run 2 channel vs bridged. I seriously doubt it'll fry his subs or his amp. Honestly, it wouldn't hurt to try.

Also if your subs are facing forward toward the front of the car, you might want to try to flip your box around and have it fire towards the back. Or vice versa. Every car is different (all trunks have different acoustics) so it's a good idea to play around with box direction and placement until you find what works. In general though you'll get punchier bass if you face forward and boomier if you face rear.

** EDIT **

Oops, I screwed up. Wire the negative from the right channel of the amp to the postive on the top VC on sub #1. It'll work the way in the diagram too but the edit is cleaner.

 

[MikeMike]

Originally posted by: virtuamike

Originally posted by: nourdmrolNMT1

Originally posted by: virtuamike

Originally posted by: quakefiend420

Originally posted by: Matt2

Originally posted by: 95SS
Hold on, you've got a stereo amp pushing one DVC sub, one channel per coil? You don't need a new amp, just some wiring help. Each sub has two sets of terminals, wire each set of terminals to one channel of the amp. This is called parallel, and will drop the load to 1/2 of the rated load per coil. If the sub has 4 or 8 ohm coils, this is fine. If it has 2 ohm coils, don't do this. With 2 ohm coils, run the sub in series, meaning from one coil to the other. You would have speaker cable from one channel of the amp to the + of one coil and the - of the other coil, and a wire between the unused connections. I'll find some pics for you.

Ok, that makes a lot of sense, I think I understand now.

HOWEVER,

I'm still gonna need a new amp cause 980 watts is not going to drive both of those 1800 watt speakers. It runs one fine and it sounds excellent, but I can't imagine cutting the power to each of those subs in half. That's why I want to get the 2400 watt amp, that'll be plenty for both subs.

well...kinda...you need to look at your amps power rating at different loads...also is that 980 watts peak or rms out of the amp? if you can run 1 ohm stable on that amp...i would go out on a limb to say you're gona be good to go...like someone else up there said, double the cone area = about 6db...and also like someone else suggested...i would run both subs in a series...

Actually what I'd do is wire each VC in series, so each sub is a 4 ohm load. Wire the subs together in parallel to produce a 2 ohm load. After that, do some praying and hope the amp doesn't fry running bridged.

It looks like the amp is rated at 220W RMS x2 @ 4 ohm whereas it'll do 560W x1 RMS @ 4 ohm. In theory since you're dropping to 2 ohm bridged, each sub will be getting more than 280W RMS (meaning bridging your amp will give you more power per sub than running each on a separate channel).

Specs here, looks like someone already tried bridging to 2 ohm

Sorry to burst your bubble, but there is no way your Power Acoustik amp is putting out 980W RMS. But if you like the way it sounds, stick with it.

Me, I went overkill and went with an ID Max and a JBL 1200.1 in my Accord. I have the gain set to 1/4 because any higher and my trunk goes ghetto, haven't gotten around to deadening the car.

Next time, do yourself a favor and don't trust the Best Buy monkeys to do your install.

just another disclaimer, an amp that is rated for 2 ohm stereo, normally will not be able to handle a 2 ohm bridged load, just because thats theoretically 1 ohm per channel, with impedence probably being higher due to impedence rise at certain frequencies, and with the vc's heating up, and etc.

for full safety, my previous drawing would work.

MIKE

Yeah but my diagram is prettier

I'm not saying your way wouldn't work, but basically this is the same concept as overclocking: getting the most out of your equipment. Someone else has already tried and run the amp at 2 ohm bridged. I'd be hesitant to try to drop down to 1 ohm bridged but 2 ohm should be fine. If anything the amp will get hot. If that happens, just let it cool and run 2 channel vs bridged. I seriously doubt it'll fry his subs or his amp. Honestly, it wouldn't hurt to try.

Also if your subs are facing forward toward the front of the car, you might want to try to flip your box around and have it fire towards the back. Or vice versa. Every car is different (all trunks have different acoustics) so it's a good idea to play around with box direction and placement until you find what works. In general though you'll get punchier bass if you face forward and boomier if you face rear.

he cant do a 1 ohm bridge only .5 ohm and hardly any amp can handle that stereo, let alone a stereo amp bridged.

good suggestion on flip

MIKE