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Bridging two subwoofers to one amp


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#1 Rossforest

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Posted 31 Oct 2008 - 16:52

Hi I recently picked up 2 jbl gt4 subs in a sealed box because i wanted more bass than my rockford punch p2 could provide, the question is could I bridge these two subs to one chanel of my for way rockford amp or do i need to get a new amp?

Here's the tech spec
Number of Channels 4
Rated Power
continuous power 50W x 4 @ 4-Ohms RMS
100W x 4 @ 2-Ohms RMS
200W x 2 @ 4-Ohms bridged RMS
Total Power
total sum of 'rated power' 400 Watts
Dynamic Power
powercube measurement (info) Front Channels
86 Watts x 2 @ 4-Ohms 0° Res
144 Watts x 2 @ 2-Ohms 0° Res

Rear Channels
85 Watts x 2 @ 4-Ohms 0° Res
142 Watts x 2 @ 2-Ohms 0° Res
Bridgeable Yes
Efficiency (average) 71% @ 4-Ohm
70% @ 2-Ohm

I am pretty sure the GT4's are 4ohm each

Finally, Just a bit of advice im sure the gurus here could give me,
Im buying the subs tomorrow in a box for £50, do you think I got a good deal? How much more bass should I expect?
Nice one!
:cheese:


Nice one everyone?

#2 richie00boy

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Posted 31 Oct 2008 - 17:00

It's a 4 channel amp, you bridge one pair of channels to make one bridged channel and the other pair of channels to make another bridged channel. Then you wire one sub on one bridged channel and the other sub on the other bridged channel.

2 subs in a box sounds a good deal if they are new. As to how much more bass, could be more or less or better or worse, totally depends on the old box and speaker combination and the new box and speaker combination.
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#3 Rossforest

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Posted 31 Oct 2008 - 17:44

Nice one mate, is there any way I could wire these subs in series through one channel of the amp? I guess thats what I was trying to say as I don't want to get a second amp if possible and the current amp sounds great with my components and isnt a bass amp as such, as for the speakers, yes they're brand new!:raz:

#4 sam.i.am

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Posted 31 Oct 2008 - 18:10

It's a 4 channel amp, you bridge one pair of channels to make one bridged channel and the other pair of channels to make another bridged channel. Then you wire one sub on one bridged channel and the other sub on the other bridged channel.


If you were to do that, I think you'd have to use a scope to ensure the gains are equal?


What's the voice coil config of the GT4's? If it's Dual 4 then you could wire them as below but they could be Single voice coils? :confused:

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AS Richie said, could be worse, could be better. Currently your single sub is getting 200w but with two subs connected it would be 100w per sub, but you'd have more cone area so it's difficult to say.

Edited by sam.i.am, 31 Oct 2008 - 18:14.

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#5 richie00boy

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Posted 31 Oct 2008 - 19:40

No you can't make the 4 channels into one big channel.

The gains would be fine set by eye.
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