4 ohm and 2 ohm???

[jus_tin]

Just trying to sort out amp and cant quite get my head round this 4 ohm and 2 ohm business. how do you choose if you want 4 ohm or 2 ohm on the amp? i've seen the amp i want but it needs to be in 4 ohm, if its in 2 ohm it will blow my speakers! is it how you wire it all in? thanks...

[Scott]

amp doesnt change, its how you wire what your attahcing to the amp thta changes the resistance

[jus_tin]

amp doesnt change, its how you wire what your attahcing to the amp thta changes the resistance

how do i know if its wired in 4 ohms or 2 ohms?

[Scott]

Use this site:

http://www.rockfordfosgate.com/rftech/woofer_wizard.asp

You can choose the configuration of the speaker/sub and then it will show you what configurations you can run and how to wire it.

[jus_tin]

Use this site:

http://www.rockfordfosgate.com/rftech/woofer_wizard.asp

You can choose the configuration of the speaker/sub and then it will show you what configurations you can run and how to wire it.

thanks for that mate, have had a look. if i could just explain a little more...

... the amp im looking at getting is a FLI 800 watts ( http://cgi.ebay.co.uk/FLI-BY-VIBE-FL800S-4-CHANNEL-AMP-4-x-100-WATTS-RMS_W0QQitemZ220128352540QQihZ012QQcategoryZ4950QQ rdZ1QQcmdZViewItem ) and i want to use 2 channels @ 80 watts rms 4 ohms to power my speakers which are 85 rms, then bridge the other 2 channels to make 240 watts rms 4 ohms to power my sub which is 300 watt rms. i just dont wanna accidentally wire it up in 2 ohm configuration incase and blow speakers!

[Scott]

wouldnt worry about blowing the speakers, jsut turn the gain down when your setting up and they wont receive the full power.

Ok basically you will have four channels. Each speaker takes one channel (for simplicity at the moment)

For your speakers use say channel one and two, left speaker to channel one, right speaker to channel two. Sorted.

For your sub for ease of use all you need is a single voice coil 4 ohm. Use the instructions on the amp to wire the sub into bridge mode (it will be one positive from one channel and the negative from the other)

More details on the sub you have needed to advise further though

[jus_tin]

wouldnt worry about blowing the speakers, jsut turn the gain down when your setting up and they wont receive the full power.

Ok basically you will have four channels. Each speaker takes one channel (for simplicity at the moment)

For your speakers use say channel one and two, left speaker to channel one, right speaker to channel two. Sorted.

For your sub for ease of use all you need is a single voice coil 4 ohm. Use the instructions on the amp to wire the sub into bridge mode (it will be one positive from one channel and the negative from the other)

More details on the sub you have needed to advise further though

the sub i got is a JBL GTO 1202D 12" (300 rms / 1200 max). im also confused because on the sub there are 4 screw ports where you connect wire to box (2 black and 2 red). why are there 4 when you only need 2 just a red and black? ... sorry if these are complete beginners questions!

[Scott]

There are two sets of connections because that particular sub has two voice coils, there are many reasons for this one of them is so you cna change the resistance which gives different power yadda yadda....


The sub you have looks like its a dual 2 ohm model. Which fits perfectly. From teh woofer wiring wizard above wire like this:


http://www.rockfordfosgate.com/rftech/woofer_wizard/1_2ohmDVC_4ohm.gif

and your laughing

[Predator_R32]

thats the way ive wired my subs too mate, your subs are similar to my kenwoods :y:

im running them off a 4 channel sub, bridged the channels, so wired like scott has put up and your away

[jus_tin]

Thanks for all the help lads!

Final question...

http://i188.photobucket.com/albums/z149/jbg_1981/jblsub.jpg

In the pic you will see how the connections are set out on sub. theres a little wire that coms out the sub and one goes in the first red connection on pic, the other goes in black connection at the back. The two connections in the middle have nothing going to them.

so... do i wire up the connections with the copper wire connected to them to the ports on the box, and with the two connections in the middle, run a wire to each, something like pic below?

http://i188.photobucket.com/albums/z149/jbg_1981/subdia.jpg

[Scott]

yes thats it