Quick amp & sub setup question please..

[peterp]

Hi all
Being new to ICE can I please ask the following question...
If I have a 240 x 2 ch mosfet amp will it be able to run a 1000w peak JBL 12 " sub in an enclosed box well?
Sorry not really clued up yet on the rules governing amp & sub matching.

thanks a lot
Peter

 

[chrisunoman]

No.

You want a 1000w (ish) amp.

Look for the RMS value of the sub (probably around 400/500w) and get an amp with the same RMS value.

 

[peterp]

I see.
Thanks for the reply.So as i've already got the amp which is 240 x 2 ch,I should look for a sub with say 450 watts rms power rating only to couple it with ?

Thanks a lot
Peter

 

[Luke]

is that 2x240w RMS then? the RMS makes a big difference

 

[chrisunoman]

Normally if an amp says its 240w x 2 channels, its 240 shared by the 2 channels, so each channel gets 120w.

So you want a sub thats 240w max.

 

[peterp]

Just quickly checked-it says 480 max @ 0.05% THD
I clearly aint got a clue what that means but I do need to make sure that I get the right(12") sub to match as I dont really want to lose quality of sound.

thanks a lot by the way for all your ongoing help.
Peter

 

[Luke]

Just quickly checked-it says 480 max @ 0.05% THD
I clearly aint got a clue what that means but I do need to make sure that I get the right(12") sub to match as I dont really want to lose quality of sound.

thanks a lot by the way for all your ongoing help.
Peter

So thats 1 channel (if bridged) giving you 480watts MAX?

OK, getting there. This suggests you've got about 200watts RMS to play with (depending on amp efficiency but wont go into that ). So look for a sub that has around 200 watts RMS rating.

Generally you'd want the amp to be slightly more powerfull than the sub can handle so clipping doesnt occur at high volume, but when you've only got a coupla hundred watts to play with, it isnt too much of an issue.

 

[chrisunoman]

:yeahthat:

Theres loads of subs around that use 200w rms, you shouldnt have any trouble finding one.

 

[Luke]

:yeahthat:

Theres loads of subs around that use 200w rms, you shouldnt have any trouble finding one.

Yep

And also peter, you sure a 12" sub is what you need? If you've only got small amounts of watts to play with, a 10" is going to be a bit louder because they're easier to move at lower frequencies. Granted they dont go as deep as a 12" but then with that amount of watts, a 12" wont be very loud on lower frequencies - if that makes sense. Basically you need more power to move the cone at lower frequencies

So, what type of music do you listen to? All is important because if you are choosing a sub to buy, you need to know what rating (RMS - which you've just worked out), size (depends on music IMO) and box type (again depends on the style of music). All need to be matched otherwise you will be sorely dissapointed. It'll be like having a stew without the dumplings so to speak

 

[chaos]

Right - 1000W 12" JBL sub? I'm guessing its the GT-4 series you're on about.
This kicks out 250W RMS. What's the RMS output of the amp? I have the 10" version in my cinq. I use an Xplod amp (XM-480GTX iirc) - has 200W RMS in 1 channel mode.
I think the sub and amp compliment each other perfectly. The sub also has an advantage when it comes to sub enclosure volume - 0.75 cu ft for my 10" - I think it's about 1 cu ft for 12".

 

[peterp]

Ok Thanks guys
I've got the option to buy a 12" sub & enclosure.Are you saying that I'd be better off going for a 10" & Box if I want to get the best sound from my set up?

 

[Luke]

Ok Thanks guys
I've got the option to buy a 12" sub & enclosure.Are you saying that I'd be better off going for a 10" & Box if I want to get the best sound from my set up?

What type of music you mainly listen to?

 

[peterp]

its mainly Old skool stuff & hip hop.

 

[Luke]

its mainly Old skool stuff & hip hop.

You'd probably want a ported 12" then

 

[peterp]

Thanks Luke for all your help on this.
regards
Peter

 

[chrisunoman]

Have you got a price limit on the sub you want?

The Alpine SWS 1241 seems a decent buy.