got a 4 channel amp (4x 100w RMS)

 

its powering 2 6x9 speakers.

 

i have the other 2 chanels free.

 

 

i have a 350w RMS sub.

 

 

shal i bridge the 2 channels for the sub?

 

or shal i just use the 1 channel (and leave the other free)

 

 

whats best? any benefits of either way?

bridge it!

 

bridging produces more power than just adding the 2 channel powers together. the bridged amp sees the sub as a lower impedance than it is so delivers more power

ok.

 

any benefits of not bridging it?

 

my old sub was only using 1 of the channels, (not bridged) and that was real bassy like.

 

so defo bridge it up yea?

worried its gonna kill the sub???

 

or is it safe

 

(but not as safe if i ran it normally?)

bridge it, its totally safe.

bridge it, its totally safe.

 

 

BANG

 

 

:rofl:

bridge it, its totally safe.

 

 

BANG

 

 

:rofl:

lol,

 

u sure now? heard it puts the amp under more stress :S

 

 

also, i know how to wire it the amp side, (+ on the first channel, an the - on the second channel)

 

 

but on my Sub, it has

 

+ and - then another + and -

 

 

know i use the same princilap as the amp, use + on the first section of the sub, and the - on the second section.

 

but what about the un-used ones? there is a wire factory fitted to them?

(going from the unused - on the first section, to the unused + on the second section)

 

heres a pic, you can see there are 4 conenctors,

so for bridged more, use the frist connector, and the last connector

 

but do the 2 in the middle need to be conneted to each other? dont know why there is a wire factory connected the 2 middle ones??

 

its because it has dual voice coils chap... makes the sub more powerful with less ampage as its effectively a 2ohm woofer.

 

connect the positive from the amp to a positive on the sub, then bridge that positive to the other positive.

 

connect the negative from the amp to the other negative and then bridge that also to the other negative.

 

that make sense?.. il find a pic... should all be in your manaul though

Edited November 27, 200817 yr by Joely P

here ya go... like this...

 

thanks joe, but that diagram is only using 1 channel from the amp, then using the 2 channels on the sub?

 

 

i have 2 channels available on my amp?

just do as we say... lol

joe,

 

whats the difference in you way (using 1 channel of the amp, and bridging the sub)

 

 

to the normal way,

 

 

using the 2 channels of the amp, and the 2 channels of the sub? 1st and 4th terminal?

heres the one im after

 

 

all cleared up now :)

Joels wiring looks correct

Z32, that last pic u posted is correct as long as your sub is deffo a 2 ohm sub?... if it isnt and you wire it like that itll be 8 ohm by the time it gets to the amp.

 

just for clarity what impedance is your sub and your amp?

thanks joe,

 

the sub and amp are both 2 + 4 ohm i think?

 

well, the sub says 2 ohm, if you wire the first 2 connectors,

and it says 4 ohm, if you use the 1st connector and the 4th connector

 

so could be 2 or 4 depending on connection???

lol,

 

u sure now? heard it puts the amp under more stress :S

 

 

 

if you wire it as per JoelyP picture then i wouldn't bridge the amp , as running it hard bridged into 2 ohms could make it overheat or protect

 

i would either do it as per your picture as bridging into 4 ohms will give the maximum power without risking the amp shutting down

 

or simply wire each voice coil to a different channel of amp

Sub is a 2 ohm Dual Voice Coil :)

You need the spec on both the sub and the amp to be totaly sure.

The Amp spec will be somthing like 200w rms @ 2ohm bridge

The sub will be somthing like 2x 100w 4ohm

 

Without the total spec it only becomes a guess and a probability!

 

Allan

Heres the amp:

 

 

104 watts RMS x 4 channel at 4 ohms

and ≤ 1% THD + N

 

284 watts RMS x 2 channel at 4 ohms,

14.4V supply and ≤1% THD + N

 

 

the sub is 2 ohm, 350w RMS

Then you need to put the sub in to a 4ohm load (ie series) and bridge one side of the amp which will give you 284w RMS

 

Simple really :)

 

Allan

agreed.. your 2nd pic is the configuration you need for the hardware you have... lucky you didnt do it as per my first otherwise you could have had fried coils :mac1:

haha cheers dudes.

 

iv just been having a lesson from my dad (physics teacher) about ohms etc.

 

got it now.

 

 

 

for years tho, i was running a 2 ohm amp, powering a 4 ohm sub??

 

that wrong? was a single voice coil too :confused:

 

lasted years, but was the amp not giving the sub what it needed?

Higher inpedence is ok its when you go below the stated impedence it becomes a problem.

 

if an amplifier is designed to run with a 4ohm load you can run any load above ie 8ohm, 16ohm, 32ohm and so on, BUT the amplifier will produce less power. ie

@ 4ohm =400w

@ 8ohm= 320w

@16ohm=200w

@32ohm= 130w

 

So you can see the pattern, there is no point spending money on a large amp and running much a higher impedance load because you lose the output.

 

If you run a 400w amp that is 400w@4ohm on a lower impedence you will get more power outof it, ie maybe 520w @ 2ohm, this becomes unstable and will go bang as the output circuit cant take the current needed to produce the output.

 

Allan

Just as a side note. When amps say 4 ohm that's only strictly for a rated output. Technically you could drive a 1 ohm speaker from an amp rated at 8 ohms if you kept the volume knob down.

 

Reason for this is ohms law:

 

I = V/R (when I= current, V= voltage and R = Resistance)

 

When you're playing music the voltage out of the amp is the thing that the amps controlling. Turn the volume up and the (RMS) voltage increases. The limit on the amplifier is the amount of current it can generate.

 

So going back to the equation, if the volume is set in way so the amp's trying to produce 40V (RMS) and we have it connected to a 4 ohm speaker we can work out the current.

 

I = 40/4 = 10 Amps.

 

Now if we do exactly the same but plug a 2 ohm speaker into the same amp we get:

 

I = 40/2 = 20 Amps.

 

So for the same amplifier settings the amp is having to work twice as hard to generate the same voltage. The explanation is a bit simplified but it's a good guide. That's why people say that speakers with smaller impedence are harder to drive. It can be done but you need to keep an eye on your amps output.

 

Dave