Speaker wiring + & -

[Hyun]

i was just thinking. let's say u have 2 speaker cables, each has a + and -.

 

so essentially u have 4 cables, just that they are "stuck" in pairs.

 

if u want to supply 3 speakers with 4 cables, in theory, i believe, you could do this:

use one cable as a common ground (negative). they split and run to the 3 speakers (one of the terminals, depending on phase). the remaining 3 cables carry the other part of the signal (conventionally positive, unless inverted phase) and connect to each speaker's remaining terminal.

 

in theory it seems to work. i wonder if anyone wanna shoot me down. target.....TARGET......

[Sarong1]

Not interested and not keen to...

[Elfenstar]

i'm assuming the 3rd is a centre speaker??? just bridge the postive from one pair and the neg from the other pair to it.

[Hyun]

err nope, in this example i was thinking of a 3-way set. running 3-way with only 2 cables, each having + -.

 

i look at it this way: from what i observe of speaker wirings, assuming we dun invert phase for easy discussion: it is legitimate to short-circuit (connect) all the negative terminals together. this is inherent in passive crossover design. that means, essentially this common ground of 0 volts is shared amongst any speaker. i dare not say that this common ground extends even further to sharing the 0 volt of LEFT and RIGHT channel ... but what i know is, in the same channel (left OR right) the common ground can be shared. and hence, by running the common ground cable, and using 3 other cables (total 4 cables, or 2 pairs as explained above), you can run 3 speakers.

 

that is provided the cable size is sufficient for the current. (e.g. they're not so thin until it's lossy. and i have come across people saying that speaker cables really dun need to be much more than 16gauge per speaker. sub signals may be an exception.)

[Slidingturtle]

yo bro, you still thinking of a way to do 3 way set up?

so this is some kind of semi active 3 way?

 

sorry, can't help here, my electronics CMI...

[User12343]

kailord,

 

why take the risk of frying the amps? how can u assume that all the negative terminal of the different amps are grounded at the same potential?

 

one extra run of cable cannot afford meh? what is the price of the amp compared to the cable run?

 

if going by your fantastic theory of this, might as well forget about running the negative terminals of the speakers back to the amp, and connect all the negative terminals to the car chassis?

Edited August 24, 2006 by User12343

[Hyun]

hi user, thanks for the reply!

 

err no lah, not so far fetched until connect common ground between all the amps.

 

this common ground is within the SAME single channel output of one amp. i was speculating on this as a way to wire 3-way speakers - such that they all share a common ground but have 3 independent signal wires.

 

i'm just toying with this idea. cos in a single channel, using a passive crossover, it seems true that a common ground for the entire speaker network is employed. for e.g. right now i'm using 2-way. and in this circuit i made, as well as in the stock circuit that came with my speakers, as well as in the circuits i've seen on the web, they all can use common ground. sure, passives can be made with independent circuits for each speaker, ultimately joining back at the crossover. even then, at the cross point, it all joins back to common ground and exits as Amp Negative cable back to amp.

 

so extending the example, the common ground can be extended further and further, as far as u want. such that if u only had 2 cables already wired, u could actually use it to channel 3-way signals, until near the speaker, where the negative has to eventually split into 3.

 

got logic? thanks!

[User12343]

you go try and let us know.

[Hyun]

yup, i might end up doing that. depends on where i end up placing my passive cross - in the boot or in kick area. any1 standby fire extinguisher? heh. or i should do it in kallang when they got SCDF exercise again ...

[Elfenstar]

I'm totally lost Ok the only input i can give you is that after changing to my aftermarket HU, I had to bridge my front speaker outputs to get my centre speaker (factory) to work.

 

Cable size etc I'm lost. but i'm using the original speaker wires and an equally thin wires for the centre speaker bridge.

[Silver_z]

Bro.... I read and read many times, but still dun understand why you wanna do that. I drew a diagram base on what I understand from. Is it what you are trying to do?

[Lionheart7004]

i was just thinking. let's say u have 2 speaker cables, each has a + and -.

 

so essentially u have 4 cables, just that they are "stuck" in pairs.

 

if u want to supply 3 speakers with 4 cables, in theory, i believe, you could do this:

use one cable as a common ground (negative). they split and run to the 3 speakers (one of the terminals, depending on phase). the remaining 3 cables carry the other part of the signal (conventionally positive, unless inverted phase) and connect to each speaker's remaining terminal.

 

in theory it seems to work. i wonder if anyone wanna shoot me down. target.....TARGET......

 

Would you love to fry your amps... :)

 

If such instance, just connect the speaker parallelLy.

[Ractis]

If all the -ve and +ve are coming from the same set of amp terminals, then the effect is only as if a smaller gauge wire is used.

 

But I think will have problems if you share the -ve across different amp channels or different amps. Might be dangerous if any polarity is connected wrongly or differently. Also, in bridged mode the -ve is not just a ground but used to carry a negative voltage, surely it wouldnt work if the -ve is now shared with the output from another amp.

 

Even if it works, I'm sure there are some sonic degradtion due to high/mid/low sharing the same cable. Some people actually advocate bi-wiring to get better sound, so this is like taking a few steps back. Not worth the risk lah :)

[Hyun]

silver_z, ur diagram is brilliant. that's exactly what i'm planning on doing!

anyone can explain any danger in terms of physics?

[Lionheart7004]

I think the diagram is invalid leh....

 

I dun think Hyun is having a pair of center speaker.

[Ivan0507]

boss maybe you can try hook up this way.your amp is 1 to 4 ohm stable .should be no problem.

[Wankie]

i think turtle is right, he trying to run 3 way from 2 way x-over or amp with not enough channels or something like that.

[Ae86]

I don't know about the dangers involved but seems to me that if you can get the 3 speakers running they will be blarring out the same frequencies so what's the point of doing this when you cannot feed to each set of speakers their allocated frequencies(high,mid,low) as you said you want to do a passive 3 way system? You still need a crossover network to split the output signal to the speakers, right?

Edited August 25, 2006 by Ae86