Speaker from PC amplifier polarity question

Thread Starter

UnnamedUser159

Joined May 3, 2016
482
hi there. my second speaker doesn`t work /because of the damaged cable/ and i opened the wooden corpse and have installed a new one but dont know how to connect it to the RCA./which i saved from the old cable/
I know that have connected to + of the speaker the one of the both cables/new ones/ that is marked with red line.

https://ibb.co/mTgLFtF

thanks
 

MrAl

Joined Jun 17, 2014
6,406
Hi,

I would think if you connected both speakers using the same method it should work ok.
Like the Center wire to + of speaker for BOTH left and right.
 

MrChips

Joined Oct 2, 2009
19,154
Do as advised above.
Put both speakers side by side. If you hear poor bass response, reverse one of the speaker connections.
 

MrAl

Joined Jun 17, 2014
6,406
Do as advised above.
Put both speakers side by side. If you hear poor bass response, reverse one of the speaker connections.
Hi,

There ground is almost always common so it must be the negative, while the center conductor is the positive.
 

SLK001

Joined Nov 29, 2011
1,445
It really doesn't matter how you connect the wires for your application (assuming the wire goes right to a speaker). All that it will do is reverse the phasing of the sound (which you cannot hear).
 

MrChips

Joined Oct 2, 2009
19,154
It really doesn't matter how you connect the wires for your application (assuming the wire goes right to a speaker). All that it will do is reverse the phasing of the sound (which you cannot hear).
If the one speaker is out of phase the low frequencies will cancel resulting in reduced bass performance.
 

ebeowulf17

Joined Aug 12, 2014
2,934
It really doesn't matter how you connect the wires for your application (assuming the wire goes right to a speaker). All that it will do is reverse the phasing of the sound (which you cannot hear).
For a single speaker that's mostly true, but when dealing with a pair of speakers, polarity matters. Both speaker polarities need to match each other unless they're playing totally different sounds. In a normal stereo listening situation they must match each other or you'll definitely hear the difference!
 

MrAl

Joined Jun 17, 2014
6,406
It really doesn't matter how you connect the wires for your application (assuming the wire goes right to a speaker). All that it will do is reverse the phasing of the sound (which you cannot hear).
Hi,

I have to agree with the others because when sound comes out of the speaker it has a particular phase relative to the other speaker. This means that at some point out in front of both speakers the two phases combine either aiding (addition) or opposing (subtraction).. If one subtracts from the other there will be some nodes out in front that exhibit wave cancellation which could leave the listener to hear a reduced volume. The most notable would be somewhere in the middle out in front of the two speakers.This would be more apparent with a test tone the same for both channels.
This could change however for speakers that are directly on the right and left of the listener but in that case we'd have to look up how the brain handles that situation. Might be the same case for headphones.

The single dimensional wave equation would yield something like this:
A*cos(kx-wt)+A*cos(kx-wt+ph)
for aiding (ph=0) and this:

A*cos(kx-wt)+A*cos(kx-wt+ph)
for opposing when ph=180 degrees.

After simplifying, we get:
twice the amplitude for the first case and
zero amplitude for the second case.
Thus the 180 degree phase shift forces a subtraction.

We could do the two dimensional case to get a more detailed map of the nodes but that could be found on the web.
 
Last edited:

MrChips

Joined Oct 2, 2009
19,154
Wavelength of the acoustic wave in air at 20°C is
1" at 13kHz
12" at 1100Hz
5ft at 230Hz

Hence wave cancellation would be very noticeable at anywhere below 500Hz.
 

crutschow

Joined Mar 14, 2008
23,141
Hence wave cancellation would be very noticeable at anywhere below 500Hz.
Yes, if you hook up the speakers out-of-phase, the midrange and highs will sound okay, but it will have a somewhat hollow sound from the missing lower frequencies and bass.
 
The standard is if the polarity of a speaker isn't marked, use a 1.5 V battery. Cone needs to push air and that will be the polarity.

Positive has generally been the center of the RCA connectors.

A speaker out of phase is noticeable.

There is a ridge on Zip cord that identifies polarity too. You would need to look up the convention.
 
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