Positive and negative does it matter ?

CavScout

Super Member
I am reuniting some old speaker cabinets with their original woofers but there are no markings on the woofers connections for positive and negative .
I also have no idea which wire is pos or neg coming from the crossover ( PROBABLY not marked anyway)
The wires are 1 Blue 1 Green.

Does it matter ?
What can happen ?
 
Yes, it matters.

Not from a damage standpoint, but from a standpoint of sound quality. Most importantly is getting both speakers wired and connected the same. Arguably of next importance is ensuring they are wired so you know the absolute polarity, that the speaker cones push out with a positive signal.

If the speakers are wired backwards of each other usually the most noticeable thing is lack of bass because the lows are working against/canceling each other.

Use a small battery like a AA or C or D and a couple pieces of wire. Momentarily connect the battery + and - terminals to the speaker terminals. If the woofer moves out then the terminal of the speaker that was connected to the + of the battery is the + of the speaker. If the woofer moves in then the terminal of the speaker connected to - of the battery would be the + of the speaker.
 
The speakers must be wired identically. For some designs, the tweeter will be in phase, for some, out of phase, can't tell you which, but they have to be the same left to right.
 
I have determined the polarity of the speakers but now I have to figure out which of the wires coming from the crossover are pos - neg.
One is green and one is blue
 
50/50 chance:p

I would pick green as the negative, as black and green are common neg & ground colors..
 
I hooked up the speaker and I did not notice much difference but the green on the neg side sounded slightly better
 
I have determined the polarity of the speakers but now I have to figure out which of the wires coming from the crossover are pos - neg.
One is green and one is blue

Wires for what?

From the crossover to the speaker box terminals, or from the crossover to the woofer, or from the crossover to the mid or tweeter, or?
 
From the crossover to the woofer

And are there terminals on the speaker box itself with wires that go from those terminals to the crossover?

And, if so, are those external speaker box terminals marked + and - or coded red and black, or?
 
The absolute polarity, commonly called "acoustic polarity" and, mistakenly, as "absolute phase", also matters. This is the direction of compression or rarefaction wavefronts. In short, does a positive signal move the speaker forward or backward. The reason this matters is that our ears were optimized by evolution to prefer compression before rarefaction.

This difference occurs because of the Wood Effect. See The Wood Effect: Unaccounted Contributor to Error and Confusion in Acoustics and Audio by Clark Johnsen (1988). You can do a search on the Internet for further reading.

Somewhat simplified, the issue is a difference in how the ear and brain process the different waveform types:
Compression Wave (0 —> Vmax —> 0)​
versus
Rarefaction Wave (0 —> Vmin —> 0)​

In this case Vmax is the peak for the positive half of the waveform and Vmin is the peak for the negative half of the waveform. They are used to convey the different halves of the waveform in an AC cycle.

Compression before rarefaction occurs in instruments and real-world sound; the ear/brain prefers this relationship. An additional complication is that the two waveform halves are rarely symmetric for real-world sound, and the speaker may exacerbate this asymmetry, distorting the sound.

You'll find that the following situations can apply:
(a) playback equipment reverses polarity (preamplifier or DAC) compared to recording
or (b) the recording's polarity was reversed in recording, playback equipment maintains it
or (c) both equipment and recording polarity are reversed
or (d) both equipment and recording polarity match​

Some equipment contains a polarity reversal switch to restores proper phase. This is different than a switch to swap the polarity of only one speaker to make both speakers have the same polarity (i.e. the +/- at the amplifier matches that at the speaker), but not absolute polarity (i.e. both speakers move in the same direction, but do not prefer compression before rarefaction). So the polarity may be mostly correct or mostly incorrect depending upon your equipment, but even when you have the right phase for the equipment the individual recording may or may not be in absolute polarity with respect to playback equipment.

In summary, configure your speaker polarity for the majority of recordings and switch it for the minority, and rejoice in discovering new depths to sound.
 
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