The Steel Guitar Forum

I know it won't make any difference in a single speaker combo amp, but I want to do it by the book. The speaker wires coming out of the amp are yellow and blue and the code on the speaker is red and black. Which way?

Sounds like a peavey amp? Yellow is positive (red) and blue is negative (black).

Right. It is a Peavey. Thanks David.

Blue wire sounds better!!

Hey Clyde, When I was a very young musician I never gave any attention to speaker wiring except that the + wire went to the + terminal on the speaker and conversely. And I found that thru the years that sometimes when I played especially near a bass player's cabinet, my guitar sounded great and with the occasional bass player, my guitar sounded wimpy and struggling. As it turned out, I learned that speaker polarity is not only important in a multi-speaker cabinet but also important on stage with many other speaker cabinets around. As you know, speakers push and pull air and those pressure waves interact with each of the other speakers on stage. If all the stage's speakers are out of phase with each other, it's going to affect the quality of the sound. The industry standard now has the positive (+) amp wire connected to the speaker terminal that gives an outward motion of a cone first; older JBL's were reverse polarity so, you have to measure which speaker terminal gives you outward movement with a positive going charge. Using a 9V battery, connect the neg. battery terminal to one side of the speaker and tap the positive battery terminal to the other; if the speaker cone moves outward, then that terminal side will be the side you connect the positive (+) amp wire to. You can't always go by the speaker marks. All speakers on stage should be tested to have the same polarity, including the PA....happy clear sound

Terry, due to the low speeds and long (and intensely varying) wavelengths, you're NEVER going to have any speakers in phase with each other.
The low A of the boowah pedal has a wavelength of over 6 meters, and the wavelength of the E9th third string at the 26th fret (arguably the highest practical note, but I've gone up almost another octave) is 17 centimeters and a bit, or seven inches.
What with open back cabs propagating from both sides, and the echoes off of every surface in the bar or basement, it seems like phase cancelation or phase reinforcement will happen or not completely at random, and is hardly worth tackling.

Take, for instance, a Fender Twin with 2 12s, playing the open A of the 6th string with B pedal.
That'll have a wavelength of just over two feet, and the centers of the speakers are a bit over a foot apart. If the two speakers are in phase, the two signals will arrive out of phase to the ears of more than a few observers.

Stuff will arrive in phase or out depending on so many variables that speaker phase will be less important than blind, random luck

To add to Lane's comment: The amplifiers do not all present the same phase to the speaker. Depending on the processing and number of stages the output
phase of the amplifiers will be different.
Also, the phase of the instrument pickup may be different.
Finally the audio signal is a complex waveform and as Lane noted the phase is dependent on frequency.

So if I don't hook it up at all, I'll never be out of phase, right? Oh wait..I'll never be in phase either.
This may be the straw that broke the camel's back to make me quit music. Seriously guys, thanks for the responses.

Sounds like a peavey amp? Yellow is positive (red) and blue is negative (black).

Clyde, my response is still the same to your question!
Dave

Georg Sørtun wrote:

Clyde Mattocks wrote:So if I don't hook it up at all, I'll never be out of phase, right? Oh wait..I'll never be in phase either.

Non-sync'ed signals cannot stay in phase for long anyway.

Even synced signals won't stay in phase, because the distance between the two speakers doesn't vary depending on pitch.
Which is what I was getting at. Everything can be perfect in the wires and transistors, but once it hits the air, all bets are off.
The only 2 way to stay perfectly in phase is to set up in an anechoic (I've not had reason to use that word in DECADES) chamber and either:
1) only use one speaker, or;
2) choose the distance between the two speakers as a whole-number multiple of the wavelength of the note, then only play that one note (or harmonics of it).

Terry Lovett wrote:...If all the stage's speakers are out of phase with each other, it's going to affect the quality of the sound.

It will affect the sound only if the speakers in question are being fed the same programming. It makes absolutely no difference if the speaker phasing of the various instruments is different because not only are the frequencies different, they're also being initiated at different times, and they're also changing very rapidly. Keep in mind that we're dealing here not with lab equipment in a controlled environment, but with different players playing different instruments through different amps, speakers, cabinets, and stage layouts. The odds of those players initiating different or identical notes at exactly the same millisecond and maintaining sync (thereby possibly causing noticeable phase reinforcement or cancellation) are probably infinitesimal.

Getting back to the original post.....

For a single speaker combo amp, it doesn't matter.

If someday you decide to run a two amp set up, regardless of what the other amp is, it might matter.

If the two amps are the same you want the amps/speakers in phase.

If the two amps are different make/model, and the speakers are hooked up properly in the amps, you might still have a problem. If one of the amps, somewhere in its circuitry, does an extra phase reversal that the other one doesn't, you may end up with a thinner sound, especially if the two amps are right next to each other. In that case, turn one of the amps OFF, swap the leads around on the speaker(s), and it should be fine.

Otherwise, what Donny said is the first thing that I thought of.
No one is playing the same thing through two different amps and effects chains, at the same time, for very long. It won't matter.
And if it does matter, and your amp sounds thin next to the bass player, who's to say that it's not HIS amp that is out of whack?