How much does speaker polarity matter?

I've never known it to matter, as long as they are both wired the same way round, as you say. Reverse wiring just one will result in a lack of bass and a 'woolly' stereo image, as I'm sure you are aware. If you think about it, any waveform driving them will have a pretty symmetrical count of positive and negative half cycles of largely similar amplitude, so there is no real reason why the speaker moving back, at a time when the diaphragm in the microphone that made the original recording was moving forward, should have any effect. The theory also assumes that the phase relationship was maintained throughout the entire recording process, and that there is no inversion taking place in amplifier stages in your player, that isn't reversed again, by the time the signal reaches the output terminals ...

Arfa

Do you want fixed "image" stereo or musicians "wandering around in space"?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

In a word, no. The only time that speaker polarity 'really' matters in non-critical situations is in cases where different speakers in a system are wired differently...leading to cancellation (one speaker is 'pushing' air, while another is 'pulling'.)

In your case, if those are the only two speakers in the car, absolute polarity is irrelevant.

Next time, use a 9v battery to check. *Briefly* touch the battery terminals to the speaker terminals. The speaker polarity matches the battery polarity when doing so makes the speaker cone extend, as opposed to pulling in. IOW, when the cone comes out, the positive battery terminal is connected to the positive speaker terminal.

jak

I don't know whether there is any standard among audio equipment manufacturers that guarantees at the speaker output the same phase as the original signal, and this could be the real issue. If there were one, then I would suggest you correcting your polarity. Probably you will soon agree yourself if you think of the sound that comes from a bass drum vigorously hit by the pedal. Antonio - Italy

Hi!

To everyone who has replied so far, thank you for your information.

I would have normally used a nine volt battery to check the polarity, but I couldn't find one anywhere in the various messes I have. :-)

I think I'll go ahead and correct the speaker polarity so that it at least matches what the radio manufacturer and speaker manufacturers say it "should" be. This will not be difficult. There are only two speakers in the car (at this time...I may add two more later the car's design permits it) However, I do see the point that one poster made about which way the speaker cone will "fire" when a large signal comes its way. It would seem logical that the speaker cone can extend much further outward than it can inward (toward the speaker basket).

Again, thanks for the info. I will keep checking into this posting if more information shows up.

William

It would matter for impulses from the waveform say as in a drum beat? Wouldn't the beat of a kick drum cause the speaker cone to move inward if the polarity is reversed? This certainly wouldn't be suitable for a sound reinforcement system.

wm snipped-for-privacy@hotmail.com hath wroth:

It doesn't matter. The speaker audio has no DC component and neither is connected to the speaker frame. The AC component of the audio is generally symmetrical about the 0 volt axis. Whether you push or you pull doesn't really matter. However, you do have to get the phasing correct between the two speakers to avoid "ping pong" stereo. Try a test CD where a train or car goes from the left to right speakers. If it sounds "real", then you got it right. If it bounces back and forth between speakers, reverse ONE of the speaker polarities.

I forgot to mail you the PS2 boards. I also found some Dallas clock blobs. Sorry. Still want them?

The speakers should move equally in and out if they are not to distort the sound.

Some people believe that "absolute" polarity matters -- that is, a compression (rarefaction) in the original sound should be reproduced as a compression (rarefaction). I experimented with this 28 years ago, and never heard an effect from simply flopping the polarity of both channels. Even if it were audible, there are no industry standards for recording polarity.

All that matters in practice is that both sides are wired identically. This gives maximum bass, and guarantees that mono components will be properly centered.

One might think that, but flipping the polarity on a kik drum mike has little if any effect on the sound through the PA. Sometimes I mike a bass drum from both sides, using a 'bassdrum' mike on the front head and a normal instrument mike on the batter head. Reversing the polarity of the batter head mike does make a difference in this instance. Ron(UK)

Basically (and I have some experience with audio and hi-fi, including an electroacoustics degree - but I am NOT an "expert"), I agree with Arfa that for MOST practical purposes, as long as both speakers are connected with the same polarity, then it'll be fine and you won't be able to distinguish one polarity from the other.

If one speaker is wired in antiphase with the other, you'll lose bass to an extent that depends on room geometry and speaker positioning - but whatever happens, it won't be good.

There has indeed been debate about whether people are sensitive to "absolute phase"; and I remember reading about higher-end DAC units for CDs that included a switch to flip phase on both channels. ISTR, an d I may be wrong, that back in the late 80s when I had a part-time job at a hi-fi shop, there was a Musical Fidelity outboard DAC unit that featured such a switch - but it was 20 years ago, so don't quote me.

Personally I don't believe that people are sensitive to absolute phase, and anyone who claims they are needs to submit to a double-blind test, and maybe if they pass, go and have a word with James Randi, who while AFAIK he isn't offering a prize for absolute phase YET, may be interested in handing out a financial prize if they can repeat the souble-blind performance repeatably. He offers a prize to those claiming to be able to distinguish between interconnect cables (providing both sets are reasonably well-executed and one pair isn't made of wet string, for example!).

As Meat Plow suggests, there COULD be an issue with high cone excursions, where on a bass kick, or similar, the cone former may hit the endstop on the way IN (away from the listener) with the speaker wired one way round, but not with it wired the other way round. However, that's a completely separate consideration unrelated to human sensitivity to "absolute phase". You just hear a nasty knocking sound when it happens and risk damaging your bass unit. If you're driving them that hard though, you may encounter problems regardless of polarity.

Summary: Make sure both speakers are wired the same way round. That done, forget worrying about it. Unless you're maybe doing an acoustics PhD.

Martin

Hi!

I must have it right then. Both speakers are wired exactly the same way. I was careful to be sure of that and even used different colored wire. The "+" lead is red while the "-" is black. Stereo separation is excellent, and sounds that do move "across" from one speaker to the other do sound "real". In fact, it's quite surprising how good the sound really is. The speakers are small, so they don't have a whole lot of bass, but otherwise the sound is good, if a bit centered on the midrange.

Yep. Dallas clock blobs (!!!) are also interesting. I have been reworking them...maybe I mentioned that.

William

Hmmmmm I would think the pressure wave created from the bass drum head upon the mic element would be mimicked at the speaker. Not that I don't trust your years of experience but I just need to get a hands on with this one.

and

I`m sure it does, but the initial pulse from a bass drum hit is a lot higher in frequency than you might think. If you look at a trace of a drum hit it`s quite a complex waveform, although there`s a lot of low frequency energy, the main transient impulse is mid band where you shouldn't be getting a lot of cone excursion. Often this mid band impulse is accentuated by a sound engineer to get the bass drum to 'pop out' over the rest of the band. The bottom end is still there, but the punch comes from higher up.

The low sound that you feel in your gut (63/80hz ish) is usually reproduced by different sub bass speaker cabinets (and amplifiers) that are easily capable of handling those kind of frequencies. Subs are generally crossed over around 80/100 cycles and can be driven with several kilowatts of amplifier power.

If you think about it, the bass drum head itself doesn't move much when it`s hit by the beater, why should the speaker.

Ron(UK)

Actually, it does move quite a bit; but the operative dimension is not the excursion, but the size of the head vs. the size of the speaker. To move as much air as a 20-someodd inch bass drum head--moving x distance--the 6 to 18 inch woofer cone has to move correspondingly farther. I'm sure there's a mathematical relationship there that I don't have the chops to calculate....

jak

The majority of the initial energy is outside the range of the subwoofer, also a bass drum (any drum in fact) is a tuned instrument. the 'x distance' excursion as you put it, is very small in relation to the sound output, maybe half an inch or so on a properly tuned bass drum. Don't go by the front head which is often far slacker than the batter head, sometimes it`s only there for show.

IMO Ron(UK)

You presume that the recording-reproduction chain is polarity accurate. IME it's a lottery.

Graham

and

have

Just so you know, I spent 2 decades gigging with several bands playing bass, rhythm, and drums. I well understand the dynamics of sound reinforcement having owned at one time a full tri-amped pa system consisting of 18s mids and horns, 24 channel board, snakes, mics, effects, compressors, gates, active crossovers and around 5K of power. I still have much of that equipment but got rid of a few amps and the separate cabinetes buying a pair of 3 way cabs with an 18" in a Theil designed enclosure, a 10" mid sitting in a large horn lens and piezo horn.

Anyway back to the subject. I know the drum head doesn't move much. But to reproduce the bass drum enough to fill a big room with plenty of low end the speakers are going to move much more than the bass head. I do fully understand that the tap part of the bass drum is frequently desired to cut through and it does add emphasis on the bass drum but I for one am not partial to hearing a lot of it. The best subs are designed to utilize both the front and back of the speaker instead of just baffling it as in but not limited to a folded horn enclosure as you probably know. My cabinets are Thiel design which utilize a tuned enclosure and a slot to allow the pressure wave of the back of the speaker to unite in phase with the front.

I suppose I'm going to go get my Yamaha sound reinforcement handbook and refresh my memory on all of this. That's a damn good book and it's been my bible for many years.

Basically you're talking about so called 'absolute phase'. Which is total rubbish spouted by some self appointed 'experts'. If you think of a sine wave, moving your head relative to the source can reverse the phase at any one point in time.

No reason to at all.