Tech Forum

Phase a speaker by using a 1.5V D-cell and attach to the speaker leads. Upon connection, the speaker diaphram will move out or in. With the cone out mark the positive battery connection as plus and the negative minus. This way the speakers will move in tandom when recieving the same signal. All very simple, as you want to move the air piston of the speaker to be optimized for volume.

I remember when my Dad built a Knight stereo tube amp in 1960 and made his own BIG speaker enclosures, he explained to me (I was 6 and had just been given my first slide rule and a small sipson VOM) what he was doing while he wired the speakers, he had just graduated from SMU with a BSEE and I absorbed electronics by osmosis.

I use a 1 ½ volt battery D, C, AA, AAA.  Whatever battery is close at hand. Connect the battery across the speaker leads and observe which way the speaker cone moves (in or out) depending on the battery polarity. Make sure all speakers move the same way using the same battery polarity. Phase is only critical on lower frequencies so it is not really a factor on high frequency tweeters where you might have difficulty observing the speaker movement.

I assume your speakers are not in enclosures that have color-coded (usually black and red) connectors. To phase speakers from their frame mounted terminal connections, use a 1.5 volt battery (an AA cell, for example).  Momentarily touch the battery terminals to the speaker terminals using whatever jumper leads you have available, and watch how the speaker cone deflects. It will move either inward or outward when the battery terminals are touched to the speaker terminals. Mark the speaker terminal that is connected to the battery's + terminal with a marking pen. Then check all your other speakers the same way, connecting the battery polarity to the speaker so that the cone movement is the same as for the first speaker, and again mark the speaker terminal that is connected to the battery's + terminal.

Simplest way to determine phase is the old VOM 'bump' test. Using an analog VOM on the low ohms scale, 'bump' or tap the speaker terminals or wires with leads, and see or feel which way the cone is moving. (Make sure your VOM has positive voltage on the Red lead, a few do not) Moving out is proper phase with positive voltage to the + terminal. A modern digital VOM/Multimeter usually does not have enough available current to make the test, so you can just use a "C" or "AA" cell battery. Observing + terminal to the speaker lead marked as such. DO NOT use any higher voltage as speaker will draw excessive current and may be damaged.

Have used this method for 50 or more years, works!

If you are replacing drivers in a speaker, the positive terminal is usually marked with a plus sign or red mark. If it’s a woofer or midrange and there are no markings, connect a 1.5 volt battery to the terminals and note whether the cone moves in or out. If it moves outward, the positive battery terminal is connected to the positive terminal of the speaker; if inward, the NEGATIVE battery terminal is connected to the POSITIVE speaker terminal. If it’s an unmarked tweeter, I don’t think you’d see any motion, but I’ve never tried.

Keep in mind that some speaker manufacturers sometimes wire some drivers out of phase (with the other drivers in the cabinet, that is—both speakers should be in phase with each other) as part of their crossover design. If uncertain, contact the manufacturer for phasing specs.

To test the phase of a speaker disconnect the speaker from any external devices (amplifier, crossover, etc) then momentarily connect an AA battery (1.5 volts) to the speaker terminals. If the cone moves outward (away from the magnet) note the polarity on the battery and mark the speaker terminals the same. If the cone moves inward (towards the magnet) reverse the battery connection. With the polarity of the speaker known, make all additional connections to the amplifier, crossover, etc following the same polarity. This test only works on cone style speakers. Do not try this on special types like ribbon speakers or delicate tweeters.

The phase can be easily checked with no test equipment. Switch your amplifier to mono to feed the same signal to both speakers and place the speakers face to face leaving only a small air gap between the grills. If the speaker wires are connected properly, both speaker cones will be moving out/together at the same time, pushing a large volume of air out the gap and producing a loud sound. Reversing the leads on one speaker will cause one speaker to move in while the other is moving out, thereby moving little air out the gap resulting in a much softer sound and revealing the improper connection. Lower frequencies work best for the test.

Put the speakers right next to each other and play something with a lot of bass. Switch the wires on one of the speakers back and forth. Whichever wiring gives the loudest bass is correct.

Proper polarity is when all the cones of the speakers, move in the same direction, when the same polarity DC voltage is applied to two or more speakers. Stereo speaker terminals are usually marked Red(+) and Black(-), so you just need to  keep them mated to the amplifier's terminal markings. If there are no marked terminals, or you just want to verify the polarity, it is easy. If you can see the speaker cone connect a 1.5V battery to the speaker wires so that the cone moves outward when the battery is applied, reversing  the battery if the cone moves inward. When the cone moves outward, the positive side of the battery, is the red (+) speaker lead, and the negative is the black(-) lead.

Another method is to connect the speakers to a monaural audio system, and have it play a male voice speaking. When you are centered in front of the speakers, the voice will appear to be coming from between the speakers when the polarity is correct. This also works on a stereo system by selecting the MONO mode.

In any case, if the polarity is incorrect, just reverse the wires at one speaker, or one speaker output at the amplifier. This is most important whenever a group of speakers are in the same area or dropouts and cancellations may result in poor audio. With separated speakers, for example in different classrooms, the polarity usually is not as important since there is little speaker interaction, but good installation practice would be to keep it uniform. As a general rule, mixed polarity of speakers will cause no equipment damage, but can result in poor audio quality.

Most bare speakers have + and - markings on their solder lugs/terminals. As a rule of thumb, connect your positive (usually RED) wire to the + terminal and the negative (usually BLACK) wire to the - terminal.  For bare speakers that have un-marked terminals, briefly connect an AA (penlight) cell to the terminals and observe which way the cone moves: if the cone moves out, the terminal the + lead of the battery is connected to is the speaker's + terminal; if the cone moves in, the - lead of the battery is connected to the speaker's + terminal.

For assembled speakers (i.e., bookshelf types), the RED connection terminal is considered the + terminal.  Be aware that some speakers simply have un-marked screw terminals.  You can check/verify the polarity using the penlight cell test above (make sure you can observe the motion of the main speaker's cone). If necessary, (re)label the terminals to match the test results.

Finally, when connecting your amplifier to the speakers, always follow a common convention regarding speaker wire connections. With all standard twin-lead speaker wires, one lead has a colored stripe (or similar marking) or a molded ridge on the insulation to denote the - output terminal of the amplifier/speaker. By connecting the marked lead to the - amplifier/speaker terminals and the un-marked lead to the amplifier/speaker + terminals for all channels of your amplifier, you'll guarantee proper phasing of all your speakers (i.e., all the cones will move in the same direction with the signals).

Hope this helps and answers your question.

The quickest way, if you can visually see the speaker, is to see if there are any markings on the solder lugs. In the absence of that, you will need a 1.5 volt battery and a 100 ohm resistor to limit current. If there are markings (assuming the same make/model) then go by those if not you need the battery method.

Attach the minus lead of the battery to one of the lugs, touch the plus side of the battery thru the resistor to the other lug and watch which way the cone moves. There are those that say to mark the lugs + and - when the cone moves in, others say the opposite. The crucial thing to remember is to be consistent. Once you have the lugs identified, the ideal way is to connect + on the amp to + on the speaker.

Briefly connect the terminals of your speaker to a 1.5V battery. If the speaker cone moves out, label the terminals + & - to correspond to the polarity of the battery. Do this with all your speakers and connect them with the +’s & -’s together. You could insert a resistor (2.2K or whatever you have handy) in the battery lead if you feel it necessary. Usually all it takes is a short tap to determine the direction of the cone movement. Many speakers terminals are marked with the polarity.

Momentarily connect a 1.5 volt flashlight battery to the speaker. When the positive terminal of the battery is connected to the positive terminal of the speaker, the speaker cone will move toward the listener.

Speaker phase can easily be determined by a 9 volt battery and direct connection to speaker leads at the speaker itself, not any equalizing circuits, the connection must be on the speaker!

Briefly touch each speaker lead to the battery. Watch carefully which direction the speaker cone moves. + battery & cone moves out gives the positive speaker terminal. You can do this with most speakers as long as the voice coil doesn’t get too much current too long. A brief touch of battery gives you the answer.

For convention sake, lets say you have speaker wire connected to your speakers. Usually there is one conductor that has a copper colored wire that you would normally connect to the speaker + or Red binding post. The silver colored wire to the - or black binding post.

An old trick - At the amplifier end of the wire, if you connect a 1.5 volt battery positive to the copper colored wire, and the battery negative to the silver colored wire, you should observe the speaker cone moving in or out. if the speaker cones are both moving the same direction, they are in phase and should be connected that way to the amplifier.

You can determine the polarity of any speaker with a 9 volt battery. Put the positive terminal of the battery on one of the leads and the negative terminal on the other lead. If the speaker pushes out the polarity is correct. If it pulls in then it is reversed. DO NOT HOLD THE BATTERY ON THE LEADS MORE THAN IT TAKES TO DETERMINE THE POLARITY.

This test should be just a touch-and-go test. The coil in the speaker does not like DC voltage. The easy way to remember this is you want your sound to radiate out not suck in..

Useing an “AA” or “AAA” cell, connect one lead (say the negative lead) to one speaker terminal, and touch the positive lead to the other terminal. If the cone moved out, mark that terminal positive and do the same to the rest of your speakers.

I’m not sure that the cone moving out really proves that the terminal is the “positive” terminal, but as long as all your speaker’s terminals are identified the same way, they will be in phase.

Very simple: connect a 1.5 Volt battery (AA or AAA) to the speaker leads while noting if the speaker diaphram moves inward or outward. Then, mark the leads as + and - according to the battery poles when the diaphrams move in the same direction. If you cannot see the diaphram movement, lightly stretch some thin celophane food wrap in front of the speaker, making the wrap as air tight as possible, then watch to see of the celophane bulges outward or “sucks” against the speaker front.

Easiest way is with a 1.5V battery and a pair of test clips. Do not leave battery connected for any length of time.

Connect one of the leads to the speaker terminal and one of the battery terminals. Then touch the other speaker terminal to the remaining battery terminal briefly while observing the direction the speaker cone moves. Mark the battery polarity on the speaker near the terminals. It should move either in or out. Do the same test on the other speaker swapping battery polarity if needed until you get the same direction of movement.

I tried this test using a digital ohmmeter but the current was to limited. An analog VOM on the RX1 or RX10 range is an alternative testing source.

Connect a 1.5 volt battery through a 10 ohm (or there about) resistor to the speaker terminals and observe the direction of the cone movement. Generally, connecting the positive terminal (usually marked with a red dot) to the positive battery connection will cause the cone to move outward. Test both speakers and mark the terminals. go make some noise.

One way to determine the polarity of a speaker is to use a battery like a single AA. You need to remove a cover so you can see the front or the back of the speaker and connect the battery to the it. The wire on the flat bottom of the battery is -(negative) and the lead connected to small protrusion is the +(positive)

When you connect the battery to the speaker, for an instant the speaker cone will move. Make a note of which way it moves and mark the speaker terminal +. Connect the same battery leads to the next speaker connections and note the direction the cone moved. If it moved the same way mark that speaker terminal +. If it moves the other way, in or out, but different than the first speaker, reverse the battery connections and when the speaker moves the same way as the first mark a + on the terminal with the + from the battery. Once all the speakers are marked, you know the phase.