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Old 02-07-2006, 08:20 PM
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determining positive from ground

I'm trying to determine where to connect the positive wire and the negative wire on the speaker. The speaker itself doesn't have any marks, however one connector is twice as wide as the other. I remember hearing something about connecting power to the speaker and seeing if the speaker jumps out or pulls in and reversing the polarity until you get the speaker jumping out. I tried searching around around but I haven't found a specific way of figuring it out. I could go into a stereo shop but they'll probably want me to bring my car in.

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Old 02-07-2006, 09:03 PM
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Doc here,

Does the speaker have a transformer,or any inductors or semi conductors on it ? In other words is it just a plain speaker with no magic?

And is the radio a modern (60's and above radio?) not a tube type?

If so, initially it won't make a difference, it will play in either configuration, BUT one will sound slightly better than the other as you reverse the wires..that's the way to go.

If I remember properly, the wide terminal is + and the narrow is - but as I said it won't make a difference if you reverse them to test what way plays better.

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Old 02-07-2006, 09:22 PM
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take a 1.5 bat and connect the two leads up . the cone will push out, note what side the pos and neg are hooked up. This will tell you which connection it pos. The speakers must be phased the same to produce the push to give the boom to the bass
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Old 02-07-2006, 10:30 PM
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They're MB QUARTs. They do have magnets and what appears to be a basic microchip board with what might be a transformer on it. I tried the battery thing using a 9v battery but it just produced static, no boom to visually see the cone move in any direction.

MB QUART DCC116 4 Ohm 50-120W
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Old 02-07-2006, 10:56 PM
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if you have the name and product part number then it would be wise to contact the manufacture. You said that the connectors were a different size, with that in mind just match em up to the radio wiring you do not need to know what is + or - they took the guess work out of it for you. That little circuit you are seeing is a cross over network for the tweeter and the base. when I say hook up a battery I am meaning monetary, the cone will only move in a direction when power is applied and then return to normal when power is disconnected.... no sound will be heard. I was just trying to explain the purpose for getting the speakers in phase.
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Old 02-07-2006, 10:56 PM
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the larger spade is usually the pos 99% of the time. do this speakers have a crossover with them. just hook one up at low vol and see witch way the cone is traveling if travels out there backwards
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Old 02-08-2006, 02:07 AM
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Here you go HOW TO DETERMINE +/-
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Old 02-08-2006, 02:33 AM
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Doc here ,

Another method To determine polarity of a speaker (or just about anything else...) Get out your DVOM, set it for the highest forward continuity..like R X 1 meg..

Touch the probes across the speaker, It should pop in one direction, either in or out, if it is out, reverse the leads, if it is in , mark the red probe terminal as + the other as -

The meter acts like the battery with a readout..and is a bit safer on the cone coils..

Is this the Speaker? If so It does have a crossover network..


From your description it sounds like you have a crossover method involved..is this correct? and if so there wouldn't happen to be a electrolytic capacitor on the board would there? If so look on it , the side marked + on the cap is the + side.

Doc.
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Old 02-08-2006, 10:32 AM
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See attached article.
This is guide that can help if this is a new system with new wiring or if none of the speaker wiring grounded to the chassis.

Some vehicles use the chassis as the common conductor for the speakers. And, The speaker you are using may have a factory installed jumper from one of the terminals to the cage (frame) of the speaker. This terminal will be the common connection point.

Using + and - can be confusing as they really refer to DC.
Audio signals are alternating for 20hz to 18,000hz.
So another way of expressing the "polarity" of the speaker is common and signal. But the most important thing is phasing.
All speakers must be connected the same.

vicrod

Re: How can I tell which connection on a speaker is 'positive'?
A single speaker will work just fine connected to an amplifier without regard to
polarity. ... Then reverse the connections on ONLY ONE of the speakers, ...
http://www.madsci.org/posts/archives...4118.Eg.r.html - 6k - Cached - Similar p

Last edited by vicrod; 02-08-2006 at 03:26 PM.
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Old 02-08-2006, 06:26 PM
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Speaker Polarity

Here's the scoop. If a speaker doesn't have any electronics on it, ie. it's just a speaker, the positive and negative connections are just the two ends of a coil of wire.

When you run a current through it, it makes a magnetic field that pushes the speaker cone back and forth in the magnetic field of the big magnet on the back of the speaker frame. The speaker can be connected either way and will sound exactly the same.

However, it gets a bit more difficult with multiple speakers. Here, polarity makes a difference. Speakers that are "out-of-phase" will tend to cancel out or mute the bass. Generally, you hook all the speakers up the same way making all the big lugs positive or all the lugs with a red mark positive or all the lugs on the right positive, you get the idea. However, if you have different speakers, this might not be optimal or it might not work well because of the speaker placement or because of the acoustic environment. Fortunately, there is way to test for optimum speaker polarity in a multi-speaker system.

Install two (or more) speakers in the car. Do not hook ANY wires to the speakers for now.

You need a really high tech piece of electronic equipment known as a "double pole double throw" (DPDT) switch that you can get at Radio Shack for about three bucks and you’ll need about 11’ of speaker wire. Make sure you do not get a DPDT switch with a “center off” position.

On the back of the switch there will be six connectors. Turn the switch over and place it so you have two columns with three connectors in each column. Let’s call the top two connectors 1 & 2, the middle two connectors 3 & 4, and the bottom two connectors 5 & 6.

Start by taking two pieces of speaker wire each about five feet long. You will notice that speaker wire has two conductors or pieces of wire and that one of the pieces is identified by a white line or a raised ridge or by a ribbed surface. Lets call this conductor the A wire and the other conductor the B wire.

Soldier the first piece of speaker wire to connectors 1 & 2, with the A conductor on connection #1 and the B conductor on Connection #2. Tie a knot about six inches from the other end of this wire and from now on we’ll call this wire the “Speaker Connection” from now on.

Soldier the second piece of speaker wire to connectors 3 & 4, with the A conductor on connection #3 and the B conductor on Connection #4. We’ll call this the “Amplifier Connection” from now on.

Now we need to set up our tester. Hook up the “Amplifier Connection” to one channel of the amplifier or radio making sure to hook the A connection to the positive or hot lead on the radio and the “Speaker Connection” to one of the speakers again making sure to hook the A connection to what you have decided is going to be the positive or hot lead on the speaker.

Now, with the volume fairly low, turn on the radio and switch the switch. In one position, the radio will play, in the other it won’t. Label the position where the radio plays through the speaker “Direct” and label the other position “Reverse”. Now disconnect the setup and let’s finish up building our tester.

Take a piece of speaker wire about four inches long and pull it apart so you have two four inch pieces of single conductor wire. Soldier one piece so it connects #1 to #6 and the other so it connects #2 to #5 on the back of the switch. You should have the two wires crisscrossed over the back of the switch.

Now it’s time to have some fun. Here’s how to use the tester.

Hook up one speaker to one channel of the radio (assuming it’s stereo) being careful to hook the positive or hot side of the radio to the positive side of the speaker. Hook the other channel of the radio and the speaker up to the tester as we did before. Turn on the radio and find some music that has pretty good base. You don’t need much volume here, just enough to hear the base. Flip the switch. The base will be noticeably better in one position or the other. If the base is better with the switch on Direct, disconnect the tester and hook the radio up to the speaker the same as the original speaker. If the base is stronger with the switch in the Reverse position, then hook the second speaker up the opposite of the first. For multiple speakers, just go on to the rest of the speakers in order.

Pretty slick, huh?
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Old 02-08-2006, 07:01 PM
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Quote:
Originally Posted by docvette
Doc here ,
From your description it sounds like you have a crossover method involved..is this correct? and if so there wouldn't happen to be a electrolytic capacitor on the board would there? If so look on it , the side marked + on the cap is the + side.

Doc.



OK I figured it out. First of all it is the speaker in your pic. There is a crossover but there are no + or - marks on any of the parts. What I did is toss out the 9v battery and used a 1.5v battery and that did the trick. It was very clear to see the cone push out in one polarity and pull in the reverse polarity. The small terminal is "-" and the bigger terminal is "+" as was stated here before. Thank you all very much for your help.
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Old 02-08-2006, 07:12 PM
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Doc here,

Good Deal! Thanks for posting back on the fix...

Doc

Wildbill,

Slick little tester..I be building one!

Doc
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Old 02-09-2006, 06:18 PM
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heres a little trick that works real well in figuring out + & - on speakers you will need a 9 volt battery,piece of short black wire,piece of short red wire,(1) momentary push button toggle switch,and a small project box you can pick up from any radio shack at least you could last time i bought any just drill a hole in the box small enough for you wires to fit through and for the toggle switch to fit in.place the battery inside of the box run 1 wire from battery to switch and from switch to outside of box then run other wire from battery to outside of box.you can put alligator clips on ends of wire to hold onto speaker terminals or speaker wire then press button if speaker pushes out then you have polarity correct if it pull in then you have polarity reversed.
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Old 02-09-2006, 10:40 PM
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Doc Here,

That was sort of my idea ,

Except I was going to use a DPST reed relay (5 volt variety) on a PC board to replace the switch, and wire one battery wire to the coil, Through a push button

The ground coil back to the battery(s) (3 ~ 1.5 volts)

Install two sets of Slide type RED/BLACK binding posts (like on the back of a speaker box..) one on the left one on the right side of the project box. The left to be Audio input + and -, The one on the right to be Speaker output + and minus.

Then run the Audio in + to the #1 NC set of contacts on the relay, and the Audio in - to the #2 set of NC contacts.

Then wire from NC 1 To NO 2 , and NC 2 To NO 1..in an "X" pattern..

The center wiper #1 to the Speaker output RED terminal, and the Center wiper #2 to the BLACK speaker output terminal.

When you hook the audio in + and - to the binding posts, and the relay is not activated, the Speaker output + and - follows suit. Audio straight through.

When you activate the push button Ergo, the relay , the speaker + and - terminals are reversed, you can hear the difference in the Audio..

In addition to that, I am planning to run a Second push button.

Tap One of the battery's for power and ground.

Run the battery Ground over to the Speaker output - terminal.

The power side of the battery to the push button, from there, out to the Speaker output + terminal.

Was even thinking of running it through a relay to Disconnect the Audio side when you activate it, but I think I can remember to disconnect the Audio in side before activating it...

This way you can push that button, and observe the speaker cone direction.

This way you get 2 in one tester, you can hear the audio difference in both directions, and before doing that check the direction of the magnet...and See the result.

Put all this on a perf board, and stick it into your 3 X 5 plastic project box.

Doc
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