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speaker polarity question

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chalmerschem
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chalmerschem posted on Thu, Apr 2 2015 4:39 PM

Hi

Apologies if this sounds a total rookie question but I has jest acquired a set of B&O S30 speakers that are wired with grey speaker cable (I am led to believe these speakers came like this from manufacture). The wire though, has no indication of which is positive and which is negative. I assume this matters! Can anybody shed any light on which wire goes to which pole on my amp.

I am totally new to B&O but I also acquired a pair of CX50 speakers (with DIN) and am now totally obsessed. The sound that comes out of the little fellas is delicious!

Many thanks in advance

 

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riverstyx
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As a quick method to determine the polarity you can do the following:

  1. Gently remove the front cover of the speaker
  2. Take a standard AA battery (not a rechargeable one) and hold one wire against the negative terminal of the battery (the flat end).
  3. Whilst watching the bass cone of the speaker, tap the other wire to the positive terminal on the other end of the battery - don't hold it on there, just tap it on briefly. Whilst it is very unlikely you would do any harm to a speaker with the power handling of the S30 even if you were to hold it there for longer, it's just not a good idea to subject a speaker coil to DC for any longer than is necessary.
  4. If the bass cone moves outwards (towards you) the negative speaker wire is the one you are holding to the negative terminal of the battery and the positive wire is the one you tapped briefly onto the positive terminal. If the cone moved inwards, it's the other way around.

Hope this helps.

Martin.

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leosgonewild
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The one with the largest connection to the speaker is - the smaller is +

"You think we can slap some oak on this thing?"

chalmerschem
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Thank you for the quick reply. The problem is I can't see any sized connections. The wire disappears through the back of the chipboard backing. 

leosgonewild
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Usually one wire is round and one is a bit square, or have a stripe or some markings on it. The round is minus and the "marked" is hot. Post a picture.

"You think we can slap some oak on this thing?"

5:8:13
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Suggested by 5:8:13

The important point is that both speakers should be connected the same way.  I am surprised that there is nothing on the wire to distinguish the positive and negative.  Failing a + or - mark; sometimes one strand is copper (colour) and the other is silver (colour); sometimes there is a ridge alongside one of the wires which you can feel with your fingers.

If you still cannot distinguish between the positive and negative wires, connect the loudspeakers to your amplifier; no harm will be done if one of them is the wrong way round.  You will now have to check that the speakers are 'in phase' by listening AND the difference is very obvious.

Play something: ideally something which is quite simple and with a single singer OR even better a single voice speaking, 

Close your eyes and listen.

If the speakers are correctly connected and 'in phase' the voice of the singer or broadcaster will appear to come from a well-defined spot between the speakers.  If not the sound will be wide and diffuse.  Reverse ONE CONNECTION ONLY at the amplifier and repeat the listening test.  If you are not experienced at this you might want to do this several times, but I am sure you will soon be confident in your judgment. It is possible to obtain test CDs with specially recorded tracks to test your system; you might have a friend who already has one, but I promise you, you can hear the difference without one.

 

 

Do not become over concerned as to whether the positive from the amplifier is connected to the positive of the loudspeaker - as I wrote at the beginning the important thing is that the connection of both loudspeakers is the same.

riverstyx
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SouthWest UK
938 Posts
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Verified by Beobuddy

As a quick method to determine the polarity you can do the following:

  1. Gently remove the front cover of the speaker
  2. Take a standard AA battery (not a rechargeable one) and hold one wire against the negative terminal of the battery (the flat end).
  3. Whilst watching the bass cone of the speaker, tap the other wire to the positive terminal on the other end of the battery - don't hold it on there, just tap it on briefly. Whilst it is very unlikely you would do any harm to a speaker with the power handling of the S30 even if you were to hold it there for longer, it's just not a good idea to subject a speaker coil to DC for any longer than is necessary.
  4. If the bass cone moves outwards (towards you) the negative speaker wire is the one you are holding to the negative terminal of the battery and the positive wire is the one you tapped briefly onto the positive terminal. If the cone moved inwards, it's the other way around.

Hope this helps.

Martin.

chalmerschem
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Thank you:) Job done! They sound beautiful!

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