andrewrx7 Posted July 28, 2012 Share Posted July 28, 2012 Hi there, I have a speaker that doesn't have any + or - markings. Is there a way to determine what the poles are? Would there be a problem if the poles were connected the wrong way round? Quote Link to comment Share on other sites More sharing options...
VTypeV4 Posted July 28, 2012 Share Posted July 28, 2012 Most speakers move forward (ie away from the magnet) when a positive voltage is applied to its + terminal. There are exceptons, I believe JBL may well be one of them. As long as you now all the speakers in your rig are all moving in the same direction, you'll be Ok. Just out of interest, what speaker is it? Quote Link to comment Share on other sites More sharing options...
andrewrx7 Posted July 28, 2012 Author Share Posted July 28, 2012 Thanks for the reply. Speakers are for a guitar cab. Both are Eminence, but different models. One is new (has +/- markings) the other is new old stock (date code is 1994) and does not have the pole markings. I put them into a cab to make a 2x10 and run individually they sound good but when run together the sound drops considerably. I am guessing the speaker with no markings was wired up the wrong way round and I am getting some form of phase cancellation. Quote Link to comment Share on other sites More sharing options...
icastle Posted July 28, 2012 Share Posted July 28, 2012 [quote name='VTypeV4' timestamp='1343512487' post='1751676'] Most speakers move forward (ie away from the magnet) when a positive voltage is applied to its + terminal. There are exceptons, I believe JBL may well be one of them. As long as you now all the speakers in your rig are all moving in the same direction, you'll be Ok. [/quote] That was the HF compression units (tweeters). The speakers followed the standard '+ supply to + terminal drives cone forward' convention. From what I remember, it was something to do with the crossovers they used to make. Quote Link to comment Share on other sites More sharing options...
stevie Posted July 28, 2012 Share Posted July 28, 2012 Sorry to contradict you, icastle, but JBL's cone drivers used to move backwards when you applied a positive voltage to the positive terminal. I believe they have now joined the rest of the universe. Andrew, this does sound like speakers out of phase. Connect a 9-volt battery to the speakers to see which way they move. With the positive battery terminal on the positive speaker terminal they should move forward. Quote Link to comment Share on other sites More sharing options...
andrewrx7 Posted July 28, 2012 Author Share Posted July 28, 2012 Thanks fellas, will test tomorrow. Looking at the other speakers I had to hand, the positives all seemed in the same place, so went with same orientation. Looks like it was the wrong 50:50! Quote Link to comment Share on other sites More sharing options...
icastle Posted July 28, 2012 Share Posted July 28, 2012 [quote name='stevie' timestamp='1343515369' post='1751712'] Sorry to contradict you, icastle, but JBL's cone drivers used to move backwards when you applied a positive voltage to the positive terminal. I believe they have now joined the rest of the universe. [/quote] There were only a handful of driver models that we'd potentially come into contact with, and those are >20 years old now. The largest proportion of negative polarity speakers were used in cinema sound systems and HF units. Official JBL statement [url="http://www.jblpro.com/BackOffice/ProductAttachments/JBL_TechNoteN1V12C_v5.pdf"]here[/url]. Quote Link to comment Share on other sites More sharing options...
andrewrx7 Posted July 29, 2012 Author Share Posted July 29, 2012 Just checked with a 9v battery and yes, the poles are opposite way round. Soldering iron, here I come! Thanks for the help, even if it were a very simple solution! Quote Link to comment Share on other sites More sharing options...
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