View Full Version : Speakers Red and Black terminals
raygreen
19-06-2014, 22:10
If speakers are wired the correct way (i.e red terminal amp to red terminal speaker) should the speaker bass cones move in or out?
In general if a positive voltage is applied to the red terminal of a drive unit, the cone should move out. However in a multi-driver speaker system, the designer may have deliberately chosen to invert the phase of one or more drivers for reasons of time alignment, though to my knowledge this is never applied to the bass driver.
walpurgis
19-06-2014, 22:26
to my knowledge this is never applied to the bass driver.
It is on Tannoy dual concentrics.
The Grand Wazoo
19-06-2014, 22:45
I find this to be a strange question - it won't do one thing without also doing the other!
I find this to be a strange question - it won't do one thing without also doing the other!
I think what Ray is asking is if a DC voltage is applied to the red terminal of a drive unit, will the cone move in or out? My understanding is that a positive voltage applied to the red terminal (or marked "+") will cause the speaker cone to move out.
It is on Tannoy dual concentrics.
Ah - I didn't know that. Do you know the reason why? Is it done to reduce intermodulation distortion?
raygreen
19-06-2014, 23:13
To explain why the question was asked - I have speaker wiring connected from the amp but the cables are buried so I don't know which is red and which is black. I know that when speaker cables are connected the bass driver appears to move either in or out (when connected correctly). I'm just not sure whether inwards or outwards is correct.
Ray, if you have connected the red terminal of each speaker to the corresponding red terminal of your amplifier, and the same for the black terminals, then everything should be OK.
Ah - I didn't know that. Do you know the reason why? Is it done to reduce intermodulation distortion?
Yes...partly
The DCs usually employ 2nd order crossover slopes and Tannoy chose to invert woofer phase to ensure that at the crossover point, both drivers were in phase.
Ray, if you have connected the red terminal of each speaker to the corresponding red terminal of your amplifier, and the same for the black terminals, then everything should be OK.
Yes, but if the cables are identical and buried how do you know that the wire poking out at one end is the same wire poking out at the other end? I think this is the problem that Ray is having.
archiesdad
20-06-2014, 16:35
Continuity test using long leads?
walpurgis
20-06-2014, 17:19
Continuity test using long leads?
Yes then polarity test.
No need to use long leads. Just fit a 1.5V battery to the wires at one end, marking the wire that the battery's +ve terminal is connected to with a piece of red tape, and then use a voltmeter to measure the voltage at the other end of the wires, again marking which wire is +ve with a piece of red tape.
Do the same for the other set of wires.
Yes...partly
The DCs usually employ 2nd order crossover slopes and Tannoy chose to invert woofer phase to ensure that at the crossover point, both drivers were in phase.
That is the same in the Linn Sara speakers I am currently refurbishing for a friend.
They also use a classic second order crossover and so I want surprised that the tweeter was wired in reverse polarity to the mid/bass driver. What I was surprised to find was that the it was the bass driver that had reverse polarity relative to the input - essentially pulling when a positive signal was applied instead of pushing.
After the refurb the crossovers will be external and it will be very easy to experiment with this aspect.
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