[audiogurujax]

Hi, I have a technical question if anyone can answer, I was measuring the DCR of my ribbon tweeters of my GT3R GT Audio works speakers and I am confused, If I use my $30 southwire multi-meter i get a resistance of 3.7 ohms but if I use my fancy $400 BK LCR meter using DCR setting I get 19.2 ohms but if I measure the resistance (R) or Impedance (Z) at 1Khz I get 3.675ohms and  3.854 ohms respectively.

Also when I measure the DCR with the BK the ribbon tweeter moves a lot but no sound, and when measuring R or Z I can hear the 1Khz tone with the SouthWire MM It does not move or make any noise when I measure the Ohms.

Why does it moves so much with the BK measuring DCR and why is the DCR value so high on the BK?

BTW I tested the BK and is calibrated!

[Speedskater]

Well 3.7 Ohms looks like the correct value.
Try measuring some low Ohm film and wire-wound resistors with the BK.

[audiogurujax]

I did is perfectly calibrated, I measures some caddock high precision resistors I have and It was on the spot even measuring .025 ohms resistors I am not sure if the ribbon have a higher resistance at higher voltage I know the BK measure with a voltage of either 3v or 6 v vs cheap MM use like 1v

[HAL]

A possible problem is that the ribbon is generating a voltage from just being in the room and vibrating from air movement or 60Hz EMI.

The BK is probably reading the AC voltage as part of its measurements, where the cheap MM is only seeing the DC portion of the measurement. 

Have seen problems with LCR meters trying to read inductance from guitar pickups due to noise induced voltage.

[rollo]

  Correct value is 3.7 according to designer according to my memory.


charles

[audioengr]

The LCR meter might be in parallel or series mode for the resistance measurement.  This will make a difference.  You need to use the right one.

[audiogurujax]

I am going to keep the LCR in DCR mode meter away from the ribbons LOL, I preffer to use it by measuring the Impedance or resistance at 1k and 10k that is more precise anyway since thats what the amp will see not the DCR. I dont want to ruin my tweeters with the LCR in DCR mode. I think the movement is because the LCR measures DC using a very low AC signal, like pulses that is why you have a slow and fast setting in DCR and I think is .5hz or 1hz. not good for a ribbon! I just ordered a new Fluke MM I will see how that one measures tomorrow when it arrive.

BTW I am changing the wiring in the tweeters, these tweeters have 16 ft of wire each and they are currently using deulund 20awg and I am changing it with TWL 14 awg internal wiring, that way all the wiring in my system will be TWL including the internal wire inside the speakers.

[Mike B.]

Are they transformer type ribbons?

[HAL]

The Fluke 87III meter works correctly with my GTA ribbons for DC resistance measurements.

[audiogurujax]

Great to know Hal, Thanks! that's the one I ordered but the new version 87V so hopefully it works correctly I am calling today BK to see why the BK is doing this and If there is a way I can adjust it.