Can someone tell me what this multi-meter reading means?

[snb778 5,000+ posts]

I know Im testing this right, but why does it read like this? Im testing a home theater tweeter horn.... its big





now this next one is showing you how big this thing is... i actually tried to hook it up in my car for fun...I wired it up to my Alpine F545 just normally so at 4 ohms its 125watts (dunno what ohm the horn is, it doesnt say on it...then I tried wiring it bridged which at 1 ohm is 500 watts I believe...i dunno...anyways, it really didnt get to loud...any ideas on why?? again, i did this just for fun.

Click to read more...

 

[squeak9798 5,000+ posts]

It could be a piezo driver, which untechnically speaking have very screwy impedance characteristics. Piezo's aren't my "thing", but I believe they act/present themselves more as a capacitor....which is the reason most do not need to be used with a highpass crossover of any sort.

For example, look at the ID CD1e or some Pro Audio piezo units...the impedance is listed in uF (microfarads).

And A LOT of cheaper home audio/pro audio horns use piezo drivers rather than true compression drivers.

 

[Fi Car Audio 10+ year member]

Yeah you about summed it up. Voltage applied to the piezo electric element causes slight separations to form between the crystals resulting in it deforming and producing sound. The material itself isnt really conductive and would not show a specific resistence like a coil of wire in a normal speaker would.

 

[snb778 5,000+ posts]

but why wouldnt it give any reading at all. Also, when I hooked it up to my Home Theater amp...it got pretty **** loud...but that cant be any more than my F545 was giving it could it... Its just a harmon Kardon from tweeter.

 

[squeak9798 5,000+ posts]

but why wouldnt it give any reading at all.

Probably out of the range that your DMM is capable of reading.

 

[snb778 5,000+ posts]

how could it be that big....or small and work with a home theater amp with enough power to get loud? I mean a meter can read above and below like at least a few hunderd or hundreths ohms right..??

 

[Fi Car Audio 10+ year member]

The piezo element is incredibly resistive. Im not sure what exact material they are using as there are a couple different ones. But it is several orders of magnitude higher than what your meter would read. If it is hundredths of an Ohm, your meter would have read a dead short... not open.

They work on a completely different principle than normal coil speakers. They are usually significantly more efficient at changing power Watts to acoustic Watts than a normal speaker is.

But, Im sure that someone else on here has to know all the ins and outs of piezo driver design. I just know the basics.

 

[ngsm13 5,000+ posts]

Do you get it yet?!??!?!?!?!

nG

 

[Mr. Opportunist 10+ year member]

Do you get it yet?!??!?!?!?!
nG

//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif i dont think he does