Check Your Used Speakers!

[Peter P.]

I bought a used pair of Heresy II's a couple months ago, joined this forum, and learned tons. People like to take apart, modify, and improve (if that's possible!) their Klipsch speakers.

 

I didn't get a chance to listen to the speaker long because I had to send my amp out for repair.

 

I picked up the repaired amp today, and I decided to poke around inside my Heresy II's. I wasn't sure the tweeters were working because I could barely hear anything coming out of them but to be fair, I've had a history of ear surgeries andI suffer tested hearing loss above 9kHz so I'm not surprised if I don't hear anything!

 

Anyway, I tested the DC resistance of the first tweeter and it was 8.5 ohms; good. Then I put a voltmeter on the tweeter leads and measured the output to the speaker, ensuring it rose

with volume; good.

 

But when I looked at the speaker leads, the BLACK lead was connected to the "+" terminal. I would expect the RED lead would be connected there.

 

So I checked the squawker and it has NO "+" marking on the terminal, just a splotch of yellow paint which I presumed must be the positive terminal.

 

The woofer had the "+" lead connected to the red lead. Genius that I am ;-), I started to see a pattern, so I corrected the red/black lead issue on the tweeter.

 

I then decided to check the other speaker.

 

Everything was CORRECT with that speaker, but I noticed the spade connectors for all 3 drivers on the second speaker were oxidized (expected) and UNINSULATED.

 

Wait a minute; I don't think that's what I saw in the first speaker! So I went back to check; the spade connectors on ALL THREE drivers on the first speaker had been

replaced with INSULATED, SHINY (almost chrome) spade connectors!

 

I have no idea why the spade connectors in just one speaker were replaced-feel free to give me ideas why. And while I'm not sure I can tell the difference now that the tweeters are operating

in-phase, there's comfort knowing both speakers are wired correctly.

 

So if you bought your Klipsch speakers used, it might be worth checking inside to ensure everything is connected properly.

 

Thanks for reading!

[WMcD]

You can check the schematic for the HII in the pinned crossover section.

 

You'll see the tweeter is connected in inverted polarity.

 

[Peter P.]

That was enlightening; thanks!

 

I wonder why they reverse polarity on the tweeter?

 

That means the OTHER speaker was wired incorrectly-the speaker with the apparently untouched terminal connectors. Break out the screwdriver...

 

I also wonder why there's no embossed "+" marking for the terminals on the squawker. At least I didn't see any; instead there was a yellow dab of paint

adjacent to one terminal, which I assumed is the positive terminal.

 

Thanks again.

[BEC]

Just go by the wire colors.  Black always goes to negative on the drivers. 

 

Bob Crites

[BEC]

For the squawker, the real indication of polarity is a white dot near the positive terminal on the plastic part of the diaphragm.  That is hard to see unless you take the horn and driver out of the cabinet, so usually someone marks that side on the back of the driver with a yellow dot.  The tricky part here is that if someone ever changes the diaphragm, he may not install the new diaphragm so it matches up with the yellow dot.  So on those, always better to go back to the source looking for the white dot on the diaphragm.

 

Bob Crites

[John Warren]

8 hours ago, Peter P. said:

I wonder why they reverse polarity on the tweeter?

 

It sounds better.

[WMcD]

The reason arises from the fact that there are delays caused by the crossover circuits and the fact that delays are caused by the drivers being offset in distance from the front panel (which is a reference point).  Actually, the natural roll off and roll up of drivers cause delays too.

 

At the crossover freq for the mid and tweeter both are sounding.  Because of the aforementioned delays the mid and tweeter output at the crossover freq are not in phase.  Apparently they are 180 degrees out of phase and this causes a cancellation and a resulting dip in overall response just there.  It is easy to see in the acoustic frequency response curve.

 

The solution is to reverse the polarity of the tweeter which puts it 180 degrees more out of phase overall and this means it is back in phase or 360 degrees relative to the mid.  Therefore, no dip.

 

WMcD

[Schu]

Does the ak-4 also reverse tweeter polarity?

As I read the schematic, I would assume so.

I can't tell if the black or the green connector is the + on an LSii...

[Deang]

On ‎12‎/‎3‎/‎2016 at 10:28 PM, WMcD said:

You can check the schematic for the HII in the pinned crossover section.

 

You'll see the tweeter is connected in inverted polarity.

 

 

Polarity is reversed, but it's on the network side, not the driver side. IOWs, when they build the network, they reverse polarity on the network side of the barrier strip (or PCB) -- you shouldn't be flipping the wires when you connect -- follow the label, or the markings on the PCB.

[Deang]

On ‎12‎/‎4‎/‎2016 at 6:28 AM, Peter P. said:

That was enlightening; thanks!

 

I wonder why they reverse polarity on the tweeter?

 

That means the OTHER speaker was wired incorrectly-the speaker with the apparently untouched terminal connectors. Break out the screwdriver...

 

I also wonder why there's no embossed "+" marking for the terminals on the squawker. At least I didn't see any; instead there was a yellow dab of paint

adjacent to one terminal, which I assumed is the positive terminal.

 

Thanks again.

 

The paint is referred to as "the factory mark". The factory tests the driver, and marks the positive side. A black mark still means "positive".