Two midranges wired out of phase in the same cabinet...

[presscot]

Hi everyone, I've got a pair of a/d/s/ AVT-148 speakers. They're 3-way tower with a 8" woofer, 2x 4" cone midranges and a 1" tweeter per cabinet. The midranges and tweeter are aligned in MTM configuration. I was surprised when I opened up the crossover network. I found that the two midranges, in the same cabinet, are wired out of phase to each other and with series wiring. Each driver is 4 ohms. So, they are 8 ohms for midrange section. I remove the crossover to use with an 8-ohm driver. They sounds normal. Nothing abnormal as unexpected. Please tell me what is the purpose of wiring the midranges out of phase? Thank you in advance.

 

[YSDR]

How do you know they have opposite polarity?
I think that they have the same polarity just with a series connection.

 

[presscot]

How do you know they have opposite polarity?
I think that they have the same polarity just with a series connection.

The negative terminals of each driver are connected together. And the positive terminals of each driver are connected to positive and negative terminals of crossover network.

 

[YSDR]

Strange. Some measurement would be helpful to identify what's going on here.

 

[awkwardbydesign]

Are they marked incorrectly? Can you play them both ways round and listen for the null?

 

[turboyam]

Are both cabs the same way?.

 

[presscot]

Are both cabs the same way?.

Yes, they are.

 

[presscot]

Are they marked incorrectly? Can you play them both ways round and listen for the null?

They’re marked correctly. It’s weird that I can hear null when midranges are connected in the same polarity.

 

[presscot]

I have open up the a/d/s/ AVF-144 center speakers which are the same series as the tower. They have the same thing as their brother. Please help me to clarify the suspicion.

 

[danny_66]

You can determine the polarity of a driver with a battery: google.

 

[Juhazi]

It sometimes happens that a new/extra worker on assembly line "corrects" something she thinks is wrong. Are the any strange paint of marker markings on contacts of drivers?

Are you the first owner?

Perhaps QC isn't 100%, can you measure the response?

 

[TNT]

... she ...

 

[Juhazi]

YouTube

 

[Juhazi]

This is how drivers are made at SEAS Norway. Lots of gentle and caring female hands there too!
YouTube

 

[awkwardbydesign]

They’re marked correctly. It’s weird that I can hear null when midranges are connected in the same polarity.

That surely means they are marked incorrectly! Do the battery check.