Gear Fails, is there a Lesson?

#9 Speakers with One Driver Out of Polarity From the Factory

by Frank White with Anthony Grimani

This comes from our list of the top 50 recurring problems in home 

theater systems - gathered over the last 25 years from more than  1,000 high-performance installation projects.

Most of us are tensioned to go to work every weekday - and some weekends, too.

Think about the Boys of Summer, though. Ah, the select few who are blessed with a sliver of providential DNA, a lotto played out in the gene pool. They get to play baseball as a profession: freaks of nature who have the ability to hit a 98 MPH fastball high and inside - blasted directly at them by another mutant. These aberrations can plaster a postage stamp sized target from 100 feet away, hitting it 19 times out of 20.

Operative word here: Play

The rest of us have to work. If we want our lunch money and rent, we gotta work. Work...um...

Webster defines work as: A job or activity that you do regularly especially in order to earn money

Yo, we hear you seething, "Nothing new here, get to the freaking point already -and thanks by the way for rubbing this fact in our faces."

We belabor the narrative, because you will, at times, receive speakers that are wired incorrectly out of the box.

Once in a while, a hookup from the speaker's printed circuit board crossover to one of the drivers is wired backward, with the positive and negative terminals inverted. We have seen speakers where the factory even used the same color for both wires; it's no wonder the poor minion at the manufacturing level didn't know what to do.

Look, we get it. You played by the rules. The marketing for your company worked: you attracted a great client. You designed with integrity and wonder. The engineering documentation was perfect. The project manager and field techs executed the plan professionally within the budgeted time and expectations.

Then you fired the system up, but the acoustical imaging was vague and the sound just sucked. It's not your screw-up in this case, but a faulty speaker still should never have reached this deep into the project without your team's notice. One hopes that final QC at the factory would catch the mistake. Some do get through, and now you have just joined the QC team... at your expense.

If this is an installed speaker, you will need to decide whether to fix it yourself or pull it out, send it back for a replacement, wait, and re-install the new one. If you can't wait, and you choose to do the repair in the field, you will need to pull the driver and invert the wires.

Quick note to our manufacturing friends: We are seeing careless production errors like this more and more frequently. Get this right; we as an industry will not continue to support suppliers that put us through this.

Dealer Solution: Meticulously check all speakers before putting them on the truck to the job site. Yes, that takes time, but less time than doing it in the field! Check each driver in the speaker with an impulse tester such as the Gold Line APT2.

Note: Drivers in some speakers are intentionally out-of-phase to make the crossover work right; better find out from the manufacturer what the polarity is supposed to be before you accidentally go about redesigning their speaker in the field. 

And now, gentle reader, it is time to get back to work....

............................................................................................................................

Check this out and other sonic challenges we've come across, as well as the superior acoustical solutions at Grimani Systems.

For more about what Frank is about check out www.weld2.com

email Frank [email protected] 

Thanks for investing a few with us on this topic. We look forward to your success!