LSi C shielding

Steve@3dai

The center what? They sent me three drivers to replace all three drivers.

I get to keep only what I had in the first place.

mantis

I thought you where going to send the entire center channel back.Not just the drivers.This is weird what your going threw.

Steve@3dai

We're still working on it, just to update people

mantis

I hope this works out.......I'm looking for Info in here.This might not be a problem for me, but I can't see how they can't shield the drivers.

[Deleted User]

Folks,
To keep everyone up to date on the progress of the LSI C problem, here's what has happened. We sent replacement tweeter and drivers to Steve who has exchanged them in his speaker and the symptoms remained the same. We then sent four of the Sorbothane isolation discs, that are normally used to separate the satellites from the bass unit in the RT3000p, to both Steve and Dan (the owner of the Sony 27"). I have heard from Dan that the discs eliminated the color shifting and reduced the level of picture jitter, on his Sony, while playing the frequency response sweep section of the Avia disc. His opinion was that while it didn't completely go away he felt the results made it acceptable. Please note that Dan had also commented that he didn't see the original problem during movie or music listening, only during the low frequency section of the test disc. Steve has probably received, or will receive, his Sorbothane discs (I made a mistake in the part identification on the first items I sent, but sent the correct part UPS red, the next day). Hopefully Steve will notice the same level of improvement. The third person who mentioned the same kind of problem should contact me at kswauger@polkaudio.com for similar help.
Here, at Polk, both Paul and I are coordinating research efforts to duplicate and cure the problem. We know the Sorbothane discs are not the final answer, but will help us understand the nature of the problem and offer a reduction in the severity of the difficulty. Anyone who knows Polk Audio's history knows we will do everything necessary to solve the problem.
Regards, Ken Swauger

hoosier21

I guessed it was a vibration thing, but why would this speaker be worse than any other center channel speaker?

Can you guys tell us, do you feel the cabinet vibrate when you do the sweep? I would think it would have to vibrate pretty hard to screw up the picture.

Steve@3dai

Well, vibration might be part of it, but it's the color shifting that I am worrying about. I should get those discs today (will ship your package tomorrow Ken). I will let you all know what's going on.

As a test, I threw a LSi9 on top of my TV (well, not threw, but you get the idea) and it also did the same thing. Which was pretty expected.

hoosier21

Solution is simple get another TV, kidding

what about your last speaker? what was it? was it on top of the TV? Could this be something to do with the TV not liking ANY vibrations? When you say it distorts the color, is it along the top or all over the whole picture?

I am very interested, the LSi might be my next adventure.

Steve@3dai

This is my first center channel. So I don't have any other experience.

It's along the top, on the right, which is the bass speaker.

My TV is just fine thank you, 34" HDTV 16x9 is nice

goingganzo

set the speaker to small? would that work? i have my 400i set to small.

Steve@3dai

It is set to small.

I got the pads today, and put them on (kinda sticky, ewww). Didn't make a whole lot of difference in my case.

The best place to see the "noise" is on the Nine Inch Nails concert DVD, track 9 (La Mer). The opening has a wicked bassline that makes my TV dance

mantis

I've been following this post since the beginning,hoping you would resolve your problem.

I think there is 2 things you can do th get to the bottom of this

1)Get a ISF certified tech out to your house to test if the centerchannel or better put why the center channel is causing you problems.My guess is that it's resting on something inside the Tv causing it.The magnetic field is sheilded in the speaker,and you replaced the drivers with new ones.Polk has been making center channels for a very long time.My guess that it's shielded correctly or other would be chimming in.

2)Move the center channel to the bottom of your Bolts stand.I know its alittle low for center channel placement,but if you raise up the front of the speakers with rubber feet,you can get it 2 sound pretty good.
Or build a center channel shelf over your tv.Others in here have done this with the cs400 as it was 2 big for there tvs.
SOMEONE WHO DID THIS WOULD YOU PLEASE CHIME IN ONHOW YOU BUILT YOUR SHELF???????

OK man I hope you get to the bottom of this.Please keep us all informed with your results.
Dan

Steve@3dai

Originally posted by mantis
My guess that it's shielded correctly or other would be chimming in.

I am the 3rd person on this thread to chime in, and we all have different TVs.

- Steven

DarqueKnight

Originally posted by mantis
Or build a center channel shelf over your tv.Others in here have done this with the cs400 as it was 2 big for there tvs.
SOMEONE WHO DID THIS WOULD YOU PLEASE CHIME IN ONHOW YOU BUILT YOUR SHELF???????

I used two identical audio equipment racks that were slightly taller than my rear projection TV. I then placed a half inch thick, 6 foot long by 1 foot wide shelf over them.

goingganzo

easyest way to buld a shelf is to get angle brachets and a piece of shelving i perfer glass you find 2 or 3 studs atach you brackets to them with 2 1/2 drywall screws you can get dreative brackets or anything you want i usto have a 19 inch glass shelf with a curved end and 2 black brackets the ones you get at home depo that hold 1000 lbs it was sweet till i got my bigscreen and had to take it down now the glass is on some little wine racks for a tabble for the rear seat

gil

Steve,
What stands are you using with the LSi9 and where can I find them reasonably priced. Did you look at any other stands besides these?

Also, curious as to how your setup sounds with no center(phantom) vs with the LSiC. Right now I am not using a center and it surprisingly seems to work well, but I do plan to get the matching center.

Also, what are you using to drive the Polks btw.

Thanks,
Gil

Steve@3dai

I am using the 18" Sanus Natural Foundations stands. They hold the speakers up quite nice. They run like $100 from Polk.

I still use the center, just have it on the floor. Not optimal, but it works for now.

I am driving them with an Arcam AVR-200.

- Steven

gil

Steve,
Sounds good. How would you think the Sanus stands (wood) compare to my heavy metal Sonus faber stands. I need a 2nd pair of stands and don't want to get another Sonus pair.

Also, any opinions of the LSi9 vs the Lsi15, each used with a sub? I am thinking of getting 15's and moving the 9's to the rear. Or I could get FX for rears and a 2nd Hsu subwoofer.

hoosier21

Any updates on this problem?

Steve@3dai

I don't know of any. Still doing it on mine.

scottvamp

Using a fairly large/heavy center speaker sitting directly on top of a crt television (*IMO* are just too small for a powerful audio HT setup anyway) is just a really bad ideal shielded or not. This isn't a puny bose speaker that sits on 20/30" tv's. Give it some space man. Be creative. Mains don't work either? My car has airbags but I am not going to smack into something to see if they work. There shielded within a reasonal small distance? It is sitting directly on your crt.

Steve@3dai

Originally posted by scottvamp
Using a fairly large/heavy center speaker sitting directly on top of a crt television is just a really bad ideal shielded or not.

Hmm, funny, I didn't think so. And my TV is plenty big for my powerful HT, thanks.

Originally posted by scottvamp
This isn't a puny bose speaker that sits on 20/30" tv's. Give it some space man.

Nope, it's a real man's center channel. And it's got a 1/4" between the plastic and the speaker, should be plenty.

Originally posted by scottvamp
My car has airbags but I am not going to smack into something to see if they work.

You should try it, it's quite fun. Lemme borrow your car real quick.

Obviously Polk looks at this as a problem, since they've spent some time working with me to find solutions. Thanks for adding to the solution. :rolleyes:

[Deleted User]

Forum readers,
We believe we have discovered the cause of the television interference, on the LSiC, it is coming from one of the inductors on the speaker's internal crossover. There is a rather large inductor in series with one of the drivers that, as a signal flows, produces a magnetic field which varies with the frequency and strength of the signal. The stronger the signal passing through this inductor the wider the magnetic field which in turn begins effecting the television's picture. Our magnetic shielding has concentrated on the tweeters and drivers and during static magnetic field testing there is complete compliance. However, under certain crossover designs and playing conditions the crossover becomes a source, as well.
Now that we know the cause we have to develop a cure, perhaps using two inductors arranged to cancel the magnetic fields, or a shielded mechanism for the coil itself. But, what ever it requires we will make available to any LSiC owner at no charge. Also, keep in mind that this is only evident under higher playing volumes and not every television set will react to the same degree. I will certainly make everyone aware of the progress of this matter and encourage everyone to contact me directly if there are any concerns. We also appreciate everyone's patience and willingness to work with us.
Regards, Ken Swauger

rskarvan

Good Job Ken !
Using this forum, you were (or, will be) succussful in solving an engineering issue that was missed in internal product development and test. Time to update those internal FMEA's.

By finding this problem early in production, Polk can save face with the vast majority of customers - thus, reducing problems associated with warranty, etc.

I prefer the reliability of an old airplane with a zillian flight miles, vs. a brand new one straight from the factory.
I prefer to buy new model car the year AFTER they have been introduced - after a few engineering bugs get worked out.
Lastly, I prefer to buy old SDA speakers vs. newer Polks.
(Just had to get that in there).

Steve@3dai

Polk comes through, once again.

I am a sucker for the latest and greatest. My WRX was only 6 months old in the US when I got it, and the LSis were fresh off the blueprint

[Deleted User]

Forum members,
Thank you for your supportive comments, believe me they are appreciated. Perhaps I can use this situation to describe how problems, such as this, are handled, at Polk. We have a Corrective Action Board (CAB) that meets every two weeks and has a representative group of people from all of the major departments, Customer Service, Engineering, Purchasing, Quality Assurance and Management. Anyone can introduce an issue concerning any problem that requires attention, from "catch cups" (the little rubber cups that hold the grille cover pegs in place) to issues as serious as the LSiC. As a participating member of the CAB I brought this problem to the board's attention. In turn, the head of the committee, Mike Carney, assigned someone in the engineering department the task of finding out everything possible about the nature of the problem. In today's meeting an engineer gave a report explaining the experimentation that he did to diagnose the problem. We responded with questions and recommended changes to the testing procedure of all future designs and began determining the best way to cure the problem. As soon as the meeting was over and I felt there was important information, I addressed the Forum. I hope this is an interesting insight as to how we operate.
Regards, Ken Swauger

scottvamp

Should'nt this have been noticed before distrubution of the product? I think many people would agree with my above point. I need a picture of a CS1000 sitting directly on top of a 13" tv. Come on visualize it. Probably havent put this exact "process" into factory testing yet. Anyway glad to see Polk satisfying customers yet again. Great job guys!!!!!!!:)

DarqueKnight

Originally posted by rskarvan

Lastly, I prefer to buy old SDA speakers vs. newer Polks.

Me too. However, the new LSi series is a step in the right direction.:D

mantis

Brittany Spears Video?????who needs sound.......

F1nut

I like to hear her say the F word!