RT 12 Speakers Rebuild

dorokusai

The treelocks FP.....ohhh. Yes post some pics please. Were they Polk part numbers or aftermarket, Parts Express parts numbers? This is very interesting.

I'd like to know what numbers were exchanged in regards to the grill clips, treelocks, etc.

As far as the woofers, same thing.

fatpiggy

Dorokusai,
sent PM check your email.

Fatpiggy

dorokusai

OK, thanks FP.

messiah

Wow Piggy, those are looking sweet! Glad to see they're coming along so well :biggrin:

fatpiggy

Thanks Messiah,
I cant take all the credit,I worked out the materials and basic design with my cabinet maker friend.I really owe him the glory his quality of workmanship and advice has been unbelievable.

Im a cow cocky ex mechanic good with animals and machines hopeless when working with wood.So I fix his truck when he needs work done, we share the love around.

Its goods to have friends in the trades when you live out in the bush, I have another friend who is a bike mechanic fantastic on Harleys, ATV,s.We share our skills between each other and have some fun at the same time, its what we do out in the country.Keeps us away from the nagging wives..heheh

Fatpiggy

cheif pontiac

Wow they look awesome, put my RT12's to shame. Good job man.

fatpiggy

Cheif,
They scrubbed up alright hey.I really didnt think they would turn out as well as they have.I think the extra timber and black gloss front actually improves the look of the design.

What I was thinking at the time was to update them to look like a model of the LSi series so if I get some LSi's down the track they will match as rears.The other good thing is the tweeter can be easily be updated down the track as the crossovers are very basic and easy to modify.

I have saved the RT 12 stickers which I peeled off the old cabinets without damage.I will stick those labels back on the cabinets rear when they are completed.Down the track into the future when Im gone someone else will own these speakers and for the record they will registered in history on the POLK forum as the only pair of cheap vinyl RT12 that had a custom make over to solid timber.

Fatpiggy

Systems

Those look great fatpiggy!

I have some RT10's and they are the only Polk's I own, and I like em.

I have 3 80 model Toyota 4 wheel drives and know an EXCELLENT mechanic that is obsessed with these trucks.
He could charge mega bucks to work on them.
He pretty much works on them for free just to keep them going.
He does not want to see them in the scrap yard because they will never be made again.

Glad to see you are keeping these great Polk's going!

fatpiggy

Pepster,
Thanks for the encouragement.Early Toyota's are the best rock solid 4 x 4's and great to work on.They really thought about what they were doing early in the piece, sadly they dont produce the same quality as they once did.Goes for most vehicle manufactures.Id say the last of well built cars and 4 x 4's was around 1995.

I havnt seen anything these days that gets me excited, well at least here in Australia, dont know how your cars are built in the USA. These days, most of our cars are death trap tin cans.

I dont care how many air bags they put in cars these days , air bags wont stop side impact crushing you to death if your T boned.I dont blame anyone wanting to drive a 4X4 in the city or better still a truck.

To give you an idea how bad cars are built these days over here , if you hit a 250lb kangeroo at 60 miles an hour your car would be a right off.If you hit a cow you would be dead.At least in the early days you would have a better chance hitting stray animals.I really dont know how the get away with thier so called safety ratings.

But as they say thats progress, me I drive a slow 84 Toyota pickup truck it will be 27 years old come next May still has the same motor got over 400k miles on the clock, it will see me out.

Fatpiggy

fatpiggy

Here is the first speaker with the foot fitted and the drivers all installed still have to build the grills and rebuild the crossovers, will be a few weeks before I get the parts.

ben62670

Congrats. Looks great!

fatpiggy

Dorokusai,
You asked me to post pictures of the condition of the new woofers I received today.It is my opinion that they were not correctly packed and the cardboard surrounding the drivers rubbed against the rubber driver surrounds and has caused the obvious wear marks on the new drivers as pictured.

When I removed the boxes from the main carton you could feel the speakers moving inside the boxes.The constant jiggling during transport would have caused the marks on the surrounds.

When I opened the boxes it was noted that the cardboard surrounding each driver was damaged at the point where the speaker rim is held in place by slots cut out in the cardboard.Possibly due to impact.

You can of course make your own opinion.

The other issue is a distorted rubber surround which can be seen clearly in the photo.Initially I assumed they were secondhand drivers as I noticed similar marks on the old drivers when I removed them from the cabinets.The marks on the old drivers were caused from the pressure of the grill.

However a distorted rubber would have been caused from extended periods of pressure being placed on the section of the rubber surround or it is a manufacturing fault that was not picked up during inspection.

I do not intend to return these drivers to Polk due to the cost of shipping.I also believe the damage to the driver is cosmetic and not really worth spitting over, however I am disappointed that my new drivers look rough.

Please feel free to comment, see attached pictures.


Fatpiggy

fatpiggy

Heres a picture of all the speaker boxes, the woofer boxes that turned up today are at the rear, the tweeters I already got a few weeks ago off Ebay.

Fatpiggy

fatpiggy

Heres some pictures of how the speakers were unpacked.You can see a minor mark caused by the cardboard slot on this driver.I had already unpacked the other drivers and only noticed the marks when I was installing the new drivers into the cabinet for fit.

Fatpiggy

fatpiggy

In this picture you can see the other cardboard packing pieces with also damaged slots that are suppose stop the drivers from moving during transport.I dont know why Polk dosnt use rim protectors like other speaker manufactures.Must cost a fortune with replacement warranty for damaged goods.

Fatpiggy

nguyendot

That sucks that they were cosmetically blemished. Maybe ask for a partial refund?
I bet they still will sound great after a break in, but yeah I'd be nitpicky too with my speakers.

mmadden28

fatpiggy wrote: »

In this picture you can see the other cardboard packing pieces with also damaged slots that are suppose stop the drivers from moving during transport.I dont know why Polk dosnt use rim protectors like other speaker manufactures.Must cost a fortune with replacement warranty for damaged goods.

Fatpiggy

They do use rims on other drivers I've seen from Polk- at least the vintage ones on the monitors and SDA. These drivers just look weird to me. I've never really seen a driver where the surround material goes all the way to the edge of the rim or where the screw hole is completely covered with the surround material. Just an odd design I guess.

I agree that the marks on that one driver appear to be cosmetic only, but still.... I know where your coming from with respect to not making an issue about it for something relatively trivial, I've had a few shipments from Amazon where I should have sent them back for a replacement due to a small defect such as a small dent in the corner of a book, or a similar cosmetic, non functional issue--esp since I paid reg price (not clearance or anything), but I didn't want to bother (in the grand scheme of things and all)--ultimately I make a decision based on the end result--will I ever see the defect anyway? I however did recently send back an item that I bought new, but appeared to be used if for nothing else but the principle of the matter.

But then again--given the effort, expense and obvious care for the visual presentation of your project, I would think it worthwhile to give Polk CS a call.

fatpiggy

I had real issues trying to organize these drivers, thought I would be smart and try and save a few dollars importing from the US via a friend who lives in the states.Well I will put it down to experience, its not the first time I have had issues with speakers suffering from transport abuse.I will live with these drivers.Just thought I would raise the issue for others in the future.The woes of re building speakers.

Fatpiggy

TrashyTrucker

FatPiggy,


These look and turned out great! congradulations,




Matt :biggrin:

fatpiggy

Update,
I have completed the repairs to the enclosures and installed all the new drivers and feet, the enclosures are now sporting the new Tri Lam tweeters SL 6001's with thier chrome domes.

I decided to use a set of part express prefit grill guides the small ones.I have fitted the cups to the enclosurses without out damaging the gloss front panel.The installation was very easy.

Monday Im off to get my sound damping...which I will glue with silicon to the inside walls.I will seal all the inside joins with silicon whilst Im at it.

Im drawing up some designs for the grills...which I should be able to give my friend to contruct for me hopefully next week...

Heres come pictures of the two completed cabinets, you can get a better look at the cedar finish.

Fatpiggy

greyford1979

I said before and I'll say it again, those really are beautiful speakers. I bet you can't wait to finally here what they sound like

fatpiggy

Hey Greyford,
Hows it going...Hows your subs going made any more progress.Have you got a thread for your new sub build.

Yes, I have dreams about these speakers..its getting bad..I cant wait to get them up and running, thats for sure. :biggrin:

I dont think I'll have them finished till after the holiday break..But things are moving forward.

Fatpiggy

greyford1979

I haven't started on my buddy's sub yet as we've been swamped at work. Hopefully I will be able to go pick up the wood tomorrow and start on the build. His gf has bought the driver and the amp, so I need to start soon since she wants to give this to him for Christmas. I will get some pics up as soon as I start the build.

fatpiggy

Greyford, sounds great, It will be good to document your next sub build.Your last sub was a cracker..Im still amazed how you managed to get that black finish with a couple of cans of black spray paint and polish ...mind blowing.

Are you still going to convert the coffee table..or have you decided on something else.

Fatpiggy

greyford1979

Yeah it's gonna be an end table that's going to sit next to his seating position. It's not going to be anything super fancy as she doesn't want to spend a ton of money on the enclosure. But I do have some plans that I think will make for a nice sub as well as an end table. I'm making it out of birch with probably some oak legs and trim, Still haven't decided on the exact stains I'm going to use on it yet. The legs and trim will be darker than the body tho. Also not sure yet if I'm gonna go with only the darker stain on the top or if I will go with a dark border and a lighter insert in the middle.

fatpiggy

Should look very nice..ya cant beat the look of timber if it goes with the rest of your decor.
We have this product here its MDF with timber glued to one side its like a wood veneer for bench tops.If I was going to make a new set of speakers from scratch I think I would use something like the pre veneered MDF.Would make life alot less complicated.I think it comes in sizes up to 2 inch thick would be great stuff for making Subs.

Fatpiggy

fatpiggy

Update: Crossover parts turned up today....So I rebuilt my crossovers.Hes some pictures for you all to look at.

Fatpiggy

fatpiggy

The first photo you can see the 2 crossovers with the burnt circuit board where the old resistors had melted.I tried to clean up the board as best as I could but the old resistors really did cook.They fell out and crumbed when I took them out.These are new 2k 5watt resistors I had already installed.

The second photo is of the Dayton crossover parts I decided to use, they are cheapest way to rebuild your crossovers.So what I got was 2 Dayton 10uf polypropylene capacitors 1% and 2 Dayton .01 bypass film foil capacitors 5% and of course 2 Xicon 5watt 2k ohm power resistors.

The third and forth pictures are the crossovers with the original Mylar capacitors still installed I have only replaced the large capacitor value 10uf and added a bypass film foil.I have left the other componets stock.

The rest of the pictures show the new capacitors installed.The only problem I had was getting the new Dayton to fit and finding a way to install the bypass capacitor.I ended up bending the wire terminal down so as the new large Dayton would fit.To get around the space issue I mounted the bypass on the back of the circuit board and I think it looks ok.


Tomorrow I will start on the cabinets sound proofing still have to work out a few things.I might try the original foam first and see how they sound before I start on lining the walls with extra padding I have bought to try.


Fatpiggy

greyford1979

That's cool man. Looks like you will finally be listening to these very soon. Can't wait to hear your thoughts on how they sound. I'll be working on another project again real soon lol.

fatpiggy

Update of my RT 12 speaker rebuild.The first crossover upgrade I did was wrong I used an incorrect tweeter circuit resistor which caused sibilance and harshness in the speakers.I finally got some new resistors a pair of German wire wound Monocor 12w - 2.2ohm ceramic blocks.Very important to use the right value resistors.

The Monocor resistor was a perfect replacement for the 5w 2ohm sandcast blown resistors.They fit perfect even though they are twice the length due to the high wattage.I just needed to fold the resistor leads under the resistor to solder to the circuit board in the original holes.

Once I installed the new resistors and fired up the speakers it was obvious the problems I was having were due to the incorrect size resistors.The sound now is cleaner with a detailed a soundstage that wasnt present.The bass which these are well known is smooth and full bodied.

I removed the original tweeters and installed the SL 6001 Tri lamanite tweeters the silver domed.The sound is much better than the original silk domes.I would recommend these tweeters as an upgrade with these speakers.The sound is brighter and suits the woofers very well.

The tweeter circuit capacitor upgrade using the Dayton 1% er's and Monocor resistors has worked very well so much so that the RT25i now sound flat compared to the RT12's.The RT12's are now very good speakers.I will now upgrade my RT25i's capacitors as Im convinced these upgrades really work.

Still have to get my speaker grills built.


Fatpiggy