RTA 12 - wiring & replacement drivers

Polk65

Last month I bought a pair of RTA 12's in "fair" condition for $100 with a few tiny nicks on some corners and one damaged mw6500 driver. They look like the ones in this photo (my tweeters have the same tiny wedge under the tweeter):

http /clubpolk.polkaudio.com/forum/attachment.php?&postid=26498

Differences between the speakers in that photo and mine are:

1) my cabinets have no rubber feet or stands.
2) my tweeters are black Peerless.
3) my tweeter coil wires are both facing the same direction - to the left side, like the left speaker in that photo. (The tweeter coils in that photo point in opposite directions).


Questions:

1) Does this make mine 12a, 12b, or 12c?
I am guessing the 12a's have the horizontal tweeters, mine are 12b's and the 12c's have the brushed aluminum tweeters?

2) With both tweeters pointing in the same direction, this leads me to think I have two "left" speaker cabinets. I unscrewed the left mw6500 driver in both cabinets and they have a blue, black, and white wire. The right mw6500 driver in both cabinets have a black and white wire. Wouldn't it make sense that the driver with the blue wire be a mirror image on the other cabinet? This usenet thread (2nd and 6th messages) mentions the RTA 12 having inner & outer drivers, one with a higher frequency. http://groups-beta.google.com/group/rec.audio.tech/browse_thread/thread/59651b48112e2fd5
http / groups-beta.google.com/group/rec.audio.tech/browse_thread/thread/59651b48112e2fd5

3) As mentioned, one of the mw6500 drivers is damaged. The voice coil has that "rubbing" sound noticeable on some low frequency music. I bought a pair of Monitor 5 JR's with damaged cabinets for $50 for parts. The mw6502 and sl2000 drivers are in excellent condition. I installed both 5JR mw6502 drivers as the outer drivers in my RTA 12's and replaced the Peerless tweeters with the Polk SL2000's. To my ears they sound fine and both the amplifier and speakers have no complaints. Are these electrically okay as replacements for the RTA 12 mw6500's? The RTA 12 crossover serials are "22 05774" and "22 05779".

4) What are the differences between the various mw650x and mw651x drivers? Different resistance, or just improvements over the years? Are they interchangeable?

after 1 month:
I am very happy with both how they sound and look. It's nice to be able to remove the top cover and reveal the crossovers to look at. These RTA 12's sound very good to my ears but to increase the bass, I have added a psw550 and am happy. The RTA 12's are currently and for the near future, my front speakers in a 7.1 setup. Surrounds are Monitor 5 JR's, and the center is a cs245i. I may change the center to something with an sl2000 and mw65xx" drivers.

F1nut

Just a quick response, more later. It doesn't matter which direction the tweeter coils are pointing, don't like them the same way, reverse one of them.

F1nut

Ok, You'll be fine with the 6502's in place of the 6500's, not that much of a difference. However, I would put the original tweeters back as most folks prefer them to the SL2000 which has a nasty spike around 12kHz-13kHz.

As for the rest, hopefully some of the other members with more knowledge of these speakers will chime in.

Polk65

Interesting. I re-read that usenet post #2 and with what the poster said I am now aware of at least four variations of the RTA 12. One with the horizontal black Peerless tweeter, (mine with the vertical black Peerless tweeter), a Polk sl1000 and a Polk sl2000.

By the way, the sl2000 four screw holes are larger than the Peerless. I got lucky with the fact that the RTA 12 top mounts use rigid wires (similar in size to a coat hanger) and are adjustable. The mount points I used are the top 2 and one at the bottom.

I now have 5 questions regarding the mw650x and mw651x drivers.
1) What are the differences between the various mw650x and mw651x drivers?
2) Different resistance, or just improvements over the years?
3) Are they interchangeable?
4) Different rms, or are they all 100w rms?
5) Are there noteworthy differences for the SDA drivers?

If I solder the Peerless tweeters back in, will they match my side and rear surround Monitor 5JR's with sl2000's ?

dorokusai

I've owned a couple RTA12's...both RTA12C....and both with different tweeters, and different paperwork. The SL1000 is smaller than the SL2000, and the new replacement RD0194.

It sounds like you are building a "FrankenPolk"....go original if you are able.

You essentially removed all resale value, to the educated Polkie, by using non-original drivers.

Does it matter? Yes...drivers are created for specific applications. Do you think Polk just said, "Well, just put in whatever makes sound"???

Ask any DIY speaker builder if voice coil diameter, vc length, Xmax, magnet weight, driver diameter, composition....matters.

I know the early days were a little cloudy, but the RTA line is commercial in Polk time.

Is it CRUCIAL for Polk's....depends on the speaker. At some point all of us will be **** outta luck, as the agenda is to provide three(3) vintage drivers.....period, regardless of application.

BUY YOUR REPLACEMENT DRIVERS NOW.

It becomes a money issue to support all these vintage models and drivers....they picked the most popular, most requested, and most used....stock only lasts so long.

If your surrounds are currently SL2000, why replace them with Peerless?

Polk65

Thank you all for any comments regarding these artifacts. All responses will be respected.

LOL - FrankenPolk

I do NOT feel bad *trying* to match together some vintage Polk masterpiecies. Screw the marketing and hype, it's what *we* grew up listening to, that *we* will remember, cherish and use as benchmarks!

Q: "Does it matter? Yes...drivers are created for specific applications. Do you think Polk just said, "Well, just put in whatever makes sound"???"

A: Hmmm... When 6500's came out, were there 15+ alternative Polk 6.5" driver models available? NO! The last time I had Polk's was 1985. There have been QUITE a few variations of the 65xx driver released since then.

As far as resale value goes, I have saved all of the original drivers for *if* the day my great-grandchildren sell these RTA 12s in the next century on Mars when I am fertilizing grass, re-sale value will be a moot point.

Until the day I see a "TL" version of anything made by Polk on the West coast, I will be *very* happy with these RTA 12's.

In the past 8 months of watching ebay and craigslist, 90% of the *drool* Polk SDA speakers are for sale in the state of Florida, and the other 9% on the East coast. Specifically in the state of Maryland. Freight cost of shipping SDA's to the West coast are equal to 1/2 the cost of an SDA unit.

Now, should I spend $48+ shipping for a single mw6500 (yep, that is what one sold for on 2005-0117 on ebay - DUH! same price for a new one from CLUB POLK! or should I buy two mw6502's and 2 sl2000's for $50 used (in perfect condition) for *MY* RTA 12's?

Q: If your surrounds are currently SL2000, why replace them with Peerless?
A: Re-read my first post. The mains are RTA 12's replaced with Polk sl2000's. Sub-woofer is a psw550, mid and rear surrounds are Monitor 5JR's (these come with sl2000's not Peerless...).

F1nut

There are 2 MW6500's for sale on ePay right now.

You need to look in CA a little harder, there are a lot of them there. I bought mine from a guy in your state, shipping was $240.00.

Polk65

I've seen two 'modified' 1.2's for sale but no 1.2tl's or 2.3tl's nearby.
F1nut, what freight company did you use?

F1nut

ABF Freight Systems at http://www.abfs.com/

Click on the "One-time or infrequent LTL shipper" to get a rate quote at a very good price. You can cut the cost even more if you can pick them up at their freight docks. Be aware that no one will help you load them up, so you might want to bring help.