This weekend's find - Polk RTA-12C

[Mystery]

I'm adding a new set to my Polk collection; RTA-12C.
From what I read, these are the best non-SDA speakers among vintage Polks.
Cabinets/grills are in excellent condition besides few scratches/nicks and all drivers/tweeters work.
These are pretty large; almost 40 inches high and weigh 75 lbs each.
Not sure if these can replace Boston A400 as my mains but it'll be interesting comparison.
Their specs mention they can go as low as 17hz (25hz +-3db) but I really doubt they go that low.

What's your experience on these?

Few pictures:

 

[steelglam]

I have the original version...the straight-up RTA-12. Different tweeter than yours, but they probably sound similar.

I love my RTA-12's, one of my favorites. They were actually the first serious speakers that I got once I moved beyond a crappy rack system and started getting more into this hobby, and they have yet to leave. I most recently got rid of a pair of Klipsch Forte's because they couldn't compete with the Polk's.

To my ears, the Polk's really just don't do anything wrong. I've heard speakers with better highs and better lows, for instance, but nothing that presented as cohesive of a picture and performed as well from top-to-bottom as the Polk's. They also present a good soundstage and can disappear.

 

[Bucky Badger]

I think that these are some of the best Polk speakers I have heard. I regret selling mine and am always looking to get another pair. The 12C's have a great soundstage and are a well balanced speaker. I personally like them better than the SDA 1's or 2's.
Congrats on getting a beautiful pair of Polk speakers. Enjoy!

 

[Mystery]

Thanks for chiming in.
These RTA-12C's have better soundstage (RTA disappear better but have strong/powerful sound) than A400's (more directional) but both I and wife like A400's silky smooth sound much better than these so A400's are staying in the living room.
I'll be moving these to bedroom where I have NLA and ADS L620.
I don't like NLA so much but L620's are very nice and these RTA-12C's should be better than both for the bedroom.
:scratch2:

 

[ofajen]

I had RTA-12Bs for over 30 years. I traded them away this summer after many years of non-use. I always loved the imaging on those speakers. Also, they seemed to have a totally natural sound that let them disappear and just leave the music. We just don't have a good place for large floor standing speakers.

No regrets selling, though, because they weren't seeing use here, and I traded them to a guy who can use them. I ended up with a pair of lowly Nova 6s in the deal, but now they are being reused as sealed subs with new Peerless drivers and have transformed both the office and living room systems for the better.

Cheers,

Otto

 

[Rome]

Those are so nice!

Rome

 

[Pickoid]

Although I have never heard these, I think they should sound quite similar to my RTA-11's, which seem essentially like the same speaker with the tweeter and crossover mounted in the cabinet instead of on top. Mine look sort of like overgrown Monitor 10's, but they have similar crossovers as the RTA-12, with labeled left and right speakers.

If all of your mid/woofer drivers are in good shape with no magnet shift, you are a very lucky man. You should immediately pull them out and run a good bead of JB Weld between the speaker basket and the magnet assembly to prevent magnet shift as you move the cabinets around.

There is a ton of info and mods for these detailed over the Polk Audio forums. I have done a lot to mine, including converting all of the wood screws to t-nuts/machine screws, recapping the crossovers, damping the speaker baskets with sound insulation (dynamat or similar), and replacing all the gaskets. I think all of these were worthwhile improvements, and were easy to do.

I haven't (yet) owned any speakers I like better than my RTA-11s. They produce a very wide soundstage that I find very pleasing to listen to. I've been A/B'ing mine with a pair of Infinity Kappa 6's, which are very good, but I give the edge to the Polks. I would love to hear the RTA-12s, since they were the TOTL of the series. Congrats on the find!

 

[shacky]

Congrats! Would love to hear the 12's. I'm finishing a recap on pair of Monitor 11's I picked up earlier this year. They have the Peerless tweeter and sound wonderful.

They may give your A400's a better run with recap and Polk's replacement tweeters :scratch2:

http://www.audiokarma.org/forums/showthread.php?t=437262&highlight=polk

http://www.audiokarma.org/forums/showthread.php?t=440579&highlight=polk

 

[ofajen]

Although I have never heard these, I think they should sound quite similar to my RTA-11's, which seem essentially like the same speaker with the tweeter and crossover mounted in the cabinet instead of on top. Mine look sort of like overgrown Monitor 10's, but they have similar crossovers as the RTA-12, with labeled left and right speakers.

You might be surprised. I think the recessed, top mounting of the tweeter makes a considerable difference in the imaging. I compared Monitor 10s when I bought the 12Bs and the difference was substantial.

Cheers,

Otto

 

[Mystery]

C version of RTA-12 are unique...

Although I have never heard these, I think they should sound quite similar to my RTA-11's, which seem essentially like the same speaker with the tweeter and crossover mounted in the cabinet instead of on top. Mine look sort of like overgrown Monitor 10's, but they have similar crossovers as the RTA-12, with labeled left and right speakers.

If all of your mid/woofer drivers are in good shape with no magnet shift, you are a very lucky man. You should immediately pull them out and run a good bead of JB Weld between the speaker basket and the magnet assembly to prevent magnet shift as you move the cabinets around.

There is a ton of info and mods for these detailed over the Polk Audio forums. I have done a lot to mine, including converting all of the wood screws to t-nuts/machine screws, recapping the crossovers, damping the speaker baskets with sound insulation (dynamat or similar), and replacing all the gaskets. I think all of these were worthwhile improvements, and were easy to do.

I haven't (yet) owned any speakers I like better than my RTA-11s. They produce a very wide soundstage that I find very pleasing to listen to. I've been A/B'ing mine with a pair of Infinity Kappa 6's, which are very good, but I give the edge to the Polks. I would love to hear the RTA-12s, since they were the TOTL of the series. Congrats on the find!

Yes, all drivers/tweeters work.
I have over 8 pairs of Polks that need JB weld or epoxy, dynamat, crossover etc...
Man, that means a lot of time that I don't have. :sigh:

Never heard RTA-11's so not sure how similar they sound but read my response below on what's unique to the C version of RTA-12's.

Congrats! Would love to hear the 12's. I'm finishing a recap on pair of Monitor 11's I picked up earlier this year. They have the Peerless tweeter and sound wonderful.

They may give your A400's a better run with recap and Polk's replacement tweeters :scratch2:

http://www.audiokarma.org/forums/showthread.php?t=437262&highlight=polk

http://www.audiokarma.org/forums/showthread.php?t=440579&highlight=polk

Re-cap is in the plan but not soon.
A400's are very detailed yet soft and smooth. It's like listening to live music.
RTA's sound little punchier and metallic.
I'll compare them later in proper setup.
Current living space is not that big to experiment placement options.

You might be surprised. I think the recessed, top mounting of the tweeter makes a considerable difference in the imaging. I compared Monitor 10s when I bought the 12Bs and the difference was substantial.

Cheers,
Otto

I agree but it's not only due to top mounting tweeter.
From my online research, RTA-12C's are the best in RTA series and they are the only ones that are really time aligned.
All other RTA series including original RTA-12 mimic that name but they are not mirror imaged and not truly time aligned.
RTA-12C's actually are mirror imaged and have different different crossovers for left and right speakers/mid-woofers unlike other RTA's that have single crossover.
http://www.polksda.com/pdfs/1985Sales.pdf
It mentions RTA-12C uses unique technology for imaging and clarity that was not in other models.
It handles upto 500 watts of power.
It utilizes phase-coherent open air driver mounting in a mirror imaged, fullsize floor-standing configuration.
This model won the AudioVideo Grand Prix Speaker of the Year Award and was selected for the prestigious CES Design and Engineering Exhibition as one of the industry's most innovative products.

However, it's only true on the B and C versions where outside mid woofers drive 60-600HZ and inside mid woofers drive 60-2000HZ.
This applies to RTA 12Bs and Cs.

--> The early RTA 12 (the ones without B or C) DO NOT roll off the outside driver and are not mirror imaged. They have only one crossover.

 

[cubdog]

Great looking Polks. I've unfortunately yet to hear a pair. Enjoy them!

cubdog

 

[Pickoid]

Interesting. I have attached a jpg of part of the user manual for the RTA-11's. Seems to contradict the information below, but I dunno. Based on this info, I think the crossovers in the 11's are similar to the 12B's.

From my online research, RTA-12C's are the best in RTA series and they are the only ones that are really time aligned.
All other RTA series including original RTA-12 mimic that name but they are not mirror imaged and not truly time aligned.
RTA-12C's actually are mirror imaged and have different different crossovers for left and right speakers/mid-woofers unlike other RTA's that have single crossover.
http://www.polksda.com/pdfs/1985Sales.pdf
It mentions RTA-12C uses unique technology for imaging and clarity that was not in other models.
It handles upto 500 watts of power.
It utilizes phase-coherent open air driver mounting in a mirror imaged, fullsize floor-standing configuration.
This model won the AudioVideo Grand Prix Speaker of the Year Award and was selected for the prestigious CES Design and Engineering Exhibition as one of the industry's most innovative products.

However, it's only true on the B and C versions where outside mid woofers drive 60-600HZ and inside mid woofers drive 60-2000HZ.
This applies to RTA 12Bs and Cs.

--> The early RTA 12 (the ones without B or C) DO NOT roll off the outside driver and are not mirror imaged. They have only one crossover.

 

[Mystery]

Interesting. I have attached a jpg of part of the user manual for the RTA-11's. Seems to contradict the information below, but I dunno. Based on this info, I think the crossovers in the 11's are similar to the 12B's.

I was replying and server crashed again. :sigh:

Hmm... interesting indeed.
I could be wrong on summing online articles.
May be the RTA-11's are an exception.
Their description reads similar to the RTA-12C's with mids driven separately.

If the 11's are mirror imaged like RTA-12C's, then they should sound similar than other monitor series.

I better check the schematics. :scratch2:

 

[shacky]

Yes yhe 11's (not 11T) are similar to 12's being mirror imaged. Unique and rarer Polk model. I need to finish mine.

I also JB welded and Dynamated my drivers. The foam insert behind the higher midrange deteriorated and need replacement too.

I'll trade you for your 12's

 

[tubed]

Other than offering congratulations on deservering acquisitions, I generally don't comment on new speaker finds especially if the new owner has happily made "a step up".
But since comparisons are being made I just have to say I thought the RTA 12c's were quite disappointing (both pairs I've had), actually not really listenable for very long especially compared to some of the speakers mentioned in this thread.
The pick below shows a pair awaiting the arrival of a happy buyer and an even more pleased seller.
Oh yes, enjoy!

 

[GoRNR]

Mystery- I recently sold a pair of RTA-12B's to another AK'er. I liked them but something had to go, so they found a better home. Anyway, they sounded very good to me with just excellent imaging and bass. While they were in my possession I also bought original Peerless tweets to try replacing the SL-series tweeters. I never got around to it. So the new owner got the tweets with the speakers. He did the swap and loves the sound a lot more. He said they are definitely smoother and maybe just a tad softer than the SL tweets were. If you want to try to maybe get a little more performance out of them, the Peerless tweets or the current RDO's that Polk sells might do the trick for you. Just something to think about if you decide they are longterm friends. Nice speakers you have either way! :thmbsp: Jim

 

[Mystery]

Thanks for comments.

Other than offering congratulations on deservering acquisitions, I generally don't comment on new speaker finds especially if the new owner has happily made "a step up".
But since comparisons are being made I just have to say I thought the RTA 12c's were quite disappointing (both pairs I've had), actually not really listenable for very long especially compared to some of the speakers mentioned in this thread.
The pick below shows a pair awaiting the arrival of a happy buyer and an even more pleased seller.
Oh yes, enjoy!

Thanks and no problem.
I always welcome opinions and constructive criticisms.
That's why I'm here.
The ones in your picture are with SL1000 tweeters that are considered to have even better sound stage than SL2000. Did you ever try replacing crossovers?

To tell the truth, may be I was expecting much better sound from these RTA-12C due to their size and TOTL model as I really like monitor 5B's and 7C's as well as CRS+.

Mystery- I recently sold a pair of RTA-12B's to another AK'er. I liked them but something had to go, so they found a better home. Anyway, they sounded very good to me with just excellent imaging and bass. While they were in my possession I also bought original Peerless tweets to try replacing the SL-series tweeters. I never got around to it. So the new owner got the tweets with the speakers. He did the swap and loves the sound a lot more. He said they are definitely smoother and maybe just a tad softer than the SL tweets were. If you want to try to maybe get a little more performance out of them, the Peerless tweets or the current RDO's that Polk sells might do the trick for you. Just something to think about if you decide they are longterm friends. Nice speakers you have either way! :thmbsp: Jim

Yes, stereo imaging is amazing on these.
Btw, peerless tweeters are not replacement for SL2000.
They'll work but without crossover modification, they won't sound what they were designed for.

I've rotated so many speakers in my living room as fronts and none of them can beat A400's so far.
JBL L166 and Yamaha NS-690 are the only ones not tried yet due to placing limitations.

 

[steelglam]

Mystery- I recently sold a pair of RTA-12B's to another AK'er. I liked them but something had to go, so they found a better home. Anyway, they sounded very good to me with just excellent imaging and bass. While they were in my possession I also bought original Peerless tweets to try replacing the SL-series tweeters. I never got around to it. So the new owner got the tweets with the speakers. He did the swap and loves the sound a lot more. He said they are definitely smoother and maybe just a tad softer than the SL tweets were. If you want to try to maybe get a little more performance out of them, the Peerless tweets or the current RDO's that Polk sells might do the trick for you. Just something to think about if you decide they are longterm friends. Nice speakers you have either way! :thmbsp: Jim

I have never heard the tweeter in the 12B's and 12C's to do a comparison, but I can vouch for GoRNR's friend by saying that the Peerless tweeter in my early/first series RTA 12's is very smooth and non-fatiguing. In fact, they are one of my favorite aspects of the speaker. So Mystery, I would second GoRNR's suggestion to be on the lookout for some Peerless tweeters if you are going to keep these for the long haul.

It's interesting that Mystery was comparing the Polk's to his Boston A400's. Right now, I have the Polk's in and out of rotation with a pair of Boston A150's. (I've found that I like mixing things up every now and then, and my moods sometimes change regarding what kind of sound I want to hear, so I try and keep two pairs of speakers for each system.) Anyhow, I think they are two very different beasts, but both are very nice. The Boston's are smoother and warmer as a whole, similar to Mystery's comments about his A400's. I also think the Boston's are probably a bit fuller in the bass department and a bit more detailed. But I think the Polk's have better highs, better soundstage, are more natural sounding, and are more cohesive top-to-bottom. Of course, I imagine the A400's are much better than the A150's.

 

[tubed]

Good Sport, Mystery
It is always fun to get new stuff!
FWIW, I was really disappointed to the point of indignation at the sound that the Polk RTA-15tls were guilty of producing.

 

[Mystery]

Good Sport, Mystery
It is always fun to get new stuff!
FWIW, I was really disappointed to the point of indignation at the sound that the Polk RTA-15tls were guilty of producing.

I have RTA-8TL but never heard bigger ones.
RTA-15TL's supposedly sound very good in HT than 2-channel music.

But never heard about any Polk being really disappointing until now about your experience with RTA-15tls. :scratch2: