Newb with new (to me) RTA-12s

nathanexplosion

So, after an introduction to Polk with a pair of RTi6 speakers and a PSW110 sub hooked up to my PC, today I picked up a pair of what I believe to be RTA-12s. The seller described them as RTA-12Bs, but my preliminary research leads me to believe otherwise. They are shorter cabinets with black pedestal stands which he says are original (and I believe him, because he says he is the original owner). They also have a vertical black tweeter with 5514 1980 stamped on the back (which I think makes them Peerless?) and no ramp thing. Other than that, I would say they haven't been recapped, or molested/modified in any way. I have the caps, as he called them, for the external tweeter/crossover, but the MDF base decayed slightly and the posts are no longer attached, though I have all the pieces to put them back together. They're pretty clean, and sound absolutely fantastic hooked up to my Sony STR-GX9ES (don't know if this is a respected receiver, but these speakers sure sound sweet!) and I am stoked for $75.

What should I look out for with these? I've read a few posts about gluing (JB weld specifically, I guess) the speaker magnets on some Polks, would that be advised here? Should I worry about the caps and recap soon, or wait and do it when there's a little more room in my budget for caps.

Mostly I'm just excited to have entered the world of vintage audio, and with what to me sound like a fantastic pair of speakers. I'll try to get some pictures up as soon as possible to help you guys, and I'll keep researching these, I may answer some of my own questions.

Nightfall

You have original RTA12's not B's. Both of the midwoofers are crossed over at the same point unlike later iterations. Sounds like you have Peerless tweeters, correct. Yes JBWelding the magnets in place is advised here, helps prevent magnet shift.

P.S. Thunder! Horse!

Mr. Bubbles

Welcome to the forum. Congrats on the speakers.

Yes JB weld the magnets properly. The drivers are old and prone to magnet shift. This will prevent any unneccesary heartache from this issue. replacing the caps will make a huge difference. Though there is a pretty big difference in sound between cheaper caps and some more expensive versions, I find the the returns diminish somewhat even from the basic metal/ poly caps once you go up the chain. I would use the best caps you can fit into your budget and feel comfortable with yourself. Don't forget the resistors as well. Dynamat, Black hole, Hurricane nuts, new gasket material, resealing the cabinets. All of these are nice mods as well. Enjoy the rabbit hole as some around here describe it.

nathanexplosion

Thanks guys. Here's a picture of one with the cover off.

Is this still the preferred way of gluing? Also, do I remove the speakers through the front of the cabinet by removing the screws? Or does the back come off in a way I'm not seeing? The big radiator won't have a magnet, right?

Thanks again!

teekay0007

Yes, you remove the drivers through the front by removing the screws. And no, the big passive radiator won't have a magnet.

Lots of people around here use the JB Weld and seem to be very happy with it. Others use Loctite epoxy, or some other types of epoxy, with good results also.

nathanexplosion

I noticed today that it looks like some of the foam on the face of the woofer is starting to lift a bit at the edge, visible in the picture above, from about 3-4 o'clock. Is this something I can fix? Should I ignore it? They seem to sound just fine, no rattles or harshness that I can hear.

westmassguy

nathanexplosion wrote: »

I noticed today that it looks like some of the foam on the face of the woofer is starting to lift a bit at the edge, visible in the picture above, from about 3-4 o'clock. Is this something I can fix? Should I ignore it? They seem to sound just fine, no rattles or harshness that I can hear.

That's not a woofer, it's a Passive Radiator. A little Aleene's Tacky Glue applied where it's lifting, should hold it down. Wipe off any excess with a damp cloth.

boston1450

? Are those speakers stable on those stand. I had a friend who had same ones & they were quite heavy IIRC. It may be the the pic makes them look ?able. Maybe cause my head is sideways Congrats. They look very nice & welcome to club Polk

nathanexplosion

They are shockingly stable, and the stands are heavier than I would've expected, and actually, the speakers are a little lighter than I thought they were going to be (the Polk website lists the weight of RTA-12Bs at 75 lbs each I believe). One was a little unstable, but I fixed that with some little rubber feet on the stand. Since I am currently using them connected to my PC (though the Sony), the stands are great, they put the speakers at a nice listening height. I keep forgetting that big thing is passive, not used to having such giant, awesome sounding speakers.

Do you guys have a recommendation for a professional who could rebuild the crossovers? I've seen VR3 on the internet, would they be good to use? I feel I would be remiss if I didn't at least get a quote from a pro.

Thanks again!

pitdogg2

nathanexplosion wrote: »

I feel I would be remiss if I didn't at least get a quote from a pro.

Trey VR3 is a professional and knows his way around a XO better than most "pros"

boston1450

Got ya on stands. Pic exploded them to looking wider than they are. Those are earlier 12's did they come with hats also-to cover tweets

westmassguy

pitdogg2 wrote: »

Trey VR3 is a professional and knows his way around a XO better than most "pros"

What am I chopped liver?

BTW, to the OP, the RTA 12s were not meant to be used with stands. I can't tell from the photo, but if the stands are pitched back at all, that would be bad.

pitdogg2

westmassguy wrote: »

What am I chopped liver?

UUmm NO ......

Sorry Westmassguy has done many here and no one ever complained about the quality of his work.




come on Dave give me a break

nathanexplosion

boston1450 wrote: »

Got ya on stands. Pic exploded them to looking wider than they are. Those are earlier 12's did they come with hats also-to cover tweets

Yes, but the previous owner said the hats were damaged in a move. I have the MDF bases for the hats, and the plastic poles which hold the cover up, and the wire brace for the top, and the cloth covers themselves, I just need to glue the plastic bits back in, or replace the MDF base (which is kind of what I'm thinking, they don't look hard to replicate).

westmassguy wrote: »

What am I chopped liver?

BTW, to the OP, the RTA 12s were not meant to be used with stands. I can't tell from the photo, but if the stands are pitched back at all, that would be bad.

They are totally level. They actually say Polk on the bottom, though I don't know if Polk themselves put that there. Mind if I send you a PM about crossover rebuilds after I get enough posts?

westmassguy

They are totally level. They actually say Polk on the bottom, though I don't know if Polk themselves put that there. Mind if I send you a PM about crossover rebuilds after I get enough posts?

The base should be about an 1 1/2" as I recall. The tweeters look to be way too high on the stands. The design was for real time array AKA RTA. The stands would mess with that.
You can contact me directly via my website if you so choose.

nathanexplosion

The top of the tweeter is currently 45 1/2" off the floor on the stands. Should I try them on the floor? I feel like they'll be lower than the desk they're next to at the moment.

boston1450

Where's the chopped liver

boston1450

Ya damaged hats are normal. Westmassguy will be very helpful-just bring the onions cause they go great with liver.. Those speakers you have & SDA's placement is very important & lets not forget what you feed them with is very important also. My friend had some & he was using a receiver that shouldnt have been used with them. He sold them off & never got to hear the speakers operate the way they were ment to be heard

Nightfall

The original RTA12's are suppose to be on stands. The later RTA12's have their own "stand" built into the bottom, unlike the flat bottomed originals.

westmassguy

Nightfall wrote: »

The original RTA12's are suppose to be on stands. The later RTA12's have their own "stand" built into the bottom, unlike the flat bottomed originals.

I see that now. Seems odd that the tweeters end up being that high, compared to the 12 B/C

Faustin

Westmassguy rebuilt my RTA 12c crossovers. Very prompt and quite pleased with the results. I have been running them with an Adcom GFA-555 and an Adcom GTP-500 11. They do require and handle alot of power. The bass is very good on them and when turned up they can easily chase you out of the room. I am not sure why Dave (Westmassguy) never mentioned the chopped liver to me. Guess I will go to the corner deli later today.

westmassguy

Faustin wrote: »

Westmassguy rebuilt my RTA 12c crossovers. Very prompt and quite pleased with the results. I have been running them with an Adcom GFA-555 and an Adcom GTP-500 11. They do require and handle alot of power. The bass is very good on them and when turned up they can easily chase you out of the room. I am not sure why Dave (Westmassguy) never mentioned the chopped liver to me. Guess I will go to the corner deli later today.

Thank you Sir. I hoard chopped liver, like you hoard Peerless. I would have sent it with your crossovers, but I was out of dry ice.

codyc1ark

Lol, love the screen name.

nathanexplosion

So today I tried to put the tops back together. Has anyone done this? Does the fabric stretch alot? It seems like the posts are too tall, or I am missing something on how it goes together.

Faustin

Did you remove the fabric in order to repair the frame? If they are like my top hats, the fabric is held in place by a rubber spline in a channel. Same principle as a window screen. I removed the fabric and hand washed the fabric covers and let them air dry. I had to re-glue a couple of the corner supports and them bought new rubber screen spline and re-assembled. The fabric does stretch and fits snug. It took a bit of time to make sure the fabric was not too tight or too loose.

nathanexplosion

Mine does have a bit of frame to the top, but it appears to be a simple metal square with round edges that match a groove in the plastic supports. I was hoping to not have to remove the cloth, since it has about 30 staples holding it down, and is shockingly clean, but I can do it if I need to.

Also, is the correct fuse a 250V .75A fast blow? The previous owner handed me a handful of fuses, but none are .75A fast blow. They currently have .75A slow blow in them.

Faustin

Her are some pics of a damaged top hat frame that is the same as mine. Mine do not have any staples holding the fabric in place. I think you will be able to see the channel for the rubber screen spline to hold the fabric in place. My 12's use a 1 amp fast blow fuse, which if I am not mistaken is the fuse that is used in pretty much all of the externally fused older Polk crossovers.