Polk RTA 12's

Mij

Back in the early eighties, I saved up all my money from a summer job, and bought a pair of RTA-12's. Twenty-five years later it is time to move on, and I need some advice.

Are these something that should be sold to a collector, or just listed on ebay or craigslist? If there is serious interest in these speakers as a collectible, I'd hate to have them go out to someone who is just looking for a bargain.

And speaking of bargains, how do you value these? The speakers are in good working condition; Grills are ok -no rips but shape has deformed a bit over the years; original stands were thrown out years ago; and rosewood cabinet sides in fair condition.

Thanks!

engtaz

post pics

engtaz

Mij

Here are the pictures (I think)

opus

what's your twenty?

MillerLiteScott

What is the theory on this speaker design?

Bass and mid-range in a sealed enclosure for a tight and punchy sound and the tweeter out in the open for a wide airy sound?

George Grand

That woofer is a big passive radiator, not really a sealed-box acoustic suspension.

dorokusai

MillerLiteScott wrote:

What is the theory on this speaker design?

Bass and mid-range in a sealed enclosure for a tight and punchy sound and the tweeter out in the open for a wide airy sound?

Real Time Array. In a nutshell, high and low frequencies move at different wavelengths and in this array they arrive at the listener at the same time. Hence the "recessed" tweeter.

The early Monitor 5-10 used an optional Polkstand which had just enough uptilt, which kicked the top of the speaker back, to give you a poor man's time alignment. You could do this with a 2x4 just under the front of the loudspeaker....or whatever you have laying around.

Vandersteen is another example of this idea and you'll notice it in many other speakers designs in one form or another. B&W used the idea, in the DM series, but used the crossover to induce the delay. They may still use it, I'm unsure.

RuSsMaN

Time aligned, yes, the wavelengths are different sizes, but the speed of sound is the speed of sound at a given altitude. The big plus is the voicecoils on the tweeters and midwoofs are aligned. Ie, if you looked at the speaker from the side, you could draw a straight line through the voicecoils.

Cheers,
Russ

dorokusai

Yes, wavelength is the best way to describe that idea. I had speed on my mind for some reason....perhaps because I just swallowed a handful of Yellowjackets.

Mij

Sorry I was out sailing.

Opus I'm in Seacoast, New Hampshire

MillerLiteScott

Sailing, That is what I use to do before kids.

Mark, Could you forward or tell me where to look for the speaker stand specs for the Monitor 5's and up. I am getting ready to build stands.

The speaker slanting back aligns (to a degree) the wavelengths from the bass, mids and tweeters. I guess this is why Schwingdings Strata Mini's have a swept back stance and now that I think about same as ML speaker. I think I understand but not really.

Thanks,

Scott

RuSsMaN

Mark has a great tutorial on Monitor 7 and 10 stands here on the boards. Get your search on.

Cheers,
Russ

MillerLiteScott

Thanks Russ.

I will. I did not know if it was on this site or off the site or even actual paper.

Russ did you get my PM?

Scott

BottomFeeder

Ok, back to Mij's question, you hijackers!

Most guys on this forum could give better answers than I, but I'll give my two cents worth. I spent some time researching the RTA12's before finding some RTA12C's. My dad has some RTA12's just like yours.

The one's in good condition seem to max out at around $200 on ebay. Some of the guys here modify theirs so they can go for a bit more. There's a guy near me who's had his in storage for 17 years (!) and he wants $400. Don't think he'll get it, however.

They're terrific speakers and are held in high regard around here. I don't think they're collector items but I agree with you that you'd like someone who'll appreciate them to get them! Try searching this forum "RTA12" and you'll find lots of good information.

I'm sure some of the really knowledgable guys on here will help you out as well. (Hint, hint!)

Mij

Thanks BottomFeeder,

I appreciate the insight.

BottomFeeder

*Bump*

Fireman32

I have the RTA12B's with the peerless tweats and I love this speaker. as per the pics they seem to be in great shape (better than mine). Before throwing them on the bay see if anyone here has intrest. I might possibly be intrested myself.

Mij

I'd rather have the speakers go to someone who appreciates them.

The speakers are actually in very good shape. The cabinet's veneer is solid with no real scrathces. The front grills are fine. The top needs a bit of work to make perfect.

The corners are rounded, and the shape is formed with what looks like a heavy plastic screening material. It looks like they used a wire frame and these plastic screen corners to define the tweeter enclosure's shape which would allow as much of the sound to travel through as possible. Over the years, the pressure of the grill cloth has deformed the corner shape slightly by pulling the screens in.

I think it could be made perfect again fairly easily by removing the cloth, and replacing the corners pieces-maybe pvc pipe painted black.

If anyone has an interest- let me know.

dorokusai

The corners may be broken, which is common in that model. Unfortunately, it's not easily fixed.