RTA-12 orginal and rebuilding RTA-11t wattage rating?

rdozz

I searched the fourm but could not come up with the RTA-12s max rms wattage rating? I looked at the schematics posted in one of the stickys and the speakers are the MW-6500s. I took them apart and verified the parts. The mw-6500s are rated at 35 watts each. I could not tell how the wattage translated through the cross-over. I am interested because they are amazing at low and med volumes but start to sound distorted when pushed. I don't mean abused when I say pushed.

I replaced the 10 inch PRs when I frist got the speakers. The spiders holding the PRs togather were completly destroyed from age. They had been stored in a location which was exposed to temp and humidy. The cabnits looked great the grills are perfect too. My uncle gave them to me, he was the orginal buyer I have the recipt from 1983 (i think). So it was a no brainer to fix them up. One more question, is it possible the distortion is caused because the spiders are weak or damaged on the mw-6500s due to there storage conditions or age?

Now I have the polk bug! I bought a pair of 11ts on craigslist for $75 knowing the tweeters were bad. After owning for a couple of months. I decided to open up the 11ts and check out the internal condition. I got taken pretty bad! None of the 6.5s were orginal. I called the guy on this obvious rip off but, he denied knowing anything. That is behind me now, it will not happen again thanks to this fourm. I have bought 3 mw-6510s and looking for one more. Also I found to new sl-2000s. I can't wait to get the last driver in. Can somebody help me with the wattage rating on the 11ts also? I noticed the mw-6510s are rated at 35 watts also.

This fourm is so much help! I want to thank everyone who contributes to the board.
over look the spelling.
Rob

F1nut

I replaced the 10 inch PRs when I frist got the speakers.

Did you replace them with Polk PR's?

The mw-6500s are rated at 35 watts each.

Where did you get that info?

One more question, is it possible the distortion is caused because the spiders are weak or damaged on the mw-6500s due to there storage conditions or age?

Using your fingers spread out evenly, gently push each driver in and listen for any noise.

Also I found to new sl-2000s.

Horrible tweeter, get the RD0194-1 from Polk.

As far as the rated power I don't recall the specs, but both models will handle just about anything as long as it's clean power.

rdozz

Thanks for the quick responce.

I got the wattage rating for the drivers in a thread on this fourm.
www.polkaudio.com/forums/showthread.php?72279-MW-6500-vs.-MW-6503

Driver: MW 6500 Driver's model #.
Brand: Polk Driver's brand name.
Fs: 31.0000 Hz (Free air resonance)
Vas: 2.6486 ft^3 (Compliance volume)
Qts: 0.2190 Total Q
Qms: 1.3000 Mechanical Q
Qes: 0.2640 Electrical Q
Sd: 0.0130 M^2 (Piston area)
Xmax: 3.1800 mm (Cone excursion, linear)
Revc: 6.5000 ohms (DC resistance)
Znom: 8.0000 ohms (Nominal impedance)
Pmax: 35.0000 watts maximum rated power


Driver: MW 6503 Driver's model #.
Brand: Polk Driver's brand name.
Fs: 29.8600 Hz (Free air resonance)
Vas: 3.0017 ft^3 (Compliance volume)
Qts: 0.3100 Total Q
Qms: 1.7680 Mechanical Q
Qes: 0.3760 Electrical Q
Sd: 0.0130 M^2 (Piston area)
Xmax: 3.1800 mm (Cone excursion, linear)
Revc: 6.5400 ohms (DC resistance)
Znom: 8.0000 ohms (Nominal impedance)
Pmax: 35.0000 watts maximum rated power

If I press on the speakers evenly, I don't get any noise.

The PRs were out of RTA-12 speakers someone parted out on ebay a few months ago.

I cannot feed my RTA-12s much more than a solid clean 15 watts (estimated). The distortion is in the low frequencies. The travel on the mw-6500 is amazing, even at low levels. The sound very full and clear as long as the volumne levels remain low to med.

soundfreak1

What does the "distortion" u are hearing sound like? What are u hearing? The distortion at volume may be comming frim your amp. If its a low freq. "rumble or "reverberation" you may be hearing the speakers "baskets "ringing" if so dynamat the baskets and this might solve your prob + tighten the base and do great things for the mids. There dozens of threads on this mod here.let us know what equip u r using to play them, that will help us help u and try to describ the " distortion" u hear as that word means a lot of diff. things to a lot of diff people.

deronb1

Wattage rating on the 11Ts is the same as the 8Ts I believe. 250 wpc at 6 ohms. Hope that helps.

SDA1C

I drive my 11t with a 425 Sunfire with no issues. You won't over "clean" power those. What is the condition of your speaker wires? Any chance there is a bare wire or something touching on the back of your amp? Or something touching when the vibrations start? I'd be checking the internal wiring too and make sure there isn't any problems with insulation or bare spots.

drumminman

Those should not be distorting, even at high levels. I have RTA 12C's I bought new in 1984. Still have the owner's manual, which states they can take up to 500 wpc.

I presently have mine in an HT set up powered by a Carver TFM 42 (375 wpc) and I can turn it up to the point where I have to leave the room. While I had my two channel system taken apart this summer I powered them with my new Dual Mono amp that delivers massive amounts of current - again they played completely clean with excellent tonal balance at volumes that overwhelmed the smallesh room they're in (14' x 12' x 9').

If all your MW's are in good working order, the first thing I'd do is Try a different amp. Then try a different source.

If your front end checks out ok I'd look at the Xovers if they have not been rebuilt. Those caps and resistors are 29 years old and should be replaced.

In good working order RTA 12C's, especially modded, sound so good it's surprising!
Good luck and let us know what you find out.

F1nut

If I press on the speakers evenly, I don't get any noise.

Ok, that should rule out rubbing voice coils.

I cannot feed my RTA-12s much more than a solid clean 15 watts (estimated). The distortion is in the low frequencies. The travel on the mw-6500 is amazing, even at low levels. The sound very full and clear as long as the volumne levels remain low to med.

The travel should not be much at low volume levels. Try this, push in and hold the PR while watching the mid-drivers. They should move all the way out and return to the resting position in about 2 to 3 seconds.

rdozz

Thanks so much! you guys are great.....

I don't have a super amp LUXMAN R114 50 watts x 2.

Moved the mw-6500 drivers with the PR and they all seemed to return to their orginal posistion. It does not take 2 to 3 seconds' all the speakers move togather. As soon as I let go of the PR the speakers return to their orginal posistion.

The top mounted cross-over does not contain any electrolytics. Is there another cross-over on the back of the wire terminals?

I am not sure how to describe the distortion other than it sounds like the MW-6500s can't handle the power in the low frequencies.

I am confused by the wattage ratings. DERONb1 stated the 11ts could handle 250 wpc. I am not smart enough to figure this out on my on. The 11t uses the MW-6510 drivers rated at 35 watts each, how does 35 watts times 2 per speaker translate to 250 wpc?

I am looking foward to completing at least one of my 11ts. I am hoping the tweeters come in today, I have already picked up 2 MW-6510s looking for 2 more. If they do then I can compare the output of the 11ts with the RTA-12s in question.

I will take some pictures when I get a chance.

soundfreak1

What f1 was telling u was push and "hold" the pr and see how lond it takes for the mw's to return (while holding in the pr
) what he is trying to find out is if u have and air leeks in the cabs or around the drivers. So try it again but hold the pr in and cound how many sec's it takes the drivers to return to thier normal possisition. Let us know its important

F1nut

The 11t uses the MW-6510 drivers rated at 35 watts each, how does 35 watts times 2 per speaker translate to 250 wpc?

Caps, resistors and inductors.

What f1 was telling u was push and "hold" the pr and see how lond it takes for the mw's to return (while holding in the pr)

THIS!

rdozz

Ok, got it thanks.

As I hold the PR the drivers stay out for much longer than 2 to 3 sec. No leaks from what I can tell.

rdozz

I am sorry, It does take 1 to 2 seconds for the speakers to return or leak off the pressure.

Again, thanks a bunch!

I am going to borrow a amplifier to see if I get different results.

F1nut

Ok, at what position on your receiver's volume control does the issue present itself?

I would still suggest checking that all the gaskets are in good condition. Check that the screws hold tight and look inside the cabinet for any obvious open seams as 1 to 2 seconds is a bit quick.

rdozz

As far volumne control position, just past 12 o clock or a little over half way.

I will check the screws and gaskets in the morning.

I am looking at a yamaha A-1000 natural sound amplifier with the class A to upgrade my system. I had one years ago and loved it. It will probably need some cap replacement but it might be a good project. I thinl this amp will be a better match to these great speakers.

Thank again!

F1nut

As far volumne control position, just past 12 o clock or a little over half way.

There it is! You're asking too much of your receiver. Turn it down before you cause serious damage to it and your speakers.

drumminman

Yep, that sounds like the problem.

I do recommend rebuilding the Xovers, both the upper and lower. Not only are the caps and resistors worn out, replacements today are of much higher quality. Using decent film caps and non-inductive resistors will dramatically improve the sound those RTA 12's put out.