RTA 11t where to begin troubleshooting

planoflyer

I am a new member of this forum and I'm searching for guidance on troubleshooting my factory original RTA 11ts. I am the original owner of these beautiful speakers. I Purchased them new in about 1990. They sat in storage for many years. Their sound in all ranges is terrible and I'm Not sure whether it's the drivers or the crossover or some combination of both. I recently took them out of storage and set them up as main channel left and right in a 7.1 surround system driven by a Denon AVR home theater receiver. I would like to know the best place to start troubleshooting. I have a technical background and an understanding of electronics at a basic level. I have the ability to do repairs and installations including soldering etc. I just need to know the best place to start .

Thanks in advance for any suggestions.

pkquat

Welcome to the forum. I am not sure what you mean by the sound is terrible in all ranges. That could be a lot of things. Specifics of what you mean, distorted, quiet, rattling, etc. would help. What speakers did you have before you pulled these out of storage.

First check to make sure the left and right speakers got wired in phase. Sometimes wiring mistakes happen. Are the red and black terminals on the speakers in the same positions for both? The colored nuts can be taken completely off and people have reversed them on accident. For that matter make sure the amp terminals are correct. Double check the speakers are the correct phase as well. Although not perfect, they should not sound terrible if they are both reverse polarity.

Is the amp set to a 4-6 ohm setting sometimes this can make a difference. We don't know which model of AVR you have. Clear any room and speaker equalization done with the AVR.

Next check the speakers. A simple test is to make sure the mid range drivers move properly. You should be able to press the upper two 6.5" drivers in about 1/8" with very light pressure. If it feels like cone does not move, it is likely the magnet has shifted and frozen the driver. This can happen even when in storage, or more often when moving them. The MW is model MW6510. There are couple of options if a driver(s) is frozen.

Original replacements can be found on ebay. There is also a member here who offers a magnet re-centering service, so don't throw them out even if you find a replacement. polk customer service (cs) may still have near the same quality as original replacements. I forget if this one was discontinued recently. Then the next best source is midwest speaker repair. They are making replacements that polk cs is no longer making. Polk cs offers free shipping if you tell them you are a forum member.

We will need more information to determine other issues.

Navy_Goat

Always a good idea to start with a visual inspection. You would be amazed how many problems, electrical/mechanical and other, can be detected with jus a thorough look around. Have a good look at the entire signal path, from the binding posts on the back side through the crossover all the way to the drivers.

I would second everything mentioned above also....

planoflyer

Thanks to both of you for your responses. I am on the road and not able to inspect the until this weekend at the earliest. That was my plan for next week. The model is RTA11t. I will post more detail when I can evaluate them. I was trying to get ahead of the project and find resources for components in case Polk doesn't carry them, and also see if it makes sense to restore the speakers wrt time and cost.

Thanks again

stevep

I love my slightly later vintage RTA 11TL's.

When I got them one of the tweeters was dead and Polk was happy to sell me a set of the upgraded RDO198 tweeters. As mentioned they offer free shipping to members of this forum by calling their customer service number to order.

CH46E

A better description of the sound would help a lot. Some guys here are pretty good at pointing us in the right direction.



Welcome.

Navy_Goat

^I spy with my little eye a pfrog...

skrol

Start by making sure all the mid-woofers move freely by gently and evenly pressing them in. Also when you press the mid-woofers in, press and hold. The passive radiators should move outward and slowly return to normal while the mid-woofer is depressed.

When playing music, make sure the mid-woofers and tweeters are producing sound.

If all that checks out, it may be time to start considering the crossover. Electrolytic capacitors do get old and dry out. My RTA11TL's had bad solder joints (not soldered connections).

CH46E

Navy_Goat wrote: »

^I spy with my little eye a pfrog...

Yes sir for sure! PHROGS 4 Life. I still see them fly over my house when BBQ'ing. DynaCorp from Patrick AFB still fly them.

planoflyer

I finally got a chance to set up and listen to my RTA11TL speakers (isolated) through a Denon AVR 1803 receiver. The receiver was setup to have only the Main L/R active with nothing else connected to the output terminals, and sound mode set to analog stereo. I played a couple of different CDs through a CD player. Nothing else was connected to the amp.
The sound overall was very "muddy" with little or no high end and the middle was predominantly muddy and flat. With my ear very close to the tweeters, I could not distinguish any output from them. The four midrange (two each speaker) were all the same with a flat, muddy sound. I liken it to listening to the music in the next room through a drywall covered wall.
The low end was present but with everything else being so "muddy", it was hard to distinguish the bass response. Both speakers were balanced and stereo separation was symmetric. Meaning the sound was balanced and equally "muddy."

The movement of the four midrange woofers are smooth and the other woofers displace proportionally when each midrange is pressed, as long as I kept the pressure on the woofer symmetric (i.e using two fingers equidistant from the center). I noticed a scratchy (paper-like) sound with all of the mid-range woofers if i pressed on a single location off center without a symmetric finger keeping the force centered. I didn't want to push on the center of the cone as it would depress the paper and possibly damage it. The woofer material does have a "sticky" feel to it; I'm not sure if that is normal.

I did visually inspect the crossover boards, and didn't observe any obvious bulging or other damage. I didn't want to de-solder anything to test the caps just yet.

F1nut

Either your tweeters are cooked or the polyswitch (small blue device on the board) is. Without the tweeters producing sound the speakers will sound muffled/muddy.

The SL2000 tweeter is a nasty sounding thing and should be replaced with the RD0194, so start there. The polyswitch can be removed and replaced with a .5 ohm resistor.

FestYboy

The woofer cones are doped paper and should be sticky to the touch. Clean with Windex (the real thing, accept no substitute). Pressing off center on most speakers will allow the coil to contact the pole or shorting ring, this is normal. Bypass the poly-switch to test the tweeters, a simple shorting wire will do the trick for testing.

skrol

When I used my Denon AVR-888 to drive my souped up RTA-11TL's I thought is was lifeless compared to driving with my Denon DRA-835R or either of my Parasound amps. My Marantz SR-7010 does magic with them for HT and music.

mikezxtt

Hello, I wish to upgrade the 11T 25015 speakers.
What do you recommend,
Tom Carter from Polk Audio customer service told me about this site, very cool!!

skrol

Welcome to the club. I have a pair of RTA11TL since new in 1990 that I have modified.

The easiest mod is to replace the tweeter with the RDO-194 (assuming you have the SL-2000 tweeter). Apply Dynamat or similar material to the mid-woofer and PR baskets. While you have the mid-woofers out, glue the magnets as they tend to shift.

Are you soldering iron capable? The next is the crossover upgrades. Replace the electrolytic capacitors with film caps. Clarity Cap or Sonicap are good for the tweeter circuit. Can go with something cheaper like Dayton Audio for the mid-woofers. Replace the resistors with Mills or Mundorf. If yours has the polyswitches, replace them with a o.5 ohm resistor.

If you search the forum, you will find other threads on upgrading the RTA11T and RTA11TL including mine.

planoflyer

Thanks again for the post and reply. It's been over a year since this discussion, but I am finally ready to start my project upgrading and resurrecting my RTA11s. Life being what it is, I was "overcome by events" and never found time to start.
SO, Now it's time to start! can someone answer a few questions so that I don't do serious or permanent damage by some rookie mistake?

1. Skrol said <Apply Dynamat or similar material to the mid-woofer and PR baskets. While you have the mid-woofers out, glue the magnets as they tend to shift.>

Can you elaborate on what "Dynamat" is and what it will do for the Mids?

2. Is there a video or task list published somewhere to help with the layout and soldering/desoldering of the new components? I do know soldering basics and have done a bit, but never with capacitors and the like. I consider myself a newbie in this regard.

stevep

Here some light reading.

https://www.amazon.com/Dynamat-10415-Self-Adhesive-Deadener-Speaker/dp/B00020CATC/

https://forum.polkaudio.com/discussion/153229/dynamat-ing

https://forum.polkaudio.com/discussion/104234/steel-driver-and-pr-rings-for-the-original-sda-srs

https://forum.polkaudio.com/discussion/172391/remember-to-epoxy-your-woofer-magnets/p1