Help with polk monitor 10a

DDAN6815

Hi
I'm new to this forum, but not so new to hi-fi, and vintage equipment. I recently acquired a pair Monitor 10a with the peerless tweeter, in excellent condition. I bought them without listening to them first, because they had no fuses. I went to the local Radio Shack and purchased two 2amp fuses popped them in, and was very disappointed. they sounded like there was no bottom at all, just highs and mid. I took what I thought was the woofer out to find out there was no magnet nor wires to the driver, I figured out then it was a passive. Im driving them with a NAD 2600 amp. when I add my sub to the equation they sound magical. My question is, could it possibly be I dont have enought power to the speakers to get the full range, or is it something else going on with them?

westmassguy

Welcome to Club Polk. The fuses should be 1 amp fast blow, not 2 amp. Check all four 6.5" woofers, and make sure they're not frozen. Magnet shift is very common with the older models. This renders the woofers essentially useless.

DDAN6815

Thank you for your response West. If the drivers are frozen, would they still sound as good as they do without the woofers involved? I also have a pair Apogee Centaures, which I said would probably never part with because of the sound they produce in the mid and highs. These speakers sounds better than my Apogees, with the help of my Velodyne sub. Its hard to think they might be frozen and what im hearing is coming strickly from those tweeters

westmassguy

You said you heard mids and treble. If the woofers are frozen, they'll still produce sound. Gently press in on the cones. They should move freely, with no rubbing. If they do move freely, and there's sound coming from each one, you may have an air leak. The Crossovers could also need work. The Electrolytic Caps used in the Lo-Pass are well past their prime.

TennMan

There is also the possibility that the mid-woofers are out of phase.

DDAN6815

So how do I go by finding out if thats the problem TennMan? Im telling you they actually sound great with the use of the sub. take the sub away, totally different speaker, got me shaking my head

DDAN6815

I will say all the drivers look new, so there may be the possibility that they were not hooked up correctly, and I also noticed that a few of the screws from the passive woofer is missing, but there also were no holes in the speaker for the screws, but looks like there might have been some speaker replacement done

TennMan

DDAN6815 wrote: »

So how do I go by finding out if thats the problem TennMan? Im telling you they actually sound great with the use of the sub. take the sub away, totally different speaker, got me shaking my head

A simple test with a 1.5 volt flashlight battery will tell you if the mid-woofers are wired correctly.

• First, remove the grilles so you can see the MWs and disconnect the speaker wires.
• Next, connect the negative terminal of the battery to the black terminal post on the back of the speaker.
• Then momentarily connect the positive terminal of the battery to the red terminal post on the back of the speaker while you observe the MWs.

If the MWs are wired correctly internally (in phase) you should see both MWs move out when you connect the battery.

Check both speakers to make sure ALL MWs, in both speakers, move the same direction when the battery is connected as described above. If they don't they will cancel each other out which will kill the bass response.

F1nut

Other things to check, air leaks. Push the PR in and hold, the mid-drivers should move out and slowly return to rest in about 3 seconds. Also, check the back end of each PR to see if the spider has come unglued.

I will say all the drivers look new

Remove the drivers to confirm they are the proper Polk MWxxxx drivers and not some junk someone put in them.

I also noticed that a few of the screws from the passive woofer is missing, but there also were no holes in the speaker for the screws, but looks like there might have been some speaker replacement done

Eight holes in the basket, but only four screws? That's normal.

DDAN6815

F1nut wrote: »

Other things to check, air leaks. Push the PR in and hold, the mid-drivers should move out and slowly return to rest in about 3 seconds. Also, check the back end of each PR to see if the spider has come unglued.



Remove the drivers to confirm they are the proper Polk MWxxxx drivers and not some junk someone put in them.



Eight holes in the basket, but only four screws? That's normal.

I did remove two of the mid drivers and they were polk speakers

Faustin

Rule of thumb with vintage Polk monitors speaker wiring is black is positive and white is negative.

DDAN6815

Thanks for he info guys. any other suggestions would be appreciated

F1nut

Have you done all that was suggested because that's all of it.

DDAN6815

SO, if they are frozen, since I understand thats a common poblem, do I replace the mid drivers?

westmassguy

Have you checked them all? If the cones don't move, they're paperweights. Some have successfully made jigs to re-align the magnets, but it's a tricky business. Better off getting replacements off eBay. Just make sure the seller packs them very, very carefully

F1nut

DDAN6815 wrote: »

SO, if they are frozen, since I understand thats a common poblem, do I replace the mid drivers?

People are trying to help you, but you're not telling us what you've done/found.

TennMan

DDAN6815 wrote: »

Thanks for he info guys. any other suggestions would be appreciated

DDAN6815 wrote: »

SO, if they are frozen...

The battery test I suggested should tell you if they are frozen as well telling you if they are wired correctly. You have received some good information to help you find your problem. Asking for more suggestions won't do any good if you aren't going to follow up on the suggestions you've already received. Do some testing and let us know what you find out.

EDIT: F1 posted basically what I had to say while I was typing.

DDAN6815

I did not do the battery test due to the fact that the wires in back of the MW are not spaded, but soldiered to the terminals. two wires on the left MW and one on the right mw, blk wires to positve, and white to neutral. all MW failed the air test I could feel the air coming out when i pushed in on the PR when the screws were loose. once they were tighted the MW did not move at all. The PR was the only driver that moved freely. all MW appeared tight but moved when pushed in on, as did the rubber surround crinched in as well when I push in on the Mw.

F1nut

I did not do the battery test due to the fact that the wires in back of the MW are not spaded, but soldiered to the terminals.

Do the battery test at the binding posts per the instructions provided.

all MW failed the air test I could feel the air coming out when i pushed in on the PR when the screws were loose. once they were tighted the MW did not move at all. The PR was the only driver that moved freely. all MW appeared tight but moved when pushed in on, as did the rubber surround crinched in as well when I push in on the Mw.

Is it me or does that not make sense to everyone else?

westmassguy

Sounds like the woofers are binding, which would explain a lot

DDAN6815

What do you mean woofers binding, and what can be done about it?

DDAN6815

Is that the same as frozen?

westmassguy

When you gently press in the cones on the 6.5" woofers, do they move freely in and out? Do you feel resistance, or hear a rubbing noise? If they move freely in and out, with no odd noises, they're probably fine.

DDAN6815

There is some resistance when I push in on the mid woofers, it does move, but not as freely as the PR. What puzzles me is all four feels the same,and I think it's unusual that all MW have the Same problem.

DDAN6815

I'm sorry, but to answer your question,they do not move freely,but there is no noise. I going to try the battery test tonight

Faustin

When you push them in they should move in approx 1/2 inch. When you push the PR in it should also move in approx 1/2 inch. At the same time that you are pushing the PR in, the 6.5" drivers should be popping out. Frozen drivers will move a bit, but if you have a good driver and a bad driver side by side you will see the obvious. I would say that if the 6.5's will not move in as far and as freely as the PR they are probably frozen.

DDAN6815

Well it appears they're frozen, I can actually live with the sound of these speakers as long as I have my sub, but knowing I'm not getting the full range,I've disconnected them. I'm trying to decide if I should purchase 4 new drivers, or is it with the investment. The cabinets are in great condition. I really like the sound of these speakers, the highs are great and very natural sounding for the type music I listen to. I have several other sets of speakers, such as My favorites The Apogees, Celestion UL6, Paradigm phatoms, and Klipsch kg3.2. So it's not like I really need another pair, but it's something special about these speakers.

F1nut

Check eBay for original MWxxxx drivers.

DDAN6815

Well it appears they're frozen, I can actually live with the sound of these speakers as long as I have my sub, but knowing I'm not getting the full range,I've disconnected them. I'm trying to decide if I should purchase 4 new drivers, or is it with the investment. The cabinets are in great condition. I really like the sound of these speakers, the highs are great and very natural sounding for the type music I listen to. I have several other sets of speakers, such as My favorites The Apogees, Celestion UL6, Paradigm phatoms, and Klipsch kg3.2. So it's not like I really need another pair, but it's something special about these speakers.

westmassguy

You're not getting anywhere near what these puppies are capable of, even with a sub, if the drivers aren't working properly. The entire bass region is missing. Pull one of the drivers, and get the model# off of it. MW6500, 6501, and 6600X were all used at various times on the early 10s. You can try eBay, or order new replacements from Polk Customer Service.

DDAN6815

How do you fix air leaks in the cabinet? ... should all drivers have some type gasket around them.