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Starting AR 5 restoration mid and tweeter problem


tcj

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purchased speakers in 1969.  Speakers been in basement for 20 years.    One speaker has what I think is normal output in all three drivers.  The other speaker has very faint out put in mid and tweeter. The woofer has output that sounds deeper then the working speaker woofer.  Both woofers have been reformed.  I am guessing there is a cross over issue with open capacitors.  Seems strange that there would be a problem in both the mid and high cross over components.   Any thoughts and how to proceed would be appreciated.

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Have read the AR3a restore manual.  Looks like woofer may have been replaced?  I don't remember having that done.

attached are the pictures requested and a few more.  Measure resistance of woofer the best i could read was between 3.5 and 4 ohms.  

Any thoughts strategy of fixing or diagnosing the problem?   thanks tomAR5-2.thumb.JPG.6c71f6b19fb5c40710867775111f3ac9.JPG

AR%-4.JPG

AR5-1.jpg

AR5-3.JPG

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As noted by Adams instead of the pots your AR5s show Lpads, never mounted on AR5, these need to add resistors for a better result.
The woofer you show should not be correct for the AR5, not even aesthetically: different dust cover, foam originally above the cone in AR5 instead it is below as it was done in the 200004-2 refoaming that you inserted in the photo), I am attaching the linq of a thread about a restoration of other AR5 pair that will be useful to you:

We await the photos of the other woofer, it may be that this is with an Alnico magnet like most of the AR5s ... could justify the difference in volume between the 2 woofers.

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I see at least four problems.

1. Someone has worked on these speakers

2. Whoever worked on the speakers installed LPads without the parallel resistors, not fatal but a source of sound imbalance between the drivers especially on the mid. (These could be later version replacement potentiometers but they are probably lpads).

3. One of your mids is a back wired replacement that might be 4ohm instead of 8 ohm which could cause a real sound imbalance.  I don't recall seeing an AR5 with a back wired mid range driver but others more experienced can comment.   You can connect the signal wire to the T & 2 terminals instead of 1 & T to hear only the mids and tweets and check for equal output.    You might need to remove the driver to verify the model or at least test the DCR to see that it is not significantly lower than the original mid.  If it is 4ohm it should have added resistance installed to be useful. 

4. The Woofer labeled AR2ax is a correct replacement for the AR5 but the red labeled woofer is a service replacement unit that is a bit more sensitive and needs a 1 ohm resistor added in series to bring its output inline with the midrange driver.

The capacitors all need replacement but they are probably not the cause of the gross differences you are hearing at this time.

On a larger viewing monitor it appears that Giorgio is correct that your replacement woofer has been incorrectly refoamed but you can worry about that later.

Your tweeters are probably barely working if at all but don't worry about that right now.  The priority is on the woofers and mids.

After reinstalling the fiberglass and woofers, my first step would be to remove the jumper wire from the 2 terminal and connect the signal wire to 1&2 to check that the woofers have identical or close to the same output.   Connecting to 1 & 2 with the wire jumper off removes the mid and tweet and most crossover components from the circuit. 

Keep in mind a huge factor in woofer performance in these speakers is having a quality seal around the woofer hole.

Edit: Use a mono signal from your amplifier.

 

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  • 2 weeks later...

As genek stated the AR5 mids are perhaps the rarest of the classic AR drivers.  You have three options that I can see.

1. Purchase a working original.  They sometimes come up for sale

2. Purchase a 4 ohm original and adapt it.

3. Purchase a Midwest AR mid replacement and adapt it using parts from your broken mid.

4. Purchase a pair of new Midwest replacement AR mids and adapt them.  This would be my last choice and is also the most expensive.  If you do this be sure and keep your current mids, they will be needed for reference.

I would try option 1 or 2 first because adapting the midwest drivers will require some extra work that could get tricky unless you are experienced at partial disassembly of dome mid ranges.

Which mid was it?

Adams

 

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Thanks for the reply. looks like 

1. Purchase a working original.  They sometimes come up for sale

2. Purchase a 4 ohm original and adapt it.

Since both woofers are AR-2ax replacements and the pots are Lpads there is no need to keep the cabinets AR5 original.  I would like to at least keep the drivers in the AR family.

My options are,  Will look for original AR5 mid.  Else:

Look for 2 four ohm AR3a/11/lst mids  for replacement in both cabinets.   Then sell the working AR5 mid.  

Would that be a better alternative then just replacing one bad mid driver and living with the good one? Subjective question,  could you hear the difference in the mids?

My understanding is that a resister is inserted in series  to maintain the 4 ohm driver impedance at 8 ohms.   Are there Crossover components that need changing?

Adding a series resister would show the amp about an 8 ohm load.  is the loss of sensitivity across the series resistor canceled by the increase sensitivity of the 4 ohm mid?

Since I an still learning, if the question can be answered by me researching let me know and I will research it. .  Thanks for the help!

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3 hours ago, tcj said:

Since I an still learning, if the question can be answered by me researching let me know and I will research it. . 

OK.  Everything you are experiencing has already been answered at some time in the AR forum.

Some reminders:

AR 2ax woofers are the same woofers that were in all but the earliest AR5s.  Your replacement woofer needs a one ohm series resistor.

The sound of a 4 and 8 ohm mid is identical if you get the DC resistance matched to the 8ohm driver.  Measure the 8ohm mid, the resistance won't be 8 ohms.

You need parallel resistors installed on the lpads for the midranges.

Your speakers will sound like AR5s except for the low tweeter output.

Your tweeters are not working correctly..........guaranteed............but if you are satisfied with what you hear that is all that matters. If you do not repair the tweeters the lpads don't need resistors.

 

 

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On 12/13/2021 at 10:15 PM, tcj said:

I am following up

Another pair of woofers that are fine and these are "matched", you can get them and sell the ones you own to make up for the expenses
A couple from the same origin is the best for aesthetics and functionality!

https://www.ebay.it/itm/304264617302?hash=item46d7959d56:g:qmkAAOSwMKVhuIEU

 

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