Removing AR Speakers Grill Covers?

Discussion in 'Audio Hardware' started by chip-hp, Dec 6, 2004.

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  1. chip-hp

    chip-hp Cool Cat Thread Starter

    Location:
    Dallas, TX
    This weekend, I picked up two pair of Acoustic Research AR-2ax speakers (from the late '60s or early '70s) ... in nice walnut cabinets ... I would like to examine the insides ... there are no screws in the back ... so I am assuming that the grill covers come off ... but there is very little clearance around the edges ... anybody got any good tips? ...
     
  2. CardinalFang

    CardinalFang New Member

    Location:
    ....
    Joe should be answering your question soon.... ;)

    I have a pair of AR-2ax speakers, but I haven't removed the grill covers yet. The guy that reconditioned them said that it was a tight fit. Maybe he used a paint scraper to pry them off? I don't remember...
     
  3. chip-hp

    chip-hp Cool Cat Thread Starter

    Location:
    Dallas, TX
    Thanks Keith ... I will look forward to Joe's reply :) ...
     
  4. Joe Nino-Hernes

    Joe Nino-Hernes Active Member

    Location:
    Chicago, IL
    The AR-2ax grilles are glued on to the front at six points. There is a drop of glue at each corner, and there is a drop of glue in the middle of the frame. Pry carefully with a wide flat head screwdriver at these points, starting with one side of the speaker. The glue is usually pretty dried out, so it should pop right off.
     
  5. Joe Nino-Hernes

    Joe Nino-Hernes Active Member

    Location:
    Chicago, IL
    If it is an earlier 2ax, you might be lucky, and have the cloth surround woofers. If it is a later model, you will have foam surrounds, that will need to be replaced. If the woofers have the cloth surrounds, and look OK, play the speakers. If they sound OK, and both level controls on the back work, don't bother opening them up any further.
     
  6. chip-hp

    chip-hp Cool Cat Thread Starter

    Location:
    Dallas, TX
    Thanks, Joe ... one pair sounds better than the other ... but I suspect that there may be a problem with one or both pairs ...
     
  7. The attenuation pots on the back of the cabinet tend to corrode very quickly. I replaced them three times on my AR3a speakers. You can easily tell if they are corroded because they produce a "crackle" sound when turned, or the tweeter or midrange driver cuts in and out as the speaker is played.

    John
     
  8. chip-hp

    chip-hp Cool Cat Thread Starter

    Location:
    Dallas, TX
    Have not noticed any crackle ... but something doesn't sound right ... maybe too much bass on at least one of them ... what did you use to clean the pots? ...
     
  9. Joe Nino-Hernes

    Joe Nino-Hernes Active Member

    Location:
    Chicago, IL
    These speakers do have excellent bass response for their size, so that is normal. So in this case, you mean that you have a lack of high frequency response. This is most likely caused by dirty level controls. Rotate them back and fourth until you can hear sound from the tweeters. I know of someone who cleans these level controls, if you cant get them to work. The only way to clean them well is to use a small dremmel tool, so that you can polish the fins.
     
  10. Rolf Erickson

    Rolf Erickson New Member

    Location:
    Los Angeles, CA
    Yes, I agree with the above guys. Is the bass on one different than the other? or is the treble different a from b. The L-pads can be "cleaned" chemically with some naphtha from the Home Depot. They do corrode on the conductive parts. Apply liquid to the moving wiper arm at the tip end and soak it somewhat while fully rotating the control shaft repeatedly to and fro. Do this for a couple of minutes, till they are really worked out.
     
  11. chip-hp

    chip-hp Cool Cat Thread Starter

    Location:
    Dallas, TX
    It took me a while to figure out how to get the grill covers off one of the pair of speakers w/o damaging them (I made a thin "L" shaped tool that I could slide between the edge of the cover and the cabinet and underneath to break the glue) ... once I got the covers off, I wasn't quite sure what I was looking at (I am a novice when it comes to fooling with the insides of a speaker) ... I know the woofer is the big speaker at the bottom ... BTW, the surrounds are foam and cracked on both ... there is a round black thing on the top left with 2 thin single cooper wires going into it ... and a small speaker (tweeter?) on the top right ...

    The upper speaker cuts in and out when I turn the Mid and Hi tweeter controls on the back ... they feel corroded ... how does one access these controls to clean them?

    I have the speakers hooked up to a Pioneer SX 3800 receiver that I was testing ... and they sound good once everything on them seems to be working ... even with the cracks in the surrounds ...

    Any words of wisdom for replacing the foam surrounds?

    BTW, on the back of the Pioneer receiver it says ...

    Caution .......................... Speaker Impedance
    A or B ............................ 4 (Ohm sign) or more/speaker
    A and B .......................... 8 (Ohm sign) or more/speaker

    What does that mean? (Now you know how little I know :) ) ...
     
  12. Doug Sclar

    Doug Sclar Forum Legend

    Location:
    The OC
    It means that the Pioneer should not be loaded with less than 4 Ohms. Most speakers are usually around 8 ohms, but not always, and that is really a semi meaningless thing. What we need to remember is that the impedance of a speaker is different at different frequencies. So a speaker may be 8 ohms at 1k but may be 5 ohms at 200 Hz. The lower the impedance of the speaker, the more power it will demand from the amplifier. If the amplifier doesn't have it you will either get distortion or draw too much current and blow the output devices.

    Also when 2 pairs of speakers are run in parallel the load on the amplifier is cut in half. That is why in your example either speaker can be 4 ohms, but if you are using 2 pairs of speakers they must be 8 ohms, because 2 8 ohm speakers in parallel is 4 ohms.

    An analogy I've used before is to think of light bulbs. They come in 25 watt, 50 watt, 100 watt, 200 watt etc. They all plug into the same 110 volt source, yet each one draws a different amount of current. They essentially all have different impedances. The lower the impedance, the more current the bulb will draw. So a 50 watt bulb would be like a 16 ohm speaker, and a 200 watt bulb will be more like a 4 ohm speaker. I realize that impedance is not the proper term to use regarding the resistance of the light bulbs, but I am merely trying to illustrate a point.

    Now your amplifier has a limit on how low a load it can drive. So does the electrical source in your house. It has much more power than most amplifiers, but if you hook up enough 'low impedance' light bulbs you will eventually blow the circuit breaker.
     
  13. chip-hp

    chip-hp Cool Cat Thread Starter

    Location:
    Dallas, TX
    Thanks, Doug :) ... These speakers are "rated" 8 ohm ... is there any relation between receiver speaker output and the receiver volume? ... cuz these speakers are pretty loud at #2 on the receiver volume control (which goes up to 10 in half increments) ...
     
  14. Doug Sclar

    Doug Sclar Forum Legend

    Location:
    The OC
    Not necessarily. How high your volume control is does not determine how much power your amp is putting out. If your preamp has a lot of gain, the volume control could be on 2. If it has less gain your volume control could be on 8. In both cases the amount of power coming out of the amp could be the same. The same with playing CD's or records. On a 'loud' cd, the signal coming into the amp could be 6db or more higher than a lower level CD. You would have to turn the volume control down on the loud one to make them sound the same. Where the volume control is is somewhat irrelevant as far as power is concerned. And another thing to remember is that all volume controls do not necessarily have the same tapers. Audio controls usually are log taper as opposed to linear taper, but there are still variations. Some may seem more sensitive at the lower extreme then at the higher extreme. In other words most may have much more change between 2 and 4 then they would between 8 and 10.

    But the higher the impedance of the load, the higher the volume control will usually be. For example if you had 16 ohm speakers instead of 8 ohm speakers, and all other factors were the same, they would not draw as much current out of the amplifier. You might have to raise the volume control to get them as loud as an 8 ohm speaker. But this does not mean you are putting out more power.
     
  15. chip-hp

    chip-hp Cool Cat Thread Starter

    Location:
    Dallas, TX
    Thanks, again ... Doug :) ... I need all the help that I can get ...
     
  16. chip-hp

    chip-hp Cool Cat Thread Starter

    Location:
    Dallas, TX
    Hey Joe ( Nino-Hernes) ... where ya been ... taking exams? :) ...
     
  17. -=Rudy=-

    -=Rudy=- ♪♫♪♫♫♪♪♫♪♪ Staff

    Location:
    US
    Actually, he WAS taking exams...and he's on his way home for the holidays tomorrow afternoon. ;)
     
  18. Joe Nino-Hernes

    Joe Nino-Hernes Active Member

    Location:
    Chicago, IL
    :agree: :agree:


    Anyhoo,

    To access the level adjustments, you must remove the woofer. Then remove all of the fiberglass filling, but don't lose any of it!! It should fit in one or two paper grocery bags. It is best to replace the level pots with new ones. They are very hard to clean, unless you have a dremmel tool. Give Larry Lagace a call (518-869-3665), he should have some in stock.

    Also, if the foam on the woofers is deteriorated, send the woofers to Bill Miller at Millersound. He does an INCREDIBLE job with AR woofers!!
    Millersound
    1422 Taylor Road
    Lansdale PA 19446
    Phone (215) 412-7700
    Fax (215) 412-0542
     
  19. Metralla

    Metralla Joined Jan 13, 2002

    Location:
    San Jose, CA
    Actually, the gentleman who runs Millersound is Bill LeGall.

    If you want to learn more about the amazing Billie, read this story on 6moons.

    http://www.6moons.com/industryfeatures/forbidden/forbidden_9.html

    There seems to be a problem with some of the pictures in this report - they used to all display. Bill owns the Infinity IRS Reference Standard Series V. More precisely, Bill owns TWO sets!!!

    [​IMG]
     
  20. steinjw

    steinjw New Member

    Location:
    Pittsburgh PA
    Gents,
    This is like hitting gold - I just joined this forum, and have a pair of old AR3a's sitting in the basement that had been given to me by an acquaintance some while back - been pondering these same questions. Guess I will give them a shot. Thanks. Jim
     
  21. Joe Nino-Hernes

    Joe Nino-Hernes Active Member

    Location:
    Chicago, IL
    Welcome to the forum!! I hope that you get your AR-3a's up and running! They are wonderful sounding speaker systems. If you have any more questions, feel free to ask.
     
  22. chip-hp

    chip-hp Cool Cat Thread Starter

    Location:
    Dallas, TX
    So how much $ are we talking about? ... I ran somewhere that Dexoite (sp) would clean the pots ...

    What does he charge? ... ballpark ... I have 2 pairs of speakers (the cabinets are a little better on one) ... I need to learn how to refoam ... how difficult is it ... on a scale of 1 (easy) to 10 (let the experts do it) ...

    Hope your exams went well! ... that's a part of college that I don't miss ...
     
  23. Joe Nino-Hernes

    Joe Nino-Hernes Active Member

    Location:
    Chicago, IL
    Deoxit will not work on these pots. They actually need to be sanded and polished. To have them cleaned is around $14 a pair. They work really nicely after they are nice and polished!

    To have Bill Miller install new surrounds, and spiders, is $60 per pair. You can do it yourself, but AR woofers need extra special care, because they need to make such long excursions. If the voice coil is off by even the slightest amount, the woofer will distort badly. To this day, I still don't trust myself with AR woofers, I allways send them to Bill.
     
  24. Metralla

    Metralla Joined Jan 13, 2002

    Location:
    San Jose, CA
  25. chip-hp

    chip-hp Cool Cat Thread Starter

    Location:
    Dallas, TX
    So, are you recommending that the pots be professionally cleaned? ... instead of replacing them? ...

    What is a "spider"? ... and what does "excursion" mean? ... what is the best way to pack and ship woofers? ... so many questions :) ...
     
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