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Got Acoustic Research AR6 - honky nasal tone?

Discussion in 'Speakers' started by duckrabbit, Jun 7, 2018.

  1. HPhillpotts

    HPhillpotts New Member

    Messages:
    6
    Hi all. Newby here, signed up for this thread because I have exactly the same issue as the op with a newly purchased pair of AR-6 speakers. They are I believe an original USA pair with alnico woofers. The caps have been replaced with new JB 10uf caps. I'd love to try and find out what's wrong.

    To my ears the honky sound is coming from the woofer not the tweeter. A couple of ideas in this thread have interested me:
    Could the woofer be out of phase with the tweeter and how would I check?
    Could the crossover be too high and how would I reduce it?
    The cabinet is very full with stuffing, would too much create this sound?

    In the meantime I will read about BSC, but I feel this is a specific error with the current components rather than an inherent design flaw of this often praised speaker.
     

     

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  2. RxDx

    RxDx Speaker collector Subscriber

    Messages:
    1,170
    Location:
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    I have a schematic with three variations of the crossover, one of which shows
    a 6uf capacitor.

    AR-6_xo_diagrams.jpg
     
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  3. spark1

    spark1 Super Member

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    1,632
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    The Great Midwest
  4. toxcrusadr

    toxcrusadr AK Subscriber Subscriber

    Messages:
    33,202
    Location:
    Central Missouri
    So, HP, you will have to figure out which version of the crossover you have there based on the rest of it. Should be pretty easy to tell - one has 3 terminals a strap on the back (A), the others have switches. One of those - B - has a cap, resistor AND an inductor in the woofer circuit, the other (C) runs the woofer wide open. Assuming parts were replaced and not removed completely, it should be fairly simple to determine which model you have.

    Those schematics also show which way the woofer is wired (in phase or out compared to the tweeter). Possible whoever did the recap hooked up em up backwards, which would usually lead to a peak in the midrange...
     
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  5. ra.ra

    ra.ra Super Member

    Messages:
    1,773
    Location:
    metro Boston
    Hi HPhillpotts, and welcome to AK. I'm not quite sure what to make of a sound described as "honky", but this confusion becomes even more so when applied to a woofer. Maybe the surround foam is not properly glued or has begun to fracture?

    If you have the alnico woofers, most likely you've got the early version "A" shown above. Learn to post some pics here (simple jpeg files under 100KB are perfect), and it will be far more possible for your symptoms to be diagnosed and analyzed with helpful suggestions. Also, among the variety of AR-6 crossovers, version "B" has a three-position switch while version "C" has a two-position switch - - easy to identify from the backside. These cabinets are typically heavily stuffed with yellow fiberglass, except that European models often had a multi-color grey-ish stuffing. Some Euro cabinets also have a different cabinet profile with a slimline perimeter.
     
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  6. toxcrusadr

    toxcrusadr AK Subscriber Subscriber

    Messages:
    33,202
    Location:
    Central Missouri
    Since the woofer plays up into the midrange, and the lower midrange is where 'honky' is in my mind, it makes sense if there is a problem in the woofer/midrange driver region.
     
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  7. HPhillpotts

    HPhillpotts New Member

    Messages:
    6
    Ds2000 likes this.
  8. ra.ra

    ra.ra Super Member

    Messages:
    1,773
    Location:
    metro Boston
    Well, yep, those are the early alnico woofers with 'A' version crossover - - thx for the pics. Not sure what's going on here, and tox is probably right that "honk" is probably originating with the woofer. Are you experiencing similar sound from both speakers? Are you able to confirm that foams have adequate glue continuity, and that woofer basket is properly sealed to cabinet cut-out? I see that re-foamer has added an external gasket at woofer perimeter - - could this be concealing a problem?
     
  9. toxcrusadr

    toxcrusadr AK Subscriber Subscriber

    Messages:
    33,202
    Location:
    Central Missouri
    It sounds like you believe the woofers are wired in correct polarity. Have you checked any of the resistors and the cap with a meter? Are you sure that 10 uf cap is new?
     
  10. HPhillpotts

    HPhillpotts New Member

    Messages:
    6
    Thanks all for your replies. I have checked the speakers today, both sound the same and seem to be wired in correct polarity. The foam woofer seal is good, although as noted the last refurbisher put a white foam underlay type material between cabinet and woofer basket. I think it's just an insurance policy for extra seal as it has been applied to the tweeters too. ItsI clear I need to get a capacitor tester to measure those values, the only other thing I can think of is the two coils in white plastic casing. Do they have a life span and need replacing?
     
  11. ra.ra

    ra.ra Super Member

    Messages:
    1,773
    Location:
    metro Boston
    The white foam ring also appears to be original and perhaps that is the problem - - you confirm that the new surround foams have been correctly installed, but perhaps this original gasket ring had been squished beyond its useful life and requires a new seal between drivers and cabinet. The coils in there should be the least of your concerns - - - relative to age, these are quite possibly the most reliable components in this discussion. They should require no attention.
     
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  12. HPhillpotts

    HPhillpotts New Member

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    It looks like general advice is to use a fresh gasket and close the system only once as once the material is crushed it looses it's ability to seal. I guess I'll check the capacitor value first and then close it up with a freah gasket. It looks very much like t&g timber flooring underlay, does it need to be anything more complicated than that?
     
  13. spark1

    spark1 Super Member

    Messages:
    1,632
    Location:
    The Great Midwest
    Mortite/rope caulk works well. Medium density foam weatherstripping is also good.
     
  14. ra.ra

    ra.ra Super Member

    Messages:
    1,773
    Location:
    metro Boston
    The original white foam gaskets are usually good for more than a single use, but they certainly do have a limited number of useful compression cycles. As spark1 has correctly noted, there are other simple materials that can suit this purpose just fine.
    Not sure I understand what you're referring to here......:confused:
     
  15. transmaster

    transmaster AK Subscriber Subscriber

    Messages:
    8,414
    Location:
    Cheyenne, Wyoming
    I replaced the 48 year old NPE’s on my Wharfdale W35’s with (NPE) Mundorf E-Cap Planes. I used a total of 8 capacitors and it cost $23 Dollars. I am very pleased with the sound. They still sound like W35’s only considerably more transparent. All of this is available at Sonic Craft which has the cheapest prices.

    Make sure your speaker gaskets are up to snuff. If anything is leaking it will really affect the sound of the woofer. Parts Express has an excellent speaker frame gasket material. It is adhesive on one side which you use on the Speaker’s mounting perimeter. It is cheap.
     
    Last edited: Jul 16, 2018
  16. HPhillpotts

    HPhillpotts New Member

    Messages:
    6
    Thanks everybody, I'm pleased to have an update on this. Reversing the woofer polarity has solved the problem .I had assumed that it was in phase with the tweeter because the red wire was on the same terminal of the woofer as the yellow on the tweeter. As in the schematic below.
    59d7abdc6c7c9_AR-6schematic(A).jpg.ced0e23514229d769ab9d29dea437dc3.jpg
    Either I prefer the speakers out of phase or positive is not the same side of each unit. Now the woofer is moving in reverse polarity with the cabinet am i compromising the sound? Changing the tweeter polarity is a pain so if it makes no odds illI keep things as they are. But if having the woofer wired backwards affects the relationship with the enclosure I should think about it.
     

     

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  17. transmaster

    transmaster AK Subscriber Subscriber

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    The LFE output on AVR’s enable you reverse the polarity of the subwoofer if needed so why not.
     
  18. HPhillpotts

    HPhillpotts New Member

    Messages:
    6
    Good point, it's the same on my Rel sub
     

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