Conference tekvax::audio

    After reading the info in this note, I was about to purchase the parts
    to refoam the surrounds on a couple of Cerwin-Vega 12" woofers I picked 
    up at a yard sale.
    
    Then, I spoke with the service guy at "The Speaker Factory" in
    Rockville, MD.
    
    He says, "Have you been TRAINED to do this?  I ruined a few speakers
    when I was learning how to do this!  It's not easy; you need to align
    the surrounds so they work when the speaker is fully in, fully out, and
    in the middle.  That's why we charge a minimum of $80 per speaker to do
    refoaming.  And remember, if it's not aligned properly, this can
    destroy the speaker outright.  And, if that happens, it is even
    possible that it might fry your receiver, if the circuit breakers don't
    work properly."
    
    Anyone have any comments on a novice attempting refoaming?  Is it
    really as difficult and risky as this guy suggests, or is he simply 
    bucking for some extra business?
    
    -- Russ

    Re: .-1
    
    Repairing speakers is not rocket science, but does require some
    training and, more importantly, the correct tools.  The C-V service guy
    was correct, the speaker itself must be "aligned" correctly.  To do
    this you must remove the dust cap and "gap" the coil.  Plastic sheets
    of the correct thickness are used for this.  Once in place, the actual
    replacement of the surround (foam) is easy.  When the glue dries, the
    next steps are to test the speaker and install a new dust cap.
    
    Typical factory surround replacement will cost between $80 and $100.
    Local replacement with generic surrounds will be less, usually around
    $50 or so.
    
    Dan
    
    P.S.  It is also critical that the correct glues be used.  There are
    different glues for attaching the surround, the coil to the cone, and
    the dust cap.

    re: .10
    
    So does this mean that I (and other novices) should not attempt to get
    kits like those mentioned from Parts Express?  Or, will P.E. sell me
    the "correct tools" along with adequate instructions needed for the job?
    
    Anyone care to reflect on their successes or failures regarding
    replacing surrounds using one of these kits?
    
    Thanks again!
    
    -- Russ

    re: .11
    
    The surround kits that are available contain shims for centering the
    coil.  I have not had good luck with these though.  Getting them
    balanced is not easy.  I have received "recone" kits from RCF (a
    typical driver for large PA systems) that contain these types of shims
    as well.  I much prefer using full shims which cover 95% of the coil
    area.
    
    Can it be done... sure!!
    
    Does it take time and practice...  YEP!!
    
    Can you make it worse...  Yep!
    
    Most importantly:
    
    Can it be fixed if you mess up?  Yep. (Unless you get glue in the gap)
    
    Dan
    

    Awhile back I replaced the surrounds on two Boston Acoustics 8" woofers
    using a Parts Express kit.  Although the kits did not include any shims
    I didn't encounter any problems.  I just simply followed the
    instructions.  Probably the most time consuming part of the process was
    removing all of the old surround material.  
    
    The glue in the first kit I was sent turned out to be dried out.  I 
    should have checked before.  But I called PE back and they sent out a
    complete new kit no charge.

    A couple of years ago I replaced the surrounds on some old JBLs.  There
    were 2-12" woofers and 2-12" passive radiators (which were exactly the
    same as the woofers except no magnet and voice coil).  I had never
    done this before, and I did not find it to be a big deal, nor did I use
    any special tools.  The thing that I found to be the biggest pain was
    trying to get all the old surround material and glue off of the
    baskets.  A good sharp razor scraper and some mineral spirits worked
    well for me.  The old glue actually peeled off of the paper cone
    easily.  Once everything was super clean, I CAREFULLY glued the new
    surround to the cone.  This is where great care must be taken to keep
    an even margin all the way around.  Then glued the surround to the basket.
    The instructions said to check for alignment by pushing in on the cone
    around the dust cap, and make sure nothing is scraping.  Mine passed
    the test first shot.  I never removed the dust caps and looked in the
    gaps, so I don't know if they were absolutely perfect.  But the
    important thing is to make sure nothing touches.  I'm sure the use of
    shims to center the coil would be helpful, but I don't feel it is
    mandatory. The speakers are still working great, so I must have done
    something right.   I bought my kits from Parts Express, and they came
    with a good set of instructions.  I just noticed in the new catalog
    they are now selling red surrounds to match your Cerwin Vegas.  Good
    Luck.
    
    Dave