Watkins woofers- what's so special about them?

Discussion in 'Infinity Loudspeakers' started by thedelihaus, Jun 22, 2007.

  1. TNHNDYMAN

    TNHNDYMAN New Member

    Messages:
    31
    Location:
    Johnson City TN
    I'm fortunate to live 15 miles from Mr. Watkins store. I've never had the pleasure to hear a pair of the large infinity's, but I have had several pair of Watkins roll thru my collection the past couple of years. I currently have one older pair of Watkins WS-1's that have the dual vc 12" driver and have the walnut cab signed by Mr. Watkins himself. The surrounds need to be refoamed and haven't had time to get to them yet. I also have a slightly newer pair that are in perfect working order and nice cabinets but no label on the backs to verify model #. I'll try to get some pics up later this week.
     
  2. cerwinbob

    cerwinbob New Member

    Messages:
    18
    I have a pair of Quantum Reference and those 15" watkins are really nice, goes down to 18 hertz ;)
     
  3. audiomagnate

    audiomagnate AK Subscriber Subscriber

    Messages:
    7,528
    Location:
    Atlanta
    Quantum Reference? 15" Watkins'? If you mean Quantum Line Source, those are 12 inch Watkins.
     
  4. cerwinbob

    cerwinbob New Member

    Messages:
    18
  5. audiomagnate

    audiomagnate AK Subscriber Subscriber

    Messages:
    7,528
    Location:
    Atlanta
    EMIRMs? 15 inch Watkins? Who knew? I thought my speakers were rare and cool, but those take it to a new level. Amazing. I would think they go lower than 18 Hz.
     
    Last edited: Mar 24, 2013
  6. totem

    totem AK Subscriber Subscriber

    Messages:
    4,539
    Location:
    Vancouver B.C.
    You don't see these often but I recall seeing and ad or writeup in some literature
    I have.
    If I can find it I will can and post it.
     
  7. cerwinbob

    cerwinbob New Member

    Messages:
    18
    Sounds nice, think they are the forefather to the IRS. Should I post pics?
     
  8. NADfinity

    NADfinity New Member

    Messages:
    9
    Location:
    Zell (Mosel) Germany
    hello cerwinbob, yes please, you should definitily post some pics because there are only a few to find in the net. :thmbsp: i would be very happy to get some photos of these amazing speakers and i think many other people here in AK would agree.

    Greetings from the Mosel river region in Germany

    Picky
     
  9. cerwinbob

    cerwinbob New Member

    Messages:
    18
    Hi Guys

    Here are some pictures I took after I finished work. Hope they will satisfy.
     

    Attached Files:

  10. cerwinbob

    cerwinbob New Member

    Messages:
    18
    The room is not up to dimension and the amplifiers are as follow.

    Bas: Dynamic Precision NO1
    Upper: Xindak monoblock
    Preamplifier: M.F. HTP
    Origninal but upgraded active crossover.
     
  11. geoff727

    geoff727 Well-Known Member

    Messages:
    631
    Location:
    Seattle, WA
    Very impressive. Collectors items....
     
  12. cerwinbob

    cerwinbob New Member

    Messages:
    18
    Got hold of a couple of RS 4,5 last weekend too ;)
     
  13. 4343

    4343 AK Subscriber Subscriber

    Messages:
    1,085
    Just clearing up a mis-conception...

    From:

    https://groups.google.com/forum/?hl=en#!topic/rec.audio.opinion/pG2grJ5bqe8

    "Bill Watkins
    6/28/00
    In article <06795498...@usw-ex0104-033.remarq.com>, tony_...@email.com
    says...


    >bill, i guess the 'short course' here is that your dual-drive
    >system lowered the impedance of the woofer around fundamental
    >resonance, making it easier for amplifiers to power the woofer
    >at and below resonance. yes?


    The benefits of the dual-drive are mainly:
    1. Extended bass, higher efficiency, smaller enclosure,
    or a combination of the above.
    2. In any case, a flatter impedance, and almost purely resistive
    load in the bass. For example, one can achieve 6 ohms
    +/- .5 ohm easily from 10 Hz through 200 Hz if desired.
    The typical woofer would vary from 6 to 20 ohms or so.
    Thus the dual-drive removes the highly inductive load
    of ordinary woofers in the region of resonance and allows
    the amplifier to deliver more power into the woofer."

    Also:

    "Bill Watkins
    6/27/00
    In article <5PU55.5406$Sn2....@news-server.bigpond.net.au>,
    tre...@rageaudio.com.au says...


    >Even one of RAO's favourite sons (Bill Watkins) in collaboration
    >with Infinity, released some of the most diabolical speakers
    >ever let loose on the domestic market (impedance-wise).
    >Trevor Wilson
    >www.rageaudio.com.au

    ---

    Trevor, I believe it's time I explained what happened
    here. My dual-drive woofer works so:
    A second voice coil (vc-2) is wound over the main voice
    coil (vc-1) in the woofer, this second coil having a
    single layer and very low impedance. Now vc-2 would
    normally have an impedance too low for safe operation.
    However around fundamental resonance the impedance of
    _any_ coil will ~triple. Now we activate vc-2 _ONLY_
    in the region of fundamental resonance (around 45 Hz)
    and it rises to ~8 ohms or so (being ~2.5 in the
    first place) which is safe. This is accomplished with
    an LC circuit tuned to 45 HZ and with the Q of the LC
    circuit adjusted to provide the response shape and
    impedance desired. Please note that the exact value
    of vc-2 and the characteristics of the LC circuit give
    _COMPLETE_ control of the impedance. The benefit of
    the dual-drive may then be taken in extended bass or
    higher efficiency in a given size box, or a smaller
    box for a given efficiency or bass extension.

    Now I set the parameters of the original QLS-1 in a
    prototype and shipped it to Infinity. It had a minimum
    impedance of 3.2 ohms, acceptable for a 4 ohm speaker.
    At that time we were operating a retail store selling
    Infinity. Our first shipment of the QLS-1's arrived,
    we tested a pair and found the impedance to be
    ~1 3/4 ohms from ~50 - 80 HZ. Now, the fun begins...
    Mr. Nudell wanted a spec down to 20 HZ, he got to
    18, as I recall, by adding ~35 grams of mass under
    the dust cap, _BUT_ he did not re-tune LC to the
    lower resonant frequency, leaving vc-2 operating
    somewhat above the new fundamental resonance, and
    creating a low impedance in that area. My name
    was already on the royalty agreement, which had no
    stipulation to cover such... I did voice my
    disapproval to no avail.

    If you check, you will find our WE-1, built and
    marketed by _my_ company had no impedance problems,
    and neither did thousands of other speakers we
    built have any impedance problems. Perhaps this
    makes things clear for the technical people here.

    Bill Watkins"

    So, just to clarify, the 2 ohm coil should never be seen as a 2 ohm load by the amplifier in a properly adjusted Watkins woofer system. It was, however seen as such in at least one Infinity speaker, due to their mis-understanding the way the Watkins interacts with the system resonance.
     
  14. tubed

    tubed Lunatic Member

    Messages:
    11,508
    Location:
    Aztlan
  15. Mark B

    Mark B Yamaha Fan Subscriber

    Messages:
    4,897
    Location:
    The Iron Range, Minnesota
    You quoted the following post of mine under the above heading.

    What mis-conception are you supposedly clearing up?
     
  16. Mark B

    Mark B Yamaha Fan Subscriber

    Messages:
    4,897
    Location:
    The Iron Range, Minnesota
    Are you using only tube amps with your QLS-1's?
     
  17. goat67

    goat67 AK Subscriber Subscriber

    Messages:
    2,593
    Location:
    Twin Cities MN
    I believe he is showing that the QLS 1 where modified by Mr. Nudell to achieve 18HZ
    but the LC circuit was not modified to make the impedance to be in the 3 to 4
    ohm range as it was designed to be by Mr Watkins it ended up being less than 2 ohms.
     
  18. tubed

    tubed Lunatic Member

    Messages:
    11,508
    Location:
    Aztlan
    Nope, Yamaha SS 2 OHM stable
    More power the better with these.
    I'd love to have the PC-5002 or two:yes:
     
  19. thermoluddys

    thermoluddys Member

    Messages:
    74
    Tried to send you a pm, your inbox is full.
     
  20. Seppo

    Seppo Work in progress

    Messages:
    1,190
    Location:
    Ontario, Canada
    Here:
     

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    Last edited: Nov 20, 2015

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