Watkins woofers- what's so special about them?

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

  1. thedelihaus

    thedelihaus Nocturnal transmissions

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    Watkins woofers- what's so special about them?

    I've heard great praise but have no idea why these woofers are so well regarded.

    anyone care to enlighten me?:thmbsp:
     
  2. macaltec

    macaltec Metal Master Subscriber

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    Dual VC's of differing impedance. Apparently to smooth out the response at low frequencies. Where one falls off the other compensates. May have something to do with the resonance frequency too, but now we are getting to the end of my knowledge. That's not to say I am even correct about what I think I know. I'm curious for more technicals myself.
     
  3. junkaudio

    junkaudio Super Member

    they don#t look very special most have nodiecast frame some dualcoils but they do sound special though other speakers looks more well build
     
  4. Army

    Army Addicted Member

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    I'll share my limited knowledge, yes dual voice coils 2Ω and 6Ω
    What makes them special (and this is only my opinion) they hit hard with a very tight fast bass response. IMHO better than most vintage speakers I've heard.
     
  5. Vitopanch

    Vitopanch Super Member

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    Deli Hail,
    Watkins developed his woofer to obtain a truly flat frequency response, free of an enclosure resonance peak, by using two voice coils of different sizes, each having it's own impedance and each responsive at different frequencies. So, the Watkins woofer creates high sound pressure levels of flat frequency response along with high efficiency from the same speaker. It also eliminates the reproduction of the enclosure resonant peak which would distort bass response.

    Vito

    P.S. I have the white paper on these if you would like a copy, PM me your email and I will send you a copy.

    P.P.S. Unparralled true bass. LOW, LOW, true bass without rolloff. Knocks your socks off
     
    Last edited: Jun 22, 2007
  6. thedelihaus

    thedelihaus Nocturnal transmissions

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    Very cool. I'll pm you my address- always looking for more knowledge. Thanky!
     
  7. Vitopanch

    Vitopanch Super Member

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    The offer is open to you as well then.

    Vito
     
  8. Nakdoc

    Nakdoc nakamichi spoken here

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    A bit more... The 8 ohm coil is the primary VC, but at resonance (woofer+cabinet) the very complex crossover shifts the signal to the second voice coil. In effect the 2nd coil operates in a narrow band. The effect is to level the speaker impedance (at resonance, impedance and efficency are at max, and cancell out) but more significantly, the phase of voltage and current remain stable (at resonance they are at 90 degrees, a tough amp load). Watkins woofers also maintained a deeper bass, because the second VC bandpass was at the low end of the speaker's response. A typical 12" in a big box might resonate at 42Hz. A Watkins could move this down to 28Hz.
     
  9. Vitopanch

    Vitopanch Super Member

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    Good points Doc,
    The second voice coil is wound over the first voice coil and is driven by the LRC which is adjusted to resonate at the resonant frequency of the woofer. This all allows more wattage intake into the woofer thereby providing more bass response. It uses the wattage of the power amplifier that is otherwise unusable in the bass range because the impedance barrier at resonance prevents it from being accepted.

    Vito
     
  10. MarkMeyer

    MarkMeyer Active Member

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    I think that's where you nail it. The dual voice coil is what allowed Watkins' woofers to reach lower than you would expect from any comparably sized woofer.

    I have a pair of Infinitessimal 0.1's, and I can tell you that the first time I cranked up these tiny little buggers, I couldn't believe what I was hearing in bass response from those little dual-coil Watkins. Throw in the Emit tweeter the Infinitessimals use, and I have never, and I mean never heard a speaker three times as big as the 0.1's sound anywhere near as good.

    Unfortunately, I just recently sent one of the woofers directly to Bill Watkins for repair, but he emailed back and said that the voice coil(s) were damaged and there are no replacements so the speaker is junk and not rebuildeable, not even by him.

    Now, I have a single Infinitessimal 0.1 looking for a mate, or failing that, I guess I could always use it as a Center Channel speaker.

    I hate it when that happens.
     
  11. John in MA

    John in MA Respect the gamba tuba Subscriber

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    I'm always fascinated with the various non-traditional ways speaker builders get around physical limitations. I wasn't very familiar with the Watkins designs in the past.

    McIntosh took a difference approach to the problem years back. Over-dampen the woofers so they naturally roll off around 100-125Hz, then use a equalizer to boost the low end up to normal. Sounds goofy when you read about it, but my 2Cs on paper are good to a flat 20.
     
  12. Mark B

    Mark B Yamaha Fan Subscriber

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    The 12" Watkins woofers in my Infinity Quantum 2's produce profoundly deep bass. Not only does the bass go very low, it's also very clean and tight. To get the most out of them requires an amp that can supply the current they need, and the amp must be capable of driving < 2ohm loads.

    The voice coils are 2 ohm and 4 ohm.
     
  13. phaedrus

    phaedrus Well-Known Member

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    Vito,

    I, too, would appreciate a copy of the white paper, while you're distributing it. Thanks!

    David
     
  14. Kencat

    Kencat Super Member

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    Vito,

    Can the white paper go into one of the stickies somehow? I think there are a gaggle of us that would like to see it :yes:

    And yup, that bass in the Quantum 2 is sure nice to behold...or is that behear :scratch2:
     
  15. Kencat

    Kencat Super Member

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    Hey Guys,

    Go to the infinity classics site and look at the Brochures posted for all the quantum and RS models that have the Watkins woofers in them. The different brochures describe the function of the Watkins in different ways, and reading them all gives a good overall picture of what is going on.
     
  16. Army

    Army Addicted Member

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    Vito

    Very cool of you to offer this to us, it's up to you who you share the white paper with, I too would like to read it.

    If you post it, I would gladly sticky the thread and then close it as an info thread.

    Your call if you want to share it with all of us and the lookie loo's
    Scott
     
  17. Filmboydoug

    Filmboydoug Nikko Freako

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    So how come no other manufacturers do this? (or do they?)
     
  18. Kencat

    Kencat Super Member

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    Two guesses on that one:

    (1) Cost
    (2) Patent rights by Mr Watkins?

    Oops, wait a second....aren't these Dual Voice Coil drivers big in the car audio world? I don't hang there so am not up on the car audio tech.
     
    Last edited: Jun 22, 2007
  19. John in MA

    John in MA Respect the gamba tuba Subscriber

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    I'd say the super-low-impedance issue also limites their popularity with some amplifers.
     
  20. phaedrus

    phaedrus Well-Known Member

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    Kencat,

    I'm pretty sure the patent has expired on those. I think Negotiableterms mentioned someone else was building them, and (if I recall correctly) he commented that the patent was expired, which would be right if they were in production in 1976.

    David
     

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