Moving woofers.Is this bad?

Discussion in 'Archived Threads 2001-2004' started by Cagri, Jan 11, 2003.

  1. Cagri

    Cagri Second Unit

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  2. Wayne A. Pflughaupt

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    Either reduce the bass control, or turn the volume down.

    Regards,
    Wayne A. Pflughaupt
     
  3. Cagri

    Cagri Second Unit

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    Wayne, thanks for your reply. Since I don't have a sub I don't know how I can reduce bass...Turning the volume down will stop them for sure, but then what is the purpose of HT if I will have to listen in very low levels?

    Actually the reply from which I quoted in my first post suggested that the moving woofers would damage the coil in time, and that is what I am trying to confirm. I understand you also say so. I also thought like Joseph that woofers could move in their excursion range without causing any damage to anything. Any other input on this please?
     
  4. Guy Usher

    Guy Usher Supporting Actor

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    Dont worry about it, it is normal and even fun to watch, if you dont have distortion or you are not overpowering them then put the grill back on so you wont see it or just forget about it.
    Some woofers move more than others but they all move, you will know if you over extend one, but as long as you have no audible distress you needent worry.
     
  5. Cagri

    Cagri Second Unit

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    Thank you Guy, good to hear that[​IMG]
     
  6. Guy Usher

    Guy Usher Supporting Actor

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    Woofers move a lot of air, they have to to produce the low bass, if your speakers are ported you should feel a lot of air rushing out when the speaker is really working, it should be strong enough to blow out a match. I used to, and sometimes still do, crank up the sound just to watch the woofers move, if they didnt move you had no sound. All speakers move, the higher the frequency the less you can see it because it doesnt have to move as much.
    A good indicator is the surrounds on the driver, you can kind of guesstimate how much travel by how big the surround is. It is not a good practice to move the driver by hand as the suspension is very delicate and requires very close tolerances, easy to push one out of alignment.
     
  7. Brett DiMichele

    Brett DiMichele Producer

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    It all depends on the size of the woofer it's Thiele/Small
    Parameters and where the speaker manufactuer has it crossed
    over.

    A Mid Woofer ( 4" to 6" or so) should be crossed over in
    the 80 to 100Hz range and an actual sub woofer should be
    used to reproduce the low notes. When you rely on a mid
    woofer to "try" and reproduce low frequencies the mechanical
    and electrical "suspension" of the speaker are generally
    not sufficient enough (not enough Xmax and Xmag) to allow
    it to reproduce bass without bottoming out the voice coil
    and former against the T-Yoke or backplate. This will cause
    damage to the speaker. Also while the power handling of a
    mid woofer is generaly much higher than a tweeter, extended
    periods of high power can warm a voice coil and eventually
    cause a burn out.

    What size are the speakers that you speak of?

    My 5.25" Mid Woofs are crossed at 100Hz and my 10" integrated
    Subs handle everything from 100 down to 20Hz.

    I thought about crossing the mids over at 80Hz but after
    talking to some of the experts over in the DIY section it
    was established that the 5mm of Xmax on my Mids is not
    sufficient to faithfully reproduce 80Hz tones without risking
    possible damage.
     
  8. Cagri

    Cagri Second Unit

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    Brett, the woofer is about 5". They have a crossover frequency of 3kHz, and it says on Kef's website;

    "Frequency responce at 15 degrees horizontally off axis +- 3db: 45Hz-20kHz,LF corner -6db:42Hz. Power handling 100W imp 8ohms. internal volume 28litres."

    Since I don't have a sub, I haven't got any chance to manage the bass. I was comforted after reading Guy's post, but now I am getting confused once again. Is 45Hz freq. response not low enough? Would I be needing a sub ? Soundwise I am happy without one, but if the speakers are gonna get hurt I shall buy one. Thanks.
     
  9. Guy Usher

    Guy Usher Supporting Actor

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    KEF Q35.2 loudspeakers. $1499
    The $1500 KEF Uni-Q 35.2 loudspeakers are a compact floor-stander model and lie in the middle of a five loudspeaker line-up in the current Q Point 2 range. The are finished in an attractive light cherry veneer (black ash is also available) and are a two-way bass reflex design of 91dB efficiency.

    Not only was the boogie factor pleasing, but the impression of air in and around the recording was evident. The progressive drive of the bass line in the chorus was engaging, however, I couldn’t help feel that the leading edges were slioghtly diminished.

    I dont think a little woofer movement will hurt a thing on these speakers, I was trying to give a simple answer, I think the woofer on this guy must be 8in+ At less than referance you will do fine, however any audible signs of strain turn it down, also I wouldnt add bass boost with tone controls at high volume levels.
     
  10. Cagri

    Cagri Second Unit

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    Wow! Guy, are you sure they sell for $1500 there in the States? I bought them last year for £200 in dark apple finish, which is around $320.
     
  11. Guy Usher

    Guy Usher Supporting Actor

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    Maybe we are not talking about the same speaker is the one you have the one I listed a minute ago?However my point is still valid. If you have a loadspeaker rated over 90db and play it below referance level without addind boost to the bottom end and you see the woofer move but hear no audible signs of distress you dont have anything to worry about. Now you will not have HT quality bass for explosions and the like, you will need a sub to reproduce those effects.
    I guess I didnt completly understand your post, I was thinking of the normal movements that bass drivers make, it didnt dawn on me that you were using the speaker for LFE as well. . .
    Sorry if I confused you.
     
  12. Guy Usher

    Guy Usher Supporting Actor

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    Those are bust out retail prices I am sure. Certainly you could do better for price. . . I was just showing what I was thinking about when I answered your post. They are fine speakers anyway you look at them.
    Get a sub soon as you can for that last bit of bottom end that you are missing, right now there are too many decent subs from 100bucks up not to.
     
  13. Cagri

    Cagri Second Unit

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    Yes it is the one that you mention in your previous post, but the price difference is too much. They are made in Britain, maybe that is why I bought them cheaper here but still there is a huge difference, strange. Well, I really can't be sure if the movements are normal, they move a lot, that is what I know [​IMG] But there is no audible distress and it is good to know they won't get hurt this way. Thank you.
     
  14. Guy Usher

    Guy Usher Supporting Actor

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    I know I have ended up confusing you more than you were before and I am sincerly sorry for that.
    turns out that in New Zealand MSRP is 1500 in the US MSRP is $600, I have read many reviews of this speaker and it gives solid bass to 40hz, you should be fine just watch for signs of distress, I would not walk away with it at high volume but as long as you are there with it and are aware of what can happen. . . Speakers are really pretty tuff customers, woofers in particular.
    Price difference is amazing maybe we can buy a bunch and finance a trip to New Zealand. . .
     
  15. Cagri

    Cagri Second Unit

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    Your posts have been more than helpful Guy, thank you. Seems 1500 NZD is around $810, still a bit expensive there but won't be worth a jetlag[​IMG]
     

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