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Thread: No sound @ 25Hz

  1. #1
    leif
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    No sound @ 25Hz

    An audiophile man passed by the other day. He brought test sample records and stuff. Among the things he tested out, was a 25Hz signal on my stereo.
    I was very surprised: The woofer on my sub was really moving, but there were no sound at all. I did not hear anything. He did not hear anything.
    Shouldn`t a B460 (2245H) make sound at 25Hz?

    Leif

  2. #2
    Senior Member HipoFutura's Avatar
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    Is is possible your hearing isn't what it used to be? LF & HF are very difficult to hear as you age. Your question makes me wonder! When I have time I'll hook up my signal generator and see where my hearing cuts out.

    Don

  3. #3
    RIP 2011 Zilch's Avatar
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    http://en.wikipedia.org/wiki/Infrasound

    If it shows on your RTA or SPL meter, the B460 is making it.

    Surprising what a test disk or signal generator will reveal about hype....

  4. #4
    Anthony L100
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    Quote Originally Posted by leif
    An audiophile man passed by the other day. He brought test sample records and stuff. Among the things he tested out, was a 25Hz signal on my stereo.
    I was very surprised: The woofer on my sub was really moving, but there were no sound at all. I did not hear anything. He did not hear anything.
    Shouldn`t a B460 (2245H) make sound at 25Hz?

    Leif
    Same deal here Leif, 30Hz I can just about hear, 20Hz I can only feel, yes, a lot of hype. Can anyone confirm HipoFutura's comment about LF hearing diminishing with age? I am very aware my HF isn't as good as it used to be, but not too sure about LF.

  5. #5
    Senior Member BMWCCA's Avatar
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    I always figured almost anything below 50Hz you just feel anyway. Did stuff fall off your shelves and cracks form in the plaster while you heard nothing?

  6. #6
    leif
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    I went to an ear specialist a while ago, and got my ears tested. My hearing was exellent. But I guess he did not test as deep as that.
    But still, 25Hz should be hearable, shouldn`t it?
    The man visiting me have quite a impressing gear himself. Unfortunately nothing from JBL. But take a look anyway: http://avforum.no/minhjemmekino/show.php/Flageborg

  7. #7
    Administrator Robh3606's Avatar
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    Well guess it depends on the levels you are getting. Do you have a subsonic filter inline?? I do test sweeps from 150Hz down to 20Hz and right about 23Hz is when I can't hear it in my room. I can see it on the RTA but can't hear it.

    Rob

  8. #8
    leif
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    Quote Originally Posted by BMWCCA
    I always figured almost anything below 50Hz you just feel anyway. Did stuff fall off your shelves and cracks form in the plaster while you heard nothing?
    Nothing was shaking, nothing sounded, and I could not feel anything on my body. But it was obvious that the woofer was working hard. That could be seen.

  9. #9
    Administrator Robh3606's Avatar
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    What about on a different floor of the house?? Could be a room mode. Is there a pair? The only time I have experienced that was with out of phase bass drivers. Is the phase OK with the mains, if the mains have any output that low??

    Rob

  10. #10
    Senior Member mbd7's Avatar
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    25 Hz on a 4343

    When I ran a 25 Hz tone thru my 4343's I heard a whistling sound from one of them. When I investigated its source I discovered that one of the screws on the back was missing and the whistling sound was generated by all the air moving through such a small hole!

  11. #11
    Senior Member Ducatista47's Avatar
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    Room Mode Calculator

    What about the size of the room? If the diagonal of the room is less than half the wavelength (I think), the wave will not propagate. Air being pushed around, but no sound. My room, for instance, cuts off at 23hz.

    Here is a very cool tool from the Harmon website:
    http://www.harman.com/about_harman/t...eadership.aspx
    Click on White Papers > Calculators > Room Mode Calculator Read

    It is a tiny tool, 128 kb, but it requires Excel.

    Clark in Peoria
    Information is not Knowledge; Knowledge is not Wisdom
    Too many audiophiles listen with their eyes instead of their ears


  12. #12
    RIP 2010 scott fitlin's Avatar
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    Below 30hz, the sound becomes very inaudible. I have run test tones through my system, and 30hz I hear plenty, 28hz still quite audible, at 25hz, I feel air moving but dont hear much, very faint sound. At 20hz, you can feel the rumbling, and hear the room vibrating, but I cant hear anything audible from the speakers.

    At a recone shop, they once showed me how they run test sweeps through a woofer, checking for rattles, and centering of the VC, he ran sine wave test tone through JBL woofer, a 2226H, 40hz was really loud, 30hz was audible but considerably lower in volume, 20hz was completely inaudible and the cone was moving alot. Then he ran a 10hz test tone through the woofer, totally inaudible, BUT, the JBL 2226H made no rattling noises, and the cone moved more than I have ever seen any woofer cone move, ever. That it could take this and not make any noise in protest was quite impressive.
    scottyj

  13. #13
    RIP 2013 Rolf's Avatar
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    Quote Originally Posted by leif
    Nothing was shaking, nothing sounded, and I could not feel anything on my body. But it was obvious that the woofer was working hard. That could be seen.
    Hi. Do you have a floor/walls made of wood or concrete? If it is made of wood, something should be moving and making sound(s).

    Also remember that almost no woofer is capable of reproducing much under 30Hz. At 25Hz most woofers is down 10db or more. The room also have a limit of how deep the sounds is possible to hear.

    There is also possible to figure out how much a e.g. 15" woofer must move to reproduce a 25Hz tone on a certain level compared to the same level at 40Hz. If you do this you will probably understand why there is so few (if any) woofers actually do it.

  14. #14
    leif
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    My room has wood floor and it is hard to describe the shape of it. It is a rather large room.
    I changed the position of the sub just now, and put it in a corner. standing uprised next to one of the 4430`s. It looked really cool standing uprised. Picture coming soon.
    I put on Yello`s The Eye, track 5. A cool song to test bass. When playing really loud, the floor is shaking very much. And I guess that can be the reason for lack of physical punch. But guess what I saw while playing? The woofer was working hard, but it had cracked in the foam. I did not see that the other day when that guy was here, so I guess it happened now. Arghhhh....
    Well, the speaker is old, and I have been waiting for it to happen. Phuhh.....
    That one is NOT cheap to recone.
    Perhaps I slould try to refoam? I did it with the 4430`s and it worked fine.


    Leif

  15. #15
    Senior Member SEAWOLF97's Avatar
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    AR3 woofer may do it.

    Quote Originally Posted by Rolf
    Also remember that almost no woofer is capable of reproducing much under 30Hz. At 25Hz most woofers is down 10db or more. If you do this you will probably understand why there is so few (if any) woofers actually do it.
    I have a pair of AR3's . rated at doing mid 20's. On some audio material, I can feel , but not hear the bass. Could never really verify what they can do. Ugly looking, looks like they've been buried (they all look that way), but put signal to them and.......
    It's the new Mother Nature takin' over
    She's gettin' us all, yeah, she's gettin' us all

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