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infrasound, need speaker and amp recommendation

Discussion in 'Subwoofers' started by chundle, Apr 25, 2005.

  1. chundle

    chundle
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    hi all
    i'm doing some experiments with infrasound, nothing particularly musical, but i need to play with frequencies in the region of 10Hz - 25Hz. Can anyone recommend a good speaker/amplifier combination that would be good for this? I don't need a lot of power, and I'm going to be varying the frequencies, so I'm not doing the usual thing of using pipes (which are generally used for particular frequencies). Any pointers would be gratefully received...
    Are there any subwoofer's out of the box that will go down to this low? looking at most specs for subwoofers say usuable frequency range of 40Hz and up, etc.
    CH
     
  2. bob1

    bob1
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    Whats the experiment some kind of infrasonic weapon? :suicide:
    You can pick up a subwoofer that will go down to 20hz ,but going down to 10hz might be a bit harder and will cost a lot more.
     
  3. chundle

    chundle
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    no not a weapon,he he! just some experiments with sensation (i.e. what people feel...).
    i know it's going to cost me a fair bit to get down to 10Hz... any suggestions how?
     
  4. Nimby

    Nimby
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    What's your budget?

    My cylindrical SVS 16-46PCi goes down to 15Hz with a gently rising tendency to +10dB at 15Hz in my 30 foot room. (large room effect LF gain can be used to increase gain at even lower frequencies)

    Easy 100dB capability at low frequencies if needed. I can rattle all the windows below that frequency (15Hz). But I am not allowed to. :blush:

    BTW: It has a built in 350 watt amplifier and is mains powered.

    My home-built, sixth-order series bandpass subs go down to below 10Hz in a 20" cube. They can make you puke on only 30 watts on a signal generator.

    You could have borrowed one (or even two) of these as they are not in use. But I doubt you are in my part of the world. (Denmark) and the postage to send them to you would be quite phenomenal. :devil:

    Regards
    Nimby
     
  5. Mark Grant

    Mark Grant
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    Not sure how you willl get 10hz, but have a look at these to give you some ideas:

    http://www.servodrive.com/contrabass.html

    Read how they work, the speaker cones are moved by a servo motor rather than magnetism, so might be interesting :)

    probably far too expensive, although I would like one to try sometime.

    Mark.
     
  6. SBanga

    SBanga
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  7. Mark Grant

    Mark Grant
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    Expensive but look at the performance :)

    Compares well in that test to the Genelec HTS6 :eek:

    Mark.
     
  8. JBL 4645

    JBL 4645
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    This sounds like the gadget he is building an experiment to curse structural damage?

    Or like he said "what people feel"…no kidding.

    InfersSonics if played at the correct frequency at around 7Hz and if played at very
    High sound pressure levels will mach the body’s resident frequency and this can result in….

    Feeling dizzy…chest pains…internal damage…and fatal death…. :oops: :nono:

    Mate I do hope you are not putting someone into harms way…because I have tried it at 8Hz and it’s not pleasant at all…

    So don’t fool around with infersSonics…too much unless you are so incline too do so…

    And knowing the consequences and the repercussions…

    You are entering a field of science that needs to be read and understood first before undertaking something that could result in injury…to the loudspeakers and amplifiers…

    Good luck

    Ashley…
     
  9. Garfield

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    What you need is a ButtKicker - no seriously that's what it's called.

    They are used extensively in simulators etc to replace those sensations not produced by sims motion alone, used in some of those fairground 'virtual' rides too.

    Some high class cinemas have them under the seats too.

    Frequencies from 5 to 200Hz !!

    check 'em out ... ButtKicker
     
  10. bob1

    bob1
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    :rotfl: Classic as far as i can remember most death is fatal.
     
  11. JBL 4645

    JBL 4645
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    That wasn’t meant to a joke playing around with infersSonics can be used for good intensions or for evil…and we have head of acoustic weapons…

    Anyway how many films have recorded soundtrack information below 20Hz if there is something that as gone past me without knowing then I want to know the details and technical specifications…

    Tactile is another form of low frequency unit like the butt-kickers and size and weight and cost issues as well…there a lots of ways too doing this add lots of 18in sub bass units and this will further increase the frequency range down lower into the infrasonic range and EQing and active electronic crossovers high powered amplifiers and some electronic triggering to produce a lower octave just under the low frequency playing…

    Sounds like universals patented SENSUUROUND for Earthquake 1974 Oscar winner best sound….

    I might play earthquake chapter 8 in a moment via the THX at 0dB that shaking feeling… :smashin:

    Ashley…
     
  12. bob1

    bob1
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    Take a look at these waterfall charts on Home Theater forum CLICK ME
     
  13. alexs2

    alexs2
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    Chundle was originally looking for means of conducting some experiments with infrasound,and also specified that it does not have to be at a high power level.

    Thus any worries about damage to internal organs or "fatal death",and acoustic weapons are irrelevant,and have already been covered in any case....no more on that thank you.
     
  14. JBL 4645

    JBL 4645
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    Yes that was fascinating, though, I do like other graphs, unlike predator vision!

    But those infrasonic notes down at 10Hz easy to reproduce acoustical, and if there was enough room for me to place 7 more JBL 4645 THX subs along with the amplifiers, taking up room in another part of the of the studio flat then, I would do this…

    But I’d only have to calculate the room and number of JBL 4645 that would be needed…

    One more JBL 4645 will suffice…as I can play an infrasonic spot frequency below 20Hz that shakes the back windows and about 20 feet away…due to the wave lengths distance…

    Adding more to this does extended and once I have calculated and plotted its levels, I’d turn the level down for the LFE and other sub bass and anything in the infersSonics range…

    Ashley…
     
  15. alexs2

    alexs2
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    JBL...you've already been asked above,and in other posts,to keep your own efforts on topic,and refrain from advice which has little or no relevance to the original post.

    Chundle is NOT looking for 8 or more subs.....just one,to conduct a few experiments with,as stated in the original post.
     
  16. chundle

    chundle
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    thanks, yes, i can confirm there are no untoward reasons for experimenting with infrasound... in fact the levels we are working with are subconscious, certainly not going to cause any structural damage!

    my budget is absolutely maximum 1000 quid; i tried out the REL Q400 but it really lost any power at all below about 13Hz. the buttkicker is unfortunately way too expensive, but sounds like it would do the trick... the SVS are also too expensive. but that home built unit in denmark sure sounds good! but unfortunately i'm not going to get into homebuild....

    any other thoughts?
     
  17. bob1

    bob1
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    How about a bit of D.I.Y.
     
  18. eviljohn2

    eviljohn2
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    I think DIY will probably be the best option as you can then design the unit for your exact specifications. I'm sure Nimby will be able to advise if you ask him nicely. :)
     
  19. Garfield

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  20. Nick_UK

    Nick_UK
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    A friend of mine did this once by frequency mixing (when you mix two frequencies, you get a sum and a difference frequency, so if you were to mix say, 400 Hz and 410 Hz, you would get 810Hz and 10Hz). He nearly ended up shaking his house down ! Also, the resonant frequency of the human digestive tract is around 7 to 9 Hz, so you could end up with a lot of vomit on your floors :rolleyes:

    Take a look at this :zonked:
     

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