How low does a sub need to go - help a beginner?

Discussion in 'Speakers' started by Brad Newton, May 7, 2003.

  1. Brad Newton

    Brad Newton Second Unit

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    Can you really hear the difference in a sub that goes down to 20 hz vs. one that only goes to 40hz? Is this something that is heard or felt or both?
     
  2. Zack_R

    Zack_R Stunt Coordinator

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    IMO there is a huge difference between a sub that can only go to 40 hz versus one that goes relatively flat to 20 hz.

    How much you can hear below 30 Hz has alot to do with your own hearing ability. 30 Hz has a whole lot of sound you can hear. 25 Hz has a combination of both and 20 Hz and below is probably more feel than hear to alot of people.
     
  3. Rob Rodier

    Rob Rodier Supporting Actor

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    It is more important to find a quality sub IMO. A lot of manufacturers doctor the specs to make their subs seem like they go lower than they really do. Sony for example has a budget sub that is claimed to hit around 20hz, the catch is that it does it at -10db, rendering it virtually in-audible. Be weary of subs that dont give a +/- spec on the frequency response rating.

    I think if you find a good sub that can hit around 30hz +/- 3db you will be happy. Of course lower is always better if quality is not being sacrificed.

    Good luck

    -rob
     
  4. Arup

    Arup Stunt Coordinator

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    It is more important to know how tight the sub is down the lows and how fast it recovers. Anything below 20Hz is subjective but a musical sub is what is more important.
     
  5. Brad Newton

    Brad Newton Second Unit

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    I was thinking of the Klipsch rsw10 sub......what kind of pefromance does it give - mainly for movies?
     
  6. Dustin B

    Dustin B Producer

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    IMO the last octave can make a big difference in some action movies, in other movies there is no difference. When I went from my Paradigm PDR10 to my Tempest sonosub there where a number of movies where the sound track almost completely changed with the addition of authority in the last octave.

    For most music sub 30hz is never seen, but there are quite a few tracks from certain genres that have the content.

    The +/- rating from manufactures is also mostly useless. Most take that measurement at below 80dB. Take it again at 100dB and there is no way a Paradigm PW2200 will rate to 18hz.

    Given the price tag there are quite a few options that will really outshine a RSW10 in a mainly hometheater setup. The RSW line drops off very fast below 30hz.
     
  7. Rob Rodier

    Rob Rodier Supporting Actor

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  8. Dustin B

    Dustin B Producer

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    If they qualified it properly it wouldn't be useless, but since all they say is this frequency range with this +/- value it's useless.

    Bare minimum qualification would be anechoic or not (if not some room details), distance to the sub, what type of signal (sine waves, pink noise etc), at what level the sweep was run and what the THD level was. If all you give is +/- almost any sub can be made to look good.

    There are many subs that post almost identical +/- 3dB specs from the manufacturer, but are a huge range in sound quality and quantity.
     
  9. Manuel Delaflor

    Manuel Delaflor Supporting Actor

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    I agree with Dustin. The FR spec is almost useless (and let's not enter on details please [​IMG]). As he said, some subs are said to reach 20Hz (or any other number) but nobody tells you at how many dB's.
     
  10. George Pappas

    George Pappas Auditioning

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    Just to give some perspective on dbs as Manuel is stating above, the Krell Master Reference powered subwoofer is probably the most devastatingly powerful monster to enter the home theater realm. I have not heard one although I'm trying to locate a retailer that has one to audition.

    It is claimed by Krell that this nuclear powerplant can overpower any room in any home of any size.

    It's mega specs are a conservative 2600 watts continuous (God only knows the dynamic power!), It can go way below 20hz but the real major statistic here is that it can crank over 120db volume at 20hz! That is not just powerful sound, it is described by those who have auditioned it as being capital punishment. Crank up the opening explosion scene on AOTC and even a call from the governor can't save you.

    A powerful sub with usable low frequency levels should strive to reach Krell's benchmark of 120db at 20hz. Not easy but the closer you get the better it is.
     
  11. Dustin B

    Dustin B Producer

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    It's way way way over priced and won't come anywhere near that spec in an actual home theater at the listening position. I'm very confident a SVS B4 Plus could out gun it at 20hz (equivalent displacement and a bass reflex design).

    I could build an Adire Tumult based sub of very similar allignment for a little over $2000 that could outperform it as well.

    There's something known as Hoffman's Iron law. The MRS can't get around it. And in an enclosure that small it would need a hell of a lot more than 2600W to hit 120dB at 20hz. And the drivers in it couldn't handle much more then what they are being feed already.
     
  12. Geoff L

    Geoff L Screenwriter

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    Not to take sides and no disrespt to Krell as they do make an excellent sub, but I must concure with Dustin on this paticular point....

    H's Law is the LAW and (Dustin already pointed out the negative points) of the Krell. A (very good sub it is) and not looking for a flame war.
    But No Question, for much less money a better, deeper, louder, and just as accurate sub could be built.
    I also agree the B4+ will out gun at 20hz and down and for substansualy less money....

    Original question:
    As to the 40hz 20hz difference and is it really needed, simply watch a film containing these 20hz freq's and lower and tell us if you think your missing something, is their a noticable difference, OH YES!

    I'm quite positive you would find that 40hz for "movie material" most likley just don't cut it.. A solid 30hz is tolerable, but for me and others, strong solid clean 20hz extension is manditory with movie material making use of it....[​IMG]
    More and more films are making use of the lower/lowest freqs in the last octave....!

    Regards
    Geoff
     
  13. Nick V

    Nick V Second Unit

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    When I went from an 8" Polk Audio sub to my dual 12" Mirage BPS-400, it was the most significant upgrade I've made in my movie watching experience to date.

    That right there is the difference between flat to ~40Hz, and flat to ~22Hz. The difference is HUGE!!
     

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