how low is low for a sub

Discussion in 'Archived Threads 2001-2004' started by Simon Brooke, Jan 16, 2003.

  1. Simon Brooke

    Simon Brooke Stunt Coordinator

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    hi,

    i am thinking about getting a new subwoofer or even making a sonotube, the question i need to know is how low should a decent sub go, my current yamaha can only go as low as 30hz,
    any advice would be great.
     
  2. Edward J M

    Edward J M Cinematographer

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    When you say your yammy can only go as low as 30 Hz, that doesn't tell much of the story.

    My personal minimum criteria for a subwoofer:

    The subwoofer should have a flat in-room frequency response from 100-20 Hz, with an F3 of 17 Hz.

    This frequency response should remain stable at all volumes within the safe operating range of the subwoofer (i.e., the FR is dynamically stable).

    It should demonstrate exceptionally low THD across the FR, but especially in the 35-20 Hz range.

    For demanding HT DVDs, it should be able to CLEANLY (10% THD or less) hit bass SPL peaks of at least 110 dB, as measured at the key listening positions with a decent SPL meter on C-Weighted Fast.

    Ed
     
  3. John F. Palacio

    John F. Palacio Supporting Actor

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    Some DVD's have been known to have material running down to 10 Hz and some CD's (Telarc's 1812 Overture come to mind) have information down to 4 Hz.

    IMHO a sub that goes down strong and clean to 20 Hz will satisfy 99% of enthusiasts.

    Best regards.
     
  4. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    I prefer a sub that's anechoically flat to about 30 - 35 Hz since I've got a big room with less room gain than most. Useable extension to 25Hz or lower for tactile response. I care more about THD in the 35-120Hz range since my hearing is starting to roll off at 35Hz and below about 28Hz its all tactile. I can't imagine how I'd distinguish between distortion and signal down there.
     
  5. Peter_A_M

    Peter_A_M Stunt Coordinator

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    I like my subwoofers to be able to go down to at least 20 Hz with noticeable presence. To my ears, a 20 Hz signal is very audible - it represents the tone "E". If you double the frequency to 40 Hz, you'll find that the represented tone is still an "E", only an octave higher. 17 Hz sounds like the note between "C#" and "D", 16 Hz like the tone "C". It starts getting iffy around 15 Hz.

    Try hooking up your subwoofer to your computer, use a test tone generator to see how low you can really hear, then decide from that how low your subwoofer should go.
     
  6. Simon Brooke

    Simon Brooke Stunt Coordinator

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    i don't understand most of the stats associated with sub frequencies, my main issue was that i felt i was missing out on so much material that is on so many movies now. i will probably start looking for something that goes down to 20hz.
    will a larger room lower the frequency response or is this a stupid question.
     
  7. Frank Carter

    Frank Carter Screenwriter

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    Most people on the DIY forum tend to tune their subs a tad under 20Hz. The lower it goes, the more of a visceral feel you get.

    With my SVS CS Ultra, I can change the tuning frequency between 20hz and 16hz. Can I tell a difference? Yes, but it's small. I keep it at the 16hz tuning point just to know that I'm getting as much of the music/movie I can.
     
  8. Peter_A_M

    Peter_A_M Stunt Coordinator

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    As many a high school teacher told me before I asked a stupid question, there's no such thing as a stupid question. [​IMG] As I see it, a larger room will lower the frequency response in that room gain will be lower than that of a small or medium room. Nothing about the subwoofer itself will change, but the accumulative effect of subwoofer + room will be less than that of a smaller room.
    Adire has a picture of the graph they use to approximate room gain, but I can't find it outside of the Sealed Shiva Applications pdf.
     
  9. Phil Iturralde

    Phil Iturralde Screenwriter

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