Frequency Response Confusion

Discussion in 'Archived Threads 2001-2004' started by Mark Paquette, Jan 16, 2003.

  1. Mark Paquette

    Mark Paquette Supporting Actor

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    My new Paradigm speakers have me a bit confused. Hopefully someone can explain what these specifications mean. In the speakers specifications they list "Frequency Response" and "Low Frequency Extension." What is the difference between these two number?

    Here's an example from the Studio 40 specs:

    Low-Frequency Extension: 34Hz (DIN)*
    Frequency Response: On Axis + - 2dB from 59 Hz- 22 kHz
    30 degrees off Axis + - 2dB from 59 Hz - 20 kHz
    *DIN 45 500 indicates -3 dB in a typical listening room.

    I'd like to know what the lowest setting is I can use for my subwoofer crossover w/o having any holes in the sound.
     
  2. Greg_R

    Greg_R Screenwriter

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    Greg
    You want to set your crossover to 80Hz.

    LF Extension is the lowest frequency that your speaker can play. The frequency response tells you that your speaker plays from 59->22khz with only a 2dB variance in the response (i.e. 80dB at 59Hz, 81dB at 68Hz, 79dB at 430Hz, etc.)

    However, Paradigm (and virtually every other speaker manufacturer) does not quote frequency response with an output level (like 80dB, 100dB, etc.). In general, the louder a speaker plays the less accurate it becomes. So, a speaker that is +-2dB from 35Hz->20kHz while playing at 100dB and low distortion levels is impressive while a speaker that is +-2dB at 40dB and high distortion is not. You can measure your own speakers with a calibrated microphone, computer & special software.

    What am a saying? You typically don't want your sub's crossover setting near the manufacturer's lower frequency response. 80Hz is about 1 octave above the lower limit of the Studio 40s (somewhere between 34Hz and 59Hz). You want to have an overlap because a crossover is not a brick wall (it's more of a progressive shift)... both your sub and mains will be playing a certain band of frequencies in the crossover region. The point is that you don't want your mains straining to play a low frequency at loud levels when your quality subwoofer could easily reproduce the sound.

    FWIW, I have my Studio 40s crossed over at 80Hz and they sound fine...
     
  3. Mark Paquette

    Mark Paquette Supporting Actor

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    Greg R-

    Thanks for the response. I think this makes a bit more sense to me now. I have been leaving my speakers crossed at 80Hz for movies and they sound great. 2 channel stereo is another story. I think they sound better run as large. To my ears they sound very flat, almost lifeless, when listening to 2 channel stereo with the speakers set to small and crossed at 80Hz. My receiver can do 40, 60, 80, 100 and 120Hz, I think. Maybe I should try a lower crossover setting for 2 channel stereo?
     

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