Frequency Gaps

Discussion in 'Speakers' started by Ralph Summa, Jun 1, 2003.

  1. Ralph Summa

    Ralph Summa Supporting Actor

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    Recently I've been researching a home theater speaker system for my Dad. I was reading an HT mag and saw a review of of a system in which the center channel could not go lower than 300 Hz and the other four channels could not go lower than 100 Hz. The peak for the sub was around 80 Hz.

    Is the gap a problem? What happens to frequencies between 78 and 300 that are sent to the center channel? Are they just lost? My Dad's receiver has a fixed 90 Hz crossover so he doesn't have much flexibility there.

    Ralph
     
  2. John Garcia

    John Garcia Executive Producer

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    Doesn't sound like a good match, particularly the center.

    A x-over is not an all or nothing deal, there is a slop associated with the drop off of the frequencies, typically expressed over one octave (6dB, 12dB, 18dB, etc...). Despite this, even with a 6dB/octave slope, it would appear this package will still have some gaps regardless of x-over, and I would not recommend it. What that means is, the sound between 78Hz and 300Hz is not completely missing, but it will trail off between them, and somewhere around 150Hz, there will be a dip/gap in the sound, and since it is right in the lower midrange, it will be noticable, IMO.
     
  3. Ralph Summa

    Ralph Summa Supporting Actor

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    That's exactly what I thought. I just think it's silly to manufacture something like this. Here's the link to the lab data for the four HTIBs that were featured in Sound and Vision. They all have pretty similar gaps.
     
  4. Phil Iturralde

    Phil Iturralde Screenwriter

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  5. BrianWoerndle

    BrianWoerndle Supporting Actor

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    I agree that the gap in the Panasonic is uncalled for. But that shouldn't eliminate it right away. All speakers have high and low points. That is what makes speakers sound different. So if you like everything else it has to offer, you might not notice the dip. An interesting note, in a differend S&V test, some PSB speakers that had an increadibly flat response were placed in 2nd place because people thought they lacked something. You are going to have to listen for yourself to decide.
     
  6. Eric C D

    Eric C D Second Unit

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    For those who are fairly new here, it's interesting to contrast this with a Bo*e-bashing thread.

    When friends ask me (usually as they are considering buying Bo*e), I tell them about the freq gaps, and how it's a problem for pretty much all small satellites - that they need to investigate carefully before accepting.

    And neutral vs. colored sound is a personal preference, not to mention *how* the sound is colored. And you also need to consider how the sound "sounds" between low volumes and high volumes.

    But an 80-300hz gap in a center channel - yeesh! Here's a (admittedly copied, so I don't make representations as to it's veracity) chart of the frequency ranges of the human voice:

    Bass voice 75-300 Hz
    Tenor voice 120-540 Hz
    Contralto voice 170-650 Hz
    Soprano voice 250-1100 Hz

    Imagine your primo HT, you put on your new Star Wars DVD [​IMG], you, quivering in anticipation for Darth Vader's first appearance. But when it happens, you are never able to figure out why James Earl Jones was replaced by a mime on the dvd.

    Is that enuff reason?
     

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