"tuned" resonant speaker.

Discussion in 'Homebrew and Kit Projects' started by K7UNP, May 1, 2010.

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  1. K7UNP

    K7UNP Ham Member QRZ Page

    Does anyone have the formula for determining the resonance of a tubular speaker enclosure? If I remember correctly, there are two scenarios. One has both ends of the tube open and one has the speaker end closed.

    I'm trying to build a "tunable" enclosure for cw work which will "peak" and "clean" signals between 6-700 hz on CW. I have long misplaced the formula.

    I think it was something like L=1100/f or something like that for both ends open. Anyway, thank you all in advance for helping this old guy to remember something...

  2. WD5HHH

    WD5HHH Ham Member QRZ Page

  3. K7UNP

    K7UNP Ham Member QRZ Page

  4. K7JBQ

    K7JBQ Moderator Volunteer Moderator QRZ Page

  5. M0WAN

    M0WAN Ham Member QRZ Page

    Here's another approach to you problem: You may get better results by feeding the speaker via a 22 ohm resistor (say) and placing a parallel resonant LC circuit across the speaker terminals. This way you will avoid acoustic ringing which may otherwise occur. I did try this many years ago to narrow a radio's response but it proved too narrow and peaky for the intended SSB use.
  6. K7UNP

    K7UNP Ham Member QRZ Page

    That is a great idea. I'm going to have to look at that as an option. Thanks so much for the input.
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