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OK, no laughing, but I have a speaker question... — Parallax Forums

OK, no laughing, but I have a speaker question...

DosManDanDosManDan Posts: 179
edited 2007-11-01 09:05 in General Discussion
I hope this doesn't fall under the duh category...· I have a 4 Ohm speaker and don't want to over drive a 1 watt amplifier that requires an 8 ohm speaker. Can I just add a 4 ohm resistor and everything will be alright?

It sure sounds like it should work, but I've been wrong before about things I thougt made sense.

Dan
·

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2007-10-31 00:14
    If this is a low power setup (as it would be with 1W), the output impedance is not critical. Often the amplifier is rated for a range like 4-16 ohms. You won't get as much power with a 4 ohm speaker and the fidelity (if there is any) is slightly less (in other words ... a tiny little bit more distortion), but you won't harm the speaker or amplifier. [noparse][[/noparse]The question is not in the duh category]
  • grasshoppergrasshopper Posts: 438
    edited 2007-10-31 01:08
    Well yes you could add one, resistance is resistance. Impedance is impedance and so on.
  • ChrisPChrisP Posts: 136
    edited 2007-10-31 03:16
    yes, you can add one, but the 4 and 8ohms refered to in a speaker are AC impedance not DC resistance,·A resistor is rated for DC resistance not AC impedance.
    Without going into something I almost dont really understand anyway..... Using your 4 ohm speaker on a 1 watt amplifier will not instantly blow the amp as long as you are careful about turning it up. The lower impedance will draw more power not less at the same gain level.

    In short, it should play a lot louder than you expect for a while if you really turn it up... Just before it quits playing at all.... [noparse]:D[/noparse]
    If the amplifier gain isnt turned up beyond 1 watt output, go for it.
  • DosManDanDosManDan Posts: 179
    edited 2007-10-31 04:39
    Ah hah!

    Impedence, I knew I forgot about something.... OK, now I get it, and I do appreciate all of your replies. It is for a Halloween prop, as you probably guessed, and yes...it will be turned up high. After reading your posts, I added a speaker jack, and ran a cord to an amplified pair of computer speakers. Want to play it safe with the sound board.

    Thanks again!
    Dan
  • skylightskylight Posts: 1,915
    edited 2007-10-31 23:15
    two 4 ohm speakers in series?
  • DosManDanDosManDan Posts: 179
    edited 2007-11-01 05:55
    I don't know, will two 4 Ohm speakers equal an 8 Ohm speaker....?

    Dan
  • Skywalker49Skywalker49 Posts: 172
    edited 2007-11-01 09:05
    2 times 4 Ohm in series is 8 Ohm.
    Make sure you have the polarity of both speakers correct.
    Polarity does not impact the load on the amplifier but impact the sound since cones move in opposite directions if polarity
    is wrong.

    Ed
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