Question regarding speaker impedance

Discussion in 'Archived Threads 2001-2004' started by greg_t, Jun 27, 2002.

  1. greg_t

    greg_t Screenwriter

    Joined:
    Jan 18, 2001
    Messages:
    1,650
    Likes Received:
    0
    Trophy Points:
    110
    I have a question regarding speakers that maybe someone could help me with. When I first got into home theater, I bought an RCA "home theater in a box". It came with 5 6ohm speakers. Over the last year or so, I have been upgrading components. I recently purchased a Denon 2802 receiver with DTS-ES. It supports speakers with impedance of 6-16ohms. Here is what I want to do. I would like to purchase a new center channel and use the old RCA one as the Back surround channel. A new center will most likely be an 8ohm speaker, while all of the others will be 6ohm. Does anyone know if the receiver would have a problem with this or is it not a good practice? I have no idea on this one so if anyone has any advice I would appreciate it. Thanks!
     
  2. Dustin B

    Dustin B Producer

    Joined:
    Mar 10, 2001
    Messages:
    3,126
    Likes Received:
    0
    Trophy Points:
    0
    No problem at all.

    A speakers impedance will vary greatly with the frequency it is playing. An 8ohm speaker may dip as low as 4ohms at some frequencies and be as high as 30ohms at others. Speakers are given a nominal impedance rating, kind of like a weighted average.

    The reason a speaker's impedance is important has to do with the amp. Technically if an amp produces 100W at 8ohms, it should produce 200W at 4ohms. Only very expensive amps actually do this (Krell, Classe etc). The amps most of us use will increase in output by anywhere from 15%-80%. Things like Kenwood and low end Pioneer recievers will do the 15% jump and won't be rated as capable of driving a 4ohm load. When you stick a 4 ohm load on them the power supply is asked to provide more power than it can, over heat and trip a thermal protection circuit. Things like Parasound and Rotel seperates will do the 80% increase and are stable into 4 ohm loads.
     
  3. greg_t

    greg_t Screenwriter

    Joined:
    Jan 18, 2001
    Messages:
    1,650
    Likes Received:
    0
    Trophy Points:
    110
    Thanks Dustin!
     

Share This Page