4 ohm LSiC and a 6 ohm receiver

ArtSaxby Posts: 6
edited January 2003 in Speakers
I just purchased an LSiC center speaker. I now see that it is a 4 ohm speaker. My receiver, a Yamaha RX-V795, has an impedance switch to go between 8 ohms and 6 ohms.

How big and issue is this? What problems or weaknesses will I notice? Do I need to return the speaker?

My other speakers are a pair of FXi30s for surround, a sub woofer (sorry not Polk), and an old set of Polk RM satellite/sub (passive sub) for the front. I know the system is not balanced with the RMs and LSiC, but I am upgrading over time.

Any advice will help.
Post edited by ArtSaxby on


  • Steve@3dai
    [email protected] Posts: 983
    edited January 2003
    Well, don't run the amp too hard as you have different impedence on channels. Other than that you should be ok for now.
    LSi 9/C/FX
    Arcam AVR-200
  • gidrah
    gidrah Posts: 3,038
    edited January 2003
    Welcome to the forum!

    If you set your center to "small" I'd assume you'd be fine. Low impedende is caused by the bass. The more current is needed to push the larger sound wave.

    There are plenty of big main speaker out there that have are 8 Ohm nominal that dip into the 2 Ohm range for the bass.
    Make it Funky! :)
  • Zen Dragon
    Zen Dragon Posts: 501
    edited January 2003
    Art - I have the RX-V795A, and my manual on page 21 says I can use 4 ohm mains, as long as I am not running additional mains on the B channel, as putting them in parallel would go below 4 ohms.
    As to what happens with 4 ohm speakers on a 6 ohm rated amp, you overdraw the current capability of the amplifier. This leads to distortion at moderate to high listening levels, as well as heating the hell out of your amps, and pre-mature amplifier failure.
    Are you sure the non-"A" version of the 795 can't do 4 ohms, (mains), look at page 21 again, only the rear and mid is rated at 6 ohms, which means you could not go native with the lsi series on all channels, unless you ran the pre-amp outs for the rears and center to an external amplifier .
    As you are inly driving the center with the low ohm speaker you should be fine with the 4 ohm as long as you don't listen at max volume levels. Listen for distortion at high volumes, this is a sign of too heavy a load on your amp. Also watch for excessive heat from the Rcvr. Keep in mind that any rcvr will run warm at high output levels, so you kinda have to be familiar with your unit to decide if it is running unusually hot.
    Hope This helps
    The Family
    Polk SDA-1C's
    Polk SDA-2
    Polk Monitor 10B's
    Polk LSI-9's
    Polk Monitor 5's
    Polk 5 jr's
    Polk PSW-450 Sub
    Polk CSI40 Center

    Do not one day come to die, and discover you have not lived.
    This is pretty f***ed up right here.
  • ArtSaxby
    ArtSaxby Posts: 6
    edited January 2003
    Thanks for the advice. It sounds like I am hearing that as long as I configure the center speaker (the 4 ohm LSiC speaker coming our of the 6 ohm port) as small, and don't really pound the system, I should be OK.

  • bertram
    bertram Posts: 53
    edited January 2003
    Art, I run 6 Polk LSi speakers @ 4 ohms each from a Denon 3803 receiver, including 2 LSi15 mains configured as large. The official rating of the Denon is 6 ohms and up as far as speakers are concerned, but their FAQ says it's OK to use 4 ohm ones. My system plays fine at pretty loud levels. Manufacturers have to err on the conservative side when they come up with these numbers. And as has been mentioned above, even speakers rated at a nominal 6 or 8 ohms can dip to 2 ohms in parts of their operating range.
    Multichannel Music:

    Sony SCD-C2000ES SACD
    Denon 3803 AVR (pre/pro duty)
    Outlaw 755 amp
    Outlaw ICBM
    Polk LSi15/LSiC/LSi9 (front/center/surround)


    Sony 9100ES DVD
    Outlaw 990 pre/pro
    Outlaw 7100 amp
    Panasonic TH-37PX50U plasma
    Polk RTi8/CSi5/RTi6/FXi5(front/center/surround/back)
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