Does impedance have to be matched on Subwoofer & Receiver like for other speakers?

Tahoua
Tahoua Posts: 7
edited October 2011 in Subwoofer Hookup & Bass Management
I have a Dolby 7.1 system. I purchased Polk speakers for Front, Surround, and Rear speakers matching 8ohm speakers with the 8 ohm impedance of my receiver. I assumed I would have to do the same when I purchase a subwoofer, but the tech specs on the subwoofers don't even include resistance/impedance? Does that mean subwoofer resistance/impedance doesn't have to be matched to the receiver? If so where do I find the specification on the Polk subwoofers? If not is there anything else that has to be matched to the receiver regarding the subwoofer?

Here are the Polk subwoofer tech specs
Post edited by Tahoua on
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Comments

  • tonyb
    tonyb Posts: 32,962
    edited October 2011
    Short answer is no, you don't have to match with a sub because it's self powered by it's own built in amplifier.
    HT SYSTEM-
    Sony 850c 4k
    Pioneer elite vhx 21
    Sony 4k BRP
    SVS SB-2000
    Polk Sig. 20's
    Polk FX500 surrounds

    Cables-
    Acoustic zen Satori speaker cables
    Acoustic zen Matrix 2 IC's
    Wireworld eclipse 7 ic's
    Audio metallurgy ga-o digital cable

    Kitchen

    Sonos zp90
    Grant Fidelity tube dac
    B&k 1420
    lsi 9's
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  • Dennis Gardner
    Dennis Gardner Posts: 4,861
    edited October 2011
    Powered subwoofers are impedance matched within themselves. The maker matches the built in amplifier in the sub to the speaker. You will be sending a line level output from your receiver to the powered sub. No worry about impedance......
    HT Optoma HD25 LV on 80" DIY Screen, Anthem MRX 300 Receiver, Pioneer Elite BDP 51FD Polk CS350LS, Polk SDA1C, Polk FX300, Polk RT55, Dual EBS Adire Shiva 320watt tuned to 17hz, ICs-DIY Twisted Prs, Speaker-Raymond Cable

    2 Channel Thorens TD 318 Grado ZF1, SACD/CD Marantz 8260, Soundstream/Krell DAC1, Audio Mirror PP1, Odyssey Stratos, ADS L-1290, ICs-DIY Twisted , Speaker-Raymond Cable
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  • Tahoua
    Tahoua Posts: 7
    edited October 2011
    Thanks for the quick & helpful responses.
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  • 20hz
    20hz Posts: 636
    edited October 2011
    besides imdepance changes drastically with frequency , plus as tonyb said its amplified anyway :)
    I knew one guy who was concerned with effeciancy (db) matching on his speakers but I cant see a big reason for that since a avr has a gain adj per channel .
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