4 or 8 ohms speakers

alphaone
alphaone Posts: 26
edited February 2009 in Speakers
I have an Onkio TX-SR805 and I am thinking to buy new speakers. Should I get 4 or 8 ohms? It supports both. In general which is best?

Thank you
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  • Face
    Face Posts: 14,340
    edited February 2009
    Unless you plan on adding an external amp, you would be better off purchasing 8 ohm speakers.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • hearingimpared
    hearingimpared Posts: 21,136
    edited February 2009
    Eight ohm speakers are easier to drive.
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  • reeltrouble1
    reeltrouble1 Posts: 9,312
    edited February 2009
    It's not really a matter of best, its a matter of design. You will see alot of nice speakers that are 4 ohm, this way the numbers look better, but looks are only skin deep, if you know what I mean, if you do not know, its probably for the best.

    Anyway, get the Polk 4 ohm speakers, they are great speakers and the rest of us will enjoy giving you recommendations for your future power needs, it's what we do.

    RT1
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  • thuffman03
    thuffman03 Posts: 1,325
    edited February 2009
    If it were me I would stick with the 8 ohm speaker on AVR's. I did look at the spec's from Onkyo and yes it does say the Dynamic Power will go down to 3 ohms with 300 watts into one channel. And I have no doubt that it will power a 4 ohm speaker without much trouble. But I like I said before I would go with an 8 ohm.

    Remember that the 8, 6 or 4 ohm spec on a speaker is an average. A 4 ohm speaker can dip down to 2 or 1 ohm.
    Sunfire TGP, Sunfire Cinema Grand, Sunfire 300~2 (2), Sunfire True Sub (2),Carver ALS Platinum, Carver AL III, TFM-55, C-19, C-9, TX-8, SDA-490t, SDA-390t
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  • mhardy6647
    mhardy6647 Posts: 34,038
    edited February 2009
    4 ohms buys you 3 dB of sensitivity (relative to 2.83 VAC, which is the usual "standard" for measuring speaker sensitivity) relative to 8 ohms... all things being equal.

    Fact of the matter is: loudspeaker impedance is a complex (in the mathematical sense) quantity that varies with frequency for most types of speakers. (ribbon drivers, IIRC, do tend to behave as purely resistive loads, so they tend to have 'flat' impedance curves). The "4 ohm" or "8 ohm" rating is a nominal impedance. Typically, it is the impedance "valley" observed a bit above a speaker system's resonant frequency -- the nominal impedance is typically measured in the neighborhood of 100 to 200 Hz for a fullrange speaker system.

    How easy or hard a given speaker is for a given amplifier to drive isn't generally represented very well by the nominal impedance... although speakers with lower nominal (or average) impedance will want more current from an amplifier, thanks to Ohm's Law.

    http://sound.westhost.com/tsp.htm

    tsp-f1.gif

    The impedance plot above is for a speaker driver (woofer), not a speaker system, but it illustrates the point rather well.
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  • reeltrouble1
    reeltrouble1 Posts: 9,312
    edited February 2009
    that why I said its simply a numbers game for design, you get that higher sensitivity, but at a cost. what seems to reely!!! matter is the type of load the amp output sees, obviously a 200 watt amplifier will not produce that power into a 50K impedance at the resonance point.

    so to the OP like I said, buy the 4 ohm Lsi, go forth and be happy, they are great speakers. Matt Polk had a few of us up to his house last Oct., the sound I heard coming from his entirely stock Lsi9 was reely!!! something reely!!!! besides when or if you are into music you will not need to upgrade from the Polk Theater line.

    RT1
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  • Mike21
    Mike21 Posts: 252
    edited February 2009
    For what its worth, I used to drive my Daki Ikon 6 speakers (6 ohms) w/ my Onk 805 with no problems.

    IMHO, the 805 will do fine with 4, 6 or 8ohms. I would not same the same about a 605/6 or 705/6.
    ____________________________________________
    Home Theater 32"LG LCD; Comcast; 7.1 Onkyo 805; Fronts: Polk M50s; Center: Polk CS2; Sides: Polk M40s; Rear: B&W LM1s; Subs: (2) Sony 12" x 100w; Samsung 1500BDP; Toshiba A-2 HD-DVDP.
    PC stereo: Viper custom PC: Windows XP; ASIO4ALL; JRiver Jukebox> Pop Pulse USB to S/PDIF conv> Monarchy DIP > Musiland MD10 DAC > Parasound 2100 pre> Aragon 4004 MKII amp> Dali Ikon6 towers; Sunfire True Sub; PSA Duet, Ultimate outlet and Noise Harvestors.
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  • Monster Jam
    Monster Jam Posts: 919
    edited February 2009
    alphaone wrote: »
    I have an Onkio TX-SR805 and I am thinking to buy new speakers. Should I get 4 or 8 ohms? It supports both. In general which is best?

    Thank you

    Consider buying the speaker that sounds the best to you when you audition them with your favorite music or movies.
    Do you hear that buzzing noise? :confused:
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