Impedance question...

Cuchulain
Cuchulain Posts: 66
in Speakers
RTiA7's are 8 ohm speakers and are bi-ampable. When bi-amped, what is the impedance each amp is shown? Still 8 ohms? 4 ohms? Thanks in advance.
AVR: Integra DTR-50.4
TV: LG 50PS70
DVD/CD/BR: OPPO BDP 93
MAINS: Polk RTiA7
CENTER: Polk CSiA6
Heights: Polk VS 625RT (in wall)
SURROUNDS: Polk TC60i (in ceiling)
REARS: Polk R1
SUB: Polk PSW 125
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Comments

  • F1nut
    F1nut Posts: 50,734
    You cannot bi-amp with an AVR, period. Bi-amping require separate amps, each with its own power supply, not a shared power supply like every AVR made. Bi-amping also requires the use of active crossovers. You want better sound, replace the stock plate jumpers with high quality speaker cable.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • Upstatemax
    Upstatemax Posts: 2,685
    8 ohms.

    If using a receiver don't expect a huge difference if any. On my Denon with my old A7's I did notice a slightly cleaner sound with better separation when "Bi-Amped" but nothing like having two amps feeding them.
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  • gce
    gce Posts: 2,158
    I Bi-Amped my A7's with my AVR and guess what? It was a waste of time. If you're looking for better sound out of your A7's get an separate Amp or Amp's.
    Anaheim Hills CA,
    HT 5.1: Anthem MRX 720 / BDP-Denon DBT1713UD / Polkaudio LSiM703 / W4S mAmp's / Polkaudio LSiM706c / Polkaudio LSiM702F/X's / SVS PC12-NSD / Panasonic TC P55VT30

    2 Channel: Rogue RP-5 / WireWorld Electra power cord / Marantz TT-15S1/ Ortofon - Quintet Black MC / Marantz NA8005 DAC / W4S mAmp's / Synology DS 216+ll-4TB / Polkaudio LSiM703
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  • Cuchulain
    Cuchulain Posts: 66
    With respect, I didn't ask people to look at my equiptment and comment on how I can get better sound. The question is about impedance. Thank you Upstatemax for the answer of 8 ohms.
    AVR: Integra DTR-50.4
    TV: LG 50PS70
    DVD/CD/BR: OPPO BDP 93
    MAINS: Polk RTiA7
    CENTER: Polk CSiA6
    Heights: Polk VS 625RT (in wall)
    SURROUNDS: Polk TC60i (in ceiling)
    REARS: Polk R1
    SUB: Polk PSW 125
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  • Upstatemax
    Upstatemax Posts: 2,685
    Cuchulain wrote: »
    With respect, I didn't ask people to look at my equiptment and comment on how I can get better sound. The question is about impedance. Thank you Upstatemax for the answer of 8 ohms.


    The nature of people on this site is to chase better sound. Don't take it personally, it's a passion for people here.

    They also look out for your wallet. Where F1nut is coming from (I think), is that in all reality it's usually not worth the cost of extra speaker wire to "Bi-Amp" with a receiver. It will cost less to use better quality jumpers than stock and not bother with the "Bi-Amp".

    However we also encourage experimentation and trying things for yourself...

    So take them as just opinions and figure out whats best for you. If you stick around you will find that pretty much everyone here will do anything they can to help you out.

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  • skrol
    skrol Posts: 3,390
    As others have said, bi-amp with a receiver doesn't work but many claim benefits to bi-wire.
    Stan

    Main 2ch:
    Polk LSi15 (DB840 upgrade), Parasound: P/LD-1100, HCA-1000A; Denon: DVD-2910, DRM-800A; Benchmark DAC1, Monster HTS3600-MKII, Grado SR-225i; Technics SL-J2, Parasound PPH-100.

    HT:
    Marantz SR7010, Polk: RTA11TL (RDO198-1, XO and Damping Upgrades), S4, CS250, PSW110 , Marantz UD5005, Pioneer PL-530, Panasonic TC-P42S60

    Other stuff:
    Denon: DRA-835R, AVR-888, DCD-660, DRM-700A, DRR-780; Polk: S8, Monitor 5A, 5B, TSi100, RM7, PSW10 (DXi104 upgrade); Pioneer: CT-6R; Onkyo CP-1046F; Ortofon OM5E, Marantz: PM5004, CD5004, CDR-615; Parasound C/PT-600, HCA-800ii, Sony CDP-650ESD, Technics SA 5070, B&W DM601
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  • F1nut
    F1nut Posts: 50,734
    The 8 ohm rating for the speakers in question is nominal as it is with most speakers. Over the frequency range the impedance will be in constant flux going higher and lower. One normally finds the lower range having the biggest impedance drop.

    So, why the question?

    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • tonyb
    tonyb Posts: 33,000
    Speakers will stay 8 ohm with or without the jumpers. Short and to the point I take it is what you wanted.
    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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  • SCompRacer
    SCompRacer Posts: 8,511
    edited October 2014
    It is typical for the tweeter to be higher in impedance than the woofer in most speakers. An example, woofer 4 ohms tweeter 8 ohms. That 8 Ohm number is nominal impedance, or an average reading. Ever ride a pedal bike? Like Jesse said, impedance changes. Think of riding that bike in hilly terrain. Harder to pedal uphill than down. 4 ohms needs more current than 8.

    Bi-wiring was mentioned. Using the same amp or AVR to connect to high and low terminals of speaker means bi-wiring to me. This is where the woofer and tweeter have individual cables from the same amp. The possible benefit of bi-wiring is that the cable natural resonances will change and the reflections and standing waves seen by the amplifier may be reduced. Whether or not bi-wiring effects are audible is debatable. One of them try it and hear what happens.

    Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *
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  • Cuchulain
    Cuchulain Posts: 66
    F1nut wrote: »
    The 8 ohm rating for the speakers in question is nominal as it is with most speakers. Over the frequency range the impedance will be in constant flux going higher and lower. One normally finds the lower range having the biggest impedance drop.

    So, why the question?

    A while back I upgraded to an AVR with pre-outs so I would have the ability to add amplifier(s) to the mix. I'm now at that point. I asked the question to better understand the power requirements of these speakers if I choose to bi-amp them; knowing amps output power differently based on the resistance their shown. From other older threads I know I need at least 200 watts or more to make these speakers perform their best.

    So I'm considering a 7 channel and a 3 because the center speaker can be bi-amped as well.

    Curious though, how does the tweeter of the CSiA6 get power if it is bi-amped?

    AVR: Integra DTR-50.4
    TV: LG 50PS70
    DVD/CD/BR: OPPO BDP 93
    MAINS: Polk RTiA7
    CENTER: Polk CSiA6
    Heights: Polk VS 625RT (in wall)
    SURROUNDS: Polk TC60i (in ceiling)
    REARS: Polk R1
    SUB: Polk PSW 125
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  • Cuchulain
    Cuchulain Posts: 66
    BTW thanks for the input from everyone.
    AVR: Integra DTR-50.4
    TV: LG 50PS70
    DVD/CD/BR: OPPO BDP 93
    MAINS: Polk RTiA7
    CENTER: Polk CSiA6
    Heights: Polk VS 625RT (in wall)
    SURROUNDS: Polk TC60i (in ceiling)
    REARS: Polk R1
    SUB: Polk PSW 125
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  • F1nut
    F1nut Posts: 50,734
    Cuchulain wrote: »
    A while back I upgraded to an AVR with pre-outs so I would have the ability to add amplifier(s) to the mix. I'm now at that point. I asked the question to better understand the power requirements of these speakers if I choose to bi-amp them; knowing amps output power differently based on the resistance their shown. From other older threads I know I need at least 200 watts or more to make these speakers perform their best.

    So I'm considering a 7 channel and a 3 because the center speaker can be bi-amped as well.

    Curious though, how does the tweeter of the CSiA6 get power if it is bi-amped?

    Got it, thanks. The issue still remains, that would not be bi-amping either. Bi-amping requires a separate amp, each with its own power supply AND the use of active crossovers. I believe if you got a separate power amp for however many channels you desire that you would be more than pleased with the result and forget all about bi-amping.

    To answer your last question, the CSiA6 top posts feed the tweeter, the bottom posts feed the two drivers.


    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • BlueFox
    BlueFox Posts: 15,251
    I wonder how many people really bi-amp their speakers. For all the questions and talk, I bet very little.
    Lumin X1 file player, Westminster Labs interconnect cable
    Sony XA-5400ES SACD; Pass XP-22 pre; X600.5 amps
    Magico S5 MKII Mcast Rose speakers; SPOD spikes

    Shunyata Triton v3/Typhon QR on source, Denali 2000 (2) on amps
    Shunyata Sigma XLR analog ICs, Sigma speaker cables
    Shunyata Sigma HC (2), Sigma Analog, Sigma Digital, Z Anaconda (3) power cables

    Mapleshade Samson V.3 four shelf solid maple rack, Micropoint brass footers
    Three 20 amp circuits.
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  • F1nut
    F1nut Posts: 50,734
    You mean REAL bi-amping? Yeah, very few.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • Thorton
    Thorton Posts: 1,324
    I've owned the A7's and now A9's. +1 to nbrowser's recommendation. I have no idea why anyone would biamp the A7's. I decent amp will do fine. Buy a nice multichannel amp for the A7's, center and surrounds (if required) and instead of using multiple channels on 1 speaker use it for other speakers. This way you can spend the money on a quality amp instead of more channels (quantity) to one speaker. Or just purchase a 2 channel amp for the A7's and run the rest with the AVR...that's how I started.
    _____________________________________________________________________________________________
    Ethernet Filter: GigaFOILv4 with Keces P3 LPS
    Source: Roon via ethernet to DAC interface
    DAC: Bricasti M1SE
    Pre/Pro: Marantz AV8805
    Tube Preamp Buffer: Tortuga TPB.V1
    Amp1: Nord One NC1200DM Signature, Amp2: W4S MC-5, AMP3: W4S MMC-7
    Front: Salk SoundScape 8's, Center: Salk SoundScape C7
    Surround: Polk FXIA6, Surround Back: Polk RTIA9, Atmos: Polk 70-RT
    Subs: 2 - Rythmik F25's
    IC & Speaker Cables: Acoustic Zen, Wireworld, Signal Cable
    Power Cables: Acoustic Zen, Wireworld, PS Audio
    Room Treatments: GIK Acoustics
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  • tonyb
    tonyb Posts: 33,000
    BlueFox wrote: »
    I wonder how many people really bi-amp their speakers. For all the questions and talk, I bet very little.

    That's because they are told by way of marketing that a receiver can do it. Then they can't figure out why manufacturers lie about it, and a double face palm when they find out their receiver doesn't put out 100 watts for all 7 channels.

    Hard to blame the posters when the manufacturers are being misleading. I guess some due diligence should fall on the user though.
    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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