Monitor Series Speaker Impedance?

isounder
isounder Posts: 3
edited December 2011 in Vintage Speakers
I am trying to determine the speaker impedance spec for two different old Monitor speakers.

One is marked Monitor Model 5JR 45053 on the rear label. The instruction book that came with it lists a Monitor 5JR +with impedance 4 ohms and efficiency 92dB. The Polk website Recent/Vintage products lists a Monitor 5JR + as 8 ohms and 90dB efficiency. Is it 4 or 8 ohms?

The other is marked Monitor Model 4 48264 on the rear label. The instruction book that came with them lists a Monitor 4.5 and 4A both with impedance 4 ohms and efficiency 92dB. The Polk website Recent/Vintage products lists a Monitor 4 as 8 ohms and 91dB efficiency. The Monitor Model 4 I have measures 14.5" high so it can't be the Monitor 4.5 (17.5" high) listed in the instruction book but could be the Model 4A which also is 14.5" high. But the lablel says it's the Model 4 48264. Is the Model 4 the same as the Model 4A?

I don't know what to believe. Any help would be appreciated.
Post edited by isounder on
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Comments

  • skrol
    skrol Posts: 3,387
    edited November 2011
    Welcome to Club Polk. There are a few variants of these speakers. If you post some pics withe grills off we might be able to help sort it out.
    Stan
    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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  • isounder
    isounder Posts: 3
    edited November 2011
    skrol wrote: »
    Welcome to Club Polk. There are a few variants of these speakers. If you post some pics withe grills off we might be able to help sort it out.
    Stan

    How do you take the grills off? Are the grills attached to a frame with fabric stretched over them? I don't want to damage them since the speakers belong to a friend of mine.
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  • isounder
    isounder Posts: 3
    edited December 2011
    skrol wrote: »
    Welcome to Club Polk. There are a few variants of these speakers. If you post some pics withe grills off we might be able to help sort it out.
    Stan

    I have attached pics of the speakers and also measured the enclosure sizes.

    Polk Monitor 5JR 45053: 19 1/2 H X 9 W X 9 D

    Monitor 5 JR 48264.jpg


    Polk Monitor 4 48264: 14 1/2 H X 8 1/2 W X 7 D

    Monitor 4 482664.jpg


    I am hoping this will help to determine the impedance ratings for these.
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  • pitdogg2
    pitdogg2 Posts: 25,582
    edited December 2011
    should be 4ohm and you can check for yourself if you have a multi-meter. Set it to ohm and stick each lead into the binding post.
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  • cristo
    cristo Posts: 231
    edited December 2011
    Do you have a multimeter?
    The measured resistance across the terminals will be in the ballpark of the correct rated impedance
    (i.e. closer to 8 ohms or closer to 4 ohms).

    sorry for the redundant post - pitdogg's correct post snuck in before mine.
    cristo

    NAD C 545BEE cd player, Philips AF877 turntable / Shure V15V-MR with JICO SAS stylus,
    Tascam 122 mkIII cassette deck, Harman Kardon 3480 receiver, Terk FM-50 antenna in the attic,
    Soundcraftsmen SE550 stereo equalizer, Polk Monitor 10a speakers
    (with Sonicraft/Solen/Mills crossover rebuild)
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  • Joe08867
    Joe08867 Posts: 3,919
    edited December 2011
    Like Pittdogg said they should both be 4ohms.
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  • skrol
    skrol Posts: 3,387
    edited December 2011
    That looks to be the Monitor 5Jr+
    Specs:
    Freq Resp: 30Hz - 26KHz
    3dB limits: 48Hz - 20KHz
    Rec amplification: 20-125 watts
    Impedance: 6 ohms
    Efficiency: 91dB

    and

    Monitor 4A
    Specs:
    Drivers: 1 - 1" tweeter,
    1 - 6.5" midrange (MW6502)

    Dimensions: 14.5"H x 8.5"W x 7.5"D
    Weight: 32 lbs/pair
    Specifications
    Frequency Response: 31Hz - 25kHz (35Hz - 25KHz)
    -3 dB Limits (55Hz - 20KHz)
    Crossover Frequency 4500Hz
    Impedance: 4 Ohms (6 ohms)
    Recommended Power: 10-100 watts per channel
    Efficiency: 92 dB
    Maximum Output Level 114dB

    Stan
    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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