Monitor 4 Series bookshelf speaker identification crossover upgrade

HI, I am new to this forum. My son gave me a pair of Monitor Series 4 speakers. I'm trying to identify exactly what model (4, 4a 4s) they are and when they were manufactured (pictures attached). I've read about the various models of this speaker on this forum. The label only says Model 4. They sound OK, but because of their age I was thinking about replacing the crossover. I've never done anything like this before but I am interested in taking on the project. I have also attached a crossover schematic for a 4a speaker which I found online. I would appreciate any advice on identifying the speaker and replacing the crossovers. Thanks.

Comments

  • pitdogg2
    pitdogg2 Posts: 24,481
    No picture came through. Please post a front pcture if only posting one. That should be pretty straight forward. I belive they have one cap and resistor in each;
  • skrol
    skrol Posts: 3,330
    edited October 2022
    An actual picture would be most helpful but ... from the info I have:

    The original Monitor 4 had a dome tweeter either Peerless (black dome) or the SL-1000 and neither had the acoustic lens over the tweeter.
    e5sp5bq7gok8.jpg


    The Monitor 4A had the tweeter with a 3 legged acoustic lens. The cabinet was 14.5" high.
    rwzo82cpjsd5.jpg


    The Monitor 4 Series 2 had the SL1500 tweeter with 2 legged acoustic lens. The cabinet was 14.25" high.qoa5suw0tc16.jpg
    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
  • irvman
    irvman Posts: 6
    Thanks for the replies. Sorry images didn't come through. After looking at the posted images, I clearly have a Model 4A. Was that an official model number, because the label on the rear my speakers shows no "A" after the 4. I am resending the schematic of the crossover that I found.
  • F1nut
    F1nut Posts: 49,711
    edited October 2022
    irvman wrote: »
    Thanks for the replies. Sorry images didn't come through. After looking at the posted images, I clearly have a Model 4A. Was that an official model number, because the label on the rear my speakers shows no "A" after the 4. I am resending the schematic of the crossover that I found.

    Yep. https://www.hifiengine.com/manual_library/polk-audio/monitor-4a.shtml

    That is not the schematic for your speakers. Just pull the crossover, all the values will be printed on the components.
    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

  • skrol
    skrol Posts: 3,330
    I believe sometimes Polk used old labels on early release model changes to use them up.
    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
  • irvman
    irvman Posts: 6
    I've seen 3 model numbers for these speakers 4, 4a 4.5. Are the drivers and crossovers different in each model? If the crossover in my speakers do not match the schematic for the 4A that I sent, then I assume that my model maybe a 4.5. I wish Polk had been better matching changes with the model numbers. From the link you sent me, I guess my speakers are 6 ohm with 91db sensitivity. They should be easy to drive with my Marantz 2215B receiver which only has 15 watt/channel.
  • skrol
    skrol Posts: 3,330
    The Monitor 4.5 looks similar to the 4A but the cabinet is bigger, measuring 17x9x9. There was also a Monitor 4.6 in the early 90's that used the SL-2500 dome tweeter and measures 17x8.5x10.
    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
  • irvman
    irvman Posts: 6
    My 4's are 14 inches high so they are definitely not 4.6's, so I assume they are 4As (see picture). I tried to remove the input plate to check out the crossover, but I couldn't get it out of the cabinet more than 1/4 inch even with gentle prying, and I didn't want to force it. Any advice of getting this out of the cabinet?

    As mentioned by some others, these speakers sound bright with not much bass. But, I don't have expensive equipment and I don't have "audiophile ears," so maybe I should not be commentlng on how
    they sound.
  • irvman
    irvman Posts: 6
    Please check out the Monitor 4 speaker picture in my previous post. Someone on AudioKarma said that the woofer and tweeter are not the original components. I would like to have this verified if possible or let me know how I can verify this. Fortunately, the speakers didn't cost me anything. My son left them with me when he moved. He obtained them from a friend. Thanks.
  • Gardenstater
    Gardenstater Posts: 4,137
    edited October 2022
    I agree with the person on AK. The MW is without a doubt not original. Bears no resemblance. Tweeter looks different from the tweeters that Skrol posted and is a bit too small for the cutout.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • F1nut
    F1nut Posts: 49,711
    As I mentioned to you on AK, that's not the original tweeter or mid-driver.

    They are not worth putting any money into.
    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

  • irvman
    irvman Posts: 6
    Thanks all for your input. I will let my son know.