"The Minimus" Project

So a buddy of mine is knee deep in the old Realistic Minimus 7s which can be had for approximately $50 bucks on EBay. There are many different iterations but apparently the ones with the metal tweeter faceplate are most desirable.

There is a mod that flattens the response to these called the "Zilch Mod"

https://www.lostinsound.space/minimus-7-upgrade/

So this is my chronicle of fun with the Minimus 7.

First step is anti-diffraction inserts!

More to come as I go! :-P

m1zryzmxxxan.jpg
qg30i55f6so3.jpg
- Not Tom

"No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
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Comments

  • gp4jesus
    gp4jesus Posts: 1,671
    Cool!
    Where to buy the felt?
    Samsung 60" UN60ES6100 LED
    Outlaw Audio 976 Pre/Pro
    Samsung BDP, Dish Rcvr, Phillips CD chgr, various game consoles

    Canare 14 ga - LCR tweeters inside* & CC outside
    BJC 10 ga - LCR mids, inside* & out
    8 ga Powerline - LR woofers, inside* & out
    *soldered

    LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Mids & Tweets- 981
    CC: Rotel RB981 -> Bi-amped CSi A6
    5 Subs: Sunfire True Sub Signature -> LFE & CC & 4 Audio Pro Evidence Subs
    Surrounds: Rotel 981 -> AR 12 ga -> RTi A3
    Power Conditioning & Distribution:
    3 dedicated 20A feeds; APC H15; 4 Furman Miniport 20s
  • F1nut
    F1nut Posts: 45,848
    Ha, I had a "desirable" pair that I took to the dump instead of trying to sell and I have no regrets.
    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

  • mhardy6647
    mhardy6647 Posts: 27,514
    The late "zilch".
    More on the Minimus 7 from the man himself at

    I am in the same camp as @F1nut, FWIW -- Radio Shack's Visonik/ads ripoffs just... weren't... great. I do still have a pair but it's completely nostalgia-driven. I am sure Zilch's mods make 'em better, for as Paul McCartney wrote (a long, long time ago) can't get no worse.

    https://audiokarma.org/forums/index.php?threads/minimus-7-loudspeakers-measurements.199790/
  • VR3
    VR3 Posts: 24,521
    I can say without question the anti-diffraction pad alone completely transforms the sound. Those edges for the grill to grip are a nightmare!

    I have been enjoying them nearfield, I imagine they would fall apart in a larger room (maybe).

    This felt/wool combo is from Madisound
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • JayCee
    JayCee Posts: 1,194
    I have a pair that were thrown in as a give-me when I bought my CRS's. Use them w/a $20 Goodwill find Onkyo receiver in the garage. Provide the needed background music for shop projects, bier drinking and throwing darts. Looks like a fun project. Interested in your impressions, Trey.
    Speakers: Polk1.2tl's (Uber Mods) Pre/Amp/DAC: PS Audio BHK Signature & 250, DirectStream Cables/IC's: MIT S1Bi-Wire/S1 Balanced +Avel Lindberg 1000VA "Dreadnought" Power Conditioner: PS Audio P15 Power Plant Power Cords: Core Power Technologies Gold, DH Labs Power Plus DIY w/Neotech NC-P301 & P311ends Streamer: Roon ROCK on wifi'd NUC & Uptone EtherREGEN, AfterDark, Emperor Double Crown Clock, Black Modernize LPS⟿Ω☯☥☮⟿🔊♩♪♫♬♩♪♫♬♩♪♫♬
  • VR3
    VR3 Posts: 24,521
    It is definitely a fun project!

    Will keep this thread updated 😜

    61q1gujilx2e.jpg
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • pitdogg2
    pitdogg2 Posts: 18,720
    edited February 27
    Duelands on a RS speaker???
    Boy you've lost your mind
    B):#

    You're knocking it out of the park with these wood projects 👍
  • VR3
    VR3 Posts: 24,521
    I KNOW RIGHT? This is a purely "fun" project! That blue cactus capacitor is a paper and oil cap, supposed to sound suh-weeet!

    Gracias!
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • mhardy6647
    mhardy6647 Posts: 27,514
    How did you tattoo the anti-diffraction mat? That is exceptionally cool. :)

    qg30i55f6so3.jpg
  • gp4jesus
    gp4jesus Posts: 1,671
    You used a laser to cut openings in the felt?
    Samsung 60" UN60ES6100 LED
    Outlaw Audio 976 Pre/Pro
    Samsung BDP, Dish Rcvr, Phillips CD chgr, various game consoles

    Canare 14 ga - LCR tweeters inside* & CC outside
    BJC 10 ga - LCR mids, inside* & out
    8 ga Powerline - LR woofers, inside* & out
    *soldered

    LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Mids & Tweets- 981
    CC: Rotel RB981 -> Bi-amped CSi A6
    5 Subs: Sunfire True Sub Signature -> LFE & CC & 4 Audio Pro Evidence Subs
    Surrounds: Rotel 981 -> AR 12 ga -> RTi A3
    Power Conditioning & Distribution:
    3 dedicated 20A feeds; APC H15; 4 Furman Miniport 20s
  • xschop
    xschop Posts: 2,022
    Do I see custom laser-cut tweeter gaskets in the future?
  • VR3
    VR3 Posts: 24,521
    Yes the felt was cut with a laser.

    Hmm, I know @F1nut had a material he found that I could totally cut on the laser!
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • VR3
    VR3 Posts: 24,521
    Dynamat! Had just enough left over

    e4o827cv479e.jpg
    hvdaoqngqgf0.jpg
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • skrol
    skrol Posts: 3,044
    I have had 3 pairs of the Minimus 7. The metal enclosure makes them very solid and seem somewhat impressive initially. My first was back in the late 80's and I was playing around with them for cross talk cancellation, messing with phasing. Then I discovered Polk Audio had already done this with the SDA. I sold them to a friend.

    Knowing they have had a cult following, I recently bought a couple few pairs of different versions for about $20 / pair including that latest with the port on the back. To be honest, I don't get the fascination with these speakers. They aren't bad but really not that impressive. I may try the mods to see if I can make them sing.
    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
  • VR3
    VR3 Posts: 24,521
    edited February 28
    If you do nothing other than fix the diffraction issue you will see a good gain. The baffle is a joke! Fix this and you may like them a lot more.
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • schwarcw
    schwarcw Posts: 7,282
    Polkie TNRabbit (RIP) did a crossover upgrade to a pair of Minimus 77s. He replaced the woofer and modded the front baffle. I think the crossover design was the product of an ad lib crossover design project on AudioKarma some years ago. The 77s sound real nice and I use them in my computer system every day. I get the power powered by a Fisher X-1000 integrated amplifier.
    Carl

  • JayCee
    JayCee Posts: 1,194
    @VR3 Just came back in from my garage. Was putting some stuff up and looked up, eye level, and the 7's said, "Come on man, give me some felt."

    So, how 'bout making me a pair and adding to the tweeter order/ship in the same box? PM me total cost for both orders and I'll send payment when you want.
    Speakers: Polk1.2tl's (Uber Mods) Pre/Amp/DAC: PS Audio BHK Signature & 250, DirectStream Cables/IC's: MIT S1Bi-Wire/S1 Balanced +Avel Lindberg 1000VA "Dreadnought" Power Conditioner: PS Audio P15 Power Plant Power Cords: Core Power Technologies Gold, DH Labs Power Plus DIY w/Neotech NC-P301 & P311ends Streamer: Roon ROCK on wifi'd NUC & Uptone EtherREGEN, AfterDark, Emperor Double Crown Clock, Black Modernize LPS⟿Ω☯☥☮⟿🔊♩♪♫♬♩♪♫♬♩♪♫♬
  • VR3
    VR3 Posts: 24,521
    No problemo, will Pm you in a bit.

    You will be surprised, really balances it out, especially considering it is just felt!
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • JayCee
    JayCee Posts: 1,194
    Thanks.
    Speakers: Polk1.2tl's (Uber Mods) Pre/Amp/DAC: PS Audio BHK Signature & 250, DirectStream Cables/IC's: MIT S1Bi-Wire/S1 Balanced +Avel Lindberg 1000VA "Dreadnought" Power Conditioner: PS Audio P15 Power Plant Power Cords: Core Power Technologies Gold, DH Labs Power Plus DIY w/Neotech NC-P301 & P311ends Streamer: Roon ROCK on wifi'd NUC & Uptone EtherREGEN, AfterDark, Emperor Double Crown Clock, Black Modernize LPS⟿Ω☯☥☮⟿🔊♩♪♫♬♩♪♫♬♩♪♫♬
  • gp4jesus
    gp4jesus Posts: 1,671
    edited March 1
    @VR3 would you consider cutting felt for any
    RTi A series speakers?

    Thanks either way
    Samsung 60" UN60ES6100 LED
    Outlaw Audio 976 Pre/Pro
    Samsung BDP, Dish Rcvr, Phillips CD chgr, various game consoles

    Canare 14 ga - LCR tweeters inside* & CC outside
    BJC 10 ga - LCR mids, inside* & out
    8 ga Powerline - LR woofers, inside* & out
    *soldered

    LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Mids & Tweets- 981
    CC: Rotel RB981 -> Bi-amped CSi A6
    5 Subs: Sunfire True Sub Signature -> LFE & CC & 4 Audio Pro Evidence Subs
    Surrounds: Rotel 981 -> AR 12 ga -> RTi A3
    Power Conditioning & Distribution:
    3 dedicated 20A feeds; APC H15; 4 Furman Miniport 20s
  • VR3
    VR3 Posts: 24,521
    Yes, I actually have some cut that should work given the slim faceplate. Can you send me dimensions height and width?
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • skrol
    skrol Posts: 3,044
    VR3 wrote: »
    If you do nothing other than fix the diffraction issue you will see a good gain. The baffle is a joke! Fix this and you may like them a lot more.

    Perhaps I'll give it a try. I think I might even have some similar material. Are you leaving grills off after the material is applied?
    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
  • skrol
    skrol Posts: 3,044
    I have a friend who used to work for Polk Audio back in the later 80's early 90's (ZSP) and worked on the Monitor Series 2, RTA (TL) SDA (TL) and S series. When I asked him about tweaks for my RTA11TL's he mentioned that they played around with putting felt around the tweeters but didn't get much benefit. Perhaps this material is better suited? It certainly looks more absorptive than regular felt.
    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
  • mhardy6647
    mhardy6647 Posts: 27,514
    That's interesting. A very early tweak suggested for the (Peerless!) dome tweeters in the Monitor Series Polks was to put a ring of felt or even cotton around the dome.

    I honestly don't remember when or where I heard/read that suggestion -- but it was a long, long time ago (probably before 1980).

  • Gardenstater
    Gardenstater Posts: 1,944
    edited March 5
    Oh .......so now you mention it.....finally! ;)

    I think that the baffle rout-outs (is that a word?) are a bit oversized and that groove will cause a diffraction resulting in a 180deg out of phase waveform that is approximately at a frequency of: Speed of Sound/distance from center of dome to the groove. I figure maybe a range of 2600 Hz to 6000 Hz for the horizontal waves. That can cause a trough in the output of the tweeter response at those frequencies. It would be MUCH worse if the tweeter bezel were a circle with a groove around it. I may fill mine with some brown modeling clay (can you get black?), in addition to the felt pads.
    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
  • VR3
    VR3 Posts: 24,521
    I keep the grills on since my pad fits perfectly snug in place

    Black modeling clay, an enigma!
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • gudnoyez
    gudnoyez Posts: 7,666
    Interested on what the results are on the RTIA's are if someone tries them out.
    Home Theater
    Parasound Halo A 31 OnkyoTX-NR838 Sony XBR55X850B 55" 4K RtiA9 Fronts CsiA6 Center RtiA3 Rears FxiA6 Side Surrounds Dual Psw 111's Oppo 105D Signal Ultra Speaker Cables & IC's Signal Magic Power Cable Technics SL Q300 Panamax MR4300 Audioquest Chocolate HDMI Cables Audioquest Forest USB Cable

    2 Channel
    Adcom 555II Vincent SA-T1 Marantz SA 15S2 Denon DR-M11 Clearaudio Bluemotion SDA 2.3tl's (Z) edition MIT Terminator II Speaker Cables & IC's Adcom 545II Adcom Gtp-450 Marantz CD5004 Technics M245X SDA 2B's, SDA CRS+

    Stuff for the Head
    JD LABS C5 Headphone Amplifier, Sennheiser HD 598, Polk Audio Buckle, Polk Audio Hinge, Velodyne vPulse, Bose IE2, Sennheiser CX 200 Street II, Sennheiser MX 365

    Shower & Off the beaten path Rigs
    Polk Audio Boom Swimmer, Polk Audio Urchin B)
  • Gardenstater
    Gardenstater Posts: 1,944
    VR3 wrote: »
    I keep the grills on since my pad fits perfectly snug in place

    Black modeling clay, an enigma!

    Yes. My biggest fear, that keeps me lying awake at night, is that it may be even harder to find than black paint!
    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
  • gp4jesus
    gp4jesus Posts: 1,671
    edited March 7
    gudnoyez wrote: »
    Interested on what the results are on the RTIA's are if someone tries them out.
    I’m game to try. Been thinking about this on my RTi A7s and my ‘A6 center.

    Correct me if I’m wrong w/ my “A7” thinking. Focus on the baffle to the edges all around the tweeter, from the top to the top of the mid, extending to the 3 & 9 o’clock positions around the mid would be a great start. Could as far as the 5 & 7 o’clock positions - but ~ an 1” below mid is a port.

    3fqo2gr6nrjk.jpeg


    For A6 center - similar thinking sideways: Below the tweeter an opening for the port. 6 &12 o’clock positions around the mids.

    rc8b6qcd9tv8.jpeg


    I realize the challenge for someone doing the trimming or (laser cutting) is very precise measurements

    Thoughts?
    Samsung 60" UN60ES6100 LED
    Outlaw Audio 976 Pre/Pro
    Samsung BDP, Dish Rcvr, Phillips CD chgr, various game consoles

    Canare 14 ga - LCR tweeters inside* & CC outside
    BJC 10 ga - LCR mids, inside* & out
    8 ga Powerline - LR woofers, inside* & out
    *soldered

    LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Mids & Tweets- 981
    CC: Rotel RB981 -> Bi-amped CSi A6
    5 Subs: Sunfire True Sub Signature -> LFE & CC & 4 Audio Pro Evidence Subs
    Surrounds: Rotel 981 -> AR 12 ga -> RTi A3
    Power Conditioning & Distribution:
    3 dedicated 20A feeds; APC H15; 4 Furman Miniport 20s
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