LSi15 crossover schematic

chamont
chamont Posts: 22
edited June 2013 in DIY, Mods & Tweaks
Hey everyone.

I'm looking for an LSi15 crossover schematic. Searches turn up nothing but dead links. Does anyone have a PDF that they can send me? Thanks.

Monty
Post edited by chamont on
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  • skrol
    skrol Posts: 3,387
    edited December 2010
    They used to be in the Vintage Forum sticky but they seem to have been removed.
    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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  • McLoki
    McLoki Posts: 5,231
    edited December 2010
    Chamont - PM me your e-mail address...

    Michael
    Mains.............Polk LSi15 (Cherry)
    Center............Polk LSiC (Crossover upgraded)
    Surrounds.......Polk LSi7 (Gloss Black - wood sides removed and crossovers upgraded)
    Subwoofers.....SVS 25-31 CS+ and PC+ (both 20hz tune)
    Pre\Pro...........NAD T163 (Modded with LM4562 opamps)
    Amplifier.........Cinepro 3k6 (6-channel, 500wpc@4ohms)
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  • MC208
    MC208 Posts: 5
    edited January 2011
    Can I get a copy as well? Gonna do the cap/resistor upgrade next weekend and would like to have a reference to confirm everything being put back it the correct spot. I'm apparently too new to PM, but I assume you could PM me?

    -MC
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  • chamont
    chamont Posts: 22
    edited January 2011
    Maybe I didn't do the PM correctly. But I never got a schematic...

    I put on my thinking cap and figured out my problem alone without the schematic. But I'd still like a copy if anyone out there has a copy. Anyone?
    Monty
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  • [Deleted User]
    [Deleted User] Posts: 1,225
    edited January 2011
    skrol wrote: »
    They used to be in the Vintage Forum sticky but they seem to have been removed.

    When I was at Polk (last month) I spoke with Stu Lumsden (VP of Engineering) and he informed me they were removed because all of the more recent speaker designs were posted as well (unintentionally). So they decided to remove them all. He didn't tell me of a plan to repost at least the more vintage ones. I hope they do at some point. Hope this helps. Cheers. :cool:
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  • MC208
    MC208 Posts: 5
    edited January 2011
    nap, thanks for the info. Thought maybe I was just looking in the wrong place.
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  • [Deleted User]
    [Deleted User] Posts: 1,225
    edited January 2011
    MC208 wrote: »
    nap, thanks for the info. Thought maybe I was just looking in the wrong place.

    I was at Polk yesterday for a conference call and wanted to address this with Stu but he was not in. I guess he was out in Vegas at CES and possibly taking some comp days. I will address this issue with him and let y'all know. Cheers. :cool:
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  • thefferon
    thefferon Posts: 2
    edited June 2013
    Greetings,

    Was anyone ever able track down schematics or other docs related to the Lsi15 speaker and/or crossover mod? If so please PM me - even if it's just contact info for Stu @ Polk!

    Thanks in advance.

    Tim
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  • VR3
    VR3 Posts: 28,732
    edited June 2013
    Bottom of page

    http://www.polkaudio.com/forums/showthread.php?38755-POLK-AUDIO-Speaker-Wiring-Schematics-amp-More-ALL-MODELS-except-SDA
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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  • The Doors
    The Doors Posts: 21
    edited January 2019
    Same. Looking for the cross-over schematic. I may have to repair my own.
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  • pitdogg2
    pitdogg2 Posts: 25,553
    https://forum.polkaudio.com/discussion/38755/polk-audio-speaker-wiring-schematics-more-all-models-except-sda#latest
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  • K_M
    K_M Posts: 1,629
    I created this cropped version, and enhanced the schematic to make it easier to read.ubtzemgfn88s.jpg
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  • The Doors
    The Doors Posts: 21
    Thanks!
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  • StewartHolmes83
    StewartHolmes83 Posts: 20
    What are you looking to improve?
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  • The Doors
    The Doors Posts: 21
    Actually just to repair the highs (left speaker) that I lost by over-powering the speakers with a quality amp.
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  • K_M
    K_M Posts: 1,629
    The Doors wrote: »
    Actually just to repair the highs (left speaker) that I lost by over-powering the speakers with a quality amp.

    almost for sure the 2 ohm resistor, commonly burns out.
    Replace with a 10 watt of same.
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  • mlistens03
    mlistens03 Posts: 2,767
    The Doors wrote: »
    Actually just to repair the highs (left speaker) that I lost by over-powering the speakers with a quality amp.

    What kind of amp? It may be of good quality, but just not have the power for these speakers...
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  • The Doors
    The Doors Posts: 21
    K_M wrote: »
    The Doors wrote: »
    Actually just to repair the highs (left speaker) that I lost by over-powering the speakers with a quality amp.

    almost for sure the 2 ohm resistor, commonly burns out.
    Replace with a 10 watt of same.

    Thanks for your response, I'll keep that in mind. I'm going to pull the cross-over network probably Friday and have a look see.
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  • The Doors
    The Doors Posts: 21
    mlistens03 wrote: »
    The Doors wrote: »
    Actually just to repair the highs (left speaker) that I lost by over-powering the speakers with a quality amp.

    What kind of amp? It may be of good quality, but just not have the power for these speakers...

    An Adcom GFA-555 II.
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  • The Doors
    The Doors Posts: 21
    I replaced the cross-over network in the right speaker 3 years ago when parts where available (yes from playing music loud but not obnoxious loud). The right held up for now but now the left gave out. What I am seeing here is that the cross-over network in the LSi-15's are weak when it comes to power handling. I was NOT driving them beyond craziness. They are just weak cross-overs as far as power handling and need modifying. Other than that, the Bass, Midrange, imaging and over-all sound is great. I'm not sorry I purchased them.
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  • VR3
    VR3 Posts: 28,732
    The LSI series was a solid, safe series for Polk. They sounded great, over built enclosures, solid drivers, conservative design. They did make it to where the resistors will blow well before the tweeters. I truly believe this is because at the time of the LSI release, the ring radiator being used was a big deal. If I am not mistaken the original ring resistor was the same style and design used in far more expensive speakers. So perhaps for Polk warranty purposes it was cheaper to replace crossovers than drivers.

    I actually recommend using the old resistor as a mounting block for the new resistor if just repairing. This atleast keeps it off the circuit board.
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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  • K_M
    K_M Posts: 1,629
    edited February 2019
    VR3 wrote: »
    The LSI series was a solid, safe series for Polk. They sounded great, over built enclosures, solid drivers, conservative design. They did make it to where the resistors will blow well before the tweeters. I truly believe this is because at the time of the LSI release, the ring radiator being used was a big deal. If I am not mistaken the original ring resistor was the same style and design used in far more expensive speakers. So perhaps for Polk warranty purposes it was cheaper to replace crossovers than drivers.

    I actually recommend using the old resistor as a mounting block for the new resistor if just repairing. This atleast keeps it off the circuit board.

    We did something a bit unusual. Removed the original resistor, and piggybacked (2) 5-watt 4 ohm resistors in parallel, to make it 2 ohms, so the board holes easily line up.

    After some listening, then changed one to a 3 some ohm to make it overall 1.75 ohms overall with the parallel 4 ohm for a tad more treble.
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  • The Doors
    The Doors Posts: 21
    VR3 wrote: »
    I actually recommend using the old resistor as a mounting block for the new resistor if just repairing. This atleast keeps it off the circuit board.

    Why would keeping the resistor off the circuit board be beneficial?

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  • EndersShadow
    EndersShadow Posts: 17,593
    The Doors wrote: »
    VR3 wrote: »
    I actually recommend using the old resistor as a mounting block for the new resistor if just repairing. This atleast keeps it off the circuit board.

    Why would keeping the resistor off the circuit board be beneficial?

    My guess, heat dissipation
    "....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963)
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  • pitdogg2
    pitdogg2 Posts: 25,553
    The Doors wrote: »
    VR3 wrote: »
    I actually recommend using the old resistor as a mounting block for the new resistor if just repairing. This atleast keeps it off the circuit board.

    Why would keeping the resistor off the circuit board be beneficial?
    EndersShadow wrote: »
    The Doors wrote: »
    VR3 wrote: »
    I actually recommend using the old resistor as a mounting block for the new resistor if just repairing. This atleast keeps it off the circuit board.

    Why would keeping the resistor off the circuit board be beneficial?

    My guess, heat dissipation

    Yes keep all surfaces off the board a bit allows better circulation.
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  • The Doors
    The Doors Posts: 21
    edited May 2019
    Thanks everybody for the very helpful responses. They were HUGE. I learned a lot. I had both the cross-over network resistors replaced with Mills 12W from Sonic Craft. All 8 were replaced and they are 1/4" off the board and glued into place. I saw where I burned out the Woofer and the Tweeter ones completely.
    BTW, I took that pic of the moon here in Southern Cal with my Canon T2i and a Tamron AF 70-300mm f/4.0-5.6 SP Di VC USD XLD lens on a tripod.

    Dan

    (DanT from 2001 on this board).
    Post edited by The Doors on
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  • The Doors
    The Doors Posts: 21
    Would a 1.8 ohm or 2.2 ohm resister work in place of the 2 ohm for the Tweeter?
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