DB840 sub in LSI15's replace the stock 8"driver!!!!!

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Comments

  • skrol
    skrol Posts: 3,330
    edited December 2013
    I have the DB840 in my LSi15's and drive them all day long with either my Parasound HCA-800II or even my Denon DRA-835R receiver. Perhaps it is the amp.

    I agree that the mids through highs are fantastic but the bass can be a bit boomy. I much prefer the bass response of my RTA-11TL's, everything else it is the LSi's. I never heard them with the stock sub. In my case, I believe that the bass is mainly due to placement but I have limitations where I can position them. I am wondering if some sort of sound absorption would work.
    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
  • jon s
    jon s Posts: 905
    edited December 2013
    I have a pair of modded LSi15s as well... I don't have any issues with amps with the speakers... I have used a Pioneer SC-67, Onkyo TX-NR906, Marantz PM-7200, Acurus DIA100 and a Sony TA-8650 with no issues... Something must be wrong with your amp...

    The DB840s do sound tighter than the stock, which tended to be a bit boomy. Never regretted the swap...

    Question: Are you sure you have the DB840SVC? If you have the DB840DVC and have it wired incorrectly, you could be set up for a 2-ohm load which would trip up most amps. Unfortunately, the alternative is to wire them in series (8-ohms) but the SVC model is the one you really have to use...
  • ematthews
    ematthews Posts: 27
    edited December 2013
    jon s wrote: »
    I have a pair of modded LSi15s as well... I don't have any issues with amps with the speakers... I have used a Pioneer SC-67, Onkyo TX-NR906, Marantz PM-7200, Acurus DIA100 and a Sony TA-8650 with no issues... Something must be wrong with your amp...

    The DB840s do sound tighter than the stock, which tended to be a bit boomy. Never regretted the swap...

    Question: Are you sure you have the DB840SVC? If you have the DB840DVC and have it wired incorrectly, you could be set up for a 2-ohm load which would trip up most amps. Unfortunately, the alternative is to wire them in series (8-ohms) but the SVC model is the one you really have to use...

    Thanks
    I checked and the are the SVC ones so no issue here.. I will keep an eye on my amp and send it back to Emotiva if there is more
    problems. Good thing it has a 5 year warranty.
  • dorokusai
    dorokusai Posts: 25,573
    edited December 2013
    One negative doesn't change the actual recommendation from Polk Audio. Not everyone will experience the same thing but 50+ have....whatever.

    When I worked for Polk we did this change in the chamber vs stock and it was an improvement.

    -d
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
  • ematthews
    ematthews Posts: 27
    edited January 2014
    Not sure what I did but just an update. I turned off my sub and disconnected it from the entire system..Moved my connections to Full output. And moved my speakers in about
    two inches... I am getting some good sound now...
    I also switched the speakers out and tried a few others I had... And to be honest, I didn't know how good these actually were... The other two speakers didn't have as much bass and the highs were very bright... These Polk's are good!
    Trial speakers
    Klipsch RF82
    Infinity P363
  • skrol
    skrol Posts: 3,330
    edited February 2014
    Caution on sub woofer selection!

    I did not realize that Polk made an 8" DXi series until I saw their boxed DXi108 sub (it is a dvc). They also have raw DXi 8" sub (DXi804 svc and dvc) that does not show up on the web page but does appear in the DXi series Owners Manual. Here is where the confusion sets in. Comparing the specs of the DB840 svc to the DXi804 svc, as listed in each ones Owners Manuals, they look identical. However, the specs on the web site "Spec" tab for the DB840 svc are different from what is listed in its OM. Usually, I would be suspicious of the web site specs and believe the OM. However, in this case I suspect that the web is correct and the OM is wrong. I have an email into Polk CS to sort out which is correct.

    When I do a speaker cabinet simulation using the LSi15 sub cabinet dimensions and OM specs for the DB840, things don't look right. They look better when I use the web site specs.

    Bottom line, the DXi804 is likely NOT a good replacement for the LSi15 sub. Stick to the DB840.

    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
  • skrol
    skrol Posts: 3,330
    edited February 2014
    To make things even more complicated, I have a sales literature sheet for the DB series which has yet different specs for some of the parameters while others match the OM and others match the web. Take heart, some are actually consistent across all three sources.
    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
  • mikeyb128
    mikeyb128 Posts: 2,885
    Have to agree. Did this mod with vr3 fortress crossovers, and these speakers continually blow my mind. I like them as much or more than my lsim system. My friends are always surprised that nice sound comes from a pair of polks...
    2 channel:
    Bryston 4B3, Bryston BDA3, Cary SLP05, Shanling CDT1000SE with parts conneXion level 2 mods, Nottingham analogue ace space 294, soundsmith Carmen MKii, Zu DL103 MKii, Ortofon MC 20 MKii, Dynavector XX2 MKii, Rogue Audio Ares, Core power technologies balanced power conditioner, Akiko Corelli power conditioner with Akiko Audio HQ power cable, Nordost heimdall 2, Frey 2, interconnects, speaker and power cables, Focal Electra 1028 BE 2, Auralic Aries Femto, Black diamond racing cones, ingress audio level 1 roller blocks, JL Audio E110 with Auralic subdude, Primacoustics room treatments.
    Theater:
    Focal Aria 926,905,CC900, SVS PB ultra x2. Pioneer Elite SC85, Oppo BDP93, Panamax M5400PM, Minix neox6, Nordost Blue heaven LS power cables.

  • ZLTFUL
    ZLTFUL Posts: 5,639
    kevintomb wrote: »
    What gets me, is often when upgrading to better parts, the values actually "change", from what stock is, even when mimicking the rated values.

    Uh...ok...
    So you're saying an 8uf cap of one brand isn't the same rating as an 8uf rating of another? Now I would agree to an extent based on +/- percentage but within 5%, human ears aren't going to hear a difference.

    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
  • ZLTFUL
    ZLTFUL Posts: 5,639
    Explain how a 2 ohm, 5% tolerance resistor can measure 2.5 ohm just because it is mounted in a speaker?
    You logic is confusing at best. Are you telling me that when I order a 2 ohm resistor that when I mount it on the crossover board, it will magically change to a different spec?
    Just measured a 22.5 ohm resistor...on a crossover board...it measured 22.53 ohms...which is within tolerance for a Mills MRA12...so where is this magical resistance chance happening?
    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
  • F1nut
    F1nut Posts: 49,666
    Explain how a 2 ohm, 5% tolerance resistor can measure 2.5 ohm just because it is mounted in a speaker?

    This should be interesting.



    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

  • ohskigod
    ohskigod Posts: 6,501
    Boys boys boys

    Put the soldering irons down, climb your basement stairs, walk out your front door, and get some sunshine. Lol
    Living Room 2 Channel -
    Schiit SYS Passive Pre. Jolida CD player. Songbird streamer. California Audio Labs Sigma II DAC, DIY 300as1/a1 Ice modules Class D amp. LSi15 with MM842 woofer upgrade, Nordost Blue Heaven and Unity interconnects.

    Upstairs 2 Channel Rig -
    Prometheus Ref. TVC passive pre, SAE A-205 Amp, Wiim pro streamer and Topping E50 DAC, California Audio Labs DX1 CD player, Von Schweikert VR3.5 speakers.

    Studio Rig - Scarlett 18i20(Gen3) DAW, Mac Mini, Aiyma A07 Max (BridgedX2), Totem Mites
  • ZLTFUL
    ZLTFUL Posts: 5,639
    kevintomb wrote: »
    Perhaps explained poorly!

    All I was trying to say, is that the stock components often measure different than their labeled values.
    I have not measured any huge variations, but read a few threads, where variations were far larger than the 5-10% Variances labeled on the Stock parts.

    That makes WAY more sense than your original postulation.
    Measuring that same 22.5 ohm resistor in the stock circuit does show a greater than 5% tolerance. But I would also expect that considering that part has an unknown life over the last 24ish years and has clearly degraded over time.

    Putting a new component in the circuit isn't really trying to replace it with a different value per say as much as it is returning the circuit to its original specs.

    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
  • Airplay355
    Airplay355 Posts: 4,298
    I just did this mod myself. I found the DB drivers on amazon for $47.50 with free two day shipping (for Prime members). I picked up two before it became impossible to find new ones anymore. So, some notes...

    I read through some posts here and saw "dental pick", so I thought GREAT idea, and bought a literal dental pick. I see now that's not what people use. Turns out, it worked really well, especially for prying out the old driver. No cabinet damage and I didn't have to unscrew the bottom plate to push the driver out. I just lifted it right out.

    I have the newer version and the grill on one speaker was so stuck on, my wife insisted that it must be glued in place. It finally came off but not without a pea sized hole in the grill cloth. Unfortunate, but this grill cloth is fragile and there really was no other way to get it off. The second grill was more loose and came out with just a tiny hole from the dental pick I used to pry it out. This hole is much more tolerable. Grills are not forever, especially the stuff they used on this series.

    I did not like the idea of mortite or some kind of messy caulk gasket. I saw someone mention cutting the DB gasket and that's what I decided to do. I used a razor blade for all the trimming. First, I cut the gasket in half, as in I inserted the blade where the driver had been and cut along the circumference of the circle so I had two circle gaskets (frontal plane, I guess?). The top part has some decorative ridges in it, so I used the bottom. There was a small ridge on the outer rim, which I trimmed off. To get this gasket to fit into the hole, I cut it again (sagittal?) so that I could lay it in the hole and overlap an area where I cut. The overlap was trimmed off. This allowed me to align 3/4 of the holes with their original position. It also kept the driver in the original position instead of pushing it farther out. I replaced the four screws that were there originally and added 4 from the DB840. I used an impact drill and the screws went in like butter without any pre-drilling.

    The VC on the woofers I got was at the bottom based on logo orientation. If mounted with the logo up, the wires were smashed against the port and I didn't want any lose wires dangling around right by the port. So I decided to invert them and just leave the logo upside down. No one is going to see it, so I don't care at all. I'd rather that than risking buzzing wires inside the cabinet.

    My port didn't seem like cardboard. It was hard and rigid. I decided not to bother with the dynamat. Since I didn't use mortite I can always pop the driver out and add it later, but for now I left it out.

    The good:

    The bass is instantly tighter. I would go as far as to say I disliked the bass from the original speaker. It was sloppy and that makes sense once I got to feel the flimsy driver compared to the stiffer DB.

    Bass is slightly deeper but not too much. Mostly I was after tighter more controlled bass. That's what I got.

    The bad:

    For those with grills that are in way too tightly, you should be prepared to ruin them or at the very least, puncture the fabric and have a hole. The only way to get the tight ones out is by pulling from underneath (as far as I can tell).

    I feel like I've made a power hungry speaker even more power hungry. This is anecdotal of course. 7guq29am547y.jpg
    djq59hqo3xhb.jpg

  • mpitogo
    mpitogo Posts: 475
    What about a DB1040 SVC for an LSi25?
    • Living Room Music-2.0 Polk Legend L800 | McIntosh C70 | McIntosh MA5200 (Treble) | McIntosh MC452 (Bass) | Sublimeacoustic K231 Active xover | Denon DP-2500A | Denafrips Ares II | Belkin Soundform Connect | iPad Air USB to DAC
    • Media Room Ht-7.2.6/13.1 (Atmos/Auro-3D) Polk LSiM707, LSiM706c, LSiM702 F/X [x4], height LSiM703 [x6], HSU VTF-15H MK2 Dual | Marantz AV8805A | Rotel RB-1590 (L/R) | Appollon NC500 11ch | Sony UBP-X800 | AppleTV 4K | JVC RS2100
    • Game Room-5.1 Polk LSi25, LSiC, LSiF/X | Marantz SR7009 | AppleTV 4K | Xbox One S | Sony PS2, PS3 | Nintendo Wii | Gaming PC | Sony 75" LCD
    • Master Bedroom Music-2.0 Totem Hawk | Marantz PM-10 | Marantz SA-10 | SONY PS-HX500
    • Office-2.0 Ascend Acoustics Sierra LX, DSW microPRO3000 | Rotel RA-1570 | Marantz HD-CD1
    • Daughter's Bedroom 1-2.0 TBD Martin Logan Forte
    • Guest Room 2-2.0 Klipsch RP-600M | Martin Logan Forte
    • Guest Room 3-3.0 Martin Logan Motion 40, 50XT | Onkyo TX-SR705 | Apple TV | Samsung 55" TV
    • Guest Room 4-2.0 QAcoustics 3030i | Sansui AU-6900 | Topping DX7s | Sansui FR-1080 | TV
    • Maintenance: Pro-Ject VC-S Record Cleaning Machine
  • Airplay355
    Airplay355 Posts: 4,298
    Hard for me to say. The engineers at Polk were the ones who did the work to find out the sub was a great drop in replacement. I don't think they tried it with Lsi25s. The subs seem cheap enough where you could get them, try them out and return them if you didn't like them or dump them on craigslist.
  • Hey gang, I have followed this thread for years and, considering its age, dont feel too dumb by keeping it going to ask a question now. I have loved my 15s for many years, but the one nagging thing about them (to me anyway) was the upper bass rolloff. I could never really smooth it out so I just set the receiver to a high crossover, and handed most of the work to a pair of 10" Hsu subs. That helped quite a bit.
    I listen to a lot of light strings and female vocals, so deep extension has never been a real priority in lieu of smoothness. So just recently I was considering selling the speakers just because it has always seemed like a bandaid fix.

    Burning question now to is have you guys found the upper woofer crossover smoother with the replacement woofer? Or is this a complete replacement crossover thing?

    On another note at the other end of the frequency spectrum (and unrelated) the highs seem 'capped' for a lack of a better word that I can come up with. That one I can live with for now though.
  • K_M
    K_M Posts: 1,627
    The mod, involves changing the side mounted woofer (8") that has a decent bit less upper bass boominess. It is a great change "IF" this particular issue bothers you.

    It can be also helped by doing what you do, crossing a sub fairly high, and adjusting the level to your preference. There are ways to mod the crossover to also remove the "issue" of bass boominess also.

    Not sure how to answer about the "highs", they seem fairly good as is, but not too forward like many speakers are voiced.
  • Thanks K_M, The highs shouldnt have entered the picture here as its not the topic. My mistake.
    Your description was enough for me to give this a try. I find the small Hsus blend nicely at the bottom, so that area of midrange is the only 'in my face' problem that I have that I was never able to fix.
  • Airplay355
    Airplay355 Posts: 4,298
    I found the mod helped with what I perceived as boomy bass. Extension is better, impact is better and the speaker sounds better when run full range. For HT they're crossed at 60hz so they really aren't doing much but for music, the full range abilities help out. I prefer not to use my sub with music unless I'm trying to annoy the neighborhood for fun.

    I find it to be a more cohesive speaker. I also figured that for $80, if I didn't like it, I hadn't wasted much.

    I don't have a problem with the highs at all. The tweeter is what draws me to this speaker. My wife and I were watching a movie the other day where a smoke alarm went off and we couldn't tell if it was in the movie or was our alarm. They're very accurate and extend plenty high for me :)
  • mm840lsi15
    mm840lsi15 Posts: 35
    edited December 2017
    Hi all,

    Just registered here to say that although the DB840 upgrade does make the LSi15 bass sound tight and nice, the MM840 sub destroyed the DB840 in my LSi15s with modded crossovers. Whereas the db840 makes the bass tight, the mm840 takes the bass even deeper, punchier, more dynamic and even thunderlike. I'd recommend anyone considering db840 swap to try mm840 as well. Make sure you use all 8 screws to make sure your mighty mm840 is secured tight in there.

    I should note that the crossovers in my LSi15s are modded, this is yet another way to make your LSi15s sound much better. Just in case, I drive my LSi15s with a pair of fully modded Adcom GFA-565 monoblocs.
    qudh67zgcj0y.jpeg
    svin7c39fc51.jpeg

    Cheers.
  • elmeri
    elmeri Posts: 6
    edited July 2018
    Now that DB840 is discontinued and hard to find, anyone have an opinion on using the new DB842?

    Quick look at the specs show it's slightly shallower (within 10mm), but slightly wider by about 5mm (179.4mm old vs 185mm new). Will there be an issue getting the larger subwoofer to fit in the LSi15 enclosure?

    It can handle much more power (up to 180W old vs 250W new, both continuous) and sensitivity is similar (84dB old vs 85dB new)

    Same frequency response: 30-200Hz

    Datasheets below:

    https://d3vqw2nv1topde.cloudfront.net/assets/Product Documents/Product Information Sheets/db sub infosheet.pdf

    http://www.polkaudio.com.au/uploads/files/Files/dbSub_MN.pdf
  • Airplay355
    Airplay355 Posts: 4,298
    Try it out and let us know :)
  • elmeri
    elmeri Posts: 6
    Airplay355 wrote: »
    Try it out and let us know :)

    Having used the DB840 in your speakers, do you think the increase in diameter will be an issue or is there some wiggle room? It's nominally 5.6mm larger according to the documentation.
  • Airplay355
    Airplay355 Posts: 4,298
    I'm not too sure. There might be enough room to fit the driver in the cutout of the wood paneling but maybe not in the MDF enclosure underneath. Check out the post on page 5 from mesquitehead. In his picture, you can see how much space there would be.

    I still think the easiest way to find out is to just grab one from Amazon and try it out. If it doesn't work, Amazon is very easy to return things.
  • K_M
    K_M Posts: 1,627
    I do not see the T/S paramaters listed for the new versions.....
  • aggie113
    aggie113 Posts: 9
    Just picked up a set of LSi15/LSiC to replace some RTi12/CSi A6. Already put in an order for the Fotress upgrade for all three and would love to see some update on the sub swap using one that can still be found in stock.
    In use: Polk LSi15s (sub upgrade), LSiC, LSi9s SVS PB 10 ISD connected to Onkyo TX-NR777. VR3 crossover upgrades ordered for fronts and center.
    Collecting dust: Polk RTi12s, CSi 6A, RTi38s
  • skrol
    skrol Posts: 3,330
    I had collected a as many Polk car sub parameters as I could find (see attachment). It gets a little confusing as there are some contradictions between what was on the web vs what was in the spec sheets.
    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
  • aggie113
    aggie113 Posts: 9
    Well, the DB842 SVC arrived today. Was able to take the cover off the old sub with help of a plastic spudger kit. It was glued in but once you get a small section to come out you can just grab it with your fingers around the edge and work it loose.
    Old sub came out easy enough. The DB842 fit right in, didn't have any clearance issues as far as I could tell and didn't have to mess with the plastic ring on it. Just used the original 4 screws for now. I have a MM842 arriving early next week and I'll try that one out in the other LSi15, and see which sounds better (if it also fits).
    In use: Polk LSi15s (sub upgrade), LSiC, LSi9s SVS PB 10 ISD connected to Onkyo TX-NR777. VR3 crossover upgrades ordered for fronts and center.
    Collecting dust: Polk RTi12s, CSi 6A, RTi38s
  • mdschlayer
    mdschlayer Posts: 209
    Great, please keep us posted. I am debating between DB842 and MM842 as well.
    LSi15's, LSiC, LSiF/x's, LSi7's, vr3 crossover upgrades, SVS PC-12 Plus, SVS SB-16 Ultra, Marantz AV8805, Parasound amps, LG OLED65C9PUA, Clarus Crimson, Signal Cable, Atlas Cable, Shunyata and Synergistic A/C conditioning, dedicated Cardas 30A and Furutech 20A AC lines, Box Furniture, Solid Tech ROS, Symposium roller blocks