Modding the sub on LSi15s

[mole']

so i have read that the upgraded sub for the LSi15 is the db840 dvc.

i see that polk has a few other subs that will fit.

db840 dvc

■8" Dual voil subwoofers optimized for high performance in virtually any enclosure type: sealed, vented and band pass.
■Wrap-around Rubber Gasket seals the sub in your enclosure for airtight performance.
■State-of-the-art laser-based Klippel measurement technology perfectly centers the subwoofer's voice coil in the magnetic field, improving X-max and BL linearity, and the sub's micro and macro dynamics, for deep, precise, bass!
■Black Matt-finish Composite Cones are unbelievably stiff for real gut-pounding bass.
■Injection molded ABS dust cap also stiffens the cone to suppress unwanted resonance for incredible low distortion, high impact bass response.
■Big beefy magnet structure and motor assembly for high output bass with tight control.
■Durable Butyl Rubber Surround for consistent, reliable performance.
■Four-layer vented voice coil runs cool while your music stays hot.
■Vented pole piece for higher efficiency and ultra-high power handling.
■Fast-On wire terminals for quick, secure hookups.

MM840 SVC

If you're looking for big bass that doesn't take up much space, the MM840 8-inch subwoofer is the right choice. Using carbon composite baskets, powerful motor structures with oversized voice coils, the MM840 punches out real tight, real serious bass you'd usually find only in the most expensive loudspeaker systems. With 250 watt continuous/500 watt peak power handling, we recommend the MM840 for small sealed (.35 cubic foot) enclosures.

■Dynamic Balance? Driver Technology for pure, distortion free sound.
■Polymer Woofer Cones and Butyl Rubber Surrounds will not break down over time and will survive the rigors of harsh automotive environments.
■High Temperature Copper Voice Coil (38mm) and Polyimide Former stands up to the most rigorous use while maintaining extremely low distortion for big bass punch and output.
■Heavy Duty Input Terminals accommodate speaker wire up to 8 AWG or twisted pairs of 12 AWG.
■Advanced Carbon Composite Basket based on the spokes of a wheel is lightweight, will not flex during peaks and looks great.
■Klippel Optimized Components for consistent, distortion-free bas.
■Available Matching Grille complements the MM Series' high-performance-wheel- inspired design.
■Dual Voice Coil Configuration (MM840 DVC) also available.


MM840 DVC

When you want more wiring options to get the most performance from your subwoofer, check out our Dual Voice Coil MM840 8-inch subwoofer. It's the same easy-to-install compact size as the Single Voice Coil. And it has all the MM signature features: carbon composite baskets, powerful motor structures with oversized voice coils. The MM840 punches out real tight, real serious bass, the kind usually found only in the most expensive systems. With 250 watt continuous/500 watt peak power handling, we recommend the MM840 for small sealed (.35 cubic foot) enclosures.

■Dynamic Balance? Driver Technology for pure, distortion free sound.
■Polymer Woofer Cones and Butyl Rubber Surrounds will not break down over time and will survive the rigors of harsh automotive environments.
■High Temperature Copper Voice Coil (38mm) and Polyimide Former stands up to the most rigorous use while maintaining extremely low distortion for bass punch and output.
■Heavy Duty Input Terminals accommodate speaker wire up to 8 AWG or twisted pairs of 12 AWG.
■Advanced Carbon Composite Basket based on the spokes of a wheel is lightweight, will not flex during peaks and looks great.
■Klippel Optimized Components using a state-of-the-art Klippel Distortion Analyzer.
■Available Matching Grille complements the high-performance-wheel-inspired design.
■Single Voice Coil Configuration (MM840) also available.


im thinking the MM series would be nice because they can handle the higer watts. all of them looks like they are 4 ohms

has anyone tried the mm840dvc? i was thinking about installing one db840dvc in one and then a mm840dvc in the other and see how it goes....

inputs????

[Face]

T&S parameters are more important than power handling.

[nhhiep]

I always wonder about this mod. if it's that cheap to put a better sub in the LSi tower. how come Polk didn't just do that? instead of doing R&D for a new sub?

[Lietuvis91]

I always wonder about this mod. if it's that cheap to put a better sub in the LSi tower. how come Polk didn't just do that? instead of doing R&D for a new sub?

Good question! I wonder the same thing...

[PSOVLSK]

I always wonder about this mod. if it's that cheap to put a better sub in the LSi tower. how come Polk didn't just do that? instead of doing R&D for a new sub?

A good question, but the upgrade does makes a difference. It's not night and day, but the bass is definitely deeper and tighter.

[mole']

so no one has tried any other replacement sub in the LSi15s then ?


i found a place on ebay that sells the db840 and the mm840 (both dvc) and they have a 30 day return policy. i just have to pay shipping back if i return anything. im gonna order a mm840 and put it in one and the db840 in the other and see what it sounds like.

[EndersShadow]

Probably due to the cost difference. Same reason they didnt use better parts for the crossover.

The stock sub's replacement is a 60 dollar part plus shipping. The db840 is 80 bucks.

Keep in mind this forum is crazy when it comes to modding the LSi's, SDA's, ect. 90% of consumers will NEVER upgrade their LSi's so why increase the price for EVERYONE when only 10% of your market will be able to tell/appreciate the difference?

[Face]

It probably would have added another couple hundred dollars to the price of the LSi15, possibly putting it in another price bracket.

[Montoya]

I'm a little confused is the DVC or the SVC the replacement? I have a pair of older MOMO 8" SVC that I want to try can these be used?

[EndersShadow]

I'm a little confused is the DVC or the SVC the replacement? I have a pair of older MOMO 8" SVC that I want to try can these be used?

The db840 SVC is the replacement, so if you want to give your MOMO a try you can, personally I would PM doro and see if its going to kill the speakers to do so...

[Face]

I'm a little confused is the DVC or the SVC the replacement? I have a pair of older MOMO 8" SVC that I want to try can these be used?Their parameters are similar enough that it can't hurt to try, although the MOMO calls for a slightly larger box. My only other concern is that the Momo is aluminum, and the crossover slope may not be steep enough to suppress it's breakup at higher frequencies.

[Montoya]

Well I dropped them in and sealed them with mini rope caulk they sound awesome. These where already broken in I had used them in my car for a short time.

[mole']

Well I dropped them in and sealed them with mini rope caulk they sound awesome. These where already broken in I had used them in my car for a short time.

which momo speaker are they?

[Montoya]

The last ones before the mobile monitor line. MM2084SVC

[Montoya]

60865

[TouchOfEvil]

Well I dropped them in and sealed them with mini rope caulk they sound awesome. These where already broken in I had used them in my car for a short time.

We need more details.

[mole']

The last ones before the mobile monitor line. MM2084SVC

hmmmmmm


60865

that look NICE!!!!!


We need more details.

what HE said......

[Montoya]

I don't have any audio measurement tools available to me but I can check the eq settings currently on my pioneer 94thx they are set based on the original speakers being installed. Then recalibrate using the newly installed set I'm sure the data will tell us something. Unless you guys have any other ideas.

[TouchOfEvil]

I don't have any audio measurement tools available to me but I can check the eq settings currently on my pioneer 94thx they are set based on the original speakers being installed. Then recalibrate using the newly installed set I'm sure the data will tell us something. Unless you guys have any other ideas.
Yeah that would be nice. Also just looking for your impressions with the new sub vs old. I did a how to write up awhile back on changing the stock out with the db sub.

[mrbigbluelight]

Good to hear of the improvement in bass, but I can't say as I'm a big fan of the looks. MOMO and Lsi15 don't make the cutest couple, IMO. :smile:

[nhhiep]

so for those who are upgrading. Assuming the price difference is $20, according to the poster above.

you're claiming that Polk put money into R&D to develop a new cheaper, lower quality speaker just to use in the LSi? which is their top of the line speakers. Instead of just reuse old parts?

This does not make any business or engineering sense in any way to me.
Also, Polk design the speaker as a whole. now you replace 1 part of it (the sub) and claim to get better sound? if this is true, Polk engineers aren't that smart then. what about the mid drivers? why aren't replacing them with Polk car speakers too?

Is there anyone from R&D or marketing department from Polk in here? I'd love to hear their thoughts on this.

[jmos]

The Lsi15's have been around for a while, how old is the DB840SVC, perhaps its advanced and in many cases as technology advances it gets cheaper?

I like my Lsi15's but they lack clear/tight bass, for me its worth a try?? I shall soon see
Regards
John

[Face]

IIRC, the LSi15's are over 10 years old, the DB840's have only been available for a fraction of that time.

[newsman]

I'm a little confused, are you guys saying these subs are direct drop in replacement for the factory ones in LSi15? Also, wouldn't MM840 be the best replacement sub cause it's a single coil and goes down to 26Hz while being 89db efficient. The DB840 and MM840D (dual coil) are 85db efficient, what is the efficiency of the stock sub? Would crossover need to be modded to be able to install the new sub.

Installing the sub should be easy if it's a just a drop in, replacing the crossover takes more skill. If it's just the sub, count me in as one willing to give it a try !!! My only concern is that typically, automotive, marine components are to not up to the level of audiophile home component...

[EndersShadow]

I'm a little confused, are you guys saying these subs are direct drop in replacement for the factory ones in LSi15?. Would crossover need to be modded to be able to install the new sub.

Yes, you need remove the gasket from the db840 and make your own, otherwise its direct drop in, no crossover modifications required.


Also, wouldn't MM840 be the best replacement sub cause it's a single coil and goes down to 26Hz while being 89db efficient. The DB840 and MM840D (dual coil) are 85db efficient, what is the efficiency of the stock sub?

Don't know about the rest of this. I just know doro heard this suggestion from Polk engineering directly, so I dont question the rest since they know their products :smile:

[mole']

I'm a little confused, are you guys saying these subs are direct drop in replacement for the factory ones in LSi15? Also, wouldn't MM840 be the best replacement sub cause it's a single coil and goes down to 26Hz while being 89db efficient. The DB840 and MM840D (dual coil) are 85db efficient, what is the efficiency of the stock sub? Would crossover need to be modded to be able to install the new sub.



i was thinking the DVC would be better suited for the replacement. i ordered a db840 and a mm840 both in dvc.

[EndersShadow]

I disagree here. Wiring a DVC v. a SVC gives you a BIG difference in ohm ratings. The SVC is a 4 ohm load (like the LSi is). The DVC is either a 2 ohm load, or 8 ohm load depending on how you wire it. That will make a difference IMHO.

[JimAckley]

It probably would have added another couple hundred dollars to the price of the LSi15, possibly putting it in another price bracket.

I dunno how, since I see them retailing for $60-80 ea. To upgrade the lineup at the consumer level at retail prices, one could assume $150/pr, which doesn't really move their price bracket at all. That's maybe $40 extra per pair in production costs, if that, for a well-improved speaker. At the retail level, since they are combining two products, they could make it maybe $100 mark up, $150 at most, since you're boosting the sales of two products through their combination

Same story for the crossovers. At wholesale costs for the parts, the upgrades would cost just a little more than a pair of 8" subs, but still wouldn't have a huge impact at the production level.

Polk could've created a true flagship for not all that much more out of their pocket, then knock the cost up $500 (which I'm aware will potentially take it out of its current price bracket) and you've created a speaker that dwarfs EVERYTHING else in the price range, and would probably bring in even more customers because of that fact. Afterall, isn't a flagship where you pull out all the stops?

[newsman]

So do you guys think that single coil MM sub would be a better sub, since it goes lower than the db model? Also, how do you make the gasket, couldn't the stock one be reused? Can anyone from Polk chime in? We are all reasonable here, so no one should expect any kind of free warranty from Polk if we mess it up :)

[EndersShadow]

So do you guys think that single coil MM sub would be a better sub, since it goes lower than the db model? Also, how do you make the gasket, couldn't the stock one be reused? Can anyone from Polk chime in? We are all reasonable here, so no one should expect any kind of free warranty from Polk if we mess it up :)

The stock 8" woofer doesnt have a gasket, and you can make one for the db840 using something called Armacell. Its super cheap, availible at Home Depot and takes all of 5 mins to create the gasket between the woofer and the cabinet.

[JimAckley]

My first thought would be to go with the db840 since it seems to be a tried and true swap. I suppose there's only one way to find out though

[newsman]

Hmm, you guys got links to any installation guides out there. I'll e-mail Polk tonight, and see if they have idea whether MM sub could be used as a replacement...

[EndersShadow]

Hmm, you guys got links to any installation guides out there. I'll e-mail Polk tonight, and see if they have idea whether MM sub could be used as a replacement...

Its ridiculously simple. All info you would ever need here: http://www.polkaudio.com/forums/showthread.php?89529-DB840-sub-in-LSI15-s-replace-the-stock-8-quot-driver!!!!!

[newsman]

Thanks for the link. So it seems like DB series gets the vote over the MM model, because later is designed for a sealed design. Kind of a shame, cause MM model goes down to 26Hz according to Polk. One thing I noticed though, is that it seems stock sub has a bigger magnet?

[Face]

Magnet size is never something I worry about when choosing a driver.

[EndersShadow]

Thanks for the link. So it seems like DB series gets the vote over the MM model, because later is designed for a sealed design. Kind of a shame, cause MM model goes down to 26Hz according to Polk. One thing I noticed though, is that it seems stock sub has a bigger magnet?

It does indeed.

[audiovue]

made a mistake and buy dvc db840, did somebody made same mistake and what:idea: happen with the sound.
regards

[Face]

Send them back.

[audiovue]

Send them back.
Yes but i buy in buying now on ebay and them i see i have made a mistake i leave a message to cancel the buying and i wish the byer accept cancelling the buy. i see the seller gave me 30 days money back and i send cancel after 5 minutes buying the db840dvc...
if the sellers are honest probably they accept the cancellation.
regards

[Montoya]

I have now tried both the momo Svc and the DB sub the momo is superior in every way I returned the DB subs after three week demo. The bass is tighter and goes a lot lower the DB sounds slow and muddy in comparison.

[audiovue]

what mod?le offre mono dvc
?

[audiovue]

what model of mono svc ?

[audiovue]

Hi,
I want exact diameter (not cut out) of the mm840svc, because it for replace the 8 woofer on my Lsi15's
the diameters of my speaker his 20.8 cm if more than that do not fit on my speaker.
the replacement for better sound is normally the db840svc by polk audio but i see the mm series and his look better!
thanks for quick response

[SpiderMan1]

need to be modded to be able to install the new sub.