(Expired) Polk Audio MM1540 & MM1540DVC 15" sub (Neodymium, Xmax 1") $89.99 FS @ Crutchfield - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 16 Old 11-11-2012, 04:48 PM - Thread Starter
Newbie
 
CowoJawa's Avatar
 
Join Date: Jun 2010
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Polk Audio Marine Certified MM1540 & MM1540DVC (Neodymium, Xmax 25mm, Recommends Sealed Box Volume 1.5 cu.ft ) 15-inch pretty shallow subwoofer, the biggest and baddest of the MM series !! Maybe Sealed Dual opposed (Epik Empire DIY) for less ?? confused.gif


Polk Audio MM1540 $89.99 Free Shipping at Crutchfield (Exp 11/11)

Polk Audio MM1540 DVC $89.99 Free Shipping at Crutchfield (Exp 11/11)


All Polk Audio Marine Certified Mobile Monitor (MM) Series Subwoofer at :

Crutchfield
Sonic Electronix
Polk Audio


Polk Audio MM woofers under (not "in") Jeep on You Tube wink.gif
CowoJawa is offline  
Sponsored Links
Advertisement
 
post #2 of 16 Old 11-11-2012, 07:14 PM
Advanced Member
 
Face2's Avatar
 
Join Date: Mar 2007
Location: Long Island, NY
Posts: 682
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Liked: 43
Ripole?

Mike
Face2 is online now  
post #3 of 16 Old 11-12-2012, 05:05 AM
AVS Special Member
 
Looneybomber's Avatar
 
Join Date: Sep 2006
Location: Lawrence, KS
Posts: 4,668
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked: 23
Well, $90 shipped, that was a good deal.

YID DIY
Looneybomber is offline  
post #4 of 16 Old 11-12-2012, 05:49 AM
Senior Writer @ AVS
 
imagic's Avatar
 
Join Date: Dec 2005
Location: Philadelphia, PA
Posts: 5,674
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 1130 Post(s)
Liked: 2278
Snap, the MoMo deal is gone. I bet it goes on sale again soon enough, but it's also nice to see it sold at full price, so I can feel like I got a bargain! Glad I grabbed one when I did - an MM1540. Great sub, running it ported. I feel the motor is not quite strong enough for a small sealed configuration (which is what Polk recommends) - it will start distorting before it bottoms out. For some folks, that could be a good thing. For larger enclosures and ported designs else, it's great. Low motor noise, decent excursion capabilities. Very, very lightweight (neo motor). Also, seemingly immune to abuse.

I know 'excurison' videos are boring, but I happen to have made one for the MoMo 15" so here it is. This actually is a small sealed config:

Find out more about Mark Henninger at
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
imagic is online now  
post #5 of 16 Old 11-12-2012, 06:17 AM
AVS Special Member
 
coctostan's Avatar
 
Join Date: Oct 2005
Location: Indy
Posts: 1,960
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 128
Wow, this looks like a pretty good driver. Even at SonicElectronix $130 price it is a deal. This might make a good replacement for my 8 MFW-15s. I'd like to see Ricci test them.
coctostan is offline  
post #6 of 16 Old 11-12-2012, 08:40 AM
AVS Special Member
 
Ricci's Avatar
 
Join Date: Mar 2007
Location: Louisville KY
Posts: 5,094
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 14 Post(s)
Liked: 204
It is 25mm xmax p2p. wink.gif Previously discussed here. http://www.avsforum.com/t/1431014/my-first-ever-diy-sub/90

Look for a picture of the back of the motor. It should tell you quite a bit. This is a driver for shallow mount apps with all of those associated trade offs. 2" voice coil but it has an LE rating of 5.1mH at 1khz which indicates no inductance rings. Power handling is rated at 425 watts (And this is a car audio driver). QES is 0.56. Total depth is less than 5". Not saying it can't be used well or sound good but shallow mount designs usually have to juggle quite a few things that end up impacting performance negatively.

At $130 you are getting into the DVC15, RS series, Alpine Type E, Obsidian 15, etc...Any of those would probably be more rugged, sound as good or better and have more displacement.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Ricci is offline  
post #7 of 16 Old 11-12-2012, 11:21 AM
Senior Writer @ AVS
 
imagic's Avatar
 
Join Date: Dec 2005
Location: Philadelphia, PA
Posts: 5,674
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 1130 Post(s)
Liked: 2278
Ricci, I took my MM1540 DVC out and measured xmech - it's a bit over 50mm p2p. The way the driver is designed, the voice coil will never hit the back plate. I don't know what the real-life xmax is - I do know that deciphering the proper specs for that driver based on Polk literature was nearly impossible and it would be great to have proper, empirical tests done. The shallow mount and light weight really do offer some intriguing installation options - for example I found the MoMo performed quite well in a dipole sub configuration.

I don't feel the discussion of the MoMo 15" on that thread you linked to was an accurate reflection of what to expect from that driver. There was a whole lot of speculation from folks who've never seen or heard one. I'm as guilty as anyone on that thread of pushing inaccurate specs for that driver. Shame on Polk, I say. Even the power handling is listed differently on their web site vs. their manual for the DVC version - Polk's website claims 425 watts RMS vs. 360 listed in the page from the manual posted in that thread - Measurements aside, I find it to be a very good sounding driver as long as it's not pushed to extremes (50mm p2p excursion). Definitely capable of stirring up the air at sub-20hz frequencies. Not so good as a mid-bass driver. Definitely not as efficient as Polk claims - it's no more efficient than most other drivers in its class.

I'd say the best application would be some sort of compact dual-opposed design - takes advantage of the size and weight advantages, while addressing some of the trade-offs. I've got mine in a 3 cubic foot sealed box, it's a good versatile sub I simply can't think of any reason to complain. I'd liken it to those new Pioneer speakers at Best Buy. Faithful transducers of sound, a 'plastic fantastic' that uses nothing but tight-tolerance manufacturing techniques to achieve quality at a price point that was previously unimaginable. To be clear, the MSRP is a joke... but priced around $100-$150, I think it's considerably better than Alpine Type E, which I've had in my house at the same time as the MoMo, side-by-side.

The one thing I do not get - There keeps being mention of neodynium magents. It sure looks like there's a traditional ferrite magent on the motor. I'm confused.

I gotta say, I really, really tortured my MM1540 - ruggedness is exactly the quality I would ascribe to the MM1540. I've destroyed a number of Alpine, Kicker, Eminence and Polk subs (DXi) but short of plugging the MM1540 directly into a wall outlet or hitting it with a sledgehammer, I don't see how you one could hope for something more rugged. This is especially true for the lightweight basket and motor - you could mount these subs in an ATV used for offroad competition and expect them to hold up, mechanically.
Quote:
Originally Posted by Ricci View Post

It is 25mm xmax p2p. wink.gif Previously discussed here. http://www.avsforum.com/t/1431014/my-first-ever-diy-sub/90
Look for a picture of the back of the motor. It should tell you quite a bit. This is a driver for shallow mount apps with all of those associated trade offs. 2" voice coil but it has an LE rating of 5.1mH at 1khz which indicates no inductance rings. Power handling is rated at 425 watts (And this is a car audio driver). QES is 0.56. Total depth is less than 5". Not saying it can't be used well or sound good but shallow mount designs usually have to juggle quite a few things that end up impacting performance negatively.
At $130 you are getting into the DVC15, RS series, Alpine Type E, Obsidian 15, etc...Any of those would probably be more rugged, sound as good or better and have more displacement.

Find out more about Mark Henninger at
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
imagic is online now  
post #8 of 16 Old 11-12-2012, 12:24 PM
Advanced Member
 
saabracer23's Avatar
 
Join Date: Feb 2008
Location: Salem, Oregon
Posts: 553
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked: 29
Real world Xmax is 25mm p2p or 12-12.5mm one way which is pretty decent at that price. Xmax is usually measured at 70% Bl. An Xmax rated at 25mm p2p makes an xmech of 50mm p2p realistic.

Dan.
saabracer23 is offline  
post #9 of 16 Old 11-12-2012, 03:48 PM
Senior Writer @ AVS
 
imagic's Avatar
 
Join Date: Dec 2005
Location: Philadelphia, PA
Posts: 5,674
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 1130 Post(s)
Liked: 2278
Edited - I'm sure we'll see it on sale for under $100 again. Actually, it's the 12" model that I wish would go on sale, I feel the motor assembly (they both obviously share) is perfect for a 12" cone - perhaps it's telling that the 12" always costs more than the 15", exen when on sale.

Find out more about Mark Henninger at
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
imagic is online now  
post #10 of 16 Old 11-12-2012, 05:35 PM
Senior Member
 
rock_bottom's Avatar
 
Join Date: Apr 2004
Posts: 430
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 14
According to the PDF manual here, what they refer to as the "Oneway/Excursion (linear)" is 25mm (page 18). It's not clear whether this is meant to refer to Xmax, Xmech, or something different. The "one-way" aspect is unambiguous though.

Edit: The Le data of 5.1mH posted in the thread Ricci referred to is that of the dual 4 Ohm voice coil version with coils connected in series. The single voice coil version has Re = 3.25Ohm and Le=3.0mH.

Edit 2: I've emailed Polk tech support and asked them if they could provide a plot of BL vs. displacement for this driver. They claim to have used the Klippel test system in the development process of these drivers, so hopefully there's a graph of BL vs. x floating around somewhere. We shall see. It would be nice to get this cleared up.
rock_bottom is offline  
post #11 of 16 Old 11-13-2012, 05:35 AM
AVS Special Member
 
coctostan's Avatar
 
Join Date: Oct 2005
Location: Indy
Posts: 1,960
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 128
Ha, I didn't take a close look. Yeah, it would be an ok deal at at $90 with 12.5mm xmax. I'd rather fork over a bit more and go with Dayton RS.
coctostan is offline  
post #12 of 16 Old 11-13-2012, 05:46 AM
Senior Writer @ AVS
 
imagic's Avatar
 
Join Date: Dec 2005
Location: Philadelphia, PA
Posts: 5,674
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 1130 Post(s)
Liked: 2278
I'll tell you exactly what happens at 25mm - the Cone makes contact with the outer edge of the spider's housing. xmech at it's finest.
Quote:
Originally Posted by rock_bottom View Post

According to the PDF manual here, what they refer to as the "Oneway/Excursion (linear)" is 25mm (page 18). It's not clear whether this is meant to refer to Xmax, Xmech, or something different. The "one-way" aspect is unambiguous though.
Edit: The Le data of 5.1mH posted in the thread Ricci referred to is that of the dual 4 Ohm voice coil version with coils connected in series. The single voice coil version has Re = 3.25Ohm and Le=3.0mH.
Edit 2: I've emailed Polk tech support and asked them if they could provide a plot of BL vs. displacement for this driver. They claim to have used the Klippel test system in the development process of these drivers, so hopefully there's a graph of BL vs. x floating around somewhere. We shall see. It would be nice to get this cleared up.

Find out more about Mark Henninger at
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
imagic is online now  
post #13 of 16 Old 11-13-2012, 09:02 AM
Senior Member
 
rock_bottom's Avatar
 
Join Date: Apr 2004
Posts: 430
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 14
Quote:
Originally Posted by imagic View Post

I'll tell you exactly what happens at 25mm - the Cone makes contact with the outer edge of the spider's housing. xmech at it's finest.

Ahhh... Thanks!
rock_bottom is offline  
post #14 of 16 Old 11-18-2012, 06:01 PM
Senior Writer @ AVS
 
imagic's Avatar
 
Join Date: Dec 2005
Location: Philadelphia, PA
Posts: 5,674
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 1130 Post(s)
Liked: 2278
I tore my Polk MM1540 apart, so I might expose exactly how much fibbing Polk is doing with this subwoofer. Tomorrow I'm posting a thread with pictures, because I'm disgusted. I made a fool of myself arguing on behalf of that driver, based on the specs and the description Polk provided. Live and learn... the MoMo is a fraud. There is no Neo magnet, there is no carbon fiber. As far as I can tell, the motor assembly is essentially the same as the 12" Polk DXi, but perhaps with worse QC! The main issue is the MoMo has a cone that is problematic - at once heavier and less stiff than it's little brother. I had to destroy it to prove to myself what I suspected, that Polk lied about this sub woofer. eek.gif

Find out more about Mark Henninger at
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
imagic is online now  
post #15 of 16 Old 11-19-2012, 07:23 AM
AVS Special Member
 
garciab's Avatar
 
Join Date: Aug 2001
Location: Princeton, TX - USA
Posts: 1,043
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 8 Post(s)
Liked: 29
Thanks for taking one for the team, Dub King! I had a design for this sub, but somehow never felt really satisfied with the specs from Polk. I'm a stickler for the details, and for them to not have consistent verbage and numbers for this woofer, just kept me away long enough. I know now to not buy this thing, no matter how cheap (in my case). Polk Audio sold out to Directed Electronics, but I'm not sure when that happened. I've wondered if that has been impacting their quality approach these days. And I say this only because Directed seems to be flipping car audio brands, which tells me their highest priority if profit first. Just my hunch.

bg
garciab is offline  
post #16 of 16 Old 11-19-2012, 07:00 PM
Senior Writer @ AVS
 
imagic's Avatar
 
Join Date: Dec 2005
Location: Philadelphia, PA
Posts: 5,674
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 1130 Post(s)
Liked: 2278
The sale is back on, however...

Here's a glimpse:

Polk DXi 12" vs. MoMo 15"

The MoMo has the black spider and the darker copper voicecoil.

Quick observations - It looks like the same magnet on both speakers, a very modest ferrite magnet, the same one you find on all the cheapest 12" subwoofers like Kenwood and Pioneer. - so much for 'Neodymium'. The MoMo actually has a smaller pole vent than the DXi. The MoMo's cone weighs twice as much as the DXi cone, but only because it is thicker, not because it is stiffer. The MoMo's basket is plastic, not 'carbon composite'. The MoMo's spider is slightly larger but it's also quite a bit stiffer, as is the rubber surround. The net effect is that the DXi actually sounds better, and might even be more efficient than the MoMo. The MoMo does get a marginally longer voice coil - 1.15" vs. 1" - a trivial difference.

I do not recommend either speaker, however I cannot think of any other driver that so misrepresents it's specs as the Polk MoMo 15" - or the rest of the MoMo series. The MM1540 is back on sale for $89.99 at Crutchfield, but there's a good reason for that. It's not worth anything more than that. I still maintain it's 'built like a tank' in the sense that it'll take a beating and sounds decent... I'm just not under any illusions anymore. The ferrite magnet is so disappointingly small for a 15", for a while I literally thought maybe it really is a Neo woofer but now I feel dumb for having been so naive. Thank you to the members here who threw their healthy skepticism my way a few months back when I was talking silly:mad:

Polk's words - "The MM1540 15" 4-ohm subwoofer handles up to 425 watts RMS, using a copper voice coil and neodymium magnet motor to drive the polymer cone with exceptional efficiency"















Quote:
Originally Posted by garciab View Post

Thanks for taking one for the team, Dub King! I had a design for this sub, but somehow never felt really satisfied with the specs from Polk. I'm a stickler for the details, and for them to not have consistent verbage and numbers for this woofer, just kept me away long enough. I know now to not buy this thing, no matter how cheap (in my case). Polk Audio sold out to Directed Electronics, but I'm not sure when that happened. I've wondered if that has been impacting their quality approach these days. And I say this only because Directed seems to be flipping car audio brands, which tells me their highest priority if profit first. Just my hunch.

Find out more about Mark Henninger at
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
imagic is online now  
Reply DIY Speakers and Subs

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off