Looking for MM840 insights

IrishChamp

I'm missing my SR124DVC something horrible and after my two Sundown e8 in a ported box just went up in smoke I'm trying to replace them with something that is more on par with the sr124. I'm very tight on space, I have about 1.4 cu.ft gross and about 4.5 to 5 inches of depth (inside clearance) to work with. I was thinking 4 MM840's powered by a PAD10001 but I've not really been able to find any insights. any time they are mentioned its in a favorable light but that's about it. do the mm subs need much room behind the magnets, I would only have .5 or so clearance, adequate for cooling?
how do they perform down low? do they have nice detail and accuracy? can I get something that will resemble the sr124 unitizing multiple mm840's?
I was thinking that 4 mm840's would be very nifty, what's the consensus here?
Other subs I'm considering are: JBL GTO804's, Image Dynamics id8v3's and Sundown e8v2's or maybe sa-8's (just two of them) but they really NEED to be Ported.
thanks

PS. if I loose about 1 inch of leg room I MIGHT be able to fit a couple mm1040's, MAYBE. I'd only go this route if the 840's don't seem like they will perform.

IrishChamp

I've been modeling the options in bassbox pro and some of the advantages the mm840's have like a large xmax don't really seem to come into play. It seems it would take 800 watts rms to max it out. Both the id8 and the gTO go lower with less power in the same size box. I just loved how musical my sr124 / 1200.1 combo was.

eloplayspolo

is there a reason your going with an 8? does a shallow mount 10 or 12 not work for u?

http://www.jlaudio.com/car-audio-subwoofer-drivers-tw5

IrishChamp

I would have no problem fitting those, however they are over four times the price of the mm 8's and over three time the price of the mm 10's . if you know where I can get a couple for a reasonable proce please let me know!
So are you implying that four mm8's will not be close to comparing to a single sr 12?
Thanks!

Edit: I might be able to fit the polk mm 10's or 12's but I'd have to buy them to know for sure and build a box. Biggest problem would be zero space in the box behind the woofer and they would be firing directly into the seat, possibly hitting the seat.

eloplayspolo

8s will never sound as good as an SR12 unless you spend some real coin.

Those can be found on ebay for 350ish.

IrishChamp

Still very expensive, but maybe a couple used will pop up somewhere.

IrishChamp

Can anyone tell me what the magnet diameter is compared to the mounting diameter of the mm subs? With that information along with the depths of the subs I'll be able to have a better idea of what I can actually fit behind my seat.
Also, how much do the grills for the speakers stick out past the mounting surface?

IrishChamp

It looks like if I really shoehorn things in I'll have about 1.75 cu.ft gross. I'm really tempted to see if I can fit two Mm1240's. Do the Speaker grills protect the subs well, the subs would literally be firing directly into the seat back.

eloplayspolo

u would only need 1 of those JLs... the hit HARD

IrishChamp

How do you think one would compare to an SR124?

eloplayspolo

It is my understanding that SPL wise, that is one of the most impressive Shallow mount subs ever....
If you want true sound quality...

http://stereointegrity.com/index.php?id=47

try and find one of those or wait for the next one. Nothing in the shallow mount form factor can touch it.

IrishChamp

Those are gorgeous and at some point I'd like to incorporate true high end exotic components into a build but with them being hard to come by and a little spendy (not too bad really but) I don't think they will end up in my truck. I'm almost 100% certain I'm going to try and squeeze two mm1240's in. I just need some confirmation on necessary clearance for the magnet (I don't know if it's vented or not) and if firing into the rear seat with the grills possibly touching the seat back will they perform.
I hope to get my hands on a BMW e30 m3 or e34 m5 in the next few years and restore it, I'll definitely want to do an exceptional sound system with light weight, compact, audiophile components that provide beautiful sound reproduction. :0)

IrishChamp

Update: I'd called Polk this morning, the guy called me back within 15 minutes and was really helpful. He told me the sub should have about 1/2 to 1 inch of space behind the magnets to breathe and for resonence, I think I can make that happen. He suggested buying the four ohm versions rather than a dual voice coil's and running it off the D 1000.1 @ 400 each at 2 ohms. He said having the single voice coil will be far more durable and that running them at 2 ohms will be more musical vs 1 ohm. I also wanted to pass on information he gave me about the new d1000.1 versus the old 1200.1. He said that it uses better board and better components and is a beefier amp and the sound quality is just as good if not better. I don't think his skill set was specific to the amps but he did suggest that the different numbers in different areas on the site could possibly be because of the unregulated power supply at something like 12.5 V versus 14.4 V. The amp is listed at 800 watts at 2 ohms, in another location at 1000 watts at 2 ohms, at 1 ohm it's listed at 1250 and 1200 in two locations.

eloplayspolo

i think you will be happy with those subs, a couple other forums have a lot of positive reviews for them.

IrishChamp

Yea, I haven't found too many reviews but absolutely everything is very positive from a SQ and SPL standpoint.

juanchibiris

eloplayspolo wrote: »

i think you will be happy with those subs, a couple other forums have a lot of positive reviews for them.

Where are the LOT of reviews?, I?ve trying to find some feedback on this subs, specially the MM1240, and besides some youtube video on the MM1540 and this review on the 12?s

http://www.mobileelectronics.com.au/products/reviews/polk_mm1240dvc_12_subwoofer/

I can find nothing.

I just want to know how are these compared to something for example JL Audio 12W3V3

IrishChamp

Crutchfield has 9 or 10 reviews, amazon a few as well. Most of what I found was simply by taking the time and searching google, key words like "forum" and "Polk mm1240 "together etc. Most of the info I found was just mentions in other threads but there are a couple dedicated threads floating around. I believe I remember a couple mentions of it compared to the w3's and I think it's a good match.

pentoncm

I'm happy with my MM1240. I have one hooked up to a 600W Alpine amp and it is more than enough power. Box is 1 cu.ft. before displacement with 1/2 pound of poly fill.

You'd be surprised how much sub placement changes things. Take a high end sub and point it towards the cabin and compare it to any mid range sub like the MM or W3 and fire it towards the rear; they will kill the higher end one.

eloplayspolo

juanchibiris wrote: »

where are the lot of reviews?, i?ve trying to find some feedback on this subs, specially the mm1240, and besides some youtube video on the mm1540 and this review on the 12?s

http://www.mobileelectronics.com.au/products/reviews/polk_mm1240dvc_12_subwoofer/

i can find nothing.

I just want to know how are these compared to something for example jl audio 12w3v3

diyma

IrishChamp

Specs from the manual, different than the website specs bud I'd think the most reliable.

IrishChamp

Svc subs show higher power handling, better frequency range and higher sensitivity.

pentoncm

There is no difference between SVC and DVC subs except for wiring them up to the amp. There are no SQ differences or anything like that. The SVC are not more sensitive than DVC subs, it just doesn't work that way. A DVC sub would let you pull in more power because you can wire it in parallel.

IrishChamp

I called Polk, they said the manual was made before the subs were being manufactured and that they've been trying to get it updated, both subs are indeed the same sensitivity, same power handling etc. seems strange things got listed so inconsistantly in the first place.....