Should I get a pair of these little subs?

[Dr Zeus]

I'd like to see if anyone has any opinions on Polk Audio's MM840dvc subwoofer. They are relativly inexpensive at $80-$120 each, and from what I've been reasearching may be a great 8" subwoofer for a mid-powered system.

The amp I'll run to push these guys is an old-school Gen X Hifonics Thor, rated for 125w per channel at 4 ohms. Wired corectly, this amp should provide conservativly clean power of ~200wRMS, with loading the amplifier down to 2 ohms per channel (DVC 4ohm coils wired in parallel).

The car I'll personally be driving and playing these in is a Nissan 370z, which is a two seater sports-car with minimal trunk space. I'll be installing these subs in place of the spare tire and under-carpet tools. I'm currently running a single Pioneer pre-IB-Flat 10" woofer which sounds decent, but have been told to try 8" woofers for maximum 'impact' punch from my electronica likeness. The pioneer 10" currently sits inside of my factory spare tire.

Has anyone heard, played, or installed Polk Audio mm840 / mm840dvc subs?



Polk'd website:
Polk Audio - Mobile Monitor Series - Mobile / Marine Speakers

[Cr@sh]

As much as I dislike the attitude and pride of those who run "Sundown audio" products there's no arguing facts and this 8"Sub Is supposed to be a killer in low end reproduction and spl! Tons of vids on it on youtube

[Cr@sh]

However I will admit I like efficiency over most other features so those polk subs may be better if you have a lower power amp. The Sundowns are rated at 400rms but I have heard of some people putting over 2k to them for burps.

[Dr Zeus]

I've seen those little sundown subs myself. I think they are more for ported enclosures with 80db 1w/1m and like you said; maximum SPL. There are a few problems with me running that sub, and believe me I looked at the sundowns, the JLw7, and dd1508. With the exception of the JL, the other two are more for bass hungry folks and dds only recommended for ported boxes. I'm looking for more sql which I know the JL would give but I cannot fit it in my car nor cover the premium cost for 1~2 of them.

1. 80db 1w/1m for that sundown would mean it would probably want a ported box to raise efficiency which is a buzz-kill for my install complexity and fondness of sealed box sound. Also, my amp although powerfull will not be able to drive more than just one of these subs but it could provide 4~500w if needed.
2. Those cost 2x as much. Granted they are probably 4x more powerful than the polks so maybe this isnt so bad off. I'd be able to buy just one of them.

How good do they sound in a sealed box?

[RiLoWa]

I know this may not be the most helpful, but I ran a single MM1040 for a while in about .65 cu.ft. sealed while I was refoaming the surround on my JL 10W6v1. Once I was done re-foaming the JL, I didn't put it back and kept running the Polk. I have since moved on and so has the vehicle, but I still think about that Polk. The vehicle was a Ford Expedition with the stealthbox installed in the side compartment.

[RiLoWa]

As a side note, I have been thinking about trying out a pair of the JBL GT0804 which are slightly cheaper and reportedly play well in a tiny .3 cu.ft. sealed box.

[Cr@sh]

Originally Posted by Dr Zeus

I've seen those little sundown subs myself. I think they are more for ported enclosures with 80db 1w/1m and like you said; maximum SPL. There are a few problems with me running that sub, and believe me I looked at the sundowns, the JLw7, and dd1508. With the exception of the JL, the other two are more for bass hungry folks and dds only recommended for ported boxes. I'm looking for more sql which I know the JL would give but I cannot fit it in my car nor cover the premium cost for 1~2 of them.

1. 80db 1w/1m for that sundown would mean it would probably want a ported box to raise efficiency which is a buzz-kill for my install complexity and fondness of sealed box sound. Also, my amp although powerfull will not be able to drive more than just one of these subs but it could provide 4~500w if needed.
2. Those cost 2x as much. Granted they are probably 4x more powerful than the polks so maybe this isnt so bad off. I'd be able to buy just one of them.

How good do they sound in a sealed box?

Probably not as well, I see your more like me where SQL matters more. Then for the price range and rms handling the mm's would probably fit your liking then. I haven't heard them so I cannot comment. It's been a long time since I could find a good sealed type sub like the IDQ max's

[spooney]

We use the ten inch version of this sub at work and we have had very few issues with any of them and they sound very good even in the terrible enclosure we are forced to put them in. I have had thoughts of grabbing a pair of these for myself.

[RiLoWa]

Just wondering if you pulled the trigger on the Polk's.

I did on one JBL GTO-804 and just finished the .6 cu.ft. vented enclosure. Very impressive little driver for $58. I must agree with all of the positive reviews around the WEB about it. So, if you haven't bought the Polk's yet you may want to give these a shot.

[Dr Zeus]

I just bought two mm840dvc subs but have not started on the new box. its gonna take a week or so.