Has anyone ever gone from Polk MMC650 to MM651um's?

[luckee37]

Several of my Polk MMC650s are blown, so I ordered the MM651um's as replacements. I'm trying to figure out if there is any way I can make these work.

My biggest question is how do I handle the input wires? The MMC650s took TWO pairs of input wires, but the MM651um's only have a single pair.

Also, the MM651um's have a wider faceplate and they are also deeper. But, I'm thinking that if I can get the wiring to work, I can move some of the working MMC650s up to the existing Deafcon cans and just drills new holes for the wider faceplates, etc. Am I oversimplifying it?

Thanks!

[Cam003]

not sure if they are rated at the same resistance, but i do know how to connected them. remove the pasive crossovers that were used for the MMC650s and plug those inputs directly to the MM651UMs, it looks as the crossovers are built into the back of the speaker. that should take care of your input issue. i am just guessing by looking at your picture.

[luckee37]

Thanks for the help. I'll give it a try this weekend.

Also, I looked at the pictures of your setup and I am super envious! I like the sub box under that port seat, in place of the cooler. I also love how clean and organized you made it. great work!

[Cam003]

Thanks for the help. I'll give it a try this weekend.

Also, I looked at the pictures of your setup and I am super envious! I like the sub box under that port seat, in place of the cooler. I also love how clean and organized you made it. great work!

That sub box may be up for $ale shortly, I have something new in mind. PM me if your interested.

[Buck]

I am trying to do this now and having trouble. I have 4 mmc650 and the original Clarion XMD3 head unit factory installed in a 2005 196 with no amp. The rear speakers were blown when I bought the boat so I just ran the fader to the front two and they sound great. This week I decided to replace the rears with mm651um. I cut off the external crossovers and wired them up but they don't sound as good as the mmc650s (almost no bass). I know it is a better speaker so I need to change something to make them sound good.

I have almost no audio experience, that's why I tried a simple unplug/rewire with similar speakers solution.

Can anyone give me some advice please. I understand it would sound better with an amp but do I need an amp for this simple setup? It didn't have one from the factory and sounded good. I use it mostly at low volume levels whether I am sitting or underway. I am not going for a high power/high volume setup.

Thanks

[luckee37]

Buck, I'm glad to hear that I'm not the only one that was crazy enough to try this. Did you have much problem with the depth of the new 651s or the size of the existing opening? I started to work on this last weekend, but I realized that I probably had to go to Radio Shack to get new connectors since the originals were soldered onto the external crossovers (and I didn't want to splice them at the time).

[Buck]

I did not have a problem with the size of the opening or the depth replacing the rear speakers only. I would have had a depth problem if I had replaced the front speaker on the observers side because the mm650 is pressed tightly against the sidewall. The depth of each speaker is nearly identical from the back of the mounting plate to the back of the speaker. The difference is the mm651um male connectors are mounted so that they overhang the back of the speaker by 1/4 inch. That makes the total distance from the back of the mounting plate to the end of the connector 2 3/4 inches. If you put a standard straight female connector on there you need a minimum 3 1/4 inches depth from the mounting surface. The mmc650 connectors are closer to the front of the speaker so they do not add depth.

I still have the problem of low bass output from the mm651um replacements. I think they should sound better than the old mmc650, but they don't (yet). I don't know enough about audio to figure it out myself.

I saw another post saying wiring could be sketchy from the factory so I'm wondering if that could have anything to do with it. Or maybe the old ones and new ones don't play well together for some reason? Seems like basically the same speaker to me.