subwoofer help

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fastmark1993

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so i got my hands on a 15" memphis mojo in a 2ft cubed ported box. dual 2 ohm. I spent 3 hours getting it in my trunk. i hooked it up to my amp and it sounds like crap. i took the sub out wired it all again, made sure my amp was wired good, checked rcas everything but my boston g2's blow this thing out of the water big time. itll hit the higher notes awesome but when you get low like late night tip by 3 6 mafia it sounds like garbage. im shooting it about 1500 watts rms. any suggestions? oh if anyone is interesed i am selling it. pictures soon.
 
Are you using an external crossover with the amp?

Make sure the amp is grounded properly.
 
What shape is the box in? Is it home made or store bought? It could be falling apart.
 
The box is to small, that's why it sounds good on the higher bass notes. Everything I've read on that 15 states 3.5-4 cubic feet per driver. And the port is massive.
IIR they recommended 30-35hz at 3.5-4 cubic feet. With a box half that size the response curve has got to be bad.
 
With your box size I am sure your port roll off is around 75hz which means anything below that is almost inaudible. Seal the box or sell the sub cause a 4 cubic foot box in our trunk just ain't a good idea...... unless you don't like your trunk..... or suspension.

Boston subs are hard to beat anyway. In my old car after I rebuilt Sappers G5 10" I slapped it in my trunk and didnt tell him. I just played some bass heavy music and rattled his brain for a while and he thought he was hearing my big box with the SPG555 in it.
He was quite amazed when I poped the trunk and showed him it was just a single little 10" Boston. :D
 
i will also have to agree that a 2ft cubed box being ported is to small. what is the box tuned too. you should get a cd that has some tones on it and start working your down the scale fine out where the box starts to sound like crap at. its probably going to be in the mid to up 40's would be my guess. have you also taken the time to tune the amp to the speaker and box yet or did ya just hook it up and start throwing wattage at it with out proper amp adjustment.

you can start by finding a cd like bass mekanic or something similar this will have your notes that you can play to find out what your box is going to sound good reproducing and where it cuts out and starts to sound do do. it should also contain some pink noise that you can use to properly adjust your gains and levels.

you could also seal up the port on that box as well and then stuff it full of poly fill.
 
who ever though it was a good ideal to put that sub into such a small box in the first place should taken out back and put down.
 
fastmark1993 said:
im building a sealed 5 cb ft box for this thing, is that gonna be good or what?
Click to expand...
No. Did you even bother to check what the subs box specs are? 2.5-2.85 is max box size if sealed. 4.5 if ported.
 
i cant find any effing info on this thing i was told it was a mojo but i dont think it is. here is a pic.

it says modular motor on the magnet. i looked through memphis' discontinued sheit and its not even on there. any help would be awesome.

2011-04-29 19.49.40.jpg


2011-04-29 19.50.03.jpg


2011-04-29 19.57.59.jpg
 
A clear picture that shows whats written on the back may help.
 
I can see it says more then that. In order to be helped you need to work with me here.
 
looks like a 15" Memphis Car Audio M3 Mojo

Memphis 15-M3154D
15" Dual 4 ohm M3 Series Subwoofer
 
Last edited:
Im never happy. I wish I was a retard. They always smile.



Anyway I gave you the proper box specs. You have a ported box thats half the size it needs to be. You want to correct it by making a sealed box twice the size it should be. You see the issue here?

I am not trying to be a dick but it comes natural. You asked for help, were given help and then state you will just ignore it and make the box you want cause you have the wood. There are better things you can do with the extra wood.


83nissan_taj-jackobs_lr.jpg
 
5.0 cu. ft. is way too big if sealed. Laser is right.

Yeah Bill, I was going by the model# that Chris listed and now I see the difference in them. Anyway, I don't do Memphis so I really don't know much about them.

If you want deep "hear me coming" bass, slot port it (vent) it.

If you want tight bass, knock off a few cu. ft. and make it sealed. I wouldn't go any bigger than 2.5 sealed. What are you using to push it?
 
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