inverting MM455's &MM120 questions

Systems

I'm going to be installing my old style 5 1/4 momo's in fiberglass kick pannels in the next few days, as well as 3 MM120's.

a couple of questions on the components,
will i recive negative effects if i invert the 5 1/4 driver?
in theory the magnet and basket will obstruct the sound to the listener, but is this just theory?

where is the recomended tweeter placement, and the recomended tweeter setting for that placement? i.e. 0db -3db etc.

is there a recomended enclosure size for the driver? bass for the driver is not important, i will be using a image dynamics mid bass driver, this is for over all sound quality.

on to the subs.
i have 3 momo 12's, I also have a JL audio 500/1, will this be suffecient power for all three subs? how about for 2 subs, and a 250/1 for the other?

the subs will be inverted, so switch the polarity of the speakers right?

can all three be in a common chamber or should it be divided?
what are the + and - effects of common chamber and divided chamber designs?

since the box will be fiberglass, what can i do to make the box sound more "dead"?

if i have a box at 2.64cuft (.79x3) should i add sound deadning foam (egg crate or other) to the inside of the box or will this throw off the subs?

how much smaller than 2.64cuft can i get away with and still get a nice sounding setup?



I'm not going for 180db on this setup, i have had the speakers laying in my room for a year and decided to put them in for the show season this summer. this will be for a SQ system mainly, that's why i'm not stressing much on the amp, just wondering if i will really be starving the subs with the one amp.
thanks for your help
Eric

Systems

Originally posted by Eric
I'm going to be installing my old style 5 1/4 momo's in fiberglass kick pannels in the next few days, as well as 3 MM120's.

a couple of questions on the components,
will i recive negative effects if i invert the 5 1/4 driver?
in theory the magnet and basket will obstruct the sound to the listener, but is this just theory?

where is the recomended tweeter placement, and the recomended tweeter setting for that placement? i.e. 0db -3db etc.

is there a recomended enclosure size for the driver? bass for the driver is not important, i will be using a image dynamics mid bass driver, this is for over all sound quality.

on to the subs.
i have 3 momo 12's, I also have a JL audio 500/1, will this be suffecient power for all three subs? how about for 2 subs, and a 250/1 for the other?

the subs will be inverted, so switch the polarity of the speakers right?

can all three be in a common chamber or should it be divided?
what are the + and - effects of common chamber and divided chamber designs?

since the box will be fiberglass, what can i do to make the box sound more "dead"?

if i have a box at 2.64cuft (.79x3) should i add sound deadning foam (egg crate or other) to the inside of the box or will this throw off the subs?

how much smaller than 2.64cuft can i get away with and still get a nice sounding setup?



I'm not going for 180db on this setup, i have had the speakers laying in my room for a year and decided to put them in for the show season this summer. this will be for a SQ system mainly, that's why i'm not stressing much on the amp, just wondering if i will really be starving the subs with the one amp.
thanks for your help
Eric

Edit: I know i'm a member i just forgot that my registered name and such, do you know where i can get it at?

also i'll attach a pic of my proposed trunk setup before i gut the trunk to start glassin.

thanks for your imput
Eric

Systems

here is the pic, this is just where i'm thinking of placing the equipment. there will be a false floor about the heighth of the amps, and the amps will be sunk into the floor. have any ideas on other ideas for the amps?

EricM3

thanks for the info on the drivers, too bad i can't invert them, the basket looks fantastic!

as far as powering the sub, i want you to know that i am not a bass head, i've already done that before. I had another setup with 3 W6 12's with a fosgate 1100.2 to each sub. been there done that.

this setup i want it to sound good (i don't listen to stuff loud) and i want it to look great. I think that the JL amp will be suffecient for my needs, can you tell me why it might not? is there something i'm overlooking?

I'm not trying to argue with you, you probably have way more experience in ME than i do, just trying to understand where your comming from
thanks
Eric

Thom

Originally posted by Kim
Eric,
For the subz... I would strongly recommend using a larger amplifier to drive all 3 MM120's. Look for amplifier that is capable of driving a very low load of 1.3 Ohms if you plan on paralleling all three drivers together.
Thanks,
Kim

Can the JL drive a 1 ohm bridged load? I think that's one of Kim's concerns.

PoweredByDodge

re - smallest size box you can do...

you can go as low as 0.75 cubic feet (per suwoofer) for the momo 12 inch if you stuff it with polyfill (not a crapload, but ya know).
i've heard them in everywhere from 0.7 to 1.25 cubic per sub, and the best results were 0.75 stuffed to 0.9 not stuffed.

as far as power -- momo's really need a little "just to get them going" so to speak. I mean if you really don't give a heck at all whether its loud or not (loud being like 145 - 150db for your daily driving car), then i think you can do like 350 - 400 watts per speaker.

As far as the JL 500.1 -- it is a regulated amp (as you probably know so i dont even need to say this) -- not only is the power supply regulated, but impedance regulation and power output as well.

This means that you can put anywhere from 1 to 6 ohms on it with anywhere from 10 to 16 volts and it will put out the same amoutn of power 485 watts (JL's spec sheet for the W7 and Mono amps rates it at 485 - 490 x 1).

even if you do 1 500 and 1 250 -- that's still only 250 watts per sub -- Kim and Thom are right, you need a little more. a 500.1 per subwoofer would not be bad at all, but I dont really think that's what you were looking for.

My suggestion would be to simply drive a 1000 watt class D (any brand) a little hard at 1.3 ohms paralled and call it a day.

The JBL 1200.1 is a fantastic dirt cheap amp that'll do 1200 x 1 into 2 or 1 ohms (same power output at both impedances), but it does not have a subsonic filter.

The MTX 81000d will do (usually) between 1150 and 1250 watts into 2 ohms, and most competitors will tell you it'll do 1500 into 1 ohm even though its "technically" not 1 ohm stable -- yet many many people have run it at 1 ohm and had no problems at all -- it barely gets hot at 2 ohms, so I doubt you'd throw it into thermal with only 1.3 on it.

so its either something like that or get yourself 3 amps that are rated 400 x 1 bridged into 4 ohms. personally... i'd save the space, wire, aggravation and just do one high quality 1000 watt class D that is either "designed" for 1 or 1.3 ohms or is "designed" for 2 but has been torture tested and proven to be able to run 1.3