hello everyone

the amp i have is an MA Audio M1889i. i have it powering an Alpine Type-R 12 @ a 2ohm load.

i have the adjustment *****:
LPF 50-250Hz
Bass Boost 0-18dB
Sub Sonic 20-50Hz

what do the LPF and Sub Sonic do and how should i adjust them?

as of right now, my amp is sliding around my trunk. would it be okay to mount it to the side of my sub box? its 3/4" MDF, so it wouldnt hurt anything, would it?
is there any other place i could mount it? i would like to put it vertically, for better heat transfer...

last question...
my trunk rattles quite badly, along with the rear panel around the back speakers. my friend wants to sell me some kind of insulation...dynamat i think. i want a cheaper way out, if possible. would some weather stripping or silicon work?


thanks in advance,
Jon.




[IMG]local://upfiles/14921/F41DE469BB8246A990C2D41D2ECC5B72.jpg[/IMG]

[IMG]local://upfiles/14921/2CD2BF01E0D64285A075B0DD193AD369.jpg[/IMG]

 

The LPF is for filtering out bad sounds.. The LPF is usualy pretty good around 80-100 HZ, I wouldn't go much higher, 60-80 is normal for rap and such.

The sub sonic thing is probably a bass boost, read the amp's manual a little to learn the exact function. You can get some extra dB by turning it up, I run mine a little under half.

Mounting to the box is fine, just use 2 screws, no reason to use all 4, unless you want to.

As for the rattles, its kind of hit or miss. You just have to work for em, find them and isolate them best you can. Metal to metal is what you want to avoid, like a jack or toll hitting the trunk, bolts, plastic items, etc.

 

your subsonic filter goes from like 20hz -50 hz. You have to look at your sub specs and see what the lowest note that the sub can play without damaging it. Example if you subs frequency is 22hz - 220hz. you wanna set you subsonic around 22-23hz to prevent the amp from powering the sub on those notes lower then these.. Your LPF low pass filter, filters out the notes above the your setting. From alpines website if you have the newest type r's your sub plays 23hz-500hz. So you wanna set you subsonic to around 23-24hz, and your low pass to 500hz. Personally i find that way to high you will get alot of extra notes, i would turn your low pass to around 200-220hz. Also by adjusting your filters to play certain notes, it helps save your amp. Sorry this turned into a story, but thats some very important info.

 

sry i didnt read the last parts of your msg. I wouldnt mount it to your box, i mean the whole purpose of the subs are to vibrate, i would try to mount it on the back of your rear seat. if they fold down its nice and easy to adjust your *****. As for dynamat, it not only helps reduce rattles, but improves sound quality, so if your worried about the money i can only say, its worth it. Otherwise if your not gonna purchase it, i would tell you to live without and deal with the rattles.

 

Set your subsonic to 30hz, anything lower than that you barely "hear" anyway, and you can't hear anything under 20hz...its a pretty big power saver on tracks with a lot of bass...especially bass test cd's.

Your Type R ranges from 15hz up to whatever, you don't have to worry about it being hurt.
Low pass depends on the rest of your system...I have 6x9's getting 100 watts rms each, so I let them carry some higher bass and midbass and cross my subs over at 60-70...but if you don't have decent inside speakers, cross it over at 80, 100 if you have to. 70-75 is ideal for a 12 like that, if you got something to pick up the slack then you can go lower...any power not wasted on reproducing frequencies you don't want it to is taking a way from overall sound quality
\
You know I just did my trunk in expanding foam, and am waiting for my e-dead to get here to finish up, but the foam helped a great deal, just put it everywhere in between metal on metal to kill rattle. Also try cracking one of your backseats a lil bit to relieve some of the sound pressure in your trunk, it will help the rattle a bit.

 

expanding foam....hot **** thats an excellent idea.
i think ill go with that.

thanks for the rest of the tips everyone

 

i wouldnt mount the amp to the back of the seat if i were you. first of all the back of the seat is not very strong and screws strip out of them easily. find a place to mount it to the floor if at all possible, most insurance companies dont cover the amp if its not mounted securely. and once you get everything in and mounted down take pictures for record if the stuff is covered by your insurance. if it wont be covered anyway, you can mount it directly to the box.

 

i have tried mounting it to the floor, and the piece of "wood" underneath it is too thin, and the screws stripped out.
and, like i said, i wanted to mount it vertically.
i dont think it would be covered my insurance anyways...

 

most aftermarket anything isnt covered by insurance, unless u pay extra. I would still mount it on the back seat, it will be vertical, and wont vibrate as much from ur sub. thats basically what at least 80% of people put it.

 

I have mine on a back seat and it sits fine..doesnt move at all.