Amp help

hrdhtdvr

How big of a amp do I need? I am confused about how much power I should buy. I would also like your opinions on what brand of amp to go with.

Front : 125 watts RMS
Rear: 50 watts RMS
Sub: 300 watts RMS

The rest of the install is in my signature. I was also wondering if a single 10" sub would be enough. But I had this question answered by reading the review section on the MM2104 product page. I would still be interested in hearing your thoughts.

I went to a local shop and talked to them about adding the sub and amps. They originally had me at $1200 for 2 alpine amps, enclosure for the sub, wires and install. I asked if he could get me in under 1k, and he switched the amps to MTX. (a 250watt for the sub and a 4 channel amp for the rest)
Should I spend the extra money and get the Alpine set up? Also, I was looking for thunderforms or Qlogics. Basically I don't want (IMHO) big ugly boxes. I would like something under the seat and discrete. We use the back seat in my truck for office work. (Wife works for Aflac and always has paper work and boxes on the floor and on the back seat)

Thanks for the help!

PoweredByDodge

for the highs - you can get a 4 channel amp

mtx thunder 564 - 70 x 4 at 4 ohms (you'll get a little more than that out of it) - $225 bucks.

here's the manufacturer's warehouse buying link - http://www.mitekfactoryoutlet.com/products/product.cfm?PN=THUNDER564&colorid=0

that'll do your fronts (6500) and rears (460) just fine. be sure to adjust the gains for the front and rear accordingly.

a single 10" sub will be enough - and you're not going to have a lot of room if you want to shove the sub under the backseat and the amps under there too - so stick with one sub bud.

for the mm2104 sub - you can use the mtx 342 - it's 340 watts x 1 at 4 ohms bridged... perfect for your sub. and it's only 175 bucks.

http://www.mitekfactoryoutlet.com/products/product.cfm?PN=THUNDER342&colorid=0

note - mitekfactory outlet is not an online store - rather, it is mtx's own warehouse clearance store. get last year's model with a full warranty and brand new in box at cheapy cheapy prices.

as far as alpine amps - i don't like them.

i'm very much an mtx man for reliability and the "throw them off a building and they still sound great" factor.

the box for your sub should NOT be made of plastic for the love of jesus mary and joseph.

you're only spending about 400 on amps... so you've got 600 left to keep you under 1,000... so you have two choices.

1- tell us the make and model of your vehicle and maybe we can locate a pre-made "custom" box that'll fit under the seat of your truck that is made out of wood.

2 - spend about 200 bucks and have a local shop build you a box that'll fit under the seat and be made of 3/4 inch MDF or cabinet grade birch plywood.


you'll also need a 4 gauge kit and some interconnects....

here's the power kit - $32 bucks that'll do both amps for you...
http://www.cardomain.com/item/LITPK404

and here's a signal cable set for the front/rear/and sub. note - you'll need 3 of these!
they're $17 each

http://www.cardomain.com/item/LITLSIX5

and of course you'll need like 60 feet of 16 gauge speaker wire for the highs...
at 20 cents per feet that's $12
http://www.cardomain.com/item/STISSW16BLK5

and speaker wire for the sub... 12 gauge
8 feet at 45 cents a foot is under $4
http://www.cardomain.com/item/STISSW12BLK2

so now you've got a total bill of $497

... that leaves you with 500 bucks left over.

lets find you a box and i bet you'll still be only at about 700 - 750 bucks.


and i'll bet my good arm that this is better stuff than the shop was going to sell you.

MacLeod

PBD has got you pretty much covered, although I like Alpine V12 amps very much. If I could afford em Id probably be running them.

Im also an MTX fan as theyre the toughest sumbitches on the market and makes tons of clean power. What else could ya ask for.

For a box, I vote for letting your shop build you one. It will be better built, and be built to fit right where you want it for about the same as a Thunderform box would cost ya.

hrdhtdvr

Thanks again for the help! When I went to the local shop, (Ricky Smith's Audio) the guy showed me the box that he would use. It is black in color so not a color match, but I think it would still look good. Not to mention, the strength over the plastic enclosures. I have one last question. I notice the specs for the amps are something like this.

4 ohm 12v
4 ohm 14v

My question is how do you know if you are pushing 12 or 14v ? How do you, if possible, change your volts?

One more thing. Capacitors. Need one? I have heard that I don't.

MacLeod

Generally youre getting 12.5 volts when the engine is at idle and 14.4 when its reved up pretty good but when you take into account the draw of instruments and such youre averaging about 13.5 or so. Virtually all quality amps are underrated so if it says 100 watts at 14.4 volts, you can count on getting at least that, regardless of voltage.

No, you do not need a capacitor.

PoweredByDodge

MacLeod wrote:

Generally youre getting 12.5 volts when the engine is at idle and 14.4 when its reved up pretty good but when you take into account the draw of instruments and such youre averaging about 13.5 or so. Virtually all quality amps are underrated so if it says 100 watts at 14.4 volts, you can count on getting at least that, regardless of voltage.

No, you do not need a capacitor.

have to disagree mac.

with the key "off", you'll have 12.25 - 12.5 volts. with the key "on" you'll have your alternator's output voltage, which is usually between 13.8 (mitsubishi, late model chrysler, nissan, etc) to 14.4 (subaru, chevy) or anywhere in between (ford = about 14.2 usually) -- it's dependant on the manufacturer of the alternator.

nippon denso and bosch alts do about 13.8 ... chrysler corporate old school do about 14.2 ... delco and delco remmy do 14.4 ... yada yada yada...

your alternator's voltage is not "turned on" by the regulator, but rather the "amount of current output up to the max current available at whatever rpm your engine is at" is regulated.

actually let me rephrase that a little - regulators can be altered to make an alternator put out a higher voltage... however, 99/100 times unless it's an aftermarket regulator or computer, then the regulator's "voltage setting" is fixed. the "current setting" varies with engine rpm, electrical load, etc.

i agree about amps being underrated when from good manufacturers... a "100 watt at 14.4 volt" amp from polk, mtx, jbl, etc... is going to be 100 watts at 13.8 volts as well, and probably 105 or 107 or whatever at 14.4 volts.

my little rule of thumb about caps - you don't need them until you hit 500 watts... then, you a) make sure you have a nice big juicey battery (900 cca or better - die hard / energizer / interstate), be sure that your alternator is at least 75-ish or better amps output at max load... and then 1 farad capacitance per 1000 watts is a good rule of thumb. so 500 - 1000 watts = 1 cap -- 1500 to 2000 watts = 2 caps. why? well unless you have a 200 amp alternator (which you dont unless you dumped 500 bucks on an aftermarket alternator) then you'll need to stiffen a half volt here and there.

for your application... i would say you don't need one, but one couldn't hurt either - hook the whole thing up, make sure you've a decent size alt and battery and call it a day - if you get MINOR headlight dimming at night with the system at full volume, snag a cap - if you get major dimming, then upgrade your alternator and battery.

SamSagaZ

well, i have 14.1V with my car on

ill add an Cap of 2-3 farads in a few weeks (after i install the c500.1)

MacLeod

PoweredByDodge wrote:

have to disagree mac.

with the key "off", you'll have 12.25 - 12.5 volts. with the key "on" you'll have your alternator's output voltage, which is usually between 13.8 (mitsubishi, late model chrysler, nissan, etc) to 14.4 (subaru, chevy) or anywhere in between (ford = about 14.2 usually) -- it's dependant on the manufacturer of the alternator.

nippon denso and bosch alts do about 13.8 ... chrysler corporate old school do about 14.2 ... delco and delco remmy do 14.4 ... yada yada yada...

your alternator's voltage is not "turned on" by the regulator, but rather the "amount of current output up to the max current available at whatever rpm your engine is at" is regulated.

actually let me rephrase that a little - regulators can be altered to make an alternator put out a higher voltage... however, 99/100 times unless it's an aftermarket regulator or computer, then the regulator's "voltage setting" is fixed. the "current setting" varies with engine rpm, electrical load, etc.

So basically youre averaging about 13.5 volts? Hmm, isnt that what I said?

And you have to take into account that although an alternator may put out 14.4 by the time the ignition, instruments, lights and whatever take their toll you aint getting the full 14.4....goes back to that whole averaging 13.5 thing.

PoweredByDodge

a running ignition system, instrument cluster, etc only draws about 20 amps. the heater is another 20 or so... so even with the heat blasting, you're only pulling 40 amps...

if you have a baby alternator, that doesn't leave you much room, but anybody with a truck is rolling around with 120 to 160 amp alternators, which gives you PLENTY of room.

hrdhtdvr

PoweredByDodge wrote:

1- tell us the make and model of your vehicle and maybe we can locate a pre-made "custom" box that'll fit under the seat of your truck that is made out of wood.

My vehicle is a 02' Chevy Silverado ext cab. 4x2 1500

As far as idling and what not, I don't really listen to the radio unless the truck is running, and I only idle in traffic.

As always, you guys are great !
Thanks for all the help.

exalted512

id go with probox. www.proboxrocks.com One of best prefab boxes out there. For your truck, they have 2 10" or 2 12" downfire thatll shouldnt run you more than $160
-Cody