///MDex

When I am comparing power, which criteria am I supposed to be using?:

"RMS Continuous Power at 12.0V"
"RMS Continuous Power at 14.4V"
"Per channel into 4 ohms"
"Max Power at 14.4V"
"Bridged"



Some amps list one, some list all, some list some, some list none.

I will not eat green eggs and ham, Sam I am......



Thanks

sirsomo

Yeah, amp ratings can get tricky sometimes. The 12V rating is closer to what it will actually put out, whereas 14.4 is more of a possible output. You can get a multimeter if you want to check the actual voltage going into the amp. Ohms deal with resistance, if you are running front or rear speakers you will probably use 4 ohms. If you are running subs, you will probably "bridge" the channels and set it up at 2 ohms. There are many variables that are different with each setup.

BananaGS

you pick one and go w it,

RMS is true power, Rating power is Max Instantaneous power.

I use RMS power, compare at 4 ohms, common for car speakers (4ohms), don't worry abour brigdged power, are you bridging your speakers, only your sub if you want to? if not, don't worry about it, (usually bridge the sub amp)

all the amps should show their RMS power rated at certain impedance (ie 4ohms), if they don't show this, then they rate it at MAX power (true RMS power = Max power / 1.4142) (if I remember it correctly)

that is in theory, manufacture play trick on the rating and rate their amps at higher/lower out of that formula, use 14v,12V condition just to confuse you........

in theory, if you lower the speaker impedance by 1/2, then you should get double the power output, the better the amp, the better this number will show, so look at the rms @ 4ohm and rms at 2ohm, then you will see, it alsmost double, the closer the number to double, the better the power supply is on at amp.

good luck dude, if you are not in competition, then you don't really care if you get 10 w more than the other...

anh

Mean Gene

Dex - Then let's get into regulated versus unregulated power supplies. RF's are unregulated which means that they will put out ( for example ) 500 wrms at 14.4 VDC. At 12.6 VDC, they may only make 400 wrms & over 600 wrms at 15.2 VDC. If U look at RF's birth certificates, they usually are tested at slightly over 15 VDC which is generally unobtainable with a factory charging system ( they tend to stop at the aforementioned 14.4 VDC charging output. JL's new amps ( & the Alpine V-12's ) are regulated - they'll put out the same power at any of the three above voltages. Check out the newest SPL rides - they're using at least 16 VDC to their amps for the extra output. This is where an adjustable voltage regulator & high output alternator come into play. My friend's USAC van ran 15.5 VDC from the regulator - talk about the light getting bright!! But anything over that voltage BLEW OUT the headlights! :eek: The Jacob's Accuvolt is a similar product that will maintain whatever output U select as long as U keep at least 9.5 VDC going into it ( it's a step-up voltage regulator ). For me, I like regulated amps for SQ because the power output from the amps is consistant. However, SPL would take an unregulated amp & ramp up the battery voltage input. Like Sirs said - 12 VDC power ratings are closer to "real world" power unless U have the adjustable regulator I mentioned. But Anh's point is well taken - just compare the same ratings of each amp ( apples to apples; etc ). Later we can get into Ohm's Law in our next physics class! Gotta get Percy to throw some of this into the book!!

///MDex

Heck yeah confusion.

Thanks guys. Yeah, I read in the Alpine lit that is is regulated no materr how much is at its door. I'm not running a huge setup or anything, nor do I forsee one in the future, so I don't think I have much to worry about blowing anything....I hope

Now granted, just like any mod on your car, the car wasn't engineered for it. Even if I'm not running a big system, should I still consider any voltage or battery upgrades? What about a bigger altenator, though that might be overkill; my systems gets plenty of juice from driving everyday with some highway miles during my commute....

I was going to say that I wish there was a book for newbies, like an audio bible or something. But wait, thats what Percy is doing! Excellent Smithers!

Percy

Gene,

Yep. Going to put that in the book. There are lots of confusing things that manufacturers do, plus it's all a numbers game. I like the Alpine ones screaming 640 WATTS MAX POWER!!! (I'm deaf now...must recover from technobabble confusing newbie hype!)

Dexter,

Not going to call it an "Audio Bible". Anything that seems to have that "B" word in it will get misinterpreted and will have a "holy wars" fought. Plus I can't see people going door to door trying to sell the thing like J's Witnesses. Don't mean to step on anyones toes if they're religious!

Scarry enough...it's called the "Lexus GS Audio Primer". Couldn't just call it the "GS audio primer" since there are Acura GS's, Buick GS's, Regal GS's....hey...how many GS's are there in the auto world?!?!

Battery upgrade. Go with an Optima or one of the newer Interstates. The Interstates reverse engineered an Optima battery and has almost the same features but with some improvements. Optima is a safe bet though. Lower internal resistance, battery acid is kept as a gel rather than a liquid and you can shoot a bullet through the thing and it still won't leak, even when mounted UPSIDE DOWN! Great stuff.

Percy