a few words on 1.4kw rockford amp

[mikee12345]

hi i just thought i would mention-

im no car audio expert,just saying what a friend has ..


2x rockford a1s ( i think they are called that)
mono ,100watts into 4 ohm, 200watts into 2ohm..
hes had them tested and they are rather conservative ratings..

and 2x10inch infinity kappa perfects in small sealed box 20l each or so.

he has bridged them together,and measured on some sinewaves,50Volts at the output..

1200-1400watts rms..

he was driving home playing some low bass,and once home,treid starting his car again,and it was completely dead!
heh hes getting a new alternator

so its abit silly at the moment

also the infinitys are Only rated 350watts rms,with that much power i dont expect them to last with sinewaves..but ofcourse if you lower the db by 3,your only doing 700watts total,saving them,and i have modeled themthe excursion is ok with 350watts (if i remember correctly)

ive modeled a ported box,its +7db output at 30hz not including cabin gain,he may build them if he gets a hatchback..at moment a VK commodore but it may be 'muddy' ,he likes music,not just sinewaves :-D

also at high excursion,the speakesr seem to go quite a long way, i dont like it ! ,im not used to high excursion subs.

hah and they distort also at high SPL, i could feel my hair resonating,i had some gel in it,so it was kinda buzzing from the air movnig around lol!

and with 20hz sine you can talk and its heavily modulated,not much harmonics,unless you turn it up too high and sounds
DISGUSTING

we need an SPL meter...

theres my few words..

 

[zx3chris]

those subs are ver well known to blowing when given too much power--they are designed for sq, so when u crank em to go so loud, the coils smoke--- just be careful. you are in a ported box so the extra cooling will help, and since ur tuning high (over 35hz?), a subsonic filter may be useful to protect from overexcursion.

-chris

 

[asauer]

I am not familiar withe the RF A1's- are they an old model? If they are rated at 200W each, then both together are not putting out 1.4KW, they're not THAT underrated.

 

[Duo]

How did you manage to come up with a rating over 1000W??? You'd need a pretty darn big amplifier and lots of output transistors. At 1000w I would expect a car amp to draw over 100A from the car. That's quite a lot of current. How big was the power wiring?

 

[thylantyr]

Car audio systems drawing 100 amperes
as an entry level system is common.
It's also common to see systems
that draw 200 - 300 amperes for
a more exotic system.

For db drag, it's common to see lots of
kilowatt amps with 20 batteries or more.

JBL/Crown have released a 6kw
car amp. real power, not fake.

 

[zx3chris]

yeah even most 'kits' now come with 4 or 2 ga cable.. and most ppl who are using more than 1 sub amp run 0/1 cable

-chris

 

[taufern]

first of all there are very few average systems that draw 100 amps...power cannot just appear in thin air...it has to come from somewhere (hint hint hint its your alternator)...almost all stock cars rarely see anything over 95-105 amps cold rated...when the car is warm you'll probably see about 80 amps at the alternator...seeing as how your class a/b amps are about 65% efficient (if you're lucky) you'd have to have a pretty hefty alternator...this is why i have a 225 amp hot rated alternator...cost me 750 bucks but is well worth it...any stock electrical systems with aftermarket systems running more than 4 awg are a joke...i installed car stereo for quite some time and know that it takes power to make power...so if you figure your amp is 70% efficient at 14.4V (usually very unlikely) you'd be drawing 100 amps to make 1000 watts...you'd likely notice your lights dimming and your voltage system hurting...plus it wouldnt be able to provide anywhere near this as most *1000* watt amps have fairly small fuses which makes it not possible...most of the rockford stuff i have experience with is about 60% efficient and is junk...

zx3 read up a little on basic electronics...im not trying to blast you im just asking you to consider your statements...a speaker is a speaker...wattage is different though...speakers have thermal wattage handling and electrical power handling...if he doesnt drive the amps or speakers to clipping then they'll both be alright...

 

[zx3chris]

taufern, mebbe i did not post enough information but i will inform you i am no amateur to basic electronics---especially when considering i am a 4th year electrical engineer and ive been into audio since i was 10.. i know quite a bit about cars and have installed in over 100 as well as made my own amplifiers, filters, crossovers---you name it------

"speakers have thermal wattage handling and electrical power handling...if he doesnt drive the amps or speakers to clipping then they'll both be alright..."

the wattage rating on speakers is the continous wattage the voice coil and wistand, THERMALLY---- what do you mean by 'electrically'?? The other kind of power handling is excursion, and that is mostly affected by the _enclosure_ as well as the power, and therefore is usually not listed on a spec sheet (unless xmax is taken into account in a given box). also, Everyone drives their amps into clipping---bc it yields extra power (as well as distortion obviously), but in a car environment that extra powre is needed to overcome the high ambient noise. typically i adjust my high amps for 3db of clipping at max preamp volume, and the subs for 6db of clipping at max volume----but of course i bet you have golden ears and can hear 3db ??

-chris

 

[Mantronic]

my 30watt home amp have peaked to 36v. at 8ohm... It rest that the sound is bad at 1 watt!

 

[mikee12345]

sorry its been awhile,i got busy and forgot to come back..

Duo=it was something like 54volts into 2ohm load (measured)

we got a fluke meter (graphical display) to ensure the signal was clean.the meter had a slow update though..

he has a new alernator now

he measured 133db(old mics) so minus about 6db from that,..

if he gets a new car(hatchback) hel get a ported box (haha super long ports with tiny Vb

cheers.