Erh...got my amp today

Yay I finally got my Orion 4002...after a train derailment in Illinois and everything. Thursday, hopefuly, I should be getting a Pioneer AVIC N2. So I will run rca cables and all of that when I install the N2. I have to save money, again, for the focals. But anyways, I noticed that the 4002 is rated with the 2006 CEA rating standards at 135 by 2 at 4 ohm. I am sooo worried that I am going to blow those focals. So I really need to learn how to use my DMM. Could anyone basically tell me the exact locations to set my DMM to and everywhere in my car to touch to get my readings so I won't blow them?

everwhere in your car to touch? what are you talking about? Just us JL's gain setting tutorial, with the DMM set for voltage.

the only places in your car you need to touch the multimeter leads to is the + and - speaker terminals

So I don't need to know what my car pushes in volts? Yay. I've had a rough week so I've been yeah. Ok watched the tutorial and what should my DMM read if I want to be pushing about 80 watts at 4 ohms?

Your not going to blow the focals man. Go to kragen and get yourself a nice pair of aftermarket focals and some focal tape. Make sure all the leads are wired and soldered correctly and bridge the system down to 1/2 an ohm. DMM ratings are overstated by at least 50-60% so if your worried about focal blowage just divide what you think your system is pushing by two and if its within the dmm rating your cool

My amp will be pushing 135 watts which is double what the focals are rated. If i wired the focals in god knows how down to 1/2 ohm...not only would that kill my amp but it would also be pushing alot over the focals rating.

Your not going to blow the focals man. Go to kragen and get yourself a nice pair of aftermarket focals and some focal tape. Make sure all the leads are wired and soldered correctly and bridge the system down to 1/2 an ohm. DMM ratings are overstated by at least 50-60% so if your worried about focal blowage just divide what you think your system is pushing by two and if its within the dmm rating your cool


What in the hell are you smoking.

Look at his other posts...he told manny to forget SI and get some Legacy subs...

Yeah i seen that. ANd to tell you the truth anytime i tune a system i never use a DMM, i usually use a bass test or a good song with short punchy bass and nice clear music, IE guitars and so forth. Then if im worried about blowing somthing i just take the rms of the speaker and the rms at whatever impendance of the amp and figure if theres 8 lines on the power/gain control, the 4 marks is 1/2 power and so forth. Ive only blown a sub once and everything else as far as comps, and 2 ways have sounded great. I have used an osciloscope (sp) with my grandfather before that was interesting, i couldnt remember what he did if i wrote it down. Got to love old fashioned techniques.

O-scope is the only way to set your gain near perfectly. And the dashes really dont mean that, as there not completely accurate, you have to get an exact reading an the second best way to do that is with a DMM.

anyone know of a good o-scope, or are they all the same?

a "good" scope is like $20k ... but since we deal in audio, that only goes up to 20 KHz, any old used scope will do

expect to pay around 1k...

Damn my grandfather has like 4 of them. I like my uncles its a DMM, and an o-oscope built into it, he said it was like $2-3K. It has a massive screen.

Yeah i know the ticks arent accurate, but i prefer to tune by ear. Make sure theres no clipping and make sure it dosent have any if much distortion.

U have an O-scope available an you dont use it? You know you can SEE clipping on an o-scope...

I use about $30 worth of equipment, and I can tune to maybe 95% accuracy of using a scope.

to answer the original question about volts ...... lets look at the equations

where P =power in watts, V= volts, I = current (in amps) and R= resistance (or impedance)

P=V*I and V=I*R If we solve the second equation for I, then I=V/R
now if we substitute that into the 1st equation, we get P=V*V/R or P=V^2/R

solving for V ..... v = sqrt(P*R), so where P = 80 watts and R =4 ohms, then V = sqrt(80*4) = 17.88 V

there is no sqrt on the computers calculator, to get the sqrt - type in the number then (while the calculator is in the scientific mode) press the x^y button, then type .5 then enter. This raises the first number you typed in to the 1/2 power (which is actually the square root).

Also, this is only a valid figure for frequencies where the impedance is 4 ohms - fortunately for mids and tweets, their impedance curve over there usable frequency range is pretty flat. Subs a whole different matter.

Yeah i need to learn to use it right again, and right now my system doesnt need it. Its the last thing it needs, maybe an upgrade but not to be tuned. I also need new wheels before i venture into the new system (basterd cops wont let them stick out any). But on a side note yes i ave access to several o-scopes.

just hook it up an watch the waves...when they start squaring there you go :)

so, this would work?:
http://cgi.ebay.com/HP-1222A-Oscilloscope-O-Scope-15MHz-2-Ch-with-Manual_W0QQitemZ180010906054QQihZ008QQcategoryZ104 247QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

God it's been forever since I've done any algebra...like almost 4 years so I might never figure out that equation. So I should look for 17.88 volts on my DMM? I checked my Cerwin Vega and I have a blown voice coil. I might be getting 2 W7s for 250. Good deal?

lol ya thats a good deal

now I feel old ..... it's been almost 30 years since I have had Algebra :rofl:

Well, I guess I am still young...don't know. But yeah...at least you still use it...I wish I did. I used to be able to look at an answer and then the problem and figure out what was done to get the answer and I was good to go...now I just drool and stuff. Wow I am near brain dead.