Nuub Help. Dont Flame.

[its_ray_ray 10+ year member]

i have never actually used my dmm to set all settings on my amps. i have always been a "by the ear" kind of guy. well my old dmm took a **** on me. so i bought a new one yesterday. can anyone explain to me how to use this formula and what-not.

i'm going to be running the audiopipe ap-3002 i picked up. and i will be running it bridged @ 4 ohms.

Can anyone explain how to use the forumla so i can tune my amp? lol

AP-3002

Frequency Response

20Hz – 20kHz

Signal to noise ratio

110dB

Channel separation

>75dB

Total harmonic distortion

Speaker impedance

2 ohm to 4 ohm

Input sensitivity

0.25V – 8V

Crossover frequency

55Hz – 5.5Khz 12dB stereo

Bass boost

0 – 18dB @ 45Hz

Output power (RMS)

Stereo 2 CH – 160W x 2 @ 4 ohms

Stereo 2 CH – 320W x 2 @ 2 ohms

Bridged 1 CH – 640W x 1 @ 4 ohms

P = Power in watts

I = Current in amperes

R = Resistance in ohms (effectively the nominal impedance)

V = Potential in volts (Voltage)

Knowns:

Resistance (nominal impedance of your speakers)

Power (desired wattage)

Unknowns:

Voltage (we'll measure this)

Current

Formulas:

P = I*V (formula for power)

V = I*R (Ohm's law)

So after a little substitution to get Voltage in terms of simply power and resistance we get

V = square_root(P*R)

Click to read more...

 

[its_ray_ray 10+ year member]

i get that to set the gain it's at 50.59v does that work with bridged mode?

 

[hornedfrog1985 5,000+ posts]

Hang on, I'll find a good thread for you.

 

[its_ray_ray 10+ year member]

i've been through a ton of threads and nothing seems to help. lol.

 

[hornedfrog1985 5,000+ posts]

http://www.caraudio.com/forum/showthread.php?p=4350457

 

[RED3 10+ year member]

I'm a noob but here goes:

160wx4 ohms =640, take sq rt of 640 = 25.29 volts for your ddm reading @ 4 ohm, for 2 ohm, same formula but use 160x2 = 320, or 17.88 volts.

If I'm wrong, I'm sure someone will spank me for it

 

[its_ray_ray 10+ year member]

this is what i got. i'm gonna be running bridged. 640x4ohms=2560

square root of 2560 is. 50.59v

so since it's bridged to i use the 50.59v still or do i half it?

 

[its_ray_ray 10+ year member]

or do i put the dmm. on the channels bridged and set the gain at 50.59v for that?

 

[jon_k 10+ year member]

OK I put the dmm in series with the battery and it blew my amp and my DMM melted. What is next guys?

 

[csu87 10+ year member]

OK I put the dmm in series with the battery and it blew my amp and my DMM melted. What is next guys?

that has nothing to do with this post so make another thread. also, your an idiot.

i believe you would hook the dmm to the bridged terminal and set it to the correct voltage that way. could be wrong though

 

[theMessenjah44 10+ year member]

i believe you would hook the dmm to the bridged terminal and set it to the correct voltage that way. could be wrong though

that's right, but with this formula, "if you know any two, you can find the third" but once that sub starts moving, your impedance (ohm load) changes, so you went from knowing voltage and resistance....to only knowing voltage.

best way to do this is to find voltage and amperage instead, get a clamp meter to measure the amperage leaving the amp, and use your dmm to find voltage

Voltage x amperage = power

 

[alvitae 10+ year member]