Impedance Question (sorry i'm a noob)

[dangallegos 0]

I have a BL 15 dual 2 ohm wired to 1 ohm. How would I find the resistance? On the specs page it says it is 1.5 ohms, but since I have it wired to 1 ohm would it be different? I am kind of lost as to what my target voltage should be.

Sorry I am just starting in the car audio scene so pardon my noob question

Edited November 26, 2007 by dangallegos

[BKOLFO4 29]

1.5 is the DC resistance. The driver's impedance playing music will be 2 ohms per coil. Set your output voltage based on the amp's 1 ohm output spec.

Brian

[dangallegos 0]

1.5 is the DC resistance. The driver's impedance playing music will be 2 ohms per coil. Set your output voltage based on the amp's 1 ohm output spec.

Brian

So if my amp output at 1 ohm is 1500 watts I should set the gain using 47 volts as the target voltage? sqr(1500*1.5)=47 volts

I am a little confused like I said I am a complete noob sorry for wasting board space.

[Miles 128]

I also have the same question. Since my sub is Dual .75 ohms, would the sub be drawing 1.5 ohm, or 2 ohm. For my amp that is the difference between having 1200, and having 800 watts running to the sub.

[dangallegos 0]

anybody?? I would really appreciate any responses

[BKOLFO4 29]

Above, you say they are dual 2 ohm coils, but them you say dual .75. Are the subs dual .75 DC resistance, as in actually dual 1 ohm impedance coils? If you wire in series, it will see the 2 ohm rating. And with impedance rise with the subs in the box, it may actually be a little higher. . .

As far as the voltage on the amps output, it should be the same if it is a decent amp that doubles its output as the load impedance is cut in half. you have to watch out when you start going below the rated minimum impedance - most amps will not double thier power again, so you have to calculate for the gain you actually get. Some times the voltage will actually drop due to the increase in current.

Example:

2000 watts @ 1 ohm = 44.72 volts

1000 watts @ 2 ohms = 44.72 volts

500 watts @ 4 ohms = 44.72 volts

Edited November 29, 2007 by BKOLFO4

[NDMstang65 403]

Don't do that.

What kind of voltage is your deck putting out on the RCA's?

Gains are meant to be matched to the RCA input voltage, not output voltage on the rails. Odds are you are going to turn the gains too high and burn something up....

[dangallegos 0]

Don't do that.

What kind of voltage is your deck putting out on the RCA's?

Gains are meant to be matched to the RCA input voltage, not output voltage on the rails. Odds are you are going to turn the gains too high and burn something up....

I have a Pioneer DEH-P6900UB. I am pretty sure they are 4V outputs.

[dangallegos 0]

Above, you say they are dual 2 ohm coils, but them you say dual .75. Are the subs dual .75 DC resistance, as in actually dual 1 ohm impedance coils? If you wire in series, it will see the 2 ohm rating. And with impedance rise with the subs in the box, it may actually be a little higher. . .

The sub is dual 2 ohm. According to the Fi website, the resistance is 1.5 Ohms/coil.

[Miles 128]

So, am I pulling the power that it's rated on my amp at 2 ohms, or 1.5 ohms?

[BKOLFO4 29]

1.5 ohms is the DC Resistance. DC Resistance is not what your amp will see. It will see impedance which is 2 ohms nominal, not 1.5. if you put a DC current through the coil, or look at the resistance with a DMM, you will see 1.5 ohms. If you measure the resistance playing an AC source, you will see a resistance higher than 1.5 ohms. It will vary with frequency, but should not fall below 2 ohms.

On top of that, when the sub is in the box, you get impedance rise, which will make the impedance the amp sees even higher, many times almost double at some frequencies.

One of my favorite posts was a guy who said:

"1.5 is the resistance, and 2 ohms is the resistance with your speaker wire".

Brian

[dangallegos 0]

1.5 ohms is the DC Resistance. DC Resistance is not what your amp will see. It will see impedance which is 2 ohms nominal, not 1.5. if you put a DC current through the coil, or look at the resistance with a DMM, you will see 1.5 ohms. If you measure the resistance playing an AC source, you will see a resistance higher than 1.5 ohms. It will vary with frequency, but should not fall below 2 ohms.

On top of that, when the sub is in the box, you get impedance rise, which will make the impedance the amp sees even higher, many times almost double at some frequencies.

One of my favorite posts was a guy who said:

"1.5 is the resistance, and 2 ohms is the resistance with your speaker wire".

Brian

Thanks for the reply Brian.

Like I said I'm new to this and I did the entire install by myself the only thing that is tripping me up is the gain setting on my amp. So when i play the test tone my target voltage should be 54 volts?

[ronrico418 0]

I was about to start a new thread but looks like I can find an answer here.

I have a Sundown SAZ3000, If I run 3 dual 2ohm Fi SSDs will I get 1.33 ohms (series coils only).

[BKOLFO4 29]

What is your amp rating, or what amp do you have? I thought you said above it is 1500 watts. . .

You have a single BL with dual 2 ohm coils wired in parallel for a 1 ohm load, correct? If it is a true 1500 watts RMS, you need to see 38-39 volts on the output.

54 volts at 1 ohm would be 3000 watts. . . .

Brian

Edited December 1, 2007 by BKOLFO4

[dangallegos 0]

What is your amp rating, or what amp do you have? I thought you said above it is 1500 watts. . .

You have a single BL with dual 2 ohm coils wired in parallel for a 1 ohm load, correct? If it is a true 1500 watts RMS, you need to see 38-39 volts on the output.

54 volts at 1 ohm would be 3000 watts. . . .

Brian

Yeah I misunderstood you it is 1500 watts. And yes I have it wired for a 1 ohm load so I will set it to 39 volts. Thanks for all your help.