Reading 1.5 ohms

[Cap'n Andy 10+ year member]

Hey guys, so I recently put together my first system consisting of the stuff in my sig. I wired my SA-12s down to 1 ohm and used a terminal cup from parts express for the box connection. I checked the ohms at the terminal and at the wires coming off the subs themselves and it read 1.5 ohms.

Any idea where the extra half ohm of resistance is coming from?

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[schackel 10+ year member]

IMP rise possibly idk if that goes into effect but thats possible

 

[pr-festiva 10+ year member]

your checking the dc resistance not impedance

 

[Cap'n Andy 10+ year member]

IMP rise possibly idk if that goes into effect but thats possible

My understanding of impedance rise is that it happens when the subs are actually receiving power. But I could be wrong.

I'm not going to rule anything out until the I figure this out.

 

[pr-festiva 10+ year member]

are you using a dmm? and is it set to dc resistance?

 

[Cap'n Andy 10+ year member]

are you using a dmm? and is it set to dc resistance?

Yes I am using a DMM and it can't read AC resistance. Granted it is a crappy multimeter but it reads 1.5 ohms very clearly.

 

[Bobby322 10+ year member]

If its a really crappy dmm maybe its just off by a lot lol. If mine is off at all its only .2 at the most.

 

[pr-festiva 10+ year member]

you know a sub very seldomly rests at its nominal impedance right,,,most will show a dc resistance below stated impedance ,some will be very close and ive had a few that were over and im sure haveing them wired together is helping it out alittle.

 

[Cap'n Andy 10+ year member]

you know a sub very seldomly rests at its nominal impedance right,,,most will show a dc resistance below stated impedance ,some will be very close and ive had a few that were over and im sure haveing them wired together is helping it out alittle.

Ok, before I installed them I checked all the coils and they all read around 3.8 ohms. I figured the wire might raise the final impedance a little, I just wasn't expecting that much.

Its kind of unfortunate, I won't be able to run my AQ1200D to its full potential.

 

[pr-festiva 10+ year member]

it happens when wiring subs together quite often.and you wouldnt be getting max out of that amp any way unless you ran straight test tones all the time and had allmost no box rise,,ac impedance is not the same as dc resistance dont woory about this so much you are not going to knotice it.

 

[Cap'n Andy 10+ year member]

it happens when wiring subs together quite often.and you wouldnt be getting max out of that amp any way unless you ran straight test tones all the time and had allmost no box rise,,ac impedance is not the same as dc resistance dont woory about this so much you are not going to knotice it.

Yeah that's cool, thanks for the info. I asked Audioque what the 1200d will do at 1.5 ohms and they said about 1085, so I set my gains for 1000 watts. It's still great, and I'm still very pleased with my first system.