impedance rise

[THATpurpleKUSH 5,000+ posts]

How do I measure this? Its my first ever attempt at an spl build. I read that you can wire the speakers below the amp's ohm stability and with the impedance rise, will bump it up around .5ohm or so to a level where the amp is stable.

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[matt_bennett05 10+ year member]

I'm here for the info party as well

 

[elancohen92 10+ year member]

freee bump,i wanna know too

 

[TaylorFade 10+ year member]

You need a clamp meter. Set your clamp to ac amps and then clamp the meter around the positive speaker lead(s) on "peak/hold." Then measure the ac volts with the same HU settings and tone by inserting them into the positive and negative speaker leads (similar to the way you would set your gains). Obviously it helps if you have another meter or a simple DMM so you can do this at the same time.

ac volts / ac amps = observed impedance.

For instance... I clamped my AB 100.1 today (at 4 ohms). I got 65 ac volts and 7.8 ac amps. 7.8 times 65 is the power output (507w), 65 divided by 7.8 is the impedance rise (8.3 ohms).

And there you have it.

 

[THATpurpleKUSH 5,000+ posts]

so where would I buy one of those meters? Would a nice dmm do it?

 

[Sleeklsc 5,000+ posts]

i measured mine with a dmm.. I set it to ohm..+ on +..- on -...I wired 3 r's to .67 and got low 1's final load.

 

[Haunz 10+ year member]

so where would I buy one of those meters? Would a nice dmm do it?

Yes. You need a true RMS DMM, and you would need to setup a wheatstone bridge. Since you probably don't know what that is, I would suggest doing some reading on google.

 

[THATpurpleKUSH 5,000+ posts]

...I wired 3 to .67 and got low 1's final load.

this is what i'm looking to do overall.

thanks for everyones help so far

 

[THATpurpleKUSH 5,000+ posts]

I assume I put the probes on the speaker/box and not the amp?

 

[outsideshot23 10+ year member]

I assume I put the probes on the speaker/box and not the amp?

you can do it where they speaker leads go into the amp.. and **** taylor. 4 ohm rise lol.. whats that box made out of cardboard

 

[TaylorFade 10+ year member]

you can do it where they speaker leads go into the amp.. and **** taylor. 4 ohm rise lol.. whats that box made out of cardboard

Well, technically it's only a 2x rise. Lol. I wired my sub to 4 ohms because I sold a Kicker amp the other day and I just wanted to show the guy it worked without having to run it @ 1ohm. I just didn't rewire the sub when I bought the 100.1. I just had to clamp it because I knew there was no way it was only doing "250w@4." How many 4 ohm clamp numbers have you seen? Lol. Loving that little AB, btw.

I see about the same 2x rise when it's wired to 1 ohm. I think it rises to 2.4 or something.