do I have to use a ammeter?

[SPL140.2 5,000+ posts]

do i have to use an ammeter to calculate the ohms of the subs during frequency testing or is there another way?

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[JimJ 5,000+ posts]

You don't use an ammeter to measure ohms, anyway //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif You use an ohmmeter //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[SPL140.2 5,000+ posts]

This is from bladeice.com--->You will then need a digital voltage meter and a clamp on ammeter. Set both to peak as it's the same. At 1 Hz intervals measure the in box impedance by playing that note and measuring the voltage and current. Impedance = voltage/amperage. Once you have a chart of the in box impedance it is possible to experiment with the wiring. So if at 60 Hz your in box impedance is making each amp 'see' 8 ohms, and by adjusting the wiring you can make the amps 'see' 2 ohms bridged (if that's what they're designed for) you suddenly have 4* the power, or to put it another way a 6dB gain before power compression.

Is there another way of doing it?? //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[JimJ 5,000+ posts]

You don't have a DMM/VOM, that will directly measure AC impedances?

Most will directly measure the impedance...

 

[SPL140.2 5,000+ posts]

The only thing I have is a dmm and a spl mic //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif I tried setting the dmm to ohms before starting the car the subs measured 2.0ohms than when the amp kicked on it was like 60.0 and I know the ohms isnt that high.

 

[JimJ 5,000+ posts]

I bet that DMM of yours will directly read impedance.

 

[SPL140.2 5,000+ posts]

I cant get a good reading with the amps on. Amps off i get 2.0 ohms when amps are on i get 60.0 ohms I dont get it.

 

[SPL140.2 5,000+ posts]

What im trying to do is chart the ohms of the subs at each frequency 30-70hz.

 

[SPL140.2 5,000+ posts]

Does it change with frequency ?

Yes, but it never got under 20.0 ohms.

 

[noob with an RS 10+ year member]

when using an ammeter, the device youre checking should not be powered. a ohmmeter works by sending current through the device and calculating how much it gets bacc.

 

[noob with an RS 10+ year member]

ok nevermind i didnt see the post about you wanting to chart the ohms in response to changing frequencies. i dont understand why you would want to do this but im sure you must know what you are doing and why if you are. haha

 

[JimJ 5,000+ posts]

i dont understand why you would want to do this but im sure you must know what you are doing and why if you are. haha

Impedance rise, resulting from the specific enclosure used...there's a good article about it over on SSAudio.

when using an ammeter, the device youre checking should not be powered.

//content.invisioncic.com/y282845/emoticons/hilarious.gif.02a037aad04aa96f19982b298a3d70a8.gif

Current is measured in series with the circuit...care to venture how you're going to measure amps in a non-energized circuit? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

a ohmmeter works by sending current through the device and calculating how much it gets bacc.

That part is true.

 

[noob with an RS 10+ year member]

oops.. i meant to put when checcin an OHMMETER the device cannot be powered. but i dunno know crap cmpared to u guys so dont mind me. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[SPL140.2 5,000+ posts]

Does anyone know the correct way of doing it?