Tuning an Amp with a DMM?

[timma100 10+ year member]

I wrote a calculator to do it for you there... so you as long as you plug your numbers in there you'll be fine.

Should I test the resistance of my sub circuit with it connected to the amp? or should I disconnect it and just test the speaker wire

 

[bgowdy 5,000+ posts]

im not sure on that one lmao.

 

[ahole-ic]

Should I test the resistance of my sub circuit with it connected to the amp? or should I disconnect it and just test the speaker wire

What would testing the circuit connected to the amp do? It would measure the amplifier's output stage's resistance in parallel with the woofer's coils. Measuring the woofer's resistance won't tell you much. It is rated in impedence.... not resistance.

 

[bgowdy 5,000+ posts]

disconnect subs then test

 

[timma100 10+ year member]

What would testing the circuit connected to the amp do? It would measure the amplifier's output stage's resistance in parallel with the woofer's coils. Measuring the woofer's resistance won't tell you much. It is rated in impedence.... not resistance.

Well then I guess that leads me to a good question, I just connect my DMM leads to the speaker wires (disconnected from the amp) right?

My bad I forgot we are dealing with AC current and not DC

Calculated impedance and measured are different. I assume I want to use measured right?

 

[ahole-ic]

Well then I guess that leads me to a good question, I just connect my DMM leads to the speaker wires (disconnected from the amp) right?
My bad I forgot we are dealing with AC current and not DC

To measure the coil's resistance yes. What does knowing its resistance tell you?..... nothing useful.

 

[timma100 10+ year member]

To measure the coil's resistance yes. What does knowing its resistance tell you?..... nothing useful.

So how should I go about finding impedance? Everything I have found says its the normal resistance calculation for parallel circuits.

 

[ahole-ic]

So how should I go about finding impedance? Everything I have found says its the normal resistance calculation for parallel circuits.

The manufacturer will have provided the nominal impedence. You most likely don't have any equipment capable of measuring it.

 

[timma100 10+ year member]

The manufacturer will have provided the nominal impedence. You most likely don't have any equipment capable of measuring it.

Now really, everywhere, and I mean EVERYWHERE. Is giving out standard resistance calculations for parallel and series sub wiring to find impedance, surely they can't all be wrong... right? Speaker Impedance Explained - Ohms

Can't even find info on my subs..... All crap about the DBXI and not the DBX //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

 

[duanebro 10+ year member]

The idea is to set your gains as high as you will ever use them. After setting the gain on your amp, then you can turn DOWN the gain/volume/eq. You don't want your xo cutting output at 50 Hz so it is suggested that you turn up the lpf as high as you can, and turn down the subsonic filter.

I didn't see the second page.

 

[ahole-ic]

Now really, everywhere, and I mean EVERYWHERE. Is giving out standard resistance calculations for parallel and series sub wiring to find impedance, surely they can't all be wrong... right? Speaker Impedance Explained - Ohms
Can't even find info on my subs..... All crap about the DBXI and not the DBX //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

Where in that TL;DR article did it say anything about resistance?

 

[sojiaraggs9000 10+ year member]

Heres a chart that has helped me a bit in the past.

 

[chillin 10+ year member]

Do not disconnect your subs

 

[ahole-ic]

Do not disconnect your subs

Why?

 

[i2ain2thunder 10+ year member]

anyone link a proper (50-60 hz) test tone that hits at a volume close to the average recorded volume?

Also Ecrack, is there much difference in the accuracy of a cheap DMM and a more expensive one?