Ohm issues (MB content)

[air_leech]

I own a Markbass SA450 head and two cabs- an Eden 2x10 cab and a Markbass 4x10 cab.

the Markbass can is rated at 8ohms.
the Eden cab is rated at 4ohms.

I took a multimeter and the reading of the impedance on the Eden cab was 9ohm (another reading on the end of a speaker cable that is plugged into the cab read 12ohm).

would it be safe to run the two cabs simultanously? I find it hard to believe Eden would claim the cab to be 4 ohm when it reads 8ohm....

if the Eden really is a 4ohm cab, would it be safe running it together with the 8ohm MB cab for a total of 6ohm?

 

[Lia_G]

Your multimeter is reading resistance, not impedance, right? Even though they both use ohms as a unit of measurement, they are two different things.

I'd be very careful. It sounds like you're flirting with a 2.67 ohm impedance by combining the cabs, which is definitely not recommended by MarkBass for that amp (or any of their amps).

Plus, even if it worked, you'd have 2/3 of your power going to the 210, and only 1/3 of your power going to the 410 ... sort of the opposite of what you'd really want.

Cheers

 

[projectMalamute]

Impedance is a value that varies with frequency, I would guess you are testing DC resistance.

 

[Jazzman]

Plus, even if it worked, you'd have 2/3 of your power going to the 210, and only 1/3 of your power going to the 410 ... sort of the opposite of what you'd really want.

Exactly. Typically, when you run a 2x10 with a 4x10, you want the 4x10 to have half the impedance of the 2x10 so that each 10" speaker is getting the same net power.

 

[BillyB_from_LZ]

...
I took a multimeter and the reading of the impedance on the Eden cab was 9ohm (another reading on the end of a speaker cable that is plugged into the cab read 12ohm).

...

The DC resistance of a 4 ohm cabinet has to be less than 4 ohms.

Are you using an instrument cable? No healthy speaker cable would have that much resistance.

And...are you sure your multimeter (and its leads) are healthy?