#1

can a head run two cabs at the same time?

#2

Depends on the amp, and to some extent the cabs, what do you have?

#3

i don't have any cabs and amps (i have a combo) but it was just a curiosity

#4

As long as the amp has enough power and you match the impedances, you can run as many cabs as you want from a single head.

*Last edited by amiguels at Jan 6, 2014,*

#5

As long as the amp has enough power, and you match the impedances, you can run as many cabs as you want from a single head.

Not true

If you have an amp that can run at 4ohms you can run a total of 4 16ohm cabs at once, 2 8ohm cabs or 1 4ohm cab.

#6

what do you mean by "has the power"? wattage?

#7

what do you mean by "has the power"? wattage?

If you run multiple cabs (like 4x12's) you will want at least 50 watts to run 2 cabs. But there is nothing set in stone except the ohms you must consider

#8

Not true

If you have an amp that can run at 4ohms you can run a total of 4 16ohm cabs at once, 2 8ohm cabs or 1 4ohm cab.

What I said is correct. What you said is exactly what i meant by "as long as you match the impedances".

If you want to run 64 cabs at 8 ohms, go ahead!

Get 8 sets of 8 ohm cabs in series, then connect the sets in parallel! But now you lack the power to drive them

Its a compromise between power and impedance.

Yes, by power I mean wattage.

*Last edited by amiguels at Jan 6, 2014,*

#9

can someone explain to me the OHM thing?

#10

What I said is correct. What you said is exactly what i meant by "as long as you match the impedances".

Yes, by power I mean wattage.

the way you worded it was that you could use as many cabs as you want, I did not want TS to be confused

But for the normal guy, a single 4x12 will be plenty for any thing you ever need.

#11

Correct, 2x12 is awsome, 4x12 will blow your house down, more than that, notify the NSA before starting up the amp because they may take it as a nuclear bomb went off xD

#12

i know i know, it was just a curiosity. How do the OHMs work with cabs?

#13

Think of impedance as a resistance (this is not true, but it works for this purpose).

If you have two resistors in series, the total resistance is the sum of the two. If you have two resistor in parallel, the total resistance is half the resistance of one of the resistors (assuming both resistor have the same resistance).

Example:

Two 4 ohm cabs in series: Total impedance = 4+4=8 ohm

Two 4 ohm cabs in parallel: Total impedance = 4/2=2 ohm

If you have two resistors in series, the total resistance is the sum of the two. If you have two resistor in parallel, the total resistance is half the resistance of one of the resistors (assuming both resistor have the same resistance).

Example:

Two 4 ohm cabs in series: Total impedance = 4+4=8 ohm

Two 4 ohm cabs in parallel: Total impedance = 4/2=2 ohm

#14

oh ok.

we learn the same stuff in school :-D

we learn the same stuff in school :-D

#15

i don't have any cabs and amps (i have a combo) but it was just a curiosity

Well in that case, you could hypothetically run a gazillion cabs as the others have said.

Ohm rates the electrical impedance of a device. An amp looks for its certain impedance. In the guitar world this is almost always 4, 8, or 16 ohms. Some amps have switches to match multiple impedance ratings, some are stuck at one specific rating. Solid state amps (as opposed to tube amps) can generally work with any impedance rating over a minimum threshold.

Speakers have an ohm rating and that is the impedance the amp is looking for. Amps actually operate at many different ohm ratings, but they are labeled based on their lowest impedance. The impedance varies depending on the frequency the speaker is operating at. There are ohm graphs for speakers and you'll see they're all over the place. For example, an 8 ohm speaker might be 8 ohms at 500hz, but then be 20 ohms at 3,000hz.

When you wire multiple speakers up they can either be wired in parallel or in series. Let's say you have two speakers wired in parallel. This essentially means both speakers get their signal directly from the amp. There's a positive and a negative coming from the amp. When in parallel, both speakers get the positive from the amp and the negative from the amp. If those two speakers are wired in series, then the signal goes from the amp, to speaker A, and from speaker A to speaker B. The positive signal from speaker A connects to the negative signal for speaker B and vice versa.

Wiring in parallel or series affects the TOTAL ohms of the two speakers. We'll say both speakers are 8 ohms. When wired in parallel, the total ohms are 4, while wired in series would make the total ohms 16. Similarly, two 4 ohm speakers would lead to total ratings of 2 and 8 ohms. Mixing different ohm speakers is a bad idea and leads to strange total impedances. I believe an 8 ohm and 16 ohm speaker in parallel leads to a total impedance of 5.333.

This became much more long winded than I anticipated. Anyway, if you are interested in this stuff, google is your friend. Well not really they harvest and sell your information, but that's besides the point. Just research this stuff if you want. But be warned, you can get stuck reading articles and watching youtube videos for days. I apologize up front for any possible inaccuracies.

#16

Think of impedance as a resistance (this is not true, but it works for this purpose).

If you have two resistors in series, the total resistance is the sum of the two. If you have two resistor in parallel, the total resistance is half the resistance of one of the resistors (assuming both resistor have the same resistance).

Example:

Two 4 ohm cabs in series: Total impedance = 4+4=8 ohm

Two 4 ohm cabs in parallel: Total impedance = 4/2=2 ohm

yup

i'll just add that it is pretty rare for cabs to be connected in series (generally you find some kinda external box for connecting cabs in series). so it simplifies the math a bit by not having to figure out the connection and formulas, you'll almost always use a parallel connection formula for hooking up cabs.

Sirakov

5

2,197

Last post:

rank-n-file

5

1,218

Last post:

pooo

20

7,752

Last post: