# Watts & Ohm???

Discussion in 'Amps and Cabs [BG]' started by Aslan, Nov 19, 2003.

1. ### Aslan

Sep 20, 2003
Stockholm, Sweden
Hi!
I have a few questions:
Lets say that I have a 4x10 in 4ohm and I put 400W into the cab, each speaker will get 100W each. Right?
If I combine this cab with a 2x10 in 8ohm, the load will be 2.67 ohm (my amp can handle down to 2 ohm). Lets say the power will be 600W in 2.67ohm. How will the watts be devided between the cabs? Will the 8ohm cab get 200W (100W/speaker) and the 4ohm cab 400W (100W/speaker)??? Will this be a good portable 6x10?

(If anyone wonders, I'm talking about the Ampeg SVT Classic series.)

Andreas

2. ### miccheck1516Guest

Feb 15, 2003
Ireland
the 4 ohm cab will get more power

3. ### De Teng

Oct 27, 2003
Utrecht, Holland
In fact... twice as many as the 8 ohm cab.

Simple explanation: due to less resistance, the current is more able to run through the 4 ohm cab.

Twice the Resistance = half the current = half the power.

Take a view at the following:

P = V.I. (power = voltage*current)

V = I.R. (voltage = current*resistance)

In the parallel situation (which is mostly what happens with combining cabs) the current will be divided unequally. Thus not in half! It depends on the resistance (ohm) which the cab has. Less resistance = more current.

So when 'I' goes down (with a higher R) P goes down. Because of the fact R1 (4 ohm) is 50% of R2 (8 ohm) the R1 gets twice as much current (I) thus produces twice as much power.(P)

Sep 9, 2001
Idaho
Yes

Yes

5. ### De Teng

Oct 27, 2003
Utrecht, Holland
Indeed! Each speaker gets 100W.

Half the current/half the speakers.

600/6 = 400/4 + 200/2

6. ### Aslan

Sep 20, 2003
Stockholm, Sweden
Thank you very much for your replies!

My idea is to "transform" my Ampeg SVT410hlf to a Ampeg 6x10, when I need it, by adding a SVT210he to it. And even another one to get a more portable 8x10 in 2ohm (=full power). And even get one 210 to smaller gigs or two separate 4x10 rigs.
Has anyone tried this?

7. ### Petebass

Dec 22, 2002
QLD Australia
I used a 4x10 with a 2x10 for many years, but both my cabs were the same nominal impedance. I wasn't thinking in terms of power distribution per speaker, I was more interested in making each cab produce the same overall volume. I didn't want to lug in the extra 2x10 cab only to find it couldn't be heard against the 4x10.

If you haven't already bought the cabs, I'd suggest you try it out both ways and go with whichever sounds best to you.

8. ### De Teng

Oct 27, 2003
Utrecht, Holland
That would be very nice indeed. Still I'm wondering if you really need the 2.10" in addition to the 4.10". Mostly a 4.10" wil do the job.

Next tuesday I am going to buy a Bag End Q10BX-D (4.10") and the owner assured me, that I really don't need anything else on stage. This guy has seen every venue in Holland, including the really big ones, but the Bag End handled it all.

So perhaps if you'll stick to you purse, may be you can sell the 2.10". But a 6.10" does RULE!!!