Stacks/Cabinets/Heads questions!?

When you see a 4 X 12 cab rated at 300 watts handling power, this means the cab has four 75 watt speakers inside like the famous Marshall 1960 cab. They just add them up. A little misleading. Each speaker can only handle 75 watts.

When you run a 100w amplifier head into a 4 X 12 cab like this, the power will be divided equally between them. So each individual speaker will get 25 watts. They are rated to handle 75 watts comfortably, so they will be fine. As others mentioned, you do want speakers rated higher than the amp. My 40 watt HRD has a 60w 12" speaker for a good example.

There are some basics about sound to understand:

1) Everytime you double the power (wattage) you get a 3 decibel increase in volume. This is just slightly louder, but perceivable. So, a 100 watt amp is just very slightly louder than a 50 watt amp, not twice as loud as most people believe. In fact, it would take about a 500 watt amp to be twice as loud as a 50 watt amp.

2) 12 decibels is considered a doubling in volume (twice as loud).

3) Two identical speakers in close proximity results in a 3 decibel increase in volume.

So, adding a 4 X 12 cab SHOULD get you about a 6 decibel increase in volume. This will not be twice as loud, but it should be noticeably louder.

However, this is a little misleading as well. If you have a 100w head with a single 12" speaker, that speaker is getting all 100 watts. But as I said earlier, if you go into a 4 X 12 cab, now each speaker will only get 25 watts each. So you lose a little bit with multiple speakers.

But all in all you do get an increase with multiple speakers simply because you are moving more air. And it will absolutely sound fuller. Multiple speakers handles deep bass better also because a single speaker can get overpowered by the bass and start to distort. The multiple speakers are sharing that power. It is spread out between them. So you get a deeper response without distorting. So this is one reason to use a 4 X 12, to get huge, but tight bass response.

Wes has covered the main Question asked. The decision to get a stack is one of those you'll have to decide. There is a big difference playing on small practice amp and a full or half stack. I don't mean volume wise. For myself the tone is line line then volume is added depending the venue. They are worth the investment.

Joe

Thanks guys, so does this mean if I have 2 cabinets, and a 100 watt head, lets use wes's example with the 75 watt speakers... So if I had 2 cabs then each speaker would be getting 12.5 watts?? or would they still all be getting 25 watts? I think it would be 12.5, but just asking.

Thanks again.