So let's go back with our previous example. Using Ohm's Law, let's see all the possible options this guy's amplifier has to offer. It can produce:
Last issue, we talked about that ambiguous but appealing specification known as power, as applied to a loudspeaker. We explained that with car audio loudspeakers, the maximum power input specified by the manufacturer is really of very little use, because a loudspeaker's actual limits depend on how we adjust the crossover, build the box and how many decibels (dB) of gain overlap in the amplifier we are willing to use. That was on the loudspeaker side.
On the amplifier side, once again, things are not as clear or direct as most of us may think. First and foremost, the amplifier output power is not a given. It's not something readily available. What do I mean? I mean that power is not like voltage. In a typical 12.6-volt car battery, you "have" that voltage sitting there, waiting if you wish. You can take a voltmeter, measure it, and it will be there. You can safely say that your battery has 12.6 DC volts. What about current? Current is not always there because it is supplied under demand. The current specification of a typical car battery is known as its cold cranking amperes (CCA), defined as the amount of amperes that a battery can deliver for 30 seconds, at a temperature of 0F, sustaining a voltage between terminals of 7.2 volts. This also means that, as current output increases, voltage between terminals decreases. This is due to the battery's internal resistance, its limitations.
What I would like you to grasp is that current is only delivered by demand. If you connect a small lightbulb to a battery, you may get 1 amp of current flow that then, and only then, you could measure with an ammeter. If you connect 15 of these lamps, all of them in parallel, you could get 15 amperes of current from that battery. Now, since power is voltage times current, power is also delivered on demand. Take an amplifier with no woofer connected to its output terminals. How much power is it producing? Nothing! Nevertheless, you would be able to measure perhaps 40 Volts RMS from those terminals. So, the amount of power the amplifier outputs depends on the load, which depends on how many woofers we plan to connect to it and how.
All this goes to say that it is extremely important to make smart woofer arrangements for the bass-dedicated amplifier in order to actually make use of its power-output capabilities, the power we paid for. Please note that the same does not apply to higher frequencies. One of the many reasons for this is that we don't need very high pressure levels at mid and high frequencies. Our ears are extremely keen to those ranges, and therefore it is easier to permanently damage them at those frequencies. But with low bass, more is generally better, either because we want to be the loudest on our block or simply because we want ...
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