amplifier DB meters

Bob,

Music is dynamic. An amplifier meter is only indicative of clipping/power. Power is a function of load (resistance/reactance) and load is a function of frequency. More expensive amplifiers will have a high speed soft clipping circuit to protect speakers (often with a clipping warning light) - this is all that is really necessary to assure good sound. A clipping meter is only a ball park device.

If an amplifier does not have meters can you hook one up or use a test meter to find out how many watts you are using?

You can - but measuring power is quite complex - very few test meters can measure this correctly. A device to measure power accurately would probably cost more than the amplifiers. Yokogawa Power Meters

Most power meters (common in the 70's) are just estimates of power - they measure voltage (easy to do) assume an RMS conversion (using a a fixed load factor and sinusoid waveform type) such as 8 Ohms....all very inaccurate and only indicative). You need to measure current very accurately as well as voltage to get power.

When my system is playing and I only ever see 4 watts on the meter with the loudest peak, I can figure that the amp is using more watts, than the meter is reading, but how much more?

4 watts metered power (referenced to an 8 Ohm load) is;

1) is actually 60 watts into a 0.5 ohm load. In this case, the limiting factor, however, will NOT be the watt rating of the amplifier but the current limitation (11 amps of current is required at 60 watts when driving a 0.5 ohm load and most amps will not deliver anything close to this level of current unless they are rated 1000 watts or more and designed to handle very low impedance loads and high current output...so basically your amp will be current limited at some point ...usually around 7 amps for a 200 watt amp and the meters on the display will, of course, never exceed 4 watts)

2) is actually 15 watts into a 2 Ohm load.

The above is a hypothetical example but it illustrates how power meters can be completely misleading.

Are your woofers in parallel or series or a mixture of both?

Bob,

Are you saying that you have a bank of 8 drivers wired in parallel or in series?

I needed to keep it 4 ohms

That's cool. Given your amps there should be absolutely no problem with that kind of load.