DYNAMIC POWER MEASUREMENTS

About the Dynamic Power Measurements

The Audio Graph PowerCube is a test instrument used to measure the output of an amplifier in accordance with IHF-202 industry standards. The IHF-202 standard is a dynamic power measurement and was developed as a means of measuring power in a manner that best represents the Real World operation of an amplifier. Many manufacturers, including Rockford Fosgate, at times will measure amplifier power into a fixed resistor (4 ohm, 2 ohm). While this method is useful in some types of evaluation and testing, it is not representative of an amplifier that is connected to a speaker and playing music.

Music

Music is dynamic; the sound waves are complex and constantly changing. In order to simulate this, the IHF-202 standard calls for the input signal to the amplifier to be a 1kHz bursted tone. This signal is input (on for 20 milliseconds) and reduced 20dB for 480 milliseconds. The signal is gradually increased in level until the amplifier's output exceeds 1% Total Harmonic Distortion (THD). At 1% distortion becomes audible, therefore, any power produced above that level is considered unusable. Many manufacturers represent their amplifiers' output power in excess of 10% distortion. They use many names for this measurement, such as Total Maximum Power or Maximum Output Power. This is not indicative of the actual usable output power.

Listening to Loudspeakers - Not Resistors

A loudspeaker is not a resistor. A resistor's value (resistance measured in ohms) is fixed. A loudspeaker's impedance is dynamic. It is constantly changing in value, dependent upon the frequency of the input signal. Therefore, measuring power with the amplifier loaded into a 4 ohm resistor is not the same as measuring power with the amplifier connected to a 4 ohm speaker. Most people do not listen to music through a resistor.

A 4 ohm speaker may experience a drop in impedance 4-6 times lower than its nominal (printed) impedance. A speaker will also create phase shifts in the signal that is passed through it. These phase shifts happen because a speaker is an inductor (voice coil) and a capacitor (compliance of the surround/spider), as well as a resistor (voice coil wire).

To simulate a speaker the Audio Graph PowerCube measures output power into 20 different loads. It tests at 8 ohms, 4 ohms, 2 ohms and 1 ohm. Each of these impedances is also tested at –60°, –30°, 0°, +30° and +60° phase angles. These different impedances and phase angles represent the shifts in impedance and phase that can occur in a typical loudspeaker.

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Rockford Fosgate 250, 800, 100, 500 About the Dynamic Power Measurements, Music, Listening to Loudspeakers Not Resistors
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150, 250, 500, 100, 800 specifications

Rockford Fosgate has long been recognized as a leader in the automotive audio industry, and their amplifier lineup, including models like the 500, 150, 250, 800, and 100, exemplifies the brand's commitment to power and performance. Each model brings unique features, technologies, and characteristics designed to cater to a wide variety of audio enthusiasts.

The Rockford Fosgate 500 amplifier, known for its impressive power output, delivers 500 watts of dynamic sound. One of its standout features is the integrated C.L.E.A.N. technology, which ensures a distortion-free experience by allowing users to set the optimal input levels. This model is ideal for those looking to drive subwoofers without compromising quality.

Another compact yet powerful option is the Rockford Fosgate 150 amplifier. This model is designed for smaller installations but does not skimp on performance. With a peak wattage of 150 watts and a built-in crossover, the 150 is perfect for enhancing speaker systems by providing clear, loud audio without the bulk. The include a low-pass crossover ensures seamless integration with subwoofers.

The Rockford Fosgate 250 takes performance a step further, delivering 250 watts. This model features efficient thermal management with an aluminum heat sink, ensuring durability and reliability even under high usage conditions. The adjustable gain control makes it easy for users to match the amplifier to their specific audio needs.

For those who seek more power, the Rockford Fosgate 800 amplifier offers an impressive 800 watts and is designed for maximum output in both mono and stereo configurations. It features a variable low-pass filter and a bass boost function, allowing users to customize their sound signature to fit individual preferences.

Lastly, the Rockford Fosgate 100 amplifier provides a solid introduction to the brand's high-performance amplifiers, offering 100 watts of power. It is an excellent choice for entry-level users who want to upgrade their sound system without diving into higher-end options. Its rugged design and reliable performance make it a preferred choice among many.

Overall, Rockford Fosgate amplifiers—500, 150, 250, 800, and 100—demonstrate a range of features tailored to meet different audio needs. Whether you are an audiophile or a casual listener, each model incorporates advanced technologies to deliver high-quality sound, making them a staple in the automotive aftermarket audio sphere.
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