Dynamic Power Measurements, Music | Rockford Fosgate 75.2, 55.2

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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225.2, 125.2, 55.2, 75.2 specifications

Rockford Fosgate has long been recognized for delivering high-quality audio solutions for car enthusiasts, and the 225.2, 125.2, 55.2, and 75.2 amplifiers are no exception. These amplifiers cater to various audio needs, whether you are looking to enhance the sound quality in your vehicle or set up a full-fledged audio system.

The Rockford Fosgate 225.2 is a powerful two-channel amplifier that offers a maximum power output of 225 watts. It features a MOSFET power supply, providing excellent efficiency and reliability under load. The 225.2 also includes a low-pass filter and built-in crossover, enabling users to tailor the sound to fit specific audio preferences by adjusting the frequency response. Its sleek design and durable construction ensure it can withstand the demands of a mobile environment.

Meanwhile, the 125.2 amplifier is designed for those who want a compact yet powerful audio solution. This two-channel amplifier delivers 125 watts of peak power and incorporates advanced technologies such as a high-level input, allowing for easy integration into factory systems. The 125.2 also features adjustable bass boost to enhance low-frequency performance, making it an attractive choice for those who enjoy bass-heavy music genres.

On the other hand, the Rockford Fosgate 55.2 amplifier is a more compact offering. Despite its smaller size, it provides impressive sound quality and power output of 55 watts per channel. Ideal for adding an extra punch to factory speakers, the 55.2 utilizes a low-impedance design to maximize efficiency. It is particularly well-suited for entry-level audio systems, making it accessible for those just starting in car audio.

Lastly, the 75.2 amplifier strikes a balance between size, power, and versatility, delivering 75 watts per channel. With features like thermal and overload protection, the 75.2 ensures both safety and performance under stress. The compact form factor makes it easy to install in various vehicle models without sacrificing audio quality.

All of these amplifiers showcase Rockford Fosgate's commitment to sound quality, durability, and user-friendly design. Each model incorporates technologies that enhance performance while offering flexibility for customization, making them excellent choices for car audio enthusiasts looking to elevate their listening experience. Whether you need a compact solution for upgraded sound or a powerhouse for a full system, Rockford Fosgate has options that cater to every need.