¿Cómo funciona un amplificador de audio para automóvil? – La etapa de entrada

Es hora de ver la etapa de entrada de cómo funciona un amplificador de audio para automóvil moderno. La etapa de entrada es responsable de la interfaz con su radio y proporciona características como el control de ganancia, los cruces, el refuerzo de graves, el control remoto de nivel y la suma de señales que su instalador usará para hacer que su sistema estéreo suene excelente y funcione de manera confiable. Si bien no necesitamos entrar en los detalles de los componentes en esta parte de su amplificador, comprender la importancia de las funciones es crucial para elegir la solución adecuada para sus aplicaciones.

Entradas de nivel de altavoz y preamplificador RCA

Su amplificador no puede amplificar una señal de audio si no puede conectar el amplificador a su radio. Casi todos los amplificadores en el mercado tienen conectores de entrada RCA que le permiten a su instalador conectar una radio de mercado secundario rápida y fácilmente. Decimos “casi” porque algunos amplificadores están diseñados exclusivamente para integrarse con sistemas de audio instalados de fábrica. Estos amplificadores pueden tener un conjunto de cables en un arnés flexible para aceptar señales.

En la mayoría de los casos, las señales de nivel de altavoz no son diferentes a una señal de preamplificador, excepto que generalmente tienen un voltaje más alto y, debido a que ya han pasado por una etapa de amplificador (en la radio o el amplificador instalado de fábrica), pueden contener un poco más. distorsión.

Ya sea que el amplificador use señales de preamplificador o de nivel de altavoz, debe tener una característica llamada Entradas diferenciales balanceadas, o una variación de esas palabras. Este circuito simple compara la señal (o el ruido) en el conductor central y el blindaje de una interconexión RCA y utiliza un amplificador operacional (un pequeño circuito integrado que se puede configurar para comparar o combinar dos señales en una sola salida) para eliminar cualquier cosa. común a ambos conductores. Si está utilizando interconexiones de par trenzado, el ruido EMI o RFI debe ser común a ambos conductores y, por lo tanto, este circuito lo reducirá o eliminará. Cuando compre un amplificador, las entradas diferenciales balanceadas son una de las primeras cosas sobre las que debe preguntarle al vendedor.

Características de procesamiento de señales

La siguiente característica importante en cualquier amplificador es la sensibilidad o el control de ganancia. This adjustment allows your installer to configure the amp to produce maximum power for a specific voltage that matches the maximum undistorted output of your source unit, or your power requirements based on the design of your audio system. The gain control is something that should be set once using an oscilloscope and a real-time analyzer (RTA), then not touched again unless the design of the system changes.

Most modern amplifiers include some form of electronic crossover that limits the range of frequencies that pass from the inputs to the outputs. A high-pass crossover only allows frequencies higher than the crossover point to pass and would be used on midrange and high-frequency speakers. A low-pass crossover allows audio signals lower in frequency than the crossover point to pass through the amp. This type of crossover would be used for woofers and subwoofers. Depending on the design of your audio system and the features of your amplifier, your installer may choose to combine high- and low-pass crossovers to create what is known as a band-pass crossover. This crossover would be used on midrange or midbass drivers to cut out low- and high-frequency information.

Many amplifiers have a bass boost control. This control operates as a single-band equalizer that the technician installing your sound system can use to reinforce a narrow band of frequencies being sent to a subwoofer. In reality, adding a narrow-bandwidth boost to your audio signal, from a purist perspective, makes no sense. Most systems sound better with proper DSP equalization to deliver smooth and predictable response across the entire operating range from 20 Hz to the upper limit of your sub around 60 or 70 Hz. A peak at any particular point will sound unnatural.

Remote Level Controls

Most high-quality subwoofer amplifiers come with a remote level control or remote bass boost control that can be installed in the front of the vehicle. This control allows the driver to turn the bass up or down to suit the music he is listening to or his mood. When shopping for an amp, look for units that offer a level control as opposed to a bass boost. As we mentioned above, adding emphasis to a narrow band of frequencies doesn’t sound as natural as turning as adjusting the overall output of the subwoofer.

Amplifiers with Integrated DSP

A friend of ours was in charge of developing a series of high-end amplifiers for one of the well-known head-unit manufacturers. The goal was to include as much flexibility as possible in terms of crossovers and signal summing. The complexity of the amp grew to a point where it was becoming difficult to fit all the switches and adjustments on the side of the amp. To provide their clients with the features they wanted, the company decided to remove all the controls and implement a digital signal processor (DSP) to handle everything. Now, the installer could combine signals from multiple sources, set crossovers very accurately and equalize the signal to deliver a smooth and predictable response from the speakers. Sure, your technician will need to connect a computer to the amp, but the results will be fantastic!

Great Features and Great Design

As important as the features of the amplifier you choose are, the design and component layout of the input stage of a car audio amplifier can have a huge effect on the performance of the amp. Keeping these components away from noisy sections of the amp like the power supply and output stage can dramatically reduce the signal-to-noise ratio of the amp. For this reason, larger amplifiers often sound and perform better than their compact counterparts. As with any design, the electronics engineers and technicians who develop the circuits and lay out the components have to balance performance, features, cost and size.

Find the Latest Car Audio Amplifiers at Your Local Car Stereo Shop

When it’s time to shop for a new amplifier for your car, truck, motorcycle or boat, make some notes about why you need an amp and what you want it to do. Armed with that information, the product specialists at your local stereo shop can help you find a solution that will meet your requirements quickly and efficiently and ensure that your mobile audio system sounds magnificent.