How To Set Gain On An Amp

For decades, car sound enthusiasts have been fiddling around with the gain command on their amplifiers in hopes of "getting more than out of them." Many professional installers have scientific, repeatable processes in place to ensure these controls are set to provide the maximum performance and reliability from your audio organisation. Let's look at the most misunderstood, and most frequently adapted, control on car audio amplifiers – the gain control.

What Is a Proceeds Control?

When a manufacturer decides to develop an amplifier, they need to make up one's mind how many channels it volition accept, how much power it will produce, what additional features it will include and what source units information technology volition work with. Because modern source units have maximum preamp output voltages that range from 1.vii to five volts, amplifiers take to be adjustable to make their full rated power when driven with these signals.

Let's make up an example: Imagine a 100 watt mono amplifier that was designed to produce full power (100 watts) when it receives 2 volts of audio signal. This is a reasonable corporeality of indicate gain, simply leaves us open to two significant issues. What if we desire to use this amplifier with a source unit that can only produce 1.seven volts? We tin't become the amplifier to full ability even with the volume control on our radio turned all the way upward. In fact, we only get 72.25 watts out of our amplifier. On the flip side, if nosotros have a source unit that can put out 4 volts of signal, then the amp would attempt to make 400 watts with our fixed proceeds setting. Since the power supply of the amp was only designed to provide enough voltage to produce 100 watts, the point would be severely clipped and distorted, and there is a great chance that the amplifier and your speakers might be damaged.

The Solution

For a single amplifier to piece of work with multiple sources, amplifier manufacturers accept to make the input signal level adjustable. We call this the gain or sensitivity control. Information technology doesn't adjust how much power the amplifier will make, but information technology does conform how much of the input signal the amp uses to make full power.

There is a secondary reason for adaptability: Not every speaker has the same sensitivity. This means that sometimes you have more power than you need. Allow'southward say your front end speakers produce xc dB of output from 1 watt of power, but your rear speakers are much larger and produce 93 dB of output from the same 1 watt of power. For them to appear to be of equal loudness at the listening position, nosotros only demand half the power to the rear speakers. We decline the sensitivity of the rear channels of an amplifier to balance these out.

Making Gains (Using Your Gain Control!)

Your installer may utilize one of many unlike processes to suit the proceeds controls of your amplifier. We desire the proceeds controls to exist as low as possible, simply still permit you to go full power from the amplifier. Why practice we want the gain low? That is, perhaps, the central fundamental to this article.

We desire the amplifier to accept an input signal with as much voltage as possible for information technology to produce full power. Having more voltage on your interconnect cables helps drown out noise. Less amplifier sensitivity (lower proceeds setting) likewise helps to reduce noise. When the amplifier gains are fix properly, yous get total power from your amp without unnecessary hiss or background racket.

There are four mutual methods for adjusting proceeds controls: past ear, with a small amplified speaker, with an oscilloscope or with a distortion detection device. Setting by ear with music is very difficult and can pb to inconsistent settings. That being said, if your installer uses a test tone, the "by ear" process can piece of work quite reliably. Using a pocket-sized amplified speaker is similar to that process – there is a exam tone, but the small speaker allows your installer to check the preamp signal from the source unit, and in and out of any point processors.

Using an oscilloscope to set an amplifier's gain control is one of the all-time ways to get an accurate reading. Oscilloscopes piece of work for whatsoever frequency, so they are very flexible. Your installer can see exactly when the amp has reached its height voltage.

Finally, companies like D'Affection Engineering science and SMD accept adult products designed specifically for mobile electronic installers to cheque for bespeak distortion on preamp or speaker signals. All y'all accept to do is plug the device in and turn it up until the red Distortion LED comes on. Bam – done! A word of warning on these devices, though: They are very accurate and can detect distortions other than signal clipping. Many product design problems have been plant when attempting to set gains with these.

How Can Y'all Check Your Gains?

If the sensitivity controls on your amplifiers are set properly, y'all should be able to get your amplifiers to misconstrue a little bit with the source unit of measurement at full volume. If you lot are wondering why a properly ready amplifier will distort, that's a great question. It's called gain overlap. Nosotros want to have a little extra sensitivity in case we are playing a song that is recorded quietly. A great example of this is the well-known "Brothers In Artillery" album by Dire Straits. Information technology needs a expert 5 actress dB of gain to get rocking. In fact, the original 1985 release from Warner Brothers Records had several songs where the loudest office of the song was beneath -five dB. "Why Worry" has a acme level of -xiii.27 dB. A nightmare for an installer trying to set gains, only, luckily, that'southward not a vocal most people stone out to.

If you tin can't turn your book control by halfway without your amplifiers running out of power (distorting), so information technology's time to visit your local mobile electronics specialist. Likewise, if you hear a significant amount of hiss at low volume levels, then yous likely need an adjustment.

Properly set proceeds controls won't brand your system quieter, and turning up the sensitivity doesn't make your amplifier more than ability. Gain controls be to ensure that your system is always working the all-time it tin. Delight leave them alone, or ask your installer about how they are set.

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