It's one of the hottest trends among young street racing and car audio enthusiasts, along with the general car buff. It's like something out of an old sci-fi movie, and you're not likely to see it in a stock vehicle. It's a display that can, among other things, tell you via your head unit if there is somebody in front of you in the dark. Some display the speed of your vehicle on your windshield. There is some thing about having a digital meter giving you information about your vehicle that makes you feel like a time traveler. Many sports cars have a digital gauge that can display multiple functions via a toggle switch. All the Formula One cars have integrated digital gauges that tell them about every aspect of the engine, from efficiency to status, and so on. A car with an audio system may not run on a race track but there are other kinds of competition lanes; sound competitors need information, too, so they can make sure everything is playing at maximum performance.
There are certain digital gauges that are more frequently used for car audio purposes. They are the following: Voltmeter, Ammeter and Temperature.
Digital Voltmeter is the most popular one because it's so important, especially since with low voltage your car audio system will sound distorted, and that can possibly cause damage to the components. The range is usually from 0 to 20 volts. You can use this to make sure your vehicle's charging system is working well, because most that are factory installed are analog gauges and they don't have pinpoint accuracy that the digital gauges offer. They usually go in the dash area; in some cases some cars in sound-offs have them mounted in the engine compartment by the battery, tied in with a hood pin switch so it comes on only when the hood is open. They usually cost around $ 150.00 on up and installation is not difficult, although integrating it in your dash is slightly harder.
Temperature meter is the second most popular indicator because this can tell you if your amplifiers are cooking or not. This gauge requires a sending unit to be attached to the component you wish to monitor. Sending units normally consist of a metal ring terminal with electronics with wire attached to it, which goes to the gauge. This way you will get an accurate reading from it. There are usually settings that can be adjusted so it will flash or sound an alarm. If you are a gauge freak then you should know there are some that can monitor up to four sending units so you could have all of your car audio components monitored. The cost is about the same as a voltmeter, but the installation cost will be higher.
Ammeter is one that very few people know about because it monitors amperage (current) flowing through a wire. This gauge consists of a sending unit that is formed like a circle; the wire runs through it and then you take the reading. There are several different rating ammeters from 0 to 100 to 250 amps. They are very good for seeing how much total amperage your system is drawing through the wire from the battery. Sometimes you will realize that your amps are not drawing what you thought they would. This also helps you monitor the output of your vehicle's alternator which is measured in amperage. Many times you won't be aware of it, but the car audio system might be drawing practically all of your current and leaving very little for the electronics of your car. The alternator charges your battery and runs the computer, lights, gauges and other electrical components, Basically The heart of your car after the main car computer. An Ammeter starts around $ 250.00 on up and requires professional installation.