Audio Output

Please 'Boom' Responsibly As most of you have noticed, the noise ordinances have become much tougher lately. Most of this is due to idiots, yes IDIOTS, who drive through residential areas with their windows down while their system is playing at full power. To make things worse, the music they listen to has all sorts of foul language that's not suitable for small children, (who may be playing outside). There are even a few people, who are even beyond idiot status, that play their systems at full power through residential areas after 10:00 PM (when many people go to bed). I don't believe that this type of behavior is good for the industry. If the fines get too stiff, people will stop buying large systems. If this happens, more people will get out of car audio (who wants a mediocre system). People get interested in things because they're exciting. A deck and four 6.5" speakers are not going to interest many of the younger car audio enthusiasts. If car audio enthusiasts keep annoying more and more people, the fines will keep getting tougher. All of this will only reduce interest in the equipment that fuels the industry. If you want to listen to your system at full volume, get out on the highway where there's little chance of bothering anyone. When you get to a red light, turn it down. If the only thing attractive about you is your 'system', you have some work to do. Bottom line... Think about what you're doing. Think about other people. It's not the end of the world if you have to turn the volume down for a little while.

Audio Output:: An audio signal is a complex AC waveform. The diagram below shows 2 sine waves. These are much less complex than music. If you play a pure tone from a test disc and monitor the output with an oscilloscope, it would look similar to one of the sine waves below. Many of the aftermarket car stereo head units have 2 different types of outputs. One type of output (the preamp output) is designed to drive the preamp level input of an amplifier, crossover or equalizer. The other type of output (speaker level output) is designed to drive a set of speakers and may also be used to drive the speaker level input of an amplifier. The main difference between the preamp signal and the speaker output signal is the current capability of the signal. The preamp level signal is a very low noise, low current output. The speaker output signal is capable of supplying much more current than the preamp output signal. The output voltage levels from the preamp outputs and speaker outputs MAY be approximately the same but the speaker drive voltage is usually higher. When the volume is low, the voltage out is low. To increase the volume, you must increase the output voltage. You are controlling the output voltage level when you set the volume level. The yellow waveform shows the same sine wave output at a lower volume setting than the white waveform.
This is one example of what audio might look like on an oscilloscope. The tallest part of the waveform is a sharp/strong beat of a snare drum. Not all such strikes would look like this but you can see that the strong hit has a fairly high amplitude. This sample is a fraction of a second long.: The following demo shows you what a sine wave looks like on an oscilloscope. When you click on the volume bar, you can see how the amplitude of the waveform changes. You can also click on the 'track' buttons (green) to change the frequency. The voltage readout indicates 'peak' voltage.
Click HERE to make this demo fill this window.
You'll have to use the back 'button' to return here.

If you find a problem with this page or feel that some part of it needs clarification, E-mail me.

This is a link to this site's home page.