Audio Control EQL Owner's Manual

. . . Level Matching for Autosound . . .?or Why is my system so noisy?byRichard ChinnAll Rights Reserved. Copyright 1986.22410 70th Avenue West, Moun

®8Minimizing Noise in Autosound SystemsNow that we’ve established some of the causes of noise in any audio system, let’s apply them to atypical autoso

®Figure 4. Bypassing the alternator output.Grounding practicesCAUTIONGround Isn’t Ground!Remember those words. Any time that you think that grounding

®2. If you mount everything on a board, connect the chassis of each component to a good, solidelectrical ground. The vehicle body is a good choice her

®11Minimizing Noise in Autosound SystemsFigure 5. RF bypassing the power supply lines.Level matchingLast but not lease is level matching. I’m presenti

®3. Now adjust the sensitivity control on the power amplifier until you hear it clipping, or thesystem is too loud.Remember: you want as much signal g

®Connecting a normal(one side of the output is actually connected to ground somewhere in thesystem) radio to an equalizer or power amplifier is easy.1

®ConclusionWe’ve covered a lot of ground in a short time. Some of the concepts presented may not be crystalclear the first time through. Take the time

®Appendix AMost noise problems with the AudioControl EQX Equalizer/Crossover and EQL Equalizer can betraced to improper level setting. The optimum sig

®Appendix BFinal Setup for the EQXThe initial part of the setup for the EQX is covered in the previous section.1. Set the HIGH FREQUENCY and LOW FREQU

®Appendix CProcedure for Powered RadiosUsing the EQX/EQL with head units with internal power amplifiers isn’t all that difficult.1. Determine whether

ContentsPageIntroduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

22410 70th Avenue West, Mountlake Terrace, WA 98043 (425) 775-8461®®

®1 . . . Level Matching for Autosound . . .?or Why is my system so noisy?IntroductionWith the advent of really high-performance automotive sound syste

®2What is noise?In any audio system, there are several potential noise sources.• thermal noise• induced noise• noise caused by a ground loopThermal No

®3Ground LoopsGround loops are insidious. They are caused by the non-zero resistance of the wire used to inter-connect the equipment. Typically, groun

®4The Meaning of Signal-to-Noise RatioSignal-to-noise ratio is a common term used on spec sheets. As common as it is, many people (bothlearned and not

®5Figure 3. The relationship between operating level, clipping and the noise floor.As you can see, the operating level chosen for any given device has

®Gain, Level, Sensitivity, and Power RelationshipsAnother source of error is the interrelationship between gain, signal level, sensitivity, and output

®7Another reason is to maximize the amount of useable range that the volume control has, which isespecially useful with units that have detented (clic