How to Use a Real-Time Analyzer to Tune a Car Audio System

by eHow Electronics Editor

If you are a fanatic about the sound quality of your car's stereo system, you will want to use a real-time analyzer (RTA). It can monitor each frequency of music across the spectrum from 20 Hertz (Hz) to 20,000 Hz and discover peaks and valleys in the frequency range. Once you know where the peaks and valleys are, you can make adjustments to eliminate them, ensuring a smooth transition between frequencies.


Get a CD that plays pink noise. Pink noise is all frequencies of the spectrum generated at the same level. It sounds like static when you play it.

Make sure that the RTA's battery is properly charged. Most devices include a readout that tells you if the battery is charged or needs charging.

Make certain that you have a good stand for the RTA's microphone. The microphone will be attached to the stand and the assembly will be put on the driver's seat in the car. The stand needs to have a base securely weighted so that it will stay in one position without moving.

Look around the vehicle and take out all items that are not a part of the interior of the car. Remove briefcases, old soda cans, everything; sound bounces off some surfaces and is absorbed by others, and these items influence the sound that is measured by the RTA.

The Test

Set the microphone stand on the driver's seat, so that the microphone is 26 inches above the seat - roughly the position of the driver's ears.

Face the microphone toward the front of the dash.

Plug the microphone into the RTA.

Play the CD with pink noise through your sound system. Set the CD player to repeat the track.

Make sure that all the doors are closed.

Take the meter and stand outside the car when you run the test.

Put the RTA in the test mode. A graph will appear on its display. This graph is a visual reading of the sound of your system from 20 Hz to 20,000 Hz. The dots beside the bars that define the frequency display a sound level of either 1/10 or 3 dB. This helps you determine how much more sound level one frequency has over another. The RTA will print out a graph.

Use the graph to adjust your equalizer to eliminate the peaks and valleys and achieve a smooth transition from frequency to frequency.


  • check You can get a CD with pink noise from any association that sponsors Sound Off contests.
  • check Use an RTA that can adjust speeds and frequency and that can take readings at flat, peak or RMS.
  • check Some machines include the IASCA test score as part of their software. IASCA is an association that sanctions and sponsors Sound Off contests. Whenever you take a measurement, the software of the RTA tells you what your IASCA sound quality score would be. This might be helpful as a reference.

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