You can use these audio test tones for use in your car to help identify strengths, weaknesses or issues with your current set up.

The files are all Windows .wav format and all play at 44.1kHz/16 bits; some are stereo, some mono.

When you listen to the tones, to start with, set all the controls on your car stereo flat by setting the bass and treble to neutral and turn the loudness off. If you have a sub, start with it switched off, then switch it on without any boost and with the cut-off somewhere around 100Hz. Once you have an idea of how things sound in their raw state - just the head unit and speakers with no electronic assistance - you can then listen to the performance of individual speakers/pairs of speakers in turn.

Pink noise in phase. This is used for testing your stereo setup. Listen to this alternately with out of phase pink noise (below) and compare the sound of the two. If your stereo is set up correctly, the in-phase pink noise will sound full and deep, and the out of phase pink noise will sound thin and tinny. If the reverse is true - the in-phase noise sounds tinnier than the out of phase - then your speakers are not wired with the correct polarity. The cure for this is to reverse the polarity of the connection on one speaker, and try the test again. The same is true of getting your front and rear speakers in phase with one another. To test this, you will need to connect your front speakers to the left channel only and your rear speakers to the right channel only, and repeat the test. Another way to do this is to disconnect your front left and your rear right speakers, listening to the front right and rear left to see if they are in phase or not. Then try the front left and rear right combination. You should also check that your subwoofer is running in phase with your other speakers in the same way - connect the left output to your sub; then connect the right output to each of your other speakers in turn, and test.

Pink noise out of phase. Used in conjunction with in-phase pink noise, above.

Swept sine wave tone, 20 Hz to 125 Hz. This tone should be the same volume all the way through - as the pitch rises is should sound smooth and even. On most systems it will sound quiet to begin with due to the depth of bass note - as low as the ear is able to hear. If you have a subwoofer, this tone should be handled entirely by that.

Swept sine wave tone, 125 Hz to 1 kHz. Again, as the pitch rises, the tone should sound the same volume and smooth throughout. This region of sound is where the majority of standing waves will occur within the car so it is likely that even a well-designed stereo will make a kind of throbbing noise as the volume is uneven throughout the sweep.

Swept sine wave tone, 1 kHz to 5kHz. Again this should sound smooth but it is likely that it may get a little loud about halfway through. This, however, is down to the design of your ears - the ear canal resonates at about 3 kHz, with slight variation for different people, and at this frequency the sound will be noticeably louder. There is also a secondary resonance at about 8 kHz which you may hear on the next tone.

Swept sine wave tone, 5 kHz to 20 kHz. This tone goes right up to the limit of human hearing.

Stepped tones, 20 Hz to 1 kHz. These are similar to the sweep tones above but quicker and a little less accurate. All the tones should be the same volume, possibly with the exception of the first few very deep bass notes.

Stepped tones, 1 kHz to 20 kHz.

This tone is an impulse function. Use this test with care - it is best listened to at reasonably high volume and is a complete test of frequency response, dynamic range, stereo separation and clarity.