The pure tone files (which are included in both the Basic and Premium tests) are composed of 26 sine signals, a total of 52 files: one set of sine signals of equal phase for the right and left channels and one set of sine signals which have waves out-of-phase for the right and left channels. The frequency of the signal with the lowest pitch is 10 Hz and the highest pitch is 20 kHz. Each file has duration of 1 minute. All tracks are recorded at 0 dB Full Scale (0 dBFS).
The following files are the in-phase, pure tone files in the Subwoofer Test Pattern suite:
10hz in-phase.wav (track 2 on audio CD) 16hz in-phase.wav (track 4 on audio CD) 18hz in-phase.wav (track 6 on audio CD) 20hz in-phase.wav (track 8 on audio CD) 22hz in-phase.wav (track 10 on audio CD) 26hz in-phase.wav (track 12 on audio CD) 30hz in-phase.wav (track 14 on audio CD) 35hz in-phase.wav (track 16 on audio CD) 40hz in-phase.wav (track 18 on audio CD) 45hz in-phase.wav (track 20 on audio CD) 50hz in-phase.wav (track 22 on audio CD) 60hz in-phase.wav (track 24 on audio CD) 70hz in-phase.wav (track 26 on audio CD) 85hz in-phase.wav (track 28 on audio CD) 100hz in-phase.wav (track 30 on audio CD) 120hz in-phase.wav (track 32 on audio CD) 150hz in-phase.wav (track 34 on audio CD) 200hz in-phase.wav (track 36 on audio CD) 315hz in-phase.wav (track 38 on audio CD) 400hz in-phase.wav (track 40 on audio CD) 500hz in-phase.wav (track 42 on audio CD) 600hz in-phase.wav (track 44 on audio CD) 1khz in-phase.wav (track 46 on audio CD) 5khz in-phase.wav (track 48 on audio CD) 10khz in-phase.wav (track 50 on audio CD) 20khz in-phase.wav (track 52 on audio CD)
Once you have inserted the CD or hooked your computer's audio output to your sound system, you can play the signals recorded in the tracks through your speakers. The sound that you hear will give you information about the overall characteristics of your speakers and audio system.
Ready? Sit in the spot where you'll be doing most of your listening. The place you choose to listen will be the focal point. This is usually the center of the room, perhaps in your favorite chair or the comfy part of the couch. Or, it could be the driver’s seat of your car.
The characteristics you need to pay attention to are: loudness of each speaker, direction (where the sound appears to be coming from), and interference such as high pitches and annoying noises, etc.
Example of the response of the 5 KHz WAV file. Responses for other frequencies are similar but can change in magnitude and frequency according to the characteristics of the speakers and the room conditions.
Begin by setting the volume of all your equipment low. Start playing the 10 Hz in-phase track. Turn up the volume until you can hear the 10 Hz signal. If you hear the signal before you have reached the maximum volume, then your low end is working.
Be careful: low frequencies can vibrate objects around if your sound system is high power and your volume is set high enough.
If you reach the maximum volume without having heard the signal, your system is either limited to output higher frequencies or the low end speakers are not connected properly. Or, you just can't hear that range.
According to Wikipedia, most humans can only hear frequencies between 20 Hz and 20.5 kHz, with hearing that is most sensitive in the 500 to 2000 Hz range. If you don't hear the lowest tones, try the higher frequencies — the problem could be your hardware, not your audio system's.
You can start playing the next higher frequency to see if there is an audible output. If you have repeated the procedure and reached the 200 Hz in-phase track and have not heard any output then this means the speakers are damaged, are disconnected, or are receiving no signal from the player. Some stereo systems can't reproduce the 10 and 20 Hz test tones. If you heard the 200 Hz signal but not the 30 Hz signal then you should assume that your equipment can't hit those low notes.
Note: Some of the higher frequency signals will most likely sound louder on most systems. This will be adjusted later with the EQ tests.
For the next part of the test you will use the 1 KHz and 10 KHz in-phase tracks. The idea here is to check the proper functioning of the speaker midrange and tweeter capabilities. If you hear distortions coming from either the left or right speaker then swap them to verify, if possible. If the distortions stay with the speaker then it needs repair. If the distortion is specific to the channel regardless of the speaker then the wire is causing the distortion, or the output of the amplifier or equipment is giving a poor signal.
The set of in-of-phase files contain equal waves running through both left and right channels, with the waves synched in both channels. In the out-of-phase versions, the waves in one channel are shifted 180 degrees with respect to the other.
In-phase sine wave (both channels are identical.)
Out-of-phase sine wave (one channel is inverted) will sound quieter than the in-phase version when properly connected.
The phase shift of the left signal in respect to the right signal will help you checking the proper wiring of your speakers. When your speakers are properly connected, the out-of-phase tones should produce a lower volume version of the sound compared to the in-phase audio file.
In normal conditions, that is when the speakers are properly connected, the sound coming out from the left and right channels adds up for the in-phase version of the tracks and cancel each other out for the out-of-phase version of the tracks. In other words, in-phase tracks sound louder than the out-of-phase tracks. If this is not the case then you should check and swap the polarity (indicated with +/- or red and black colors) of the cables when hooking up the speakers.
10hz out-of-phase.wav (track 3 on audio CD) 16hz out-of-phase.wav (track 5 on audio CD) 18hz out-of-phase.wav (track 6 on audio CD) 20hz out-of-phase.wav (track 7 on audio CD) 22hz out-of-phase.wav (track 11 on audio CD) 26hz out-of-phase.wav (track 13 on audio CD) 30hz out-of-phase.wav (track 15 on audio CD) 35hz out-of-phase.wav (track 17 on audio CD) 40hz out-of-phase.wav (track 18 on audio CD) 45hz out-of-phase.wav (track 21 on audio CD) 50hz out-of-phase.wav (track 23 on audio CD) 60hz out-of-phase.wav (track 25 on audio CD) 70hz out-of-phase.wav (track 27 on audio CD) 85hz out-of-phase.wav (track 29 on audio CD) 100hz out-of-phase.wav (track 31 on audio CD) 120hz out-of-phase.wav (track 33 on audio CD) 150hz out-of-phase.wav (track 35 on audio CD) 200hz out-of-phase.wav (track 37 on audio CD) 315hz out-of-phase.wav (track 39 on audio CD) 400hz out-of-phase.wav (track 41 on audio CD) 500hz out-of-phase.wav (track 43 on audio CD) 600hz out-of-phase.wav (track 45 on audio CD) 1khz out-of-phase.wav (track 47 on audio CD) 5khz out-of-phase.wav (track 49 on audio CD) 10khz out-of-phase.wav (track 51 on audio CD) 20khz out-of-phase.wav (track 53 on audio CD)