Ear Training for Critical Listening with Pink Noise

“All of life is a dispute over taste and tasting.” – Friedrich Nietzsche

The raging debate over objective (everything is measurable) versus subjective (only the listening experience counts) theories of audio evaluation will, no doubt, rage on. The rational among us will carefully choose bits of wisdom from both sides as we develop our ability to critically evaluate audio gear, and then hopefully learn the the most important lesson of all: when the evaluating is done, just relax and enjoy the music.

In this post I’d like to provide you with a simple tool to help you get some objective ear training.

First, let me admit that though I like to measure stuff, I do believe there is a significant limit to what the measurements will tell you. Measurements can tell you if one headphone has more bass or treble than another, for example, but they can’t really tell you much about how lush, or airy a particular headphone sounds. There is really only one way to know what something sounds like, and that is to listen to it. Critical listening is a skill, however, and your listening skills can be improved with practice to become a bit more grounded and objective.

My favorite way to quickly get a read on the character of a pair of headphones is to listen to pink noise. Pink noise is a type of noise know also as 1/f noise. It has equal amounts of energy in each octave. When you listen to pink noise it should be a very smooth sounding wash of noise. No particular frequency or range of frequencies should be more noticeable than any other; nor should there be any apparent gaps or missing frequency ranges. If you do hear one range of frequencies more strongly than another it means that somewhere in the reproduction chain some frequencies are being emphasized, and since electronics will only modify the noise slightly any anomalies that you are able to easily hear are most likely from the speakers or headphones. It’s also worth noting that it is much easier to hear frequencies that are being emphasized than it is to hear frequencies that are de-emphasized or missing.

The biggest difficulty when training yourself to listen for errors in pink noise is that no audio system is perfect, and therefore any system you listen to with pink noise will have some errors. Fortunately, with enough experience, you will easily be able to imagine what perfect pink noise would sound like even if you’ve never heard it, and will be able to hear any frequencies altered.

To help you improve your critical listening skills, I’ve created a set of pink noise tracks that you can burn to a cd. (You can download a .pdf of the track list here.) The first two tracks are straight pink noise without any modification. The remaining tracks all have modifications to the equalization of the noise that you should be able to hear fairly easily. After you’ve been through the disc a few times, put your cd player on random play and then try to identify the tracks by ear. I think you will be surprised at how quickly you will be able to identify the artifacts in eq, and at how much better you will be able to identify the sonic characteristics of gear you are evaluating by using the long pink noise in track one in your evaluations.

Here are some examples of tracks from the disc. Please note, the sample tracks here are 320kbs mp3 files and are compressed, they may therefore have some artifacts that make it slightly more difficult to hear the artifacts that are being highlighted. The files on the download that you can burn to a CD are wav files and are not compressed and should demonstrate the artifacts somewhat more clearly:

Sample Tracks(Click the image to hear track.) Pink Noise Flat, no EQ. Pink Noise with the high frequencies boosted. Pink Noise with the lows boosted. Pink Noise with a boost in the mids. Pink Noise with a cut (or notch) in the mids.

Okie dokie! If you are still interested in some ear training, just download the Ear Training Disc Files. CAUTION: This is a BIG! 11GB .zip file that includes all 26 tracks as .wav files, and includes the track list as a Word document. Once downloaded, you will need to unzip it, and then burn the .wav tracks to a music CD.

If you find you’ve enjoyed this training, you might enjoy “The Golden Ears Audio Eartraining Program” by KIQ Productions which is similar in concept to the pink noise tests I’ve provided here, but includes examples and exercises in identifying: the effect of compression and fast and slow compressor release times; equalization problems; ranges of 1 – 10% and 10 – 30% Total Harmonic Distortion; anomalies in the stereo image (reverse image, mono summation, polarity reversal, pseudo-stereo etc.); channel-to-channel time differences; gated and ungated reverb; 1/3 octave changes and double octave cuts and boosts; and much more.