Here are the audio files referred to in Music Electronics
. The preferred format for the files is the lossless compression FLAC format. High quality .mp3 versions are available as well for those who have little or no experience of FLAC.
This track consists of a 261 Hz tone with 50% third harmonic (783 Hz). In the first 5 seconds, the third harmonic has a zero phase relationship with the fundamental. In the second half, the third harmonic has a 90 degree offset.
This is the reference track.
In this track, the musical example in track example.flac is distorted by a small amount.
This track uses the Baxandall-Walker difference technique to isolate the distortion introduced in the previous track.
In this track, distortion components (once again isolated from the music) are reduced to a level equivalent to a total THD of 0.1%.
In this track, distortion components are reduced by another 20dB, equivalent to an overall THD level of 0.01%.
This track consists of two parts - one of which cuts from one to the other. In the first part a pure tone of 1kHz is presented. In the second part the tone has distortion (THD = 1.7%).
This is track example.flac filtered with a digital, Chebyshev, 6-pole, low-pass filter (with 0.1dB pass-band ripple) and a turnover at 16kHz.
The original music signal high-pass filtered with a digital, 6-pole Chebyshev filter with a turnover frequency of 16kHz (0.1dB pass-band ripple).
A frequency sweep with a level -80dBFS (80dB below peak level).
Frequency sweep at -90dBFS.
In this track, the original music example is attenuated by 60dB, so that the peaks reach -60dBFS.
In this track the -60dB attenuated music signal in the previous track has been re-amplified 60dB; to return it to a normalised listening level.
Absolute silence. This track has no modulation.
The Excel spreadsheet of the DFT is available here
The Excel spreadsheet "Hit Calculator" - invaluable for composing to picture.
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© Richard Brice 2012. All rights reserved. Newnes, CYP other information by permission