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. 2016 Feb 1:20:2331216515626131.
doi: 10.1177/2331216515626131.

Harmonic Frequency Lowering: Effects on the Perception of Music Detail and Sound Quality

Martin Kirchberger  1 , Frank A Russo  2
Affiliations

Harmonic Frequency Lowering: Effects on the Perception of Music Detail and Sound Quality

Martin Kirchberger et al. Trends Hear. .

Abstract

A novel algorithm for frequency lowering in music was developed and experimentally tested in hearing-impaired listeners. Harmonic frequency lowering (HFL) combines frequency transposition and frequency compression to preserve the harmonic content of music stimuli. Listeners were asked to make judgments regarding detail and sound quality in music stimuli. Stimuli were presented under different signal processing conditions: original, low-pass filtered, HFL, and nonlinear frequency compressed. Results showed that participants reported perceiving the most detail in the HFL condition. In addition, there was no difference in sound quality across conditions.

Keywords: frequency compression; frequency lowering; frequency transposition; harmonic; hearing loss; music perception.

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Figures

Figure 1.
Figure 1.
Examples of the input–output mapping functions for the different frequency lowering schemes frequency transposition (FT), linear frequency compression (LFC), and nonlinear frequency compression (NFC). (FT: cut-off frequency 5 kHz, peak frequency: 6 kHz, frequency shift 3 kHz; LFC: compression ratio 3:2; NFC: cut-off frequency 2 kHz, compression ratio 1.7).
Figure 2.
Figure 2.
(a) Spectrum of a tone dyad of two complex tones with fundamental frequencies at 800 Hz (black) and 2000 Hz (blue). The cut-off frequency for the nonlinear frequency compression (NFC) condition was set to 2 kHz and the frequency shift for the frequency transposition (FT) condition was determined at 3 kHz, half the peak frequency at 6 kHz. New components to the original version after frequency lowering are marked in green. (b) Spectrum of a tone dyad of two complex tones with fundamental frequencies at 800 Hz (black) and 2000 Hz (blue). The cut-off frequency for harmonic frequency lowering (HFL) was set at 4 kHz. New components to the original version after harmonic frequency lowering are marked in green.
Figure 3.
Figure 3.
Schematic of the different input–output functions that were evaluated in the main test.
Figure 4.
Figure 4.
Long-term average spectra of the four music segments in the OV/LP condition, the HFLo condition and the spectra of the lowered signal for a gain weight of 0 dB.
Figure 5.
Figure 5.
Example screen of the main test.
Figure 6.
Figure 6.
Mean ratings and standard errors for detail and quality in the 5 conditions under test (Orig: Original, NFC: nonlinear frequency compression, HFLi: harmonic frequency lowering with individual cut-off frequency, HFLo: harmonic frequency lowering with default cut-off frequency, LP: low pass).
See this image and copyright information in PMC

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References

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