Sine Sweep - Lower Spectrum (20-200 Hz)

Background

These audio files scan the lower range of audible frequencies, from 20 Hz to 200 Hz in a 10 s time span.

When the time scale is logarithmic, sweeping between 20 Hz and 40 Hz (one octave) or from 100 Hz to 200 Hz (one octave) will take the same time. When the time scale is linear, sweeping from 20 Hz to 40 Hz will be much faster, and equal to the time taken to sweep from 100 Hz to 120 Hz (3 semitones).

Applications

Use these files to determine resonant frequencies in your room. These resonances occur in every enclosed space. Sound waves are bouncing from the walls, ceiling and floor and interact with the original wave and between themselves. At given frequencies, this interaction is stronger than others (standing waves). The frequency of each resonance is directly related to the room's dimensions (room modes). When you play a sound having the same frequency as a natural resonance of the room, that note will sound much louder (constructive interference), or weaker (destructive interference) depending on your listening position.

The 20-200 Hz sweep can also be used to check the transition between your subwoofer and main speakers.

The sound files

As you play the file, pay attention to sudden changes in level. In this frequency range, those changes can only be due to room resonances, or - if you use a subwoofer - to a mismatch between the subwoofer phase / position / crossover frequency and your main speakers.

Related pages

Other Sweep Tones

• Our Custom Sweep Tone Generator
• Sine Burst Tones, 20-200 Hz

External Links

• Room acoustics @ U. of Salford
• Room modes crash course
• Room Mode Calculator
• Setting-up your subwoofer