Frequency Sweep Test

What a frequency sweep shows

An audio sweep — a sweep tone — glides through every frequency between two points, so problems that only happen at one frequency stand out: a rattle at 140 Hz, a dip where the room cancels the sound, a speaker that stops at 12 kHz. Music hides these because it is always playing many frequencies at once.

The three preset sweeps

Marks subtract a typical reaction time of about a third of a second, so they land close to the frequency that actually caused the sound.

Speaker rattle test

Most rattles live below 400 Hz, where the speaker cone moves the most. Run the rattle hunt at a moderate level, mark every buzz, then:

1. Open the tone generator and hold the marked frequency.
2. Press lightly on the grille, the cabinet, the case, and any object nearby.
3. When the buzz stops, you have found it. Tighten, pad or move it.

If nothing you touch changes it and it also appears at low volume, the speaker itself may be damaged — run the crackle check on a phone.

High frequency hearing test

This hearing frequency test checks only the top of your range. Use headphones, a quiet room and a low volume. Play the hearing-range sweep and tap the moment the tone disappears. Then run it on Left and Right separately.

• Many adults stop hearing somewhere around 15–17 kHz; the limit drifts down with age and noise exposure.
• A big difference between your ears is more meaningful than the number itself.
• This is a rough check, not a hearing test. Headphones vary, and some cut off before your ears do. If the limit is far below 12 kHz or the ears differ a lot, see an audiologist.

Never turn the volume up to chase a tone you cannot hear.

Logarithmic or linear?

A logarithmic sweep spends equal time on every octave — 20 to 40 Hz takes as long as 10 to 20 kHz. That matches how we hear pitch, and it is what the presets use.

A linear sweep moves the same number of hertz every second, so it races through the bass and spends most of its time in the treble. Use it in Custom when you need a constant Hz-per-second rate, for example for a measurement rig.

Why some parts sound louder

The sweep plays at one level throughout. It sounds loudest around 2–5 kHz because human hearing is most sensitive there, and quieter at the extremes because both ears and speakers roll off. Small bumps and dips are normal — no speaker or room is perfectly flat.