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Subwoofer Test Tones

These subwoofer test tones play sustained low-frequency sine tones (20–100 Hz) and slow bass sweeps straight through your subwoofer or speakers. Use them to check that your sub actually reproduces a given note, to find its drop-off point by ear, and to compare placements. Each tone fades in slowly so there is no thump.

ℹ This is an uncalibrated listening aid, not a measurement. It plays a clean sine tone — it cannot tell you SPL in decibels, the sub’s true frequency response, or its distortion. Crucially, most laptops, phones, and earbuds cannot reproduce below ~50–80 Hz, so a silent low tone may be your device, not your sub. Your ears are also far less sensitive to deep bass (equal-loudness), so low tones need more level to sound as loud. For real numbers, use a calibrated SPL meter or a measurement mic with REW.

⚠ Safe-volume warning. Sustained high-level bass can damage subwoofers, drivers, and your hearing, and can shake objects loose. Start with the volume LOW and raise it slowly. Deep tones can be physically intense even when they sound quiet — if your sub makes mechanical, flapping, distorted, or rattling noises, turn it down immediately. Never run loud test tones for long periods.

Idle

Sustained test tones (Hz)

Low-frequency sweep

Master volume 15%

Pick a tone or a sweep to begin. Start with the volume LOW.

Placement comparison workflow

Play a single sustained tone where the bass is currently weak or uneven — 40 or 50 Hz is a good start.
Walk to your usual listening seat and judge how loud and even the bass feels there.
Stop, move the sub to a new spot (corners, along a wall, the “subwoofer crawl”), then play the same tone again.
Keep the master volume fixed between trials so you are comparing positions, not levels.
Choose the placement where the tone is loudest and most even across seats. This is a by-ear comparison — for real numbers, measure with an SPL meter or a measurement mic and REW.

How It Works

This tool uses your browser’s Web Audio API to synthesise a pure sine tone at a chosen low frequency and route it — through a gain stage that controls the volume — to your audio output. That output is whatever your computer or phone is connected to: built-in speakers, headphones, a soundbar, or a hi-fi/home-theatre system feeding a subwoofer. Each bass test tone is the intended sound only — a straightforward speaker test signal; nothing is recorded, measured, or uploaded. Each tone fades in slowly (about half a second) to avoid the loud thump a sudden bass transient can put through a cone, and fades out briefly when you stop to avoid a click.

The discrete buttons play sustained tones at 20, 25, 30, 40, 50, 60, 80 and 100 Hz — the region a subwoofer is meant to cover. The two sweeps glide smoothly between 100 Hz and 20 Hz (and back) over about twelve seconds, on a logarithmic path so each octave gets equal time. Sweeping down is the easiest way to find where your system drops off: listen for the point where the bass fades, thins out, or vanishes, then switch to the nearest fixed tone to confirm it by ear. You can also use a sustained tone at a known room-mode frequency — typically between 40 and 80 Hz in most rooms — while walking around to identify standing-wave nodes where bass is thin and antinodes where it booms; comparing several positions with the same tone is the essence of the subwoofer crawl technique.

Two honest limits matter. First, this is uncalibrated: what you hear is your whole playback chain — amplifier, sub, crossover, room, and your ears — not the sub in isolation, and there is no decibel reading. Second, the human ear is dramatically less sensitive at low frequencies (the equal-loudness effect described by the ISO 226 curves), so a 30 Hz tone needs far more level than a 100 Hz tone to seem equally loud. And if a low tone is silent, suspect your device before your sub — most laptops, phones, and earbuds simply cannot move enough air below 50–80 Hz. Treat the result as a guide, and reach for an SPL meter or a measurement microphone with REW when you need a real measurement. If you want to estimate where a sub’s useful range begins, the companion subwoofer frequency calculator can help you think through enclosure size and tuning before you start listening tests.

Frequently Asked Questions

I pressed a low tone and heard nothing — is my subwoofer broken?

Probably not. Most laptops, phones, tablets, and earbuds physically cannot reproduce below about 50–80 Hz, so a 20 or 30 Hz tone will simply be silent on them — that is the device, not your sub. Try the tone on the actual system with the subwoofer, make sure the sub is powered on with its level up and its crossover set above the test frequency, and remember that deep bass needs more volume to be audible. If higher tones (60–100 Hz) also produce nothing on a real sub, then check connections and settings.

Can this tell me my subwoofer’s frequency response or output in decibels?

No. This is an uncalibrated listening aid that only plays tones. It has no microphone and makes no measurement, so it cannot report SPL in decibels, a frequency-response curve, or distortion. What you hear is your whole playback chain and room combined, judged by ear. For real numbers, use a calibrated SPL meter for level, or a measurement microphone with free software like REW (Room EQ Wizard) for a response curve.

How do I find my subwoofer’s drop-off point by ear?

Set a fixed, moderate master volume and run the downward sweep (100 → 20 Hz). Listen for the point where the bass clearly fades, thins out, or disappears — that is roughly where your system stops reproducing usefully. Then play the nearest fixed tones around that point to confirm it. Keep in mind this is by ear and uncalibrated: room gain can boost the lowest notes at some seats, and your ear’s falling low-frequency sensitivity makes the bottom octave seem to drop off sooner than it really does.

Why do the deep tones sound so much quieter than the higher ones?

Because human hearing is far less sensitive at low frequencies. The equal-loudness contours (ISO 226) show that a 30 Hz tone must be played much louder than a 100 Hz tone to be perceived as equally loud. So a deep tone can be moving plenty of air — and stressing the sub — while still sounding faint. Raise the volume cautiously, and watch for mechanical or distorted sounds rather than chasing loudness.

Is it safe to play loud bass test tones?

Sustained high-level bass can damage subwoofers and drivers and can harm your hearing, so start with the volume low and raise it slowly. If the sub makes flapping, mechanical, buzzing, or distorted noises, turn it down at once — that is the driver hitting its limits. Keep loud tests brief, and never use a long, loud tone to “test” endurance. The slow fade-in here protects the cone from a thump, but it does not make a loud tone safe.

What crossover frequency should I set when using these test tones?

The crossover (LPF) setting on your subwoofer or AV receiver determines the highest frequency the sub reproduces. A common starting point is 80 Hz — the THX standard and Dolby’s recommendation for most satellite/bookshelf systems — though you may go lower (e.g. 60 Hz) if your main speakers reach down confidently. Set the crossover above any tone you want the sub to play, then use the 60–80 Hz buttons here to confirm the sub actually produces those notes. The subwoofer crossover optimizer can help you pick the right hand-off point for your specific speakers.

Why does bass sound louder in corners — and how do these tones help me use that?

Room boundaries reinforce bass through what acousticians call room gain and boundary loading. A subwoofer in a corner uses two walls and the floor as acoustic mirrors, often adding 6–9 dB of perceived level compared to a mid-room placement. However, corners also excite room modes (standing waves) more strongly, which can make certain notes boom while others vanish. Play a sustained 40 or 50 Hz tone at a fixed volume and walk the room — the loudness swings you notice map the standing-wave pattern. Moving the sub even half a meter can dramatically shift which frequencies boom or thin out at your listening seat.

What is the “subwoofer crawl” and can I do it with this tool?

The subwoofer crawl is a placement technique where you temporarily put the sub at your listening seat and crawl around the room while a tone plays, listening for where it sounds loudest and most even — that position is where you should place the sub. Yes, you can do it here: play a sustained 40 or 50 Hz tone at a low-to-moderate volume, put the laptop or phone at ear height at your seating position, then move around the room (or move the sub to candidate spots) keeping the master volume constant. The spot that sounds fullest and most consistent across your seats is the best placement.

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