Use tremolo when you want a part to pulse. It works on any sound, even a drum loop, and it's usually synced to the tempo so the pulses land on the grid.
Use vibrato when you want a held note to sing. It only works on sounds with a clear pitch, it sounds most natural at about 5 to 6 Hz with a small depth, and it's normally left free of the tempo, the way a singer's is.
At a glance
| Property | Tremolo | Vibrato |
|---|---|---|
| What moves | Volume | Pitch |
| How an effect does it | Multiplies the sound by a gain the LFO sets | Plays the sound through a short delay whose length the LFO keeps changing; on a synth, the LFO goes straight to the pitch |
| Depth is measured in | Decibels of dip, or a percentage | Cents of pitch swing, or a percentage |
| Typical rate | 1 to 10 Hz, often synced to the tempo | About 4 to 7 Hz, set by feel |
| Works on | Any sound, including drums and noise | Sounds with a clear pitch |
| The mix knob | Makes the dips shallower | Turns it into a chorus |
| Stereo version | Auto-pan | Each side bends the opposite way, which sounds wide and unsteady |
| Sped up to audio rates | Amplitude modulation, a close relative of ring modulation | FM synthesis |
| Best for | Clean guitar, electric piano, pads, rhythmic chopping | Leads, solo lines, strings and held notes |
What's the difference between tremolo and vibrato?
Both effects make a sound waver on a regular cycle, and both do it with an LFO, a low frequency oscillator: a wave too slow to hear as a tone, whose only job is to turn a setting up and down for you. What separates them is the setting it's wired to: in a tremolo the LFO moves the volume, and in a vibrato it moves the pitch.
The quickest way to hear that is on a sound with only one frequency in it, which is why the lab opens on a 110 Hz sine wave. Turn the tremolo on and the single peak on the spectrum stays exactly where it is while its height rises and falls, five times a second. Switch to vibrato and the peak keeps its height and slides sideways instead, a little above 110 Hz and a little below. Your ear hears that sliding as a note going sharp and flat.
Real voices and instruments blur the line a little. A singer's vibrato is mostly a movement in pitch, but the loudness of the voice usually wavers with it. An effect keeps the two apart.
The names on guitar amps and instruments
If you learned these words from guitar gear, you may have them backwards, and Fender is the reason. Its 1960s amps have a channel labelled Vibrato whose knobs move the volume, which makes it a tremolo, while the tremolo arm on a Stratocaster bends the pitch of the strings, which makes it a vibrato. The tremolo lesson has more on how that happened.
The vibraphone has the same mix-up built into its name. Under each bar hangs a tube that makes the note louder, and a motor spins discs at the top of the tubes so they open and close. The bar sets the pitch, and the discs leave it where it is; what they change is how loud the tube makes the note. The shimmer of a vibraphone with its motor on is a tremolo.
Classical players use tremolo for something else again: a string player moving the bow back and forth on one note as fast as possible. Vibrato means the same thing in an orchestra as it does in a plug-in. When this page says tremolo, it means the volume effect.
What each one does to a sound, in numbers
The tremolo in step 2 of the lab has a depth of 60%, so at the bottom of each cycle the volume falls to 40% of full. In decibels that's 20 × log₁₀(0.4), about −8 dB, and at the top of the cycle it's back to full. The pitch doesn't move at all.
The vibrato in step 3 swings the pitch by about 40 cents either way. A cent is a hundredth of a semitone, so 40 cents is a little under half a semitone. On a 110 Hz tone that moves the frequency between about 107.4 Hz and 112.6 Hz, five times a second, and this time it's the volume that stays where it was.
Tremolo depth is easiest to think about in decibels, because that's how loud the dip sounds. The percentages on most plug-ins work like the lab's: the number is how much of the level the LFO takes away at the bottom of each cycle.
| Depth | Lowest level | Dip | Sounds like |
|---|---|---|---|
| 25% | 75% | −2.5 dB | A gentle sway |
| 50% | 50% | −6.0 dB | A clear swell |
| 60% | 40% | −8.0 dB | The throb of an amp tremolo |
| 70% | 30% | −10.5 dB | A strong pulse |
| 90% | 10% | −20 dB | Close to chopping |
| 100% | 0% | Silence | Full chop |
Vibrato depth is measured in cents. Somewhere between about 10 and 30 cents suits a synth lead, and past about 60 cents most parts start to sound out of tune. The vibrato lesson has a full table of what the lab's depth and rate settings come to in cents.
How do tremolo and vibrato effects work?
A tremolo is the simpler of the two. It multiplies every sample of the sound by a gain between 0 and 1 that the LFO sets, so the sound gets quieter and louder and nothing else about it changes. It adds no delay, and the depth means the same thing whatever the rate: a 60% tremolo dips by 8 dB at 1 Hz and at 8 Hz.
Recorded audio has its pitch baked in, so a vibrato has to change the playback speed. It sends the sound through a delay a few milliseconds long and lets the LFO change the length of that delay. While the delay is getting longer the sound coming out is stretched and plays slightly flat, and while it's getting shorter the sound is squeezed and plays slightly sharp. It's the Doppler effect, the same thing that lowers the pitch of a siren as it drives past you.
Because the pitch follows how fast the delay is changing, a faster rate bends the pitch further at the same depth: the lab's 15% depth gives 40 cents at 5 Hz and about 64 cents at the lab's top rate of 8 Hz. The whole sound also comes out a few milliseconds late, 6 ms on average in the lab, which only matters if you blend it with an unprocessed copy on another track.
Synths skip the delay. They send the LFO to the oscillator's pitch and the depth is set in cents directly, so rate and depth stay independent. A synth's tremolo sends an LFO to the amplifier instead. Both are on almost every synth with an LFO, and the LFO lesson covers the routing.
When to use tremolo and when to use vibrato
Tremolo works on anything, because every sound has a volume. On a clean guitar or an electric piano it's the throb of a 1960s record. On a pad, a deep tremolo synced to sixteenth notes turns a held chord into a rhythm part, and on drums or noise it chops the sound into a pattern. Since it doesn't touch the pitch, it can't put a part out of tune, so you can push it hard.
Vibrato needs a note to bend. It suits single lines with long notes: synth leads, solo strings, a whistled hook, the held note at the end of a vocal phrase. It works less well on chords and full mixes, because it bends every note by the same amount at the same moment, which sounds like a warped record. That can be the point, for a lo-fi or tape effect, but it won't sound like a player's vibrato. On noise or a hi-hat it does almost nothing you can hear, since there's no pitch to move.
Syncing to the tempo
Tremolo is a rhythmic effect, so it's usually synced. To turn a note value into a rate, divide the BPM by 60 to get beats per second, then multiply by the number of pulses per beat. At 120 BPM that's 2 Hz for quarter notes, 4 Hz for eighths and 8 Hz for sixteenths. Unsynced, a tremolo drifts against the groove, which can sound loose and vintage on a guitar and messy on anything programmed.
Vibrato is the opposite. Singers and string players set the speed of their vibrato by feel, mostly between 5 and 7 cycles a second, and it has no link to the tempo, so a vibrato locked to the beat tends to sound mechanical. Leave it free unless that's the sound you want.
The mix knob does different things
On a tremolo, mixing in the dry sound only makes the effect weaker. Take the step 5 setting, a 70% depth that dips the level to 30%, and set the mix to 50%. Half the sound now stays at full level and half follows the LFO, so the lowest point is 0.5 + 0.5 × 0.3 = 0.65, a dip of 3.7 dB. It's still a tremolo, just a gentler one, which makes the mix knob a second depth control.
A vibrato changes character. The moving copy and the steady original play at slightly different pitches, beat against each other and cancel at some frequencies, and that blend is a chorus. A short delay like the lab's 6 ms can even sound close to a flanger. If a vibrato sounds swirly when you expected a clean wobble, check that the mix is at 100%; many vibrato pedals have no mix knob at all. The chorus lesson compares the two.
Stereo works differently too. Run a tremolo's left and right LFOs half a cycle apart and the sound swings from speaker to speaker, which is auto-pan. Do the same to a vibrato and one side goes sharp while the other goes flat. The correlation between the channels drops and it sounds wide on headphones, but on speakers the two sides meet in the room and some of a chorus's beating comes back.
Using both at once
A rotary speaker can't help doing both. The Leslie speaker on a Hammond organ spins a horn for the treble and a drum for the bass. As the horn swings towards you and away, the Doppler effect bends the pitch, and as it points at you and then away, the volume rises and falls. The room's reflections blur the two together, which a single tremolo or vibrato plug-in can't copy.
On a synth you can build the same thing from two LFOs, one on the pitch and one on the volume. Keep the vibrato small, 10 to 20 cents, and let the tremolo carry the movement you want people to notice. Running the two at slightly different rates stops the movement repeating in an obvious way.
Speeding them up into audio rates
The lab stops at 8 Hz, because both effects change into something else when the LFO gets much faster. A tremolo multiplies the sound by the LFO, and that adds two new frequencies either side of every note, as far away as the LFO's rate. At 5 Hz they're so close to the note that you hear them as the pulse. Past about 20 Hz they start to sound rough, and at a few hundred hertz they're new pitches. That's amplitude modulation, and ring modulation is its close relative.
A vibrato pushed to audio rates with a lot of depth becomes frequency modulation. The pitch moves so fast that you stop hearing a wobble and start hearing new harmonics, which is how Yamaha's DX7 makes its sounds. The FM synthesis lesson starts there.
How to choose and set up either one
- Decide what should moveIf you want the part to pulse or chop, use tremolo. If you want held notes to sing, use vibrato. If the sound has no clear pitch, like drums, noise or a full mix, vibrato won't do much, so use tremolo.
- Set the rateFor tremolo, switch on tempo sync and start at eighth notes, then try quarters and sixteenths. For vibrato, start at 5 to 6 Hz and leave it free.
- Set the depthFor tremolo, start around 50%, a 6 dB dip, and go deeper for a stronger pulse. For vibrato, start low and raise it until you hear the wobble, then back off a little; on a synth, 10 to 30 cents.
- Check the mixVibrato belongs at 100% wet. Tremolo can sit lower if you want the pulse gentler.
- Bring it in where it's neededAutomate vibrato so it arrives on long notes, or use a delayed LFO on a synth. Tremolo is often strongest on one section, such as a verse guitar or a breakdown pad, so try it there first.
- Compare at the same loudnessA tremolo lowers the average level, so match the volume before you decide whether it helped. The lab does this for you.
Common mistakes
Using vibrato when you wanted tremolo
On a guitar amp labelled Vibrato, or a plug-in modelled on one, check which one you're getting. If the notes go out of tune with the backing, it's pitch vibrato; if the level pulses and the tuning holds, it's tremolo, whatever the label says.
Too much vibrato depth
A wide vibrato on a part that has to sit in tune with a bass line or a chord pad makes it sound sour. Keep it under about 30 cents on anything that isn't meant to be dramatic, and less on a pad.
Vibrato on a whole mix or a chord part
Every note bends together, so a full mix or a chord part sounds seasick. If you want movement on chords, tremolo or a chorus is usually the better choice.
Leaving a tremolo free-running on a programmed track
A tremolo at 5.3 Hz over a track at 124 BPM drifts against the beat and sounds like a mistake. Sync it, or set the rate by the arithmetic above.
A compressor after the tremolo
A compressor turns down the loudest moments, and on a tremoloed part those are the tops of the pulses, so it partly undoes the effect. Put the tremolo after any compression on the track.
Training your ears to tell them apart
The quiz under the lab plays the current sound through either the tremolo or the vibrato, with the screens covered and the rate and depth changed each round, and asks which one it is. Start on the sine or the lead, where a pitch change is easy to hear. Then try it on the chords, and listen for whether the chord goes out of tune or only gets quieter.
Questions people ask
Is a Leslie speaker tremolo or vibrato?
Both. The spinning horn moves towards you and away from you, which bends the pitch the way a passing siren does, and it points at you and then away, which moves the volume. Its fast speed is usually called tremolo and its slow speed chorale, but you hear pitch and level moving together at either speed.
Does a vibraphone make vibrato or tremolo?
Tremolo, mostly. A motor spins discs at the top of the tubes under the bars, opening and closing them. The tubes only make each note louder and the bar sets the pitch, so as they open and close the level pulses while the pitch stays where it is.
Which should I use on a vocal?
Vibrato, if you use either, and only on long held notes, since a vibrato plug-in moves every note by the same amount and that sounds mechanical on a voice. Tremolo on a vocal is an obvious effect, used for a choppy, stuttering sound and often synced to the tempo.
Can I use tremolo and vibrato together?
Yes. A rotary speaker does it on its own, and on a synth you can send one LFO to the pitch and another to the volume. Keep the vibrato small and let the tremolo set the rhythm, or run both at the same slow rate for a woozy, seasick sound.
What does tremolo mean in classical music?
For string players, tremolo means moving the bow back and forth on one note as fast as they can, and on a mandolin or guitar, tremolo picking means the same with a plectrum. Both repeat the note rapidly. Vibrato means the same thing in an orchestra as it does in a plug-in: a wobble in pitch.
Is vibrato the same as chorus?
They're built the same way and sound different. A vibrato is a moving copy of the sound with none of the original left. Mix the original back in and the two beat against each other, and that blend is a chorus, which is why turning a vibrato's mix knob down to 50% turns it into one.