# What is the limit to which humans can precisely time notes on an instrument or perceive notes as precisely timed?

I have the tendency to either rush individual notes or let them drag behind (see this other question of mine). To cure this I'm recording myself to a click on a DAW and try to see which of the notes in a melody I usually play too early, and which ones I play too late. Of course, there is always some jitter, as I'm not a robot (and that is a good thing).

The question now is: What is the time (might be bpm dependent) that I should consider a note "too late" or "too early", compared to the beat, to work on it. A natural measure would be "when would humans feel that a note is dragging or rushing", but how much is this in ms or in percentage of (for example) one beat note?

• Use your ears. If you've achieved the musical results you want, taking your musical style and instrument into account, then you're close enough. Commented Jan 8 at 10:29
• @PiedPiper beginning music students often think they're "close enough" but aren't. Commented Jan 8 at 10:32
• @phoog OP knows they're not close enough yet. Commented Jan 8 at 10:35
• This seems like a straightforward and scientific question, but there are a lot of variables. (Not the least of which is that you're asking about human neurology and ability, which is a pretty un-straightforward science!) Guaranteed, individuals will differ in both their learned abilities and their maximum potential. And the nature of the musical material might affect the ability (texture, other instruments playing, counter-rhythms, etc.). It will even vary with the tempo, perhaps in a predictable mathematic way or perhaps not. Your earlier question, "what can I do about it," is much easier! Commented Jan 8 at 15:22
• …however I don’t know waveform. The interface and computer negotiate a latency, broadly, which should be mentioned somewhere in preferences. From here you can see how much delay you would expect from the vst and whether any kind of other compensation is going on. Set the latency as low as possible until the computer struggles is the usual advice, however if you are trying to investigate very accurate timing on an entry level audio recording system it may be frustrating, and a lot of money and time has been spent over the years trying to fix these issues. What’s your audio interface? Commented Jan 9 at 11:21

It's very subjective to 'the moment' and also dependent on the genre of music in question. What is considered emotive, exciting, phrasing in one piece may be perceived as sloppy or late execution in another.

That said, when I was working in a fancy studio with high budgets and little room for error my secondary specialism (primary being tuning parts with melodyne etc.) was editing drums. Ideally no editing was the objective but if a band or specifically drummer wasn't getting locked in to the degree desired then editing was needed, generally this was with smaller bands on a lower budget but it happens with very experienced bands too.

When required to make a drum edit I would of course take stylistic considerations into the task, but to answer the question on what's percievable I would tend to work toward either a 10ms or 3ms edit, the latter taking quite a lot more time of course. Other engineers at the studio would send me a part to edit while I was on downtime and they would carry on tracking (of course, tracking to a sub optimal part was not ideal but time is money in studios). The 3ms / 10ms choice would essentially be how I would set the 'nudge' settings in protools, the resolution of each edit I made. 10ms is about enough to take a sloppy part and make it sound 'in time'. This is heavily dependant on the tempo of course but I've found percentage deviation of the position of a transient is less important than absolute deviation. Though this relationship MAY be non linear as using varispeed, which is (generally) speeding up a recording in post does tend to make all timing errors sound less egregious, but it doesn't effect the feel a rhythmic player is imparting.

I should be clear this is with rock/pop recordings where tempo is strict and room for performer time manipulation for the purposes of feel very limited.

So within about 10ms, ±5ms about the objective ideal, a part would sound in time and probably not perceptible as 'bad' to most listeners.

If I were doing a 3ms edit then I would spend time on each snare (for example) pushing and pulling it to get the feel required. 3ms deviation is very hard to recognise, even when I was doing this 10 hours a day every day for many (misspent perhaps?) years of my life! But once you learn to hear it it becomes the difference between something sounding amazingly locked in, ala Steely Dan or similar, and just, well, 'in time'. I want to be clear I was not aiming towards aligning with a grid of the tempo, editing in the way I describe is all done by ear and with an understanding that the most 'locked in' a drum part may sound may be with all the snares (for example, rarely the kicks) behind the beat, or ahead of the beat for that matter.

So I would say a good evaluator of performance at the highest professional level would work at around the 3ms level being the smallest possible margin of error thats perceivable and editable. That sounds small but I think most accomplished and experienced musicians would hear the difference between a drum loop where snares were all exactly on beat compared to where they were all dragging by 3ms. This is probably a skill that only has need to develop in the western popular music field, where metronomic accuracy, and deviation from it to create pushy or pully feels, is an important but relatively unique concept.

That said, a further understanding of perception of delay can be investigated when recording and dealing with the latency of native audio systems (that is, the audio processing is happening on a general purpose computer, not a specialised low latency device). A critical drawback of earlier audio interfaces was inherent latency in the system, so much so that insanely expensive hardware solutions were the norm (think early Protools). A latency of 5ms - 10ms in recording is definitely noticeable, though not perhaps to the average listener. A performer used to perceiving audio feedback to the tune of the speed of sound (which is probably the limiting factor given the nature of the audio reproduction and perception systems we use) is used to near instant response when sitting next to their drum or guitar amp, and a processing delay of even 5ms was considered 'not that good' for audio interfaces, suggesting some kind of perceived difference down to this level.

Anecdotally, I perceive when playing electric bass (not talking of editing now) about 2ms of latency as feeling odd, and this will potentially impact a recording I make, though it's very subjective at this speed and I would hope I could do a good job at much higher latency. This is specifically on headphones and electric bass, where you get used to the instant feel of finger>string>pickup>electric-signal. It’s more a situation of being very slightly off-put by not hearing what your fingertips are feeling, rather than anything being ‘late’.

That said, you could be way less accurate than this and still be considered playing perfectly 'in time', especially if you are not playing a style that values these quite silly levels of precision (which is most music, to be honest, although these silly levels of precision have their place for a certain sound!).

EDIT - More Detail on the editing process

It seems like lots of people have read this post so I thought I should add a bit more context in case anyone reads and feels it sounds like an impossibly large task to edit in the way I mention, it's not really that bad, ProTools makes this sort of editing very easy.

Using tab-to-transient + shift you can select all of one drum/note, up to the start of the next, then you can split with b then nudge around with m and n to your nudge resolution. Once you reached the end of the section you want to edit you can use an inbuilt feature called 'fill gaps and crossfade' that deals with any gaps caused by delaying rushy notes.

3ms was the resolution, not the accuracy for every beat. 3ms is almost imperceptible, JUST imperceptible. Thats a good threshold for a tool, now a double tap of 'n' is clearly noticeable, a triple tap and you can fix a flaw. If you had time you could spend a bit more time with single taps to get the feel just right. If the part was bad enough to be pressing nudge 6 times I'd scrap 3ms and go to 10.

With practice you could do it touch-type speed (almost) so its a mad process to hear happening.

Also, the aim here is NOT to hear a decent eg. drum track then try to doctor its feel. Generally you would be editing a section where the groove is sloppy or mistakes were made, once mistakes are fixed it can all sound a bit plastic, with the luxury of time you may then be able to go in with the 3ms tool and push it around until it sounds great. Occasionally the snare might be generally too lazy in eg. the chorus, but click, tab, shift+tab, b, n, n per snare and say 32 - 64 snares in a chorus is not that bad all in all.

For this sort of editing you need 100% isolation, or you will get an impossibly phasey mess. You also almost always edit all the drum tracks grouped together as one for the same reasons, your cymbals start sounding very very odd if you leave the overheads out of the drum group by mistake...

And lastly, the need to edit is not always because someone did a bad job. A common problem is bands that get signed often work really hard and are very good musicians but they haven't studied music deeply for years, or had training and a sound practice ethic to be become world class performers, besides that would probably knock all the edge off your average band anyway! But pressure is high, budgets strained and sometimes aspirations of label/producer/band not matching reality ('We want this one to sound really like Dreamtheater!.....').

• Regarding the 2ms of latency, do you always wear headphones when playing? Sound travels 60cm in that time, so you would have to have the amp right next to your ears to get below that.
– ojs
Commented Jan 9 at 9:30
• Yeah I’m specifically talking about tracking bass with headphones on, that’s about the only way you’d be able to notice I’m sure! But with headphones on and flipping around the latency settings you can spot that slightly detached feel. It’s more that your fingertip feel doesn’t quite line up to what you are aurally perceiving, rather than actually hearing anything being late! I think there is some perception of even very small latencies on speaker setups, we're subconsciously aware of what we should be hearing considering our distance from speakers, but I agree 2ms is a bit of a stretch there! Commented Jan 9 at 14:35
• I can't tell any difference until I pull it far enough to cause an echo. You had a full isolation both? Or is there a trick to do this to a live multi track recording? How often was it actually sloppy drums and not just latency? I couldn't even get 'em to toss in a snare hit I'd missed, let alone pull them all 3ms one way or another. This place was like 5k an hour? Commented Jan 11 at 13:08
• @Mazura Well, nice studios, Rockfield and Leeders Farm (now gone), big records recorded there but not 5k an hour! That experience of yours is odd, it only takes a minute to drop in a snare enough to cover a little mistake so not sure what they were worried about... It was never latency, we were on protools hd usually or tape, the computer just controls the relays (former) and the system is latency free. I added an edit above to your other Q's! Regarding feeling it, you can only really hear 3ms in context (just), so I think it was more my fingertips it may not be as sensitive with sticks.. Commented Jan 11 at 21:51

Answering the question as asked, a trained human (i.e. drummer or bassist) can hear variations of a few milliseconds in a steady rhythm with clear attack like metronome or hi-hat.

I have seen some analysis where musicians have been found to play at that level of precision. On the other hand, it is common to play slightly off beat (usually behind) in a controlled way. How much behind, depends on many factors but the common range is between 20 to 70 milliseconds. Other common variations are playing straight rhythms with slight swing, and swing with ratio that is not exactly triplets or dotted notes, etc.

I came across a video about overly precise tempo notation a few moths ago, and I'm quite sure I found the link under a question right here at Music SE.

It's called This BPM is trash, and here's why, by Adam Neely. The most relevant part here is the second segment, called Part 1: Time perception.

According to the author, and some research work he's quoting, the reliably (consciously) perceptible difference in timing is on average about 30 ms - though I'm not personally convinced it should be expressed in ms, rather than percentage of the beat in the given tempo (which is not given and I don't trust myself to measure it). Another study he quotes right afterwards said that people notice a change of tempo by about 3 bpm at "moderate" tempos (he's talking about 69 vs. 72 bpm, but isn't that more of a slow tempo than moderate?), or more generally a change of tempo by about 6 to 8 percent.

I don't have any independent source to compare his claims against.

• I agree with the percentage of the tempo being relevant here, for most humans it's much easier to detect a given lack of precision when the notes are played fast than when it's very slow. Also Adam Neely being a bass player, he may have talked about being (with consistance) ahead / on / behind the beat as a fundamental aspect of the bass groove (IIRC he talks about it in some videos) Commented Jan 11 at 16:59

(I'd rather have posted this as a comment, but I'm prevented from doing so due to my rep points. If this answer proves to be a faux pas, I'll gladly delete if prompted by any feedback)

What I want to add is rather small and really only relevant in the context of the answer given by OwenM. Regarding what he says about noticing a 2ms latency when playing bass with headphones on: I've had a related experience when playing electric guitar. On one occasion I used a 1/4" patch cord coupler to add another 25 foot patch cord between me and the amp just to see what it might be like to play on a big stage. I was really surprised to find how pronounced the difference was. What OwenM said about his perception coming from tactile feedback vs purely from the sound picked up by hearing seems to make sense to me. I imagine that watching a video of myself playing wouldn't be much different if I watched it for a second time but 25 feet further from the speaker.

I hope this was worth mentioning.

(EDIT: I had to remove my calculation of the time needed to travel the extra 25 feet due to the extra patch cord. I kept getting different numbers. I'll leave the calculations to the reader in the event that anyone is curious.)

• The speed of sound is about 1125 feet/second, 1.125 feet per millisecond. So that would be... how many milliseconds for 25 feet? My math gets 22 ms, not 4. Commented Jan 10 at 2:23
• If I understand you correctly, you're saying that the electrical signal took 4ms to travel the 25 feet of patch cord. If my math is correct, electricity will travel that distance in about 0.00003 ms. See en.wikipedia.org/wiki/Speed_of_electricity Commented Jan 10 at 2:32
• @piiperi Reinstate Monica I shouldn't have relied on one of the comments which said that sound travels 60cm in 2ms to make my calculations. I will edit in the correction you suggest. (I guess I should do my own research for verification first, right?) Commented Jan 10 at 4:31
• Sound does travel about 60 cm in 2 ms in air, one foot is about 30 cm. 25 ft is about 750 cm, or 7.5 m. I assume you were talking about air distance and you walked 25 ft away from the amp. Commented Jan 10 at 4:36
• @Stu Smith What I meant was that the extra patch cord let me stand 25 feet further from the amp and resulted in the sound taking longer to reach me. My original number is probably wrong. It looks like I should have given a time of about 22ms as the additional time needed for the sound to reach me. For simplicity, my approximation assumed the travel time of the electrical signal to be zero seconds since I couldn't possibly detect such a tiny amount of time like 0.000003 ms. I will try to edit in something with better wording to reflect what I have just said here. Thanks for the heads up. Commented Jan 10 at 4:44

Sound travels about 1ft in 1 millisecond. A typical small ensemble will span something like 10 feet, a large ensemble like an orchestra can span several tens of feet. People don't notice the members of these groups being "out of time" with each other, so in terms of the relative timing of components of an ensemble consistent relative delays of a few to maybe a few tens of milliseconds do not seem un-musical.

• I have heard from other sources that full size orchestra needs a conductor, because they hear each other out of time. The question was also about jitter between individual notes, not constant delay.
– ojs
Commented Jan 10 at 18:55
• Latency, delay, is not a big problem because it can be compensated, adjusted to. A lot of that adjusting happens automatically, and can be worked around with organization. Jitter is a problem because it cannot be compensated, it is timing error. Jitter cannot be corrected with any sort of organizing, only by playing better. Commented Jan 10 at 21:51