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I was listening to Abbey Road but it's just Bass and it sounds like the low E string is a hair flat in a lot of the songs. How did they get away with that?

When I was in the pep band many years ago playing guitar, the bass player told me he did the same thing deliberately. I didn't really challenge him, but I've never done the same even after picking up the bass. Does it somehow give the horns more latitude to be slightly flat, or something? Or is it just superstitious baloney?

In summary, is there any good reason to tune the lowest string of the bass instrument a hair flat?

luser droog
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    It's my understanding that the extreme ends of the piano, both high and low, are also intentionally made "out of tune". As to why .... – Aaron Nov 02 '20 at 02:19
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    On the piano, my understanding is that the overtones of the lowest strings are not harmonic because they're so stiff and not *string-like*. So they're detuned slightly so the overtones of low octaves don't clash so much. ... Maybe being slightly out could create a chorusing effect with the guitars and make the tonic chord sound fatter? – luser droog Nov 02 '20 at 02:31
  • Does the lead answer (by Miguel Zapata) on this Quora thread lend any insight? [Why do bass guitars always sound slightly off-key and out of tune even if they have been perfectly tuned?](https://www.quora.com/Why-do-bass-guitars-always-sound-slightly-off-key-and-out-of-tune-even-if-they-have-been-perfectly-tuned) – Aaron Nov 02 '20 at 03:19
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    The effect of string thickness on the piano causing inharmonic partial and that being compensated for by *stretch tuning* is a factor for both high and low notes on the piano. It could be that the low E string on a bass is thick and stiff enough that a bit of stretch tuning helps there. But a lot of bass tones, including McCartney’s don’t have a lot of the upper partials very audible. – Todd Wilcox Nov 02 '20 at 03:51
  • @Aaron - a strong pluck may *initially* make the pitch sound slightly higher - same with guitar, just watch the tuner needle - but very soon, any note will settle to its real pitch. Not convinced that low B strings are floppier. Mine aren't. On the OP's video, sounds to me like the lower strings are in tune, but the higher notes are out. In fact, some of the playing sounds pretty amateur. – Tim Nov 02 '20 at 07:52
  • Listening to only the first 30s of that, the first time he hits the bottom string, a fretted G, it's sharp - so that theory goes straight out of the window. I didn't check the rest of it to see if he had a bad zero fret he was compensating for. – Tetsujin Nov 02 '20 at 07:52
  • @Tetsujin - wherever the zero fret was, isn't that a reference point that the whole intonation works from? So if that's out to the rest of the frets, is that what you mean? – Tim Nov 02 '20 at 10:42
  • If the zero fret [or nut, whichever] was flat to the rest of the neck, it would make sense to tune slightly flat to pull the fretted notes in. I'd always consider that in the late 60s tuning was somewhat more 'optional' than it is these days. "Close enough for jazz" ;-)) – Tetsujin Nov 02 '20 at 12:38
  • @Tetsujin - is that the right way? Flat open string - wouldn't you tune it a little sharp? – Tim Nov 02 '20 at 14:24
  • Not if you wanted your F to be right. Crappy old guitars [in which I include 1960's Hoffners ;) have a tendency to be high at the nut, making E flat, F sharp, then getting better up the neck, if the intonation's right. Of course, he could afford to get it fixed… but did he? [This is all pure speculation anyway, I didn't listen through enough to be sure] Or he could have just hit that first low G a bit too hard. I switched it off at that point. – Tetsujin Nov 02 '20 at 15:59
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    Late note: John says that's the Rikki in his answer below & research shows he's right. Having been a Riiki player for over 40 years [mine is a mid 70's 4001], I perhaps ought to have recognised the sound - but even re-listening, it doesn't sound like any Rikki I've ever played. Possibly wired mono or just front pickup [which I've never done] & that heavy compressor is throwing me. Or he had flat-wounds… idk… Anyway - Rikkis can suffer from high nut. I fixed mine so long ago, I'd almost forgotten ;) – Tetsujin Nov 02 '20 at 17:09
  • FWIW, I used to tune my lowest string flat because when I would hit it, it would be sharp at the begining. – JacobIRR Nov 02 '20 at 21:43

2 Answers2

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Thanks for a great question. Being a bassist and an admirer of Paul and the Beatles it was great to hear isolated bass tracks from the Abbey Road album.

In answer to your summary question, there really is no good reason to tune the low string on a bass flat. Doing that defeats the purpose of trying to play in tune. Assuming your bass is intonated properly if you play notes of the same pitch on different strings with that method the notes on the E string will be flatter than the same notes on other strings. Where is the logic in that? I can play devil’s advocate and say why just the E string? Why not all of them gradually slightly more than a P4th apart from each other? Imagine what that would sound like.

As for Abbey Road, I did a flex pitch analysis of Come Together amd Something in Logic Pro and made some interesting discoveries.

Come Together

The tuning is better and the tone is more pure which makes me think he used his Rickenbacker for this song. The D string is a little flat in relation to the others but aside from that the bass is pretty much in tune.

Something

This has to be the Höfner. The notes are darker and more warbly, especially the low notes. The notes fretted high on the neck play sharp and the open strings play flat so the intonation is off. Also on the E string notes there is a pitch dive after the initial attack, probably a characteristic of the short scale instrument and the hollow body. Check out the pitch analysis of the chromatic descending line in the bridge: enter image description here The E string is very flat and I’m sure it is not intentional because the fretted notes are more in tune than the open strings. I’m guessing he tuned using the 5th fret method and that actually might have been a good thing.

I remember Paul saying the Höfner had some tuning issues. It’s amazing how we don’t really notice it much in context though. I’m sure the guitar going through the Leslie and the organ background help it all blend togehter.

In conclusion I know pianos use stretch tuning, where the octaves are tunes at intervals slightly larger than an octave so the low end is a bit flat and the high end is a bit sharp. The reason for this is the unique characteristics of that instrument. It would be pretty difficult to emulate that on a bass. Maybe a bass can be tuned a few cents flat overall to try and match the low end of the piano, say if they are going to be playing unison lines but not just the E string IMO.

leftaroundabout
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John Belzaguy
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    If the action on the Hofner was pretty awful (= high), then tuning the open strings a tad flat would put fretted notes back in tune, do you think? Not sure if digital tuners were around at that time, so tuning to each other was the standard way, and with no keyboard to reference, any old where used to do. As so many '60s bands did. – Tim Nov 02 '20 at 10:47
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    @Tim High action could be the cause of the upper register notes being sharp. I believe Paul said he liked a fairly high action. His sound suggests he played on the hard side which can alter pitch too. The Hofner has a floating bridge so a very slight accidental nudge can take it out of correct intonation as well. As far as tuning goes, Abbey Road (the album) has piano, Rhodes or organ on just about every song so I’m sure they matched them or at least used tuning forks for reference. – John Belzaguy Nov 02 '20 at 16:04
  • @Tim I also wanted to mention the open E on Something actually registered as a D# 46 cents sharp! A little more than “a tad”, huh? Also, to me action that’s too low is just as or more awful as high action but then again I play a lot of upright... – John Belzaguy Nov 02 '20 at 17:18
  • At least low action won't take a fretted note out of tune - unless it catches the string on the next fret up! That D# was on the way to being E, almost, be fair... – Tim Nov 02 '20 at 17:21
  • @Tim if you look at my pitch analysis it looks like it started out as an E! – John Belzaguy Nov 02 '20 at 17:25
  • The stretched piano tuning is due to the harmonics of the strings being out-of-tune: Piano strings are not ideal strings, they are very thick for their length, so they behave a bit like vibrating, tensioned rods. This shifts the frequencies of the harmonics up. So, for an octave to sound perfect on the piano, it has to be stretched from the 2x factor to match the first overtone of the low string to the fundamental of the high string. The too short strings at the low end and, and the too thick strings at the high end of the scale need much more stretching than the better balanced center strings – cmaster - reinstate monica Nov 03 '20 at 20:21
  • That said, bass strings are also relatively thick and short for their frequencies, especially on a short scale bass, so the same kind of stretching results when you tune the bass strings relative to each other. – cmaster - reinstate monica Nov 03 '20 at 20:24
  • @cmaster-reinstatemonica Regarding the stretching you say results when you tune, there are several different ways to tune a bass, such as 5th fret to open string, matching harmonics on adjacent strings, electronic tuner, tuning fork(s). Which results in this stretching, the harmonics? Also, are we talking cents or fractions of a cent? – John Belzaguy Nov 04 '20 at 18:33
  • @JohnBelzaguy Frankly, I do not know how strong this effect is on bass strings, but it should be comparable to a piano (similar string length). The effect kicks in with harmonics tuning. Frets do not care about harmonics and using them stretches the string. A good setup has the fret position correct for the effect of this stretching, but frets are inherently imprecise. For the piano, the answer is the railsback curve, which is depicted in https://commons.wikimedia.org/wiki/File:Railsback2.png . This gives a tuning shift between the E and A note that you have on a bass as around 8 cents. – cmaster - reinstate monica Nov 04 '20 at 21:13
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The range of the bass never necessitates this tuning complication well known from piano tuning. The "hair" would end up so thin, for a bass, so as to have no effect whatsoever and I have never seen anyone to do this as an explicit tuning step. But it may be implicit in our tuning methods.

I don't find the idea entirely absurd for a fretless plucked instrument with an extra low (and relatively short) lowest string. Am I calling the E string relatively short? Yes I am, it's meant relatively to its thickness. There are two ways to make a string sound extra low. Either you make the string longer, but then the bassists need to grow orchestral player's big hands and perhaps even make uncomfortable detours into their C extensions. Or you alter the weight/stiffness ratio but that makes the string relatively thicker, which is the same thing as making it "relatively shorter".

A string has the shape of a thin cylinder. The thinner it is, the closer it is to a line segment. A line segment has harmonics at integral multiples of the base frequency; a thin cylinder has them a tiny bit further apart of each other. Especially the F2/F1 ratio is affected.

The E string is not normally played in the thumb position because there it becomes a thick enough cylinder that it's no longer perfectly in tune even with its own harmonics (thus sounding a bit muddy). So it usually ends up used only for notes too low to be played on any other string. Its overtones have to be in tune with those higher strings' fundamentals and overtones, while its own fundamental is "free" to be tuned wherever, as long as it is not audibly out of tune with its own overtones (a condition which is only approximately reachable, and not alterable by ordinary tension based tuning). In fact, a common bass tuning technique tunes the 4th harmonic of E to match the 3rd harmonic of A, which would, if executed perfectly, result in the thicker string's fundamental ending up a super-thin hair flat compared to the thinner string's fundamental. Won't that affect all of E, A, D strings equally? Yes it would theoretically all of them, but the thickest cylinder would be affected the most. So if anyone would ever barely perceive or barely measure the effect, it would be probably on the E string.

Won't the same effect be encountered on a cello as well? Well, there are two differences here. One is psychoacoustic. We are better at detecting pitch differences by ear in the cello range than in the contra octave. The fundamental frequency is always physically much "louder" than any of its overtones, but we might have quite a bit more of a tolerance for the fundamental to be a little bit off on the E string (because it is so low), without any such tolerance for the pitch of any of its simultaneously present overtones (also coming from the E string, not just from sympathetic resonance of anything else). The other reason (as Edward has pointed out) is that bowing, as opposed to plucking, provides stable energy transfer to the string, therefore the phase of all the harmonics isn't synchronized among themselves just at the beginning of the tone, but continuously (which is called mode locking). So the harmonics are no longer stretched apart from each other when using the bow, they have to compromise (weighted by energy, thus favoring the fundamental). And the bass gets tuned specifically for pizzicato performance more often than any other instrument in the violin family.

Where does fretlessness come in? Well, any of the above, imperceptible as it is, is sure to drown, on the physical level, in intonation inaccuracies (finger position, finger force angle, action height). But fret positions on a cheap instrument can mess up with intonation even more. So tuning methods which have to rely on anything other than open strings and their overtones will have their own bigger problems to balance than non-integral ratios between harmonics. Tuning is an exercise in compromises, so as to offend the ear the least.

TL;DR - The tuning method matters. When I'm tuning the E string using pizzicato flageolets, or when I'm tuning the bass to match a particular piano, my ear probably locates the pitch of the E string by its overtones more than by its fundamental, and the fundamental does indeed end up a tiny bit flat compared to the fundamental of any other string, while still providing the optimal tuning for subsequent pizzicato play.

Jirka Hanika
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  • "The range of the bass never necessitates this tuning complication well known from piano tuning." [This image](https://en.wikipedia.org/wiki/File:Railsback2.png) says that we expect a piano's low B (which appears on a standard 5 string bass) to be about 30 cents flat, and the low E would be about 20. [(See Also)](http://www.synthmind.com/ch5.html) Considering that an electric bass is more inharmonic than a piano (citation needed), we should expect stretch tuning to be a concern for bass tuning. So why don't we stretch? I'm not sure, but my bass sounds most in tune slightly flat... – Edward Nov 03 '20 at 05:04
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    Also, a bowed cello is not inharmonic, as the bowing motion phase-locks the harmonics. [Source](https://newt.phys.unsw.edu.au/jw/harmonics.html) The difference is not purely psychoacoustic. – Edward Nov 03 '20 at 05:11
  • @Edward - The range of a typical piano, is a little over 7 octaves of open strings. Even a six stringed bass can't get close to that. However, whenever I play bass and piano together, I shamelessly tune the bass 1-1 to the piano, consequently my bass ends up those 20 cents flat on the fundamental, too. I can't hear that but I can see that on my tuner (using a fairly complicated procedure). – Jirka Hanika Nov 03 '20 at 07:19
  • Matching a piano's tuning exactly would give a stretch from about -30 to 0 cents, compared to -30 to +30 for the piano's full 7+ octave range. Yes, that's smaller, but is that insignificant? – Edward Nov 03 '20 at 13:15
  • @Edward - Yes I think so. My only experience is with a standard 4 stringed upright, -20 to 0 cents per your image. I can't find solid numbers on human pitch resolution ability around contra G (50 Hz); this is probably highly individual, but probably a magnitude worse than what the right hand typically plays on a piano (300 Hz to 1000 Hz). I don't think I can resolve 20 cents down in the former range, while I could detect 3 cents harmonically up in the latter range. Guess which frequencies I will be matching if tuning plucked strings by ear. – Jirka Hanika Nov 03 '20 at 16:13
  • And that's exactly the reasoning for stretched tuning. 20 cents flat at 50Hz is insignificant, but having the upper harmonics in tune is important, and you achieve that by tuning (roughly) 20 cents flat. – Edward Nov 03 '20 at 16:35
  • @Edward - Right. But other days I use a frequency based tuner which has has sort of precision of about 4 cents (1 Hz near 440 Hz) and the end result works for me, too. Weeelll... the tuner uses an autocorrelation algorithm with high and low pass filters. I could reconfigure it so that it would stop hearing the overtones and see what would happen then. But I still believe that the pitch freedom on the bottom end is just optional. I don't need to take advantage of it for an instrument playing mere 3 octaves. – Jirka Hanika Nov 03 '20 at 18:11