This is a curiosity of mine. Each time I attend a concert, I look at the double basses to see whether they have either a C extension, 5 strings, or neither. For the concerts that I have attended in the UK, the answer seems to be mostly C extension. However, on TV or discs, I see 5 strings occasionally; I think (not claim) that this seems to be more common in Germany.

What are the pros and cons?

Is the extra string always C to just enable an octave below the cello or is it sometimes B to retain the spacing?

Also what music requires it or may use it? I have not noticed notes below the standard 4 string bass being used in concerts that I have attended but, of course, my musical tastes and powers of observation might be the explanation.

Answers on 5 strings bass guitars are also welcome. I get the impression that the extra string is more commonly B on these.

  • I'd be interested to find out what the string spacings are on 4 and 5 double basses. On bass guitars, there seems to be a choice between 5 strings squashed into 4 string necks, and wider necks allowing the same spacing between strings for 5, as the 4 has. It may make bowing slightly tricky, don't know.
    – Tim
    Apr 26, 2017 at 12:31
  • The bowing issue may explain why the C extension seems more popular. It has a capo like device which can be locked at each of the extension notes. So, it could be locked at E and then I expect that it can be played like a standard bass. On the downside, when the lower notes are needed, I guess that the fingering is a little awkward.
    – badjohn
    Apr 26, 2017 at 13:09

4 Answers 4


Five-string basses in orchestra would be tuned BEADG (from low to high). Another option, which would be used more for solo work, would be EADGC, with the fifth string being an additional higher string instead of a lower one.

There are a number of pieces that call for (explicitly or implicitly) lower notes than the typical 4-string bass can play. Schubert's 8th symphony has a falling bass line down to a low C in the cello score, but for the bass score, the last two notes, the D and C are written up an octave. Most recordings include the implied notes using either 5-string basses or basses with extensions. I've heard a recording of Rachmaninov's Rhapsody on a Theme by Paganini in which there are clearly basses playing pizzicato on a low B. I imagine a lot of newer music takes advantage of this capability, as these basses become more popular and accessible.

Pros for extensions:

  • Extended range while keeping the same neck width
  • They can be retroactively added to 4-string basses with minimal modifications

Cons for extensions:

  • More awkward fingering on lower notes, though some basses have special mechanisms to help deal with that
  • Adding an extension requires drilling a hole through the scroll, as well as mounting the extension to the bass, so if it is ever removed, the bass will be marred

Pros for 5-string basses:

  • Even more extended range down to B
  • More natural fingering, just an additional string
  • The bass is often designed with 5 strings in mind, so it is a more natural fit

Cons for 5-string basses:

  • The fingerboard is wider, which may make for difficult fingering for those with smaller hands
  • Bowing may be trickier
  • Unless the bass is purpose built for 5 strings, it may not be large enough or have big enough components to fully support the low notes
  • Retrofitting 5 strings to a 4 string bass had not occurred to me. I knew that the extensions were often added but I expected that 5 string basses were built that way.
    – badjohn
    Dec 18, 2018 at 23:10
  • I don't think it's common, and it is definitely not preferred. However, I was more referring to using the same body design but putting 5 strings on it during manufacture, so widening the neck, different scroll design for 5 tuners, etc, but the body isn't larger, the bass bar, etc aren't beefier, so the sound is less powerful, and the bass may even be weaker.
    – Johonn
    Dec 20, 2018 at 0:36
  • Ah, that is easier to see.
    – badjohn
    Dec 20, 2018 at 0:41
  • I've used 5 string (eelectric) basses witth 5 strings, that fitted into figerboards designed for 4 strings. They work, but they're certainly not for me. Might work for guitarists who want to be budding bassists.
    – Tim
    Mar 27, 2021 at 19:48
  • It's certainly possible to be far more agile on a low B string than on a C extension. Some C extensions have levers. Others require you to move your hand up to the fingerboard extension. Either way, it's hard to play fast.
    – Ian Goldby
    Jul 27 at 14:27

I can't can't speak to double basses, but as for bass guitars

Answers on 5 strings bass guitars are also welcome. I get the impression that the extra string is more commonly B on these.

A 5-string bass guitar typically adds a low B, but I have heard of people using a high C instead. A 6-string bass guitar typically adds both a low B and a high C.

As for usage I see most 5 string players in the metal and jazz genres. Metal because they want the special effect of getting extra low notes. And jazz players like the extra option but tend to use it sparingly. Then there are quite a few people that think they want a low B until they realize that it usually sounds a bit floppy and muddy.

Most 6 string players I have seen have been jazz players that like playing solo or with busier chordal passages. The extra range gives you a lot more arrangement options. I personally kind of want a 6 string for this reason—I love playing solo using the upper range of the bass.

  • Thanks. I had forgotten about 6 string basses. I guess that the extra low string might work better on a double bass since it is larger. A bass guitar can get away with low notes for its comparatively small size due to its amplification but there may be a limit to the effectiveness of this.
    – badjohn
    Apr 26, 2017 at 9:26
  • 1
    Yeah a lot of it comes down to string tension. On a typical bass guitar low B, it's just not quite enough. You can mess with string gauges or use a longer scale bass, but I'd guess a lot of that is easier with a double bass.
    – user37496
    Apr 26, 2017 at 10:40

5 String Double Basses are becoming more popular these days because they've improved the design also they weigh less than a Bass w/ a C Extension.

  • You can see that the neck is only a bit bigger than a 4 String Bass, the strings are closer together so that it feels more comfortable to hold, the B String is hanging off the Side, & there's just enough curvature in the bridge to where you can change your bow angles. Thomas George & Martin have really solved the play ability problem w/ 5 String Basses (same goes for basses w/ more strings than that) meaning you can now play Gospel Music in an Unplugged setting.
    – user68506
    Mar 27, 2021 at 19:30
  • As someone who has tried 5 strings, and who actually uses "low G" extension strings (B string extended, not "low C"), I find this video to be the most objective and complete explanation of below-E problems ever put online. You hit every nuance and addressed every problem. Bravo!!
    – Denise Wal
    Mar 23, 2022 at 4:10

I can only answer referring to electric basses. As already stated, 5 string basses use either a high C or low B. The low B is more common, as the high C takes the bass into guitar territory. One of the reasons I prefer 5 string is that there is often no need to play on the first few frets, as a lower note is available on that B string. Occasionally, it's nice to finish a song on a root note lower than the usual E, though.

The 6 stringers are often used by jazzers, especially where there's no guitar player, to form partial chords.

As an aside, I used to play with an 8 string player - low F# to high F. Quite interesting!

  • An 8 string bass? That's exotic. F# nearly an octave below the usual E? That must be really floppy. Also close to the limit of our hearing.
    – badjohn
    Apr 26, 2017 at 11:12
  • 1
    @badjohn - not floppy, just quite thick! Felt rather than heard.
    – Tim
    Apr 26, 2017 at 11:14
  • I was thinking of user37496's comment that even the more common low B can be floppy.
    – badjohn
    Apr 26, 2017 at 11:17
  • Played quite a few 5 strings over several years, and never found a floppy B string. I use .125".
    – Tim
    Apr 26, 2017 at 11:33
  • 1
    It's a Marmite thing. I actually changed a 4 string so that it has BEAD. That's nice to play, but I then miss the pop-ability of the G string. But it's good for lending out at open mic venues. It gets returned quite soon.
    – Tim
    Apr 26, 2017 at 12:24

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