Updated: Feb 19, 2020
Of all life's great, unsolved mysteries, when a bass player should take a part down an octave remains perhaps the most puzzling.
Ok, that might be a bit of an overstatement, but there are certainly several factors that should be considered before one decides to take the plunge and belt out a low C (or any other low note). In this post, I will compile a list of reasons that explain when it might be appropriate to take things down an octave and make good use of that extension we all love some much. I'll do my best to provide supportive musical examples and personal experience from myself and other players, too.
A Little Background
The history of the double bass is one riddled with inconsistencies- regional tuning practices, fluctuating numbers of strings, and a seemingly infinite range of sizes meant that at any given time, composers in different countries were often writing bass parts for wildly different instruments. This, of course, led to discrepancies in which note composers were to regard as the bass' lowest.
The matter is further complicated by the fact that in a great deal of orchestral repertoire the basses often double the cellos an octave below. This is fine until the cellos start playing below their low E and the bass section either has to transpose those ottava bassa notes, omit them, or find some other solution to playing parts written for an instrument that still has yet to fully standardized.
Modern players, luckily, have two (common) options if they want to play those sub-E low notes: the C-extension or the five-string bass. I won't go into to all the details or pros and cons of the two, but I will say that both options represent viable, albeit very different, ways to play notes that fall below the low E. For the rest of this article I will refer to everything with regards to the C-extension but know that the same rules and anecdotes apply to five-string basses as well.
When Should I Take It Down An Octave?
If you're like me, when you first got your extension you were probably a little too trigger-happy to use it. Every Eb, D, Db, or C suddenly seemed like a good candidate to take down the octave but you soon realized dropping everything gets old quickly and ultimately causes extension notes to lose their potency. I think it's important, especially for those new to the world of extensions, to consider whether or not adding extension notes where they aren't written a) draws undue attention to the bass section and b) serves the music and is aesthetically/artistically-appropriate. I know I certainly never considered either of those basic rules and probably (definitely) made a fool of myself more than once as a result.
Don't be like Gareth.
How About Some Specific Examples?
General rules are great and all, but specific examples are even better. I have compiled a list of where I feel it is acceptable to play notes or entire passages down an octave and I will do my best to provide a good explanation for why I feel it is musically-appropriate to do so. I will also touch on some times when you probably shouldn't go down an octave and look at a few instances in other genres of music where making use of your C-extension might be a good idea.
Without further ado...
1. Doubling The Cellos (Or Another Instrument):
In most cases, if the cellos and basses are playing in octaves and the writing falls below the E natural one ledger line below the bass staff, I think it is perfectly acceptable for the basses to use their extension and follow the cellos into the abyss. There are countless instances of this in the repertoire, but one of my favorites comes from the second movement of Brahms' first symphony.
The cellos and basses are an octave apart up until the F# beginning beat 2 of measure 55 where Brahms, keeping the writing idiomatic, notates the bass part an octave higher. This sounds fine given Brahms was likely writing for a bass without access to any notes below E1, but in my opinion, the line loses a lot of depth once the cellos and basses start playing in unison. The phrase cumulates in a brooding low C# two measures later and bringing the basses down an octave adds an authoritative fundamental that would be otherwise lost playing the part exactly as written. I should also add that this excerpt is standard audition rep and I would only consider taking that line down if I was playing in a section, not at an audition.
There are several recordings with the basses going down the octave for this excerpt, but this one is my favorite:
Schumann's Symphony 2 also has a passage where the basses could easily follow the cellos below the E down to C. This occurs early in the first movement and though I like the sound of it down an octave, I think it could be argued that Schumann was trying to lighten the texture to make way for the clarinet entrance that comes right after the cellos and basses stop playing. There are recordings of it done both ways so take your pick.
There is the possibility that he was trying to keep the writing in the range of the bass, but that then raises the question of how to treat the two low D's in the third measure of the movement. Either way, this is a good time to exercise critical thinking when determining whether or not to keep going down an octave.
2. Line Continuity
I frequently use my extension to preserve continuity in a line and maintain good voice leading. Sometimes composers will write awkward intervallic jumps when the line they are writing goes below the bass' low E. Frustratingly enough, they always seem to do this in legato sections...
I can think of two really bad instances of this off the top of my head but I know there are plenty more. Brahms Symphony 3 has one: F, Fb, then Eb up a major seventh. Please, just take it down.
This one came out an obscure opera that I played earlier this year and shall remain nameless. The basses are the only ones playing those two measures and the warmth of that pizzicato decrescendo gets interrupted by the twang of the half-position Eb, not to mention how uncomfortable it sounds to end that scale up a seventh. Once again, take it down if you can.
3. Adding Depth/Power
Some composers take a more conservative, by-the-book approach to orchestration and keep bass parts strictly within the "normal" range of the instrument. Loud passages that could easily double the low brass or cellos at the octave might be written in unison. While this is perfectly acceptable and an effective way to keep bass writing idiomatic, a well-placed low note can do wonders to fill out the bottom end of an otherwise "anemic" orchestration. Strauss and Mahler were no strangers to this and frequently wrote parts below the low E, not only during moments of intensity but also during moments of tenderness and exposure.
If I was playing a piece of music and was confronted with a chance to add a low note in a section like either of the above, I would be wary of doing so unless the rest of the music was particularly loud or densely orchestrated. Extension notes during quiet passages can be obtuse if not carefully planned or explicitly written in the part. Erring on the side of caution is the better option in such moments.
The bass's inherent depth in its lowest register is also something that can be exploited to provide a mysterious, ethereal atmosphere to a piece of music. The fugue starting "Von der Wissenschaft" (On Science and Learning) from Also Sprach Zarathustra does this particularly well. The listener's curiosity gets appropriately piqued by the strange texture of the cellos and basses playing this nearly silent line that emerges from the lowest notes of the orchestra. This section fascinates me so much that I plan on writing a blog post on it in the near future.
4. What About Jazz?
Sometimes I will use my extension when I'm playing jazz but like when I am playing classical music, I make sure that any really low notes I add serve the music. I have found that most of the time, I rarely need to go below the low Eb and even then it's infrequent and only during walking lines. Playing around with extensions can be a bit cumbersome when you are trying to walk a good bassline and most of the time those super-low notes are just a hindrance.
A bunch of big band charts that I have played have lines like this one which can be cool down the octave. This one came out of a really warm-sounding chart (I forget the name) I played a couple years ago. The line occurs under the melody and I took it down the second time through to give everything room to grow and add a new texture to the arrangement. It turned a bunch of heads (in a good way) and the director loved it.
5. How About Low B?
Two pieces in the standard literature have a written low B- Pines of Rome and Also Sprach Zarathustra. I know of one recording of Brahms' First Symphony with an added low B in the first movement 8 measures before F. If you are going to add a low B, tread with caution (and tell me about it).
I hope that this article helps dispell some of the ambiguity about when/when not to take things down an octave. I know I was in the dark with it for a while and having a reference such as this would have been tremendously helpful when I got my extension. The advice and examples I gave I learned from personal experience and talking with professional players so if you have anything to add that I might have missed, please feel free to share!