# Music Question: What is a "flat" instrument?
**URL:** https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594
**Category:** Cafe Society
**Created:** [November 20, 2008, 3:02am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594 "2008-11-20T03:02:03Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@FrustratedIdiot](https://boards.straightdope.com/u/FrustratedIdiot)
#### Post date: [November 20, 2008, 3:02am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/1 "2008-11-20T03:02:03Z")
I have heard of B-flat trumpets. What are they? How can an instrument be “flat”? I thought that flats and sharps (accidentals?) only occur in relation to something larger (key? mode?).
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### Author:  [@seodoa](https://boards.straightdope.com/u/seodoa)
#### Post date: [November 20, 2008, 3:07am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/2 "2008-11-20T03:07:14Z")
> [@FrustratedIdiot](#):
>
> I have heard of B-flat trumpets. What are they? How can an instrument be “flat”? I thought that flats and sharps (accidentals?) only occur in relation to something larger (key? mode?).
Cecil explained the concept of instrument keys pretty well [here](http://www.straightdope.com/columns/read/286/why-are-saxophones-made-in-different-keys).
ETA: The article is about saxophones, but the same idea applies to trumpets. (He mentions cornets in the article, which, of course, are closely related to trumpets)
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### Author:  [@FrustratedIdiot](https://boards.straightdope.com/u/FrustratedIdiot)
#### Post date: [November 20, 2008, 3:12am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/3 "2008-11-20T03:12:04Z")
> [@seodoa](#):
>
> Cecil explained the concept of instrument keys pretty well [here](http://www.straightdope.com/columns/read/286/why-are-saxophones-made-in-different-keys).
>
> ETA: The article is about saxophones, but the same idea applies to trumpets. (He mentions cornets in the article, which, of course, are closely related to trumpets)
I thought that the key of C is natural (no flats or sharps). Why are they called B-flat instruments?
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### Author:  [@Colibri](https://boards.straightdope.com/u/Colibri)
#### Post date: [November 20, 2008, 3:13am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/4 "2008-11-20T03:13:07Z")
Moving to Cafe Society from GQ.
Colibri
General Questions Moderator
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### Author:  [@seodoa](https://boards.straightdope.com/u/seodoa)
#### Post date: [November 20, 2008, 3:19am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/5 "2008-11-20T03:19:51Z")
> [@FrustratedIdiot](#):
>
> I thought that the key of C is natural (no flats or sharps). Why are they called B-flat instruments?
Because on a B-flat instrument, if you play a C (the same fingering that would get you a C on a C-version of the instrument) you get a B-flat not a C.
Did you read Cecil’s article? :dubious:
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### Author:  [@FrustratedIdiot](https://boards.straightdope.com/u/FrustratedIdiot)
#### Post date: [November 20, 2008, 3:24am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/6 "2008-11-20T03:24:56Z")
> [@seodoa](#):
>
> Because on a B-flat instrument, if you play a C (the same fingering that would get you a C on a C-version of the instrument) you get a B-flat not a C.
>
> Did you read Cecil’s article? :dubious:
I did. I was just under the impression (I don’t know much about music theory) that flats and sharps are used only in relation to something else.
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### Author:  [@seodoa](https://boards.straightdope.com/u/seodoa)
#### Post date: [November 20, 2008, 3:29am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/7 "2008-11-20T03:29:20Z")
> [@FrustratedIdiot](#):
>
> I did. I was just under the impression (I don’t know much about music theory) that flats and sharps are used only in relation to something else.
They are! The flat is in relation to the key B! That is why it is a B-flat Trumpet, not a “Flat Trumpet!” It is true that C has no flat (C flat = B natural) but B has a flat. And it is this B-Flat note that you get when you play a C on a B-flat trumpet, hence the name.
Were it a C trumpet, playing a C will get you a C. An E-flat trumpet would give you an E-flat when you play a C.
As Cecil said, the idea is that instead of changing the fingering to transpose music, you can just change to a different instrument and use the same fingering. Yes, it means more instruments, but it makes it easier for the player.
ETA: For example, on a “C trumpet” playing a middle C is accomplished with all valves open (O O O) a B-flat is first valve closed (X O O). On a “B-flat trumpet,” playing all valves open (O O O) would give you a B-flat, not a C. First valve closed (X O O) would give an A-flat.
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### Author:  [@Raguleader](https://boards.straightdope.com/u/Raguleader)
#### Post date: [November 20, 2008, 3:33am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/8 "2008-11-20T03:33:56Z")
Totally incidental here, but I am reminded of a cartoon where these bad guys are trying to get into some ancient vault type place, with a musical lock on the door. Some captive good guy (archeologist, historian, something like that) tells them they have to sing a note in the key of B, so one of the henchmen steps up, sings a note, and is squashed by a falling rock, causing the villain to shout…
_She said B, not B FLAT!_ 😃
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### Author:  [@FrustratedIdiot](https://boards.straightdope.com/u/FrustratedIdiot)
#### Post date: [November 20, 2008, 3:34am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/9 "2008-11-20T03:34:47Z")
> [@seodoa](#):
>
> They are! The flat is in relation to the key B! That is why it is a B-flat Trumpet, not a “Flat Trumpet!” It is true that C has no flat (C flat = B natural) but B has a flat. And it is this B-Flat note that you get when you play a C on a B-flat trumpet, hence the name.
Why is it in relation to the key of B?
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### Author:  [@friedo](https://boards.straightdope.com/u/friedo)
#### Post date: [November 20, 2008, 3:35am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/10 "2008-11-20T03:35:55Z")
Here is a good thread about [transposing instruments](http://boards.straightdope.com/sdmb/showthread.php?t=483074) which may be of interest to the OP.
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### Author:  [@seodoa](https://boards.straightdope.com/u/seodoa)
#### Post date: [November 20, 2008, 3:39am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/11 "2008-11-20T03:39:01Z")
> [@FrustratedIdiot](#):
>
> Why is it in relation to the key of B?
Please stop and look at the name of the trumpet.
It is called a “ **B** -flat trumpet” That is why the flat is in relation to B. It doesn’t have to be. If you wanted to, you could buy an “E-flat” trumpet where playing C gives an “E-flat.” For an “ **E** -flat trumpet” the flat would be in relation to E.
Not to sound condescending, but do you understand what a flat is in music?
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### Author:  [@fachverwirrt](https://boards.straightdope.com/u/fachverwirrt)
#### Post date: [November 20, 2008, 3:39am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/12 "2008-11-20T03:39:42Z")
> [@FrustratedIdiot](#):
>
> Why is it in relation to the key of B?
Not the key of B. Just the note B. A B-flat instrument plays a whole step lower than it is written, therefore a written C comes out as a B-flat. It really doesn’t have anything to do with keys or key signatures.
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### Author:  [@FrustratedIdiot](https://boards.straightdope.com/u/FrustratedIdiot)
#### Post date: [November 20, 2008, 3:41am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/13 "2008-11-20T03:41:48Z")
> [@seodoa](#):
>
> Please stop and look at the name of the trumpet.
>
> It is called a “ **B** -flat trumpet” That is why the flat is in relation to B. It doesn’t have to be. If you wanted to, you could buy an “E-flat” trumpet where playing C gives an “E-flat.” For an “ **E** -flat trumpet” the flat would be in relation to E.
>
> Not to sound condescending, but do you understand what a flat is in music?
A flat is the same as a sharp, it just depends on the key (I think).
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### Author:  [@seodoa](https://boards.straightdope.com/u/seodoa)
#### Post date: [November 20, 2008, 3:45am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/14 "2008-11-20T03:45:52Z")
> [@FrustratedIdiot](#):
>
> A flat is the same as a sharp, it just depends on the key (I think).
Okay, fachverwirrt brought up a good point. It is not the key it is the note. And sharps and flats are only identical in so much that A-sharp and B-flat are identical notes. A sharp is half a step higher than a natural note, the flat is half a step lower.
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### Author:  [@friedo](https://boards.straightdope.com/u/friedo)
#### Post date: [November 20, 2008, 3:46am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/15 "2008-11-20T03:46:41Z")
> [@FrustratedIdiot](#):
>
> Why is it in relation to the key of B?
I think you’re getting unnecessarily confused by terminology. The word “flat” just means “pitched lower by a certain amount” and the word “sharp” means “pitched higher by a certain amount.” The certain amount is called a semitone, and is equal to the difference between any two adjacent piano keys (white or black.)
In the 12-tone system (all the common music you’re probably familiar with), there are 12 notes per octave. Several of these notes have two names.
The notes are:
C, C-sharp, D, D-sharp, E, F, F-sharp, G, G-sharp, A, A-sharp, B
Put another way, they are:
C, D-flat, D, E-flat, E, F, G-flat, G, A-flat, A, B-flat, B
The ones with two names (sharps and flats) are the black keys between the white keys on your piano. The reasons for this two-name system are due to historical accidents revolving around the development of tuning systems that will make your head spin, but we’re stuck with it.
Keys (in the tonal sense) are eight-note subsets of these 12. The key of C major consists of all the natural notes (white keys). The other major keys start on different notes, but all contain the same intervals as C major. B-flat major has the notes:
B-flat, C, D, E-flat, F, G, A.
Note that if you count the semitones between each note in B-flat major, they’re the same sequence of semitones between the notes in C-major and every other major key.
A B-flat trumpet is a _transposing instrument_. All this means is that, if you put your fingers in the position that plays a C on a normal trumpet, the B-flat trumpet plays a B-flat. If you finger a D on a normal trumpet, the B-flat trumpet plays a C, and so on.
See the other thread I linked for the reasons why you would want such an instrument in the first place.
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### Author:  [@FrustratedIdiot](https://boards.straightdope.com/u/FrustratedIdiot)
#### Post date: [November 20, 2008, 3:47am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/16 "2008-11-20T03:47:45Z")
> [@seodoa](#):
>
> Okay, fachverwirrt brought up a good point. It is not the key it is the note. And sharps and flats are only identical in so much that A-sharp and B-flat are identical notes. A sharp is half a step higher than a natural note, the flat is half a step lower.
Why is it not called an A-sharp trumpet? Is it just convention to name all of these instruments X-flat instead of Y-sharp?
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### Author:  [@Darth\_Sensitive](https://boards.straightdope.com/u/Darth_Sensitive)
#### Post date: [November 20, 2008, 3:48am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/17 "2008-11-20T03:48:20Z")
It’s like putting a capo on the neck of a guitar, only that doesn’t really work on trumpets.
With a capo, you get to keep all the same chord fingerings and just start further on up the neck. If the default key for a guitar is C (I’m just making this up to an extent, I’ve never heard anyone talk about that kinda stuff), then if you stick a capo on the 4th fret, you’re now in E, and farther up the neck.
It’s definitely possible to learn weird chord fingerings to be able to play, say, Folsom Prison Blues in the same key as your backing track for a talent show, or you can just say “Screw it”, I’m going with what I knew beforehand and plop down a few bucks at the music store.
Only trumpet players have to plop down a bit more.
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### Author:  [@seodoa](https://boards.straightdope.com/u/seodoa)
#### Post date: [November 20, 2008, 3:50am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/18 "2008-11-20T03:50:26Z")
> [@friedo](#):
>
> I think you’re getting unnecessarily confused by terminology. The word “flat” just means “pitched lower by a certain amount” and the word “sharp” means “pitched higher by a certain amount.” The certain amount is called a semitone, and is equal to the difference between any two adjacent piano keys (white or black.)
>
> In the 12-tone system (all the common music you’re probably familiar with), there are 12 notes per octave. Several of these notes have two names.
>
> The notes are:
> C, C-sharp, D, D-sharp, E, F, F-sharp, G, G-sharp, A, A-sharp, B
>
> Put another way, they are:
> C, D-flat, D, E-flat, E, F, G-flat, G, A-flat, A, B-flat, B
>
> The ones with two names (sharps and flats) are the black keys between the white keys on your piano. The reasons for this two-name system are due to historical accidents revolving around the development of tuning systems that will make your head spin, but we’re stuck with it.
>
> Keys (in the tonal sense) are eight-note subsets of these 12. The key of C major consists of all the natural notes (white keys). The other major keys start on different notes, but all contain the same intervals as C major. B-flat major has the notes:
>
> B-flat, C, D, E-flat, F, G, A.
>
> Note that if you count the semitones between each note in B-flat major, they’re the same sequence of semitones between the notes in C-major and every other major key.
>
> A B-flat trumpet is a _transposing instrument_. All this means is that, if you put your fingers in the position that plays a C on a normal trumpet, the B-flat trumpet plays a B-flat. If finger a D on a normal trumpet, the B-flat trumpet plays a C, and so on.
>
> See the other thread I linked for the reasons why you would want such an instrument in the first place.
Thanks, much more thorough explanation than I was willing to type out. The thread is nice as well, although I think Cecil gives a pretty decent explanation as to why you would want a transposing instrument.
Of course, as Cecil noted in his article, the matter is made more confusing by the fact that (at least in America) B-flat trumpets are more common than C.
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### Author:  [@fachverwirrt](https://boards.straightdope.com/u/fachverwirrt)
#### Post date: [November 20, 2008, 3:55am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/19 "2008-11-20T03:55:41Z")
> [@FrustratedIdiot](#):
>
> Why is it not called an A-sharp trumpet? Is it just convention to name all of these instruments X-flat instead of Y-sharp?
Honestly? I don’t know. Of course you have to choose one or the other, so it seems “they” (whoever “they” are) chose B-flat. And E-flat rather than D-sharp.
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### Author:  [@fachverwirrt](https://boards.straightdope.com/u/fachverwirrt)
#### Post date: [November 20, 2008, 4:04am UTC](https://boards.straightdope.com/t/music-question-what-is-a-flat-instrument/473594/20 "2008-11-20T04:04:36Z")
Actually, strike that. It’s a B-flat and not an A-sharp because calling it an A-sharp trumpet would make it play down a diminished third, and the transposition would be far more complicated.
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