I'm not certain because I don't have the books in front of me, but I think that if you look in the ISTD technique book it says tango is in 2/4. It probably does vary though. Not all songs that sound alike are written in the same time signature.
What little Tango sheet music I've seen was written in 4/4. Most dance teachers will count in the dance for beginners classes - 1,2,3,4 (or maybe 5,6,7,8) and most people will count four beats.
However! The ISTD in its infinite wisdom defines Tango as having a time signature of 2/4. They then go on to say that a slow is one beat and a quick is half a beat, and count the bar as 1,&,2,&. In the teachers exam you have to demonstrate figures whilst counting in beats and bars, which means the first count of each bar is used to count the bars themselves. This isn't to bad for 4/4 timing, you just count 1 2 3 4 2 2 3 4 3 2 3 4 etc but for Tango they want 1 & 2 & 2 & 2 & 3 & 2 & and it gets confusing which "2" is which.
I don't think they elected to define it that way contrary to facts. I think there are tangos written in 2/4 so it's not an unreasonable choice. I can't remember though. While I have plenty of sheet music and fake books, I don't think they include many tangos. And yes, no matter what the music or technique book says, many people probably still think 1234 and not 1&2&. But as you imply, in an ISTD teaching exam, you have to count 1&2& or you'll be marked wrong. Still, I think there is some justification to counting it in two like that, even if it does get a little weird around bar 2 (see your sequence at the end). It should tend to make your movements more stacatto as they should be for tango. Counting in four can lend itself to movements like foxtrot, smooth and flowing. If you count in two though, it can help to hold you back and not be so smooth. And tango's supposed to be sharp so this is a good thing. Just another thought while looking over the messages.
Tango is supposed to be 2/4. But some orchestras record 4/4. Being that the orchestra is selling hopefully to others than dancers. They find that it is difficult to have a vocalist singing in 2/4. One exception is Doris Day singing Hernandos Hideway. If you dance two walks and a progressive sidestep and a walk into a link dancing to 4/4 you are now out of phrase with the music . If the music is 2/4 you are not out of phrase.
Those figures amount to two bars whether danced in 2/4 with slow = 1 beat or 4/4 with slow = 2 beats which most people default to, so I don't see how you get out of phrase.
I have problems relating 2/4 and 4/4 to the tempo of the music. At 33 bars per minute this give either 66 or 132 beats per minute. These beats are crotchets (quarter notes in US parlance) so what decides the length of each beat?
As I understand it musicians base their timing on beats per minute. If so, and they probably use about 132 for tango, why don't the ISTD define Tango as 66 bars per minute?
The last time I looked the Progressive side step has three steps and four beats, Q.Q.S. So in 4/4 time. two walks = 1234. Progressive Side Step 1234. one more walk on the mans RF. 1 2 and the Link 3 4. now you are out. If you continue into a Closed Promenade into a Reverse Turn you will be dancing 3412. The same thing will happen on a Four Step unless you do a head flick to use up two beats. Or just stand still. With 2/4 Tango none of the above will happen. We have teacher here who when travelling through Europe asked one of those top Orchestra leaders why they were recording in 4/4. He was told that they had put out an album and recalled and re-cut because 2/4 was not popular. I hope this helps.
The time signiature is not important, the phrasing is. If you write tango with the shorter measures, then it is performed with a bit of a two-measure phrasing.
Some of the step combinations seemingly leave you with an incomplete measure or phrase, but that's because the combination shouldn't break on figure boundaries, but on musical boundaries.
Consider for example two walks and a link. S S QQ __ with an unfilled S left over. That's usually the initial slow of a closed or open promenade or something, but the thing it it's also the conclusion of this phrase, a releasing of springlike compression in both the bodies and the music.
Going further, think about how it's often common when starting (in practice) in promenade in the swing dances to take a preceding step out in PP on the last beat of the previous measure before beginning the figure. In tango we are actually doing the same thing, only the figures are in effect defined across barlines. Suprised at that idea? Look at how the ISTD actually defines the foxtrot figures - they go across barlines too, though it's more common at least in the US to change the definitions of feather and three in order to be able to teach them each as 3 measure-aligned steps.
The ISTD is almost always writing foxtrot figures with the last step actually being the first step of the next figure. But I don't think they ever say that this is what they're doing. Of course you figure it out soon enough when you realize one figure ends on the same foot that the next one is supposed to start. However, I'm writing to note that the IDTA does not do this. It's been a while since I looked at the IDTA books (slightly older ones, I haven't gotten the latest revisions yet), but I am fairly sure that they do not write foxtrot figures like the ISTD does. When it ends, it ends, none of this last step of this figure = first step of next figure business. So you could say that instead of modifying ISTD definitions, people are using the IDTA definitions instead.
It's not unusual for figures to cross musical bar lines. Basic American foxtrot with its SSQQ rhythm does it all the time. So does east coast swing. Around here people dance 3 count hustle, dancing four steps in three beats to music in four -- you're off the musical bars 3/4 of the time. Quickstep is often in a SQQS pattern putting it in the same category as the SSQQ rhythm -- six beats for four steps over 1.5 bars. Probably others, but I'm not taking the time to sit and think about them. :)
Many thanks to everyone who responded to my message, even Sarcastic Smoothie!
This is a question in a postal quiz and has proved very difficult to find a definitive answer. From all your comments I will take 2/4 as my answer as that seems to be the overall opinion, and hope for the best.
In Australian New Vogue a Tango must be 4/4 Tempo. It is highly likely that soon unless you have some old recordings you may find it hard to find a 2/4 Tango. Evidently they are not popular with the buying public. I know my teacher who is a leading competitor treats all Tangos as 4/4. After all they never know what is going to be played. If we strike a 4/4 Tempo and we do a Four Step we will need to put a head flick to take two beats otherwise we would be stepping into a Closed Promenade on 1 2... It needs to be 3 4. if the music is 4/4. But if we dance a 2/4 routine to a 4/4 Tango there is a problem.
International Style Tango. 2/4 is from a book printed several years ago. Nobody can make an Orchestra record in 2/4 if they find it doesn`t sell to the genral public. If they relied on ballroom dancers only to buy their product they would go out of business. As previously written you may find it hard to find a recently recorded 2/4 Tango. And if we look at the Tempos from Dancesport USA for the Tango . What does it say. 31 Bars Per Minute. That is 31.. 1234`s in one minute.