Hi I'm quite new to ballroom dancing. I'm curious that how do you know what types of music to dance to when listen to particular song. I have been trying to recognise or pick up the number of bars, time signature but end up in failure.

Any input would be greatly appreciated

This basically comes from practice. A good way to get some practice is right here on this site. Visit the Learn the Dances section then pick a dance. When you do, there will be a link to Blah Music. Click it and you'll be taken to a page with a bunch of audio clips of songs suitable for that dance. Listen to as many of these as you can, for as many dances as you're interested in. Pay attention to the rhythm of each, the tempo/speed, and overall feel of the music. Try to figure out what's the same in all of the say cha cha music. With enough practice you'll get it and having all of these clips available here is a good start.

You probably want more than that though. First thing you need to do is be able to count the beats and measures to tell if the music is in 3 or 4. The first beat of a measure is accented/stressed which usually makes it a little louder. Waltz and Viennese waltz are in 3, everything else should be in 4 (or at least sound that way). So play some clips and count along. When you get that down, you've made your first separation -- you know waltzes from everything else! :) The difference between the two types of waltz is speed -- if the music is slow, it's regular waltz, if it's fast, it's a Viennese waltz. You've got two already. ;)

For music in 4, which is vast amounts of music, it's a bit harder. This stuff may be a bit vague, but I'll try to clear things up later if I can find some magazine articles I remember talking about this subject. Try starting with cha cha -- most of the music should have a pronounced "cha cha cha" beat to them. If you count in 4 as 1 2 3 4, 1 2 3 4, etc. you're going to hear an extra half beat in there to make that "cha cha cha" rhythm. It should sound like 1 2 3 4&1 2 3 4& etc. Don't worry too much about the beat numbers, but listen for that "cha cha cha" sound. It should be clear in most music and now you've got your third dance. Samba and tango have fairly distinct rhythms, too, but I hestitate to explain samba and don't know if I could do tango well in words. Try listening to them and see if you can hear them though. Others are a little hard to explain, like foxtrot. Think of Frank Sinatra songs for this, a lot of his stuff is good for foxtrot. The music should have a sort of easy flowing, walking feel to it, just the way the dance is supposed to move. Quickstep and swing/jive/lindy almost go together. I'd guess you're familiar with this kind of music even if you don't realize it. Do you remember the Gap commercials some years ago with the kids dancing swing? Well, that's an example of swing music. Some of the old big band stuff is swing, too. The sound clips on this site will give you plenty to listen to. The main way you'll decide if you do quickstep or swing/jive/lindy is the feel. Both will usually be quick music, but the swing/jive/lindy will feel bouncy while the quickstep will feel more smoothly flowing. West coast swing is a bit different and, around here at least, is usually done to somewhat slower music that has a blues kind of feel/sound to it. Swing above means east coast swing, by the way, and doesn't have to be as fast as quickstep, jive, or lindy. It can also feel a bit more grounded, more swingy than bouncy. It's hard to explain, but if you don't get what I mean now, you probably will later on after hearing enough ballroom music.

I know I'm leaving some dances out here, but I'm not sure how to give decent descriptions of them off hand. As I said, much of this just comes from practice. Listen to ballroom music enough and you'll just start to get it after a while. Use the clips here as a start and try to tell what's the same about them. When you go to dances, try to figure out what the dance is before asking someone. After a while, you'll be getting more and more right, to the point where you won't need to ask anymore because you'll know. If I can find those articles, I'll try to give you a summary from them. I hope this helps. Good luck. :)

Gan,
An excellent question: first you must be able to count the eight Quarter beat segments of any Ballroon dance music. Quarter beats are the main musical notes that dance steps are patterned on or guided by for rhythmic dancing- Is there any other kind of dancing? If there are lyrics to the music, the eight beat segments are easier to pick out. The HEAVY beat in a bar of music of four beats, is the first Quarter beat.
However, your best bet is to have a friend help you pick out these musical phrases that run into sixteen Quarter beats, (two eight count segments).
Latin music is recognised by the instrumentations, heavy with Conga and bongo drums and xylophones, giving hollow wooden echoes, some wind instruments and minimal brass.
You can do Salsa, Mambo, Samba or cha cha to this music. With a little experience, you will recognize Samba from Salsa, and the other latin dances.
American popular dance music is easier to recognise; soft bass and soft drum rhythms with piano and brass instrumention. Foxtrot and Lindy (Swing variations) can be danced to any American pop music; Lindy is more adaptable to the faster heavy beat (90-120 bpm) Bal and Shag need the fastest beat(120-180), while foxtrot works best with smooth medium beat music (60-90 bpm). These are just variable guide lines, give or take 20 or 30 bpm for any of the above.
And when in doubt, observe what other dancers are doing to the music, and use that as a quide.
Black Sheep
j.lanza@sbcglobal.net

dancing is coool only i dont know how to dance i think modeling i s better

Modeling Vs Dancing!
Learning any Ballroom dance takes 30 minutes with an experienced dancer or teacher, and minimal expence, and you will have a social asset built in with an activity that well keep you physically fit for as long as you dance.
Models spend mucho time and money learning with no or very little job opportunities, and too many compromising situations.
Get started with Lindy (Swing) dancing.
Send me the word, "Lindy" and I will Email; you the 'Lanza Magic Pill' a single page of self teaching instructions that will have you dancing Swing on rhythm in 15 minutes, Gratis!
j.lanza@sbcglobal.net
Joe Lanza aka Black Sheep

I'm not sure I follow you. A song that's written in 4/4 has 4 beats to one measure and a quarter note gets one beat. What do you mean by "eight Quarter beat segments"? A song in 4 has four beats per measure. If you're talking about the eighth notes, those are half beats, and I wouldn't call them "the main musical notes". The time signature tells you that by the bottom number -- that's the type of note that gets one beat. A song in 3/4 like waltz or Viennese waltz has 3 beats per measure, a quarter note getting one beat. There are only six half beats (eighth notes) in that case and if you try to count in 8s, you're going to be confused. If you only meant to talk about music in 4, you should have said so to be clear. And your talk of eight quarter beats is confusing -- that would be two measures of music if it's written in 4. Sixteen quarter beats give 4 measures. But it sounds like you're calling these just 1 and 2 measures. Maybe you can explain what you mean a little more clearly? Because I think what you have now sounds a bit confusing.

And I wouldn't bet on lyrics making the beats clearer -- the way some singers play around with rhythms, syncopating beats, and stuff, it can actually be harder to find the beat if you listen to the vocals. You should pay attention to the rhythm section (drums, etc.) because they're the ones who are really keeping the beat for the music and they should be playing a nice, steady rhythm. It may be a bit fancier that just 1234 or 1&2&3&4&, but it should be even so that you can pick out the beats fairly easily. The singer can help, if he/she isn't doing funny things with the rhythm. So you can use the vocals to help, but you shouldn't rely on them. The rhythm section that's keeping the beat is what you really should depend on. Besides, if you get so used to using vocals to pick out beats, what are you going to do when there are none, for instrumental songs?

Dronak,
A bar (Measure) has four Quarter beats (Notes) correct! However, 4/4 time music is phrased in two bar segments = eight quarter beats.
A phrase, the smallest segment of our 4/4 music, is a complete line or sentence, e.g. " Jack and Jill went up the hill (2Q)"; that takes two bars of music or SIX quarter beats and ONE half beat (8Q Total). The next two bars make a second segment of two bars, " To fetch a pail of water". (1Q, 1H, 1Q, 1Q, 1Q, 1H).
Move these notes under each word above.
Black Sheep

OK. First, I think phrasing is too advanced for someone who is "quite new to ballroom dancing". This is something you shouldn't really worry about until after you've got down some steps, technique, etc. and don't need to think so much about basic stuff like that. Then you can worry about dancing on phrase to the music. And what constitutes the "smallest segment of our 4/4 music" depends on how you want to break things down and define things. By the time signature's definition, the smallest "unit" is the quarter note. Measures are certainly smaller units than phrases and phrases don't have to be two bars, they can be 4 our 8 or 12 or 16. In speech or writing is the smallest unit a sentence, a single word, or one of the syllables that make a word? For music that's like is it a phrase, a bar, or a note within the bar? For our case here, recognizing what dance goes with what music, I think the phrasing is almost irrelevant. You don't need to hear the phrases to pick out the beats, tempo, and rhythms that identify a song as a particular dance. As long as you can pick out the first beat of each measure so that you'll be dancing on time, the musical phrasing really isn't important for a beginner. Gan, this is useful stuff to know eventually, but I wouldn't worry about it right now if I were you.