CHR is essentially "pop", or mainstream music. It gets the big audience numbers--for instance, right now, the #10 song on the pop charts sees similar audience numbers as the #1 song in country, which carries the next highest audience. The #12 song on pop, relatively speaking, can be the #1 song in HAC in audience share. #15 on pop gets #1 in rhythmic and urban. #24 in pop translates to about #1 in urban AC and AC. #28 in pop translates to #1 in alternative. So CHR is the major chart, and it more or less drives a ton of single sales: every song in the top 33 of CHR right now, for instance, is in the top 100 of itunes. With the exception of two songs, every song in the top 15 of CHR right now is in the top 21. This does not necessarily translate to album sales that hit expectations, given that acts that chart high in CHR tend to have outsized expectations compared to those that chart high in other genres, but when you drive singles sales, it builds up your brand, and over time should help album sales. There are acts (like Jason DeRulo, etc) that are more singles than album-driven, but many acts that hit it big in CHR, with over 100K in sales (a very good number in today's awful album-selling market).
What constitutes CHR? Here they are:
Established CHR/pop artists. Obviously, there are types where CHR is the home-base for the artist--established artists who are known to get a slew of number one or even top ten hits in the past get that fast-track, higher-than-normal audience share and bullet at their song's initial stages (Justin Timberlake, Jason DeRulo, Miley Cyrus, Selena Gomez, Demi Lovato, Katy Perry, Rihanna, Eminem, are some that come to mind).
Disney or Nickelodeon-bred acts. Disney has become a churner for what we call Disney princess types--a string of acts, from Britney Spears and Christina Aguilera in the late 90s to now, to Hillary Duff, to Demi Lovato, Miley Cyrus and Selena Gomez and possibly to a future wave that includes Zendaya and others. They make pop their home-base, after extensive Radio Disney play during their formative teen years. These can include other acts like the Jonas Brothers, and earlier in the mid-2000s, Jesse McCartney, as well. XFUS tried to create several of these Radio Disney-to-CHR, or "teen" connections if you will, for Emblem3 and Fifth Harmony, to launch them as a direct-to-CHR pop act. But Idol sees virtually no success for straight to pop acts, because as a singing competition, as we'll see, it relies more on HAC transitions.
*Teen acts, essentially: like Cody Simpson, Austin Mahone, Justin Bieber initially before he became established.
The European/British import (DJs, singers, boybands). There's another strong group I'd like to call the European imports, primarily from Britain around 2009 to now, but lately, also showing up with DJs and the like from Netherlands, Sweden, and elsewhere. This started with the EDM wave which picked up from the autotune shenanigans of 2005-2007, with people like Taio Cruz from the UK introducing their dance-pop into the mainstream. These usually started with about a one-year lag time from Europe to the states: these artists have had major hits with their song throughout Europe, and America is the last part to conquer, although as of late, a few acts have been aiming straight for the American audience after seeing the floodgates open. Notably, there was a brief invasion of XFUK, with Olly Murs, Cher Lloyd, but most notably, One Direction hitting the top ten in CHR, and 1D in particular became a CHR mainstay (their home base, along with the other types mentioned above). The Wanted and Icona Pop had a hit single. Adele became a huge albums-seller with her old-school soul as well as churning out hit single after hit single, paving the way for other similar singers like Emeli Sande from the UK. With the electronic based dance music DJs like David Guetta (Sweden) and Calvin Harris (UK) got in the act and became relative mainstays, and soon Ellie Goulding and Ed Sheeran, both from the UK, picked up the baton and became mainstays with strings of several hits.We saw Of Monsters and Men (Norway), one-hit wonder Gotye (Belgium) start out at HAC and impact pop, and UK band Bastille got in the mix (starting out as alternative). Now, we have Sam Smith and the boyband Rixton from the UK really making a dent, and others like 5 Seconds Of Summer (from Australia) trying to capture the One-Directionesque teen demographic where American boybands have failed (such as Emblem3 and Midnight Red, among others). Tiesto is a DJ from the Netherlands, and Nico and Vinz are a singing group from Norway. Where once there might been only a space for maybe up to three or four European acts at any given time in CHR, there is absolutely no barrier to entry now. Once you stake your claim and make a name for yourself here (Sheeran, Adele, Goulding, 1D), you'll get that initial bullet and audience number, and that has paved the way for a number of European acts who have had hit singles overseas that they feel confident enough to bring their sound to America. And many of them are finding radio play and singles success, at the least.
The HAC "Crossover". The last group, some of which overlaps with the European imports, are what we call the "crossovers". Crossovers primarily occur with HAC, as HAC is virtually synergistic and operates hand in hand in CHR now (even ten years ago, HAC would abstain from anything that approached R&B and hip hop-esque quality; now, we even see Eminem and Jason DeRulo's songs played there). If a song does well in HAC (say, top five or even top 8) there's a good chance the artist's handlers will attempt to cross that single over to pop. HAC is still a natural home for the 25-35 market, so they tend to like their songs more meaningful, folksy, a bit of a rock edge, and somewhat adult contemporary. So, while we were in that "folk" revolution which we are still somewhat in right now, Of Monsters and Men, Gotye and others used that leverage to cross over to pop. Phillip Phillips, from AI, OneRepublic and the Lumineers did the same thing. Christina Perri and Sara Bareilles represent for the girls here, with singer-songwriter vibes. Right now, American Authors is doing this with "Best Day Of My Life". HAC also leeches off from pop, as songs that do well in pop almost always get play in HAC now, as mentioned due to the synergy; HAC doesn't drive singles sales, even though their audience share goes from 20-40 for a top 15 single in this branch, but it creates a reasonable audience share that can propel singles to pop, and it can drive singles in the bottom half of the 100s in itunes sales, depending on the song. A lot of songs in HAC are pop crossed over to HAC songs as mentioned, and a few songs rising on HAC that will attempt pop. Of course, there will be many HAC starting songs that peter out and don't make it anywhere. This is also the branch that many of the Idol contestants typically take--the singer/songwriter chops are typically what racks up votes since AI7, and that jibes well with the standards of HAC. In the early iterations of AI7-AI8, HAC was a great platform to propel the Idol contestants to create at least a reasonable pop hit before they fade. But lately, they stay and peter out at HAC, and stay HAC; second or third singles peak lower down the ranks, and starting HAC acts do not make it far in general. This goes for many of the contestants cast in the Voice as well, although they haven't signed anyone to experiment with how long those contestants could stay at HAC (or make it to pop). Usually, HAC acts need to cross to pop to generate not just single sales, but also album sales. So it provides radio ears and provides the CHR-platform, but does not do much to move the needle in relevant aspects, unless your name is established (like OneRepublic).
The Rhythmic "Crossover". We've been talking a lot about how European imports have dominated pop from either a HAC crossover or pop-entering setting. Well, here's one format that the Europeans cannot (or have not, yet) really invaded: rhythmic. Nope, DJs and European dance-pop don't count here. While established US acts still carry their weight, as well as the few that attempt via HAC, it's really rhythmic which has the American stamp on it. It's obviously beats and hooks-oriented, and the subject material is sketchy for anyone who is not in tune with the vapidness of the pop or hip hop scene for the past fifteen or so years. But, beats and hooks sell. In the rhythmic, and frankly, urban format's heyday, it was like what the European imports are to CHR today: you churn out a song that gets high on the rhythmic and urban charts at around 2000-2008, you'd likely have a hit at CHR. T-Pain, Lil Wayne, Chris Brown (not now CB, but younger CB) absolutely feasted off this synergistic relationship between pop, rhythmic and urban, and made names for themselves for both singles AND album sales. Now? There is synergistic quality with rhythmic and CHR, with Rihanna, B.O.B. and Jason DeRulo, among others, who release singles to both platforms immediately. But still, songs that hit the top five of rhythmic (ideally top three) get chances at pop, with reasonable success (John Legend's "All Of Me" being a major one, but others like DJ Snake and Lil Jon's "Turn Down For What" and Kid Ink feat Chris Brown's "Show Me" also doing quite well). CHR music currently might be mostly European import dance music (which bypasses rhythmic) and established pop acts to counterweight the HAC crossovers, but there are always about 5-6 rhythmic-to-pop crossovers on the CHR charts at any given time. The hip hop and rap aspect of rhythmic tends to be album sellers, because the artists generally have a strong social media presence, and are featured and connected with the top dogs in some way (like T.I., Eminem and Jay Z), but singles sales are really dependent on whether they can get that audience and potential CHR crossover. However, some rhythmic songs (such as Iggy Azalea's "Fancy" and DJ Snake feat Lil Jon's "Turn Down For What") go viral, and as will be mentioned below, that helps with the propulsion in radio for the single. Rhythmic is completely avoided in singing competitions, because face it, rhythmic and urban formats don't really require singing, and there's little to no creativity or motivation to cast contestants with that sort of creativity on the part of the shows. XFUS has attempted rhythmic and urban types primarily with XFUS1 with Chris Rene and Marcus Canty's singles, but they didn't really go anywhere.
*Note that there are more rhythmic than actual urban crossovers, since urban is the format which really houses the rappers--although there are a few exceptions, such as Drake, Macklemore and Jay-Z ("Hold On We're Coming Home", "Can't Hold Us", "Thrift Shop", "Suit and Tie", "Holy Grail") who can get songs on to CHR, but not with regularity. But these rappers can cross to rhythmic, and they have a really reliable album-buying audience. Where Chris Brown has moved from CHR to rhythmic, Beyonce has increasingly moved from CHR to urban. Juicy J, Schoolboy Q and Wiz Khalifa release their singles onto urban as well and move albums, and all of them have been featured rappers in CHR-aiming audiences. Rap has been a big part of CHR in the early 2000s, and while that has declined, there is always a space there for the heavy hitters of rap.
The Alternative "Crossover". So far, in the 2010 and beyond, really, only Imagine Dragons has made a name as a relative mainstay for itself using the alternative crossover format. Many, but not all, of the alternative songs go from alternative to HAC to pop to build up, and that process can typically take almost half a month. Imagine Dragons did it. This multiformat synergy was also seen with Capital Cities "Safe And Sound", which went from alternative to HAC to pop, and it was such a slow grower in pop that it was nearly a year from its initial alternative charting that it fell off the charts. That was forever. In general, a song that is a hit in the alternative charts doesn't want to stay there--the audience ears are very low, and it doesn't really sell (typically, top five in alternative sells in the lower half of the 100s to the early 100s). But, alternative, like rhythmic and urban, was once a HUGE part of the CHR brand in the early 2000s, especially with bands like Linkin Park, Simple Plan, Good Charlotte and others really impacting CHR that way and becoming CHR mainstays. Now...like rhythmic, not so much, but there is always space for about 5-6 of them at any given time, and usually at any given time there is one in the top 15. We recently saw Bastille's "Pompeii" and The Neighbourhood's "Sweater Weather" do the same thing Imagine Dragons' "Radioactive", "It's Time" did, for instance. Now, it looks like the next one up is Kongo's "Come With Me Now". The alternative sound is beats-oriented now instead of whiny emo as it used to be, but it still houses familiar rock acts like Coldplay, Kings Of Leon and others. So, there is international flavor to it, from Britain to South Africa (Kongos). Alternative has a beats-oriented and vocal/lyrical hipster edge to it that usually makes it hard to cover for singing competitions, and differentiates it from HAC, which is why most contestants never target alternative. Emblem3 of XFUS seemed as if it could have branched here though. Like rhythmic, alternative groups tend to sell really well, with Arctic Monkeys and the Black Keys, groups that have been touring nad been around for a while, always maintaining a very loyal fanbase with large album sales especially compared to their poor singles sales and small audience share. In that sense, it's kind of like rhythmic, in a way.
The Song Gone Viral. These can come from anywhere, but namely, these are singles that are released and chart very high (think top 10-20) for a prolonged period of time, that the song's handlers just have to release it to pop to see how it can last. This can consist of joke songs that go far (like Psy's "Gangnam Style" or The Chainsmokers' "#Selfie"), ones that don't go far (Ylvis' "What Does The Fox Say?"), soundtrack songs that usually do not make it far on radio (because it contrasts heavily with the playlist; such as Idina Menzel's "Let It Go"). Aloe Blacc's "The Man" is a song that went viral when it was released, which really gave it that initial propulsion and audience rating. The high charting aspect is important for initial propulsion, and if the song keeps rising up the itunes charts, that usually creates the larger bullet to help the song keep on rising.
The Organic Attempt, or "Slow Grower". Direct to CHR songs that take a long team to chart. MKTO's "Classic" for example.
A few notes: Active Rock and Country have no crossover. Active Rock houses indie groups that have little chance of drawing an audience, and post-grunge groups like Three Days Grace, Theory of a Deadman that have completely evaporated from the modern scene. As many have covered, many of those post-grunge listeners have turned to the increasingly dominating bro-country on country radio, with Florida-Georgia Line taking the role of Nickelback (and even having a hit with Nelly on CHR with "Cruise"). But country as usual, unless you sell out like Taylor Swift, has no hope of going into CHR, as usual.Singing competition types do not use active rock, as the contestants are forced to sell mainstream songs and indie types would never sell out like that; they mostly go to country, but most of the country females are screwed since country radio never plays females anymore, with Miranda Lambert, Carrie Underwood, and possibly Sara Evans and Sheryl Crow being major exceptions, although Cassadee and Danielle created moderate hits (Cassadee sold that single in particular). But their album sales are lukewarm, and largely, album sales have been fairly moderate for most country acts, unless you are Luke Bryan or a traditional country act who can hoard the old-timers who buy albums.