How does Chavah pick which songs to play?


Listener Greg W. asks,

Is there a way to tell what plays at any given time? I know we can request songs, so the programming must be tied to algorithms and lots of techy stuff…

I’ve been asked this question often, so it bears a post I can link to in the future.

It’s a fair question because in some ways, Chavah acts like traditional AM/FM radio station (song requests!), while in other ways, it acts more like music playlist ala Pandora (song stream for each user). What’s going on? How does Chavah decide what to play?

In a nutshell, Chavah chooses songs for you based on your song likes/dislikes, and weaves in live song requests from listeners.

That’s the super-simplified version of the truth. The fine grained details I explain below.

Chavah plays songs she thinks you’ll like

Unlike traditional AM/FM radio, Chavah plays a unique stream for each user. That means Judah in Minnesota is hearing Marty Goetz – V’ne Emar, while Jesse in Chicago is hearing Miqedem – Hine Eloheinu. Two users, two different streams of music. Each of the thousands of Chavah users gets their own custom stream of songs.

Chavah plays songs based on what you like, or what songs you’re likely to enjoy. In this way, you tend to hear music you like.

How does Chavah know what I like?

Because you tell her using your thumb-ups and thumb–downs, and because of what the Messianic community on Chavah likes.

When Chavah chooses the next song to play for you, she weighs 5 factors:

  1. Song ranking on ChavahCommunity rank. Chavah tends to play songs with higher ranking more often. (High ranking means they have been thumbed-up often and thumbed-down rarely.) Chavah figures that if a lot of other people like this song, you might like it too.

  2. imageSong like status. If you’ve previously thumbed-up a song, Chavah is more likely to play it for you. If you thumb-up a song, it’s twice as likely to play as an unranked song.  Corollary: if you’ve thumbed-down a song, Chavah is far less likely to play it. Thumbed-down songs are 1/10th as likely to play as an unranked song.
  3. image Album. If you’ve thumbed-up several songs from an album, Chavah will play more songs from that album. This album weight varies depending on how many songs from a particular artist you like. At the highest end, for songs where you already like many of the songs on the album, such songs are twice as likely to play.
  4. image Artist. If you’ve thumbed up several songs from a particular artist, Chavah will play more songs from that artist. The artist weight here mirrors the album weight: if you already like many songs from the artist Lamb, then Lamb songs will be twice as likely to play.
  5. image
    Song tags
    . Most songs are have one or more tags – traits describing the song. As you thumb-up songs, Chavah learns the type of music you like, and plays more of that. For example, if you thumb-up lots of songs with the “uplifting” tag, Chavah will play more uplifting songs. This works in tandem with other tags: if you tend to like encouraging songs with violin, those types of songs will be played even more often.

That’s it! Chavah takes those 5 things into mind when choosing your next song. Clever girl!

Anonymous users

What if you’re not signed in? In that case, Chavah chooses a song based on community ranking alone: Chavah will tend to play songs with higher rankings.

Details about song rankings

A few more words about community rank. You can view a song’s community ranking yourself, under the song name:

Here, Baruch Haba by Lamb is ranked +106, meaning at least 106 users have thumbed-up this song. (Thumb-downs subtract from this number.) Chavah weighs that against the average song ranking and assigns it the Great rank standing.

What is rank standing? Chavah groups songs by ranking into several standings:

  1. Best – These are the top-ranked, very best songs on Chavah, rated far above the average song rank.
  2. Great – While not the top songs, they are rated at least twice higher than the average song on Chavah.
  3. Good – These songs are rated well by the Messianic community on Chavah.
  4. Average – These songs are near the average ranking on Chavah, but have more thumb-ups than thumb-downs.
  5. Poor – These songs have a negative ranking; they’ve been thumbed-down more than thumbed-up.
  6. Very Poor – These are the lowest-ranked songs on Chavah. Far more users have thumbed-down. They may be eventually removed from Chavah.

Let’s look a a concrete example.


Here I’m playing a song with a +11, Average ranking. What does that mean?

The Average categorization is based on the average song rank. To determine the rank standing, Chavah takes the average ranking of all songs on Chavah; at the time of this writing, the average song rank is +47.

If a song is near +47, Chavah categorizes that song as Average ranking. But if the song is at 1.5x the average (+70), Chavah will categorize it as Good ranking. As the ranking increases, so does Chavah’s categorization.

An extra rule is in play here: if the song has a significant negative ranking (e.g. –4), meaning more users have thumbed it down than thumbed-up, Chavah will rank that song as Poor. And if the net negative ranking is greatly negative (e.g. –15), Chavah will mark that as Very Poor ranking. Such songs will rarely be played on Chavah. If the ranking is poor enough

And what about song requests?

So far I’ve only talked about the song-choosing aspect of Chavah. She plays the stuff you’re likely to enjoy. What about song requests?

imageLike live AM/FM radio, Chavah plays live song requests from listeners, with some caveats.

The requested song will play immediately for the person who requested it. Meanwhile, it will play for everyone else after their current song ends.

Another caveat is that if you’ve already thumbed-down the song that someone else requested, Chavah won’t play it for you.

A final caveat is that a single user can only do 2 song requests per hour – this is to prevent abuse, such as a single user continually request a song/artist/album. The song request will still play for the requester, but everyone else will hear only the first 2 song requests in that hour.


Weaving these two aspects – songs you’ll like and song requests – Chavah aims to play a God-glorifying selection that aligns with your musical tastes. We continually tweak these variables to get the right mix – too much in one direction, and there’s no variety. Too much in the other direction, and it’s near random. So we’re continually improving Chavah’s smarts in this regard.

We hope you like the Messiah-honoring mix, fine Chavah fans.


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