Automatic Beat Detection

Audio Surgeon contains contains a module that calculates or determines the tempo (BPM) of an audio file or song. Tempo can be an important parameter for musicians and DJ's. For example, DJ's like to use BPM for creating playlists of songs with similar tempos.

Audio Surgeon uses tempo as a unique parameter for determining duplicates. In addition, AS has the ability to change the tempo of a file or group of files. When it does this it uses the calculated BPM or Tempo as the starting point for such changes.

Before implementing this feature we compared and tested several different technologies. Here is a summary of what we found:

1

The BPM readings from Audio Surgeon were comparable to, and as accurate as, the best available technology.

2

The BPM technologies we tested worked well with Rock, Country and Pop music. They were less reliable with Jazz. They were the least accurate with Choral and Orchestral music where there often is no defined pulse.

3

There are times when the bpm reading may be off by 50%. This is due to the fact that the programs are not given the “metrical level”. In other words, they are not told, and have no way of knowing, the time signature for each song, e.g. does the quarter note get 1 count, or the eight or the half. By default these programs typically will display the faster of the BPM rates.

Even when the numerical BPM value being displayed for a particular song is not correct, the program is detecting a musically correct pulse, i.e. in time with the music. For example Audio Surgeon calculates the BPM of the song “Hotel California” to be 148. The true value from the sheet music is 74, or ½ that value. In the bigger picture both values accurately depict the pulse of the song.

Below is a comparison table of BPM data comparing Audio Surgeon to its competitors across a range of different musical genres.

Audio
Surgeon
Competitor
1
Competitor
2
Competitor
3
Actual BPM
Rock
Hotel California 148 148 148 148 74
Baby, Now That I've Found You 118 118 118 117 118
Telephone Line 142 144 144 144 72
The Heart of the Matter 176 176 176 89 87
Louder Than Ever 139 NA 185 140 70
Pop
Candles 176 174 115 89 87
Just the Girl 111 111 111 112 112
Come Clean 117.58 117 118 117 58
Here We Go Again 142 142 142 144 143
Heaven 124.5 124 NC 123 NA
Orchestral
Vivaldi four Seasons - Winter 148 145 144 148 141
Arrival of the Queen 108.01 107 163 108 80
Hallelujah 102 172 NA 105 85
Mozart Piano Concerto No. 21 166 114 115 115 55
Pachelbel Canon id D 130 132.44 117 133 60
Jazz
Take Five 168 170 124 172 81
One Finger Snap 238 155 NC 92 128
Take the A Train 79 158 170 161 80
The Girl From Ipanema 123.74 125 123 126 61
Sing, Sing, Sing 108.54 108 NC 110 110
CHORAL
O Nata Lux (Lux Aeterna) 168 NC NC 144 72
Like Snow (Midwinter Songs) 152 NC NC 144 72
Lament for Pasiphae (Midwinter Songs) 138 NC NC 136 66
Midwinter Walking 176 173 NC 112 86
Intercession in Late October 152 NC NC 117 100

To learn more about Audio Surgeon go to our main page. There you will find an introductory video as well as an overview of the major features found in Audio Surgeon.