Modern multieffects, rackmount ones in particular, can time the delay to the song tempo.

Here's the formula: 

60.000/t

where 60.000  are milliseconds in a minute;

           t  is the song tempo.

The  result in milliseconds is a quarter-note delay, i.e. an echo repeating notes a quarter-note later. To set shorter repetitions, say 1/8 or 1/16, just divide this value by 2 or  4; for eighth-note triplets by 3. 

By putting played notes and repeats at equal volume, we can create more complex rhythms; this was used by U2's guitarist in the intro to "Where The Streets Have No Name" (tempo q=126, delay=357 mSec). 

This delay is not  quarter-note, however. The repeat is 3/16 later (dotted eighth). Just take the formula and multiply by 3/4 (i.e. divide by 4 and multiply times 3).

It is important to experiment this method with a metronome to gain the max precision and understand how every delay time sounds. 

Often the multieffect allows for delay placement: we can put repeats in stereo, to have for example the direct sound center, the first repeat far right and the second repeat far left, or put the direct sound far left and the repeats far right.

We can also pan different delays in the stereo field, say 1/4 right and a dotted eighth left.

Here' s a useful table:

TEMPO            1/4             1/8         1/8·        Triplet           1/16

    70                  857            429        642          286              214

    72                  833            417        624          278              208

    74                  811            405        608          270              203

    76                  789            395        592          263              197

    78                  769            385        576          256              192

    80                  750            375        562          250              188

    82                  732            366        548          244              183

    84                  714            357        535          238              179

    86                  698            349        523          233              174

    88                  682            341        511          227              170

    90                  667            333        500          222              167

    92                  652            326        489          217              163

    94                  638            319        478          213              160

    96                  625            313        468          208              156

    98                  612            306        459          204              153

 100                   600            300        450          200              150

 102                   588            294        441          196              147

 104                   577            288        432          192              144

 106                   566            283        424          189              142

 108                   556            278        416          185              139

 110                   545            273        409          182              136

 112                   536            268        401          179              134

 114                   526            263        394          175              132

 116                   517            259        387          172              129

 118                   508            254        381          169              127

 120                   500            250        375          167              125

 122                   492            246        368          165              124

 124                   484            242        362          161              121

 126                   476            238        357          159              119

 128                   469            234        351          156              117

 130                   462            231        346          154              115

 132                   455            227        340          152              114

 134                   448            224        335          149              112

 136                   441            221        330          147              110

 138                   435            217        326          145              109

 140                   429            214        321          143              107

 142                   423            211        316          141              106

 144                   411            205        308          137              103

 148                   405            203        304          135              101

 150                   400            200        300          133              100

 152                   395            197        296          132                99

 154                   390            195        292          130                97

 156                   385            192        288          128                96

 158                   380            190        284          127                95

 160                   375            188        281          125                94

 162                   370            185        277          123                92

 164                   366            183        274          122                91

 166                   361            181        271          120                90

 168                   357            179        267          119                89

 170                   353            176        264          118                88

 172                   349            174        261          116                87

 174                   345            172        258          115                86

 176                   341            170        255          114                85

 178                   337            169        252          112                84

 180                   333            166        250          111                83

 182                   329            164        247          109                82

 184                   326            163        244          108                81

 186                   322            161        241          107                80

 188                   319            159        239          106                79

 190                   315            157        236          105                78

 192                   312            156        234          104                78

 194                   309            154        231          103                77

 196                   306            153        229          102                76

 198                   303            151        227          101                75

 200                   300            150        225          100                75

© Lelio Padovani 2002