The metronomic repetition of the delay is a technique thats mainly used to create songs with particular characteristics. As seen in the previous page, the regulation of the delay (in milliseconds) sets the repetitions in the various sixteenths of the bar. Lets see how to calculate the values.
As an example lets evaluate a metronome time of Quarter = 120. The first thing to do is to change the metronome time into milliseconds by dividing:
60,000 / 120
The first figure is the number of milliseconds in one minute, while the second is the metronome time. The result indicates how many milliseconds the quarter movement will last (500).
Now divide 500 by four to assign the value of the sixteenth and the octave: 500/2 = 250 (ascending octave); 250/2=125 (the first ascending sixteenth).
To find the last sixteenth, add 250 + 125 to get 375. In this way we get the three repeat notes on the sixteenth that we can program (the first sixteenth in beat coincides with the original note, therefore the value is 0). The 60,000 is fixed seeing the metronome is always calculated in beats per minute, and therefore to do any calculation of this type you must divide 60,000 by the metronome time. In the example below, the setting just seen gives us this chart:

To have the beat of the delay on the last sixteenth of the quatrain, will should therefore program the delay at 375ms. Many equipment have the subdivision of milliseconds in equal numbers (0,2,4,6,8 etc.) and consequently you must round the number up or down (in the above example, we would program 374 or 376ms). The difference of 1ms doesn't influence the time at all.
A system similar to the one described above was used by Nuno Bettencourt in the performance of the song "Flight of the wounded bumblebee" on the Extreme "Pornografitti" (1990) album using a guitar and a drum machine. The speed of the metronome is Quarter = 204: Bettencourt plays in octave using a single beat delay programmed on the last sixteenth (approximately 222ms), and indeed the results are amazing.

In the stave you can read the sound response of the execution, while in the table you can clearly see the part played.
Lets look at another similar procedure, this time from Eddie Van Halen's Live "Right here, right now" (1991). The part in question is from the song "316". In this part the metronome time is Quarter=116, and once again the repetition time is on the last sixteenth: the delay is therefore programmed to 388ms, with a single repeat.
Van Halen plays in hammer-on with the left hand, raising the volume control of his guitar on every note (the execution is in octave).

In the stave line we have the sound response, while in the table we have the actual part played by the Dutch guitarist.
The delay times vary greatly from model to model. Usually the maximum amount of delay never surpasses two seconds. With higher delay times we can talk about sampling, which is a term that indicates an equipment's ability to record a sound. These are instruments used in recording studios and are generally not adapted for the guitar.
Remember that a little delay is never bad. Generally a delay of 400-600ms, with a small amount of feedback (two or three repetitions) but with a low effect level, is good to use in a majority of the sounds that don't require a specific delay setting. Mixed with the reverb it creates a dry guitar sound which, if adjusted correctly, doesn't disturb the performance of the other instruments. Avoid its use if you have to play some rhythmic parts where the guitar must have a clean sound: in this case the delay could counter the rhythmics.
In the next section we will analyze another widely used effect, the reverb.