Most modern sound cards offer a variety of effects, such as reverberation and chorus, but unless you use an external software or hardware FX processor, you'll find that an "echo" effect is generally not available.

This effect can be very effective to "fatten" the sound, especially in techno and similar musics. It's actually quite easy to implement in NWC. Here's a procedure which will do a "pan echo" effect on a selected melodic line:

• Write your melody line as usual. Assign to it a pan setting at or near center, and for best results use a percussive patch: piano, guitar, harp, bells, xylophone, and marimba are but a few suitable patches.
  
  
• Create from three to five new staves, and assign each to a new channel, and the same instrument patch. Set the staff volume progressively lower on each succeeding staff, and alternate the pan settings from hard left (0) to hard right (127).
  
  
• Copy the original staff to each of the new staves.
  
  
• Add rests to each of the "echo" staves, to give a progressively increasing time delay. The larger the rest, the slower the echo. The absolute time delay will depend both on the rest value, and on the tempo of the piece; experiment until you get the results you're looking for.
  

A sample NWC file, echodemo.nwc is provided as an example. To see what's happening here, select Page Setup and check the group marked "Hidden."

Chorus effect is not present or effective on all midi playback devices, so this approach seems to me the only one for a wide-usable application. Adjusting the length of the rests to make echo is at the will of the users.

I think that if we want a "chorus effect", we may use the same technique; simply change the rests inserted to smaller values (less than a 1/4th of second, or even less).
In the same manner, one can do a "reggae guitar" (or keyboard) by copying a 2nd staff, with the chords just at the end of the note normally played, but this time with a short duration.