package main

import (
  "fmt"
  "os"
  "time"
  
  "github.com/go-mix/mix"
  "github.com/go-mix/mix/bind"
)

var (
  sampleHz   = float64(48000)
  spec = bind.AudioSpec{
    Freq:     sampleHz,
    Format:   bind.AudioF32,
    Channels: 2,
    }
  bpm        = 120
  step       = time.Minute / time.Duration(bpm*4)
  loops      = 16
  prefix     = "sound/808/"
  kick1      = "kick1.wav"
  kick2      = "kick2.wav"
  marac      = "maracas.wav"
  snare      = "snare.wav"
  hitom      = "hightom.wav"
  clhat      = "cl_hihat.wav"
  pattern    = []string{
    kick2,
    marac,
    clhat,
    marac,
    snare,
    marac,
    clhat,
    kick2,
    marac,
    marac,
    hitom,
    marac,
    snare,
    kick1,
    clhat,
    marac,
  }
)

func main() {
  defer mix.Teardown()    
  
  mix.Debug(true)
  mix.Configure(spec)
  mix.SetSoundsPath(prefix)
  mix.StartAt(time.Now().Add(1 * time.Second))

  t := 2 * time.Second // padding before music
  for n := 0; n < loops; n++ {
    for s := 0; s < len(pattern); s++ {
      mix.SetFire(pattern[s], t+time.Duration(s)*step, 0, 1.0, 0)
    }
    t += time.Duration(len(pattern)) * step
  }

  fmt.Printf("Mix, pid:%v, spec:%v\n", os.Getpid(), spec)
  for mix.FireCount() > 0 {
    time.Sleep(1 * time.Second)
  }
}

make demo

make demo.wav