Question 1

How do I convert BPM to milliseconds for delay?

Accepted Answer

Divide 60,000 by the BPM to get a quarter note in milliseconds. Halve it for an eighth note, multiply the quarter by 0.75 for a dotted eighth, and divide it by 3 for an eighth-note triplet.

Question 2

What is the dotted eighth delay time at 120 BPM?

Accepted Answer

375 ms. A quarter note at 120 BPM is 500 ms, and a dotted eighth is three quarters of that.

Question 3

How do I keep delay times in sync when the drummer speeds up?

Accepted Answer

A fixed millisecond value or a single tap only matches one tempo. To follow a live drummer, the delay has to receive tempo continuously, through MIDI clock or a tap on every beat. DrumClock listens to the drums and sends both.

BPM	Quarter	Eighth	Dotted 8th	8th triplet	16th
60	1000	500	750	333	250
62	968	484	726	323	242
64	938	469	703	312	234
66	909	455	682	303	227
68	882	441	662	294	221
70	857	429	643	286	214
72	833	417	625	278	208
74	811	405	608	270	203
76	789	395	592	263	197
78	769	385	577	256	192
80	750	375	562	250	188
82	732	366	549	244	183
84	714	357	536	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	479	213	160
96	625	312	469	208	156
98	612	306	459	204	153
100	600	300	450	200	150
102	588	294	441	196	147
104	577	288	433	192	144
106	566	283	425	189	142
108	556	278	417	185	139
110	545	273	409	182	136
112	536	268	402	179	134
114	526	263	395	175	132
116	517	259	388	172	129
118	508	254	381	169	127
120	500	250	375	167	125
122	492	246	369	164	123
124	484	242	363	161	121
126	476	238	357	159	119
128	469	234	352	156	117
130	462	231	346	154	115
132	455	227	341	152	114
134	448	224	336	149	112
136	441	221	331	147	110
138	435	217	326	145	109
140	429	214	321	143	107
142	423	211	317	141	106
144	417	208	312	139	104
146	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	285	127	95
160	375	188	281	125	94
162	370	185	278	123	93
164	366	183	274	122	91
166	361	181	271	120	90
168	357	179	268	119	89
170	353	176	265	118	88
172	349	174	262	116	87
174	345	172	259	115	86
176	341	170	256	114	85
178	337	169	253	112	84
180	333	167	250	111	83

Tap tempo and delay time calculator

Delay times from 60 to 180 BPM