Relationship Between BPM and Delay Settings

I believe Karl asked about BPM also, not just the modulation settings. Here is my simple take on it all. I know little about music theory, but recall some basics and pieced the rest together from help from the posts here and some practice. I don't claim this is absolutely correct, but it's my take on what I have learned so far. This is a step by step tutorial that relates the analysis to the first riff in the song "Bad".

Modulation is the amount of chorus-like effect within a delay repeat. Instead of just a plain delay, which repeats the exact note, modulation is like adding chorus to each delayed note. Edge almost always uses modulation (therefore TC2290, DD20, SDD3000 - all modulated delays). The depth sets the amount of modulation and the frequency or rate is the number of cycles. If you listen carefully, you can hear within a delayed note the "wa-wa-wa". Together they provide a nice smooth chorus like effect within the delay.

Modulation is entirely separate from the delay time (ms) between the notes and the BPM. First, the song is played at a certain tempo measured in beats per minute (BPM). You use MixMiester to determine the BMP of the song. Then you play in tempo with the song (1-2-3-4 or 1&-2&-3&-4&). But, many times, the delayed notes don't land on the quarter notes of the beat (assuming a 4/4 tempo - four quarter notes with 4 beats per measure).

The Edge many times uses a dotted 8th note delay. Let me use an example and explain a point that does not come across clearly in Mick's Bad tutorial (I discussed this with Mick and he thought I should share my thoughts and see if you agree with my analysis). I am not even close to having Mick's experience, but I have done the math and I believe there is a subtle mistake in the way he explains the delay timing and tempo in the Bad tutorial (obviously, I say this with the utmost respect for Mick, as he has been my mentor here and "I'm not worthy!"). BTW, PLEASE UNDERSTAND THAT I AM NOT CLAIMING THAT Mick plays the song incorrectly; therefore, this is my attempt to explain why what he is playing is correct, and what he says with regard to tempo that is incorrect.

If I have made any mistakes, please feel free to correct me. No pride of authorship here.

First, for the purposes of this example (simplification of the calculations) lets assume that Bad (which uses a dotted 8th note) is played at 100 BPM (so the tapping of the beat will equal 100 quarter notes per minute). Use Lyle's BPM converter at http://psionicaudio.com/misc/tempo.htm and you get the following:

It's easier to start with the quarter note, as each beat is a quarter note.

STEP 1

Quarter note delay = 600ms

Where does this come from?

1 second = 1,000 milliseconds (ms)
1 minute = 60 seconds = 60,000 ms
60,000 ms / 100 quarter note beats = 600ms per beat (or per quarter note)

A whole note (one entire measure) = 600ms x 4 = 2400ms (top of Lyle's calculator)

So, if you set your tempo to 100 BPM (or tap in 100 beats per minute on a delay) and you set the delay to a quarter note, the delayed note will repeat every 600 ms. But the 600ms is meaningless unless you play at a tempo of 100 BPM. This is an important concept to understand because the BPM and delay setting and type of delay note are all related.

In other words, if you play just one note, the delayed note will occur 600ms later. If you play one note and then another note 600ms later, you are playing at 100 BPM because 100 BPM means one beat every 600ms (4 beats per measure). If you play this tempo with a quarter note DELAY setting, you will play right on top of the delayed signal and wont hear it.

Original Note -> repeat at 600ms -> hit 2nd note at 600ms after original note (which will occur right on top of the repeat of the original note)

THIS IS IMPORTANT - the DELAY SETTING AND TEMPO ARE TWO SEPARATE THINGS - DON'T MIX THEM UP. This will become clearer in the next step.

STEP 2

An 8th note is double as fast as a quarter note.
8th note = 300ms (again, see Lyle's calculator set at 100 BPM)

Set the delay to 8th note. If you strike a single note, the delayed note will occur 300ms later. Ok, now let's take the same steps as above. IF you play at 100 BPM, this means that every QUARTER note beat happens every 600ms (NOT THE DELAY SETTING. I AM REFERENCING THE TEMPO). In other words, tap your foot with the tap light and you have a quarter note beat every 600 ms. If you set the delay to an 8th note and play a string (1-2-3-4) in quarter notes (or 100 BPM) you will hear the delay IN BETWEEN every one of your string picks (the delay occurs twice as fast as your picking of the tempo):

Original Note -> repeat at 300ms -> hit next note 300ms after delayed note (or 600ms after original note) and so on……

So the above is an 8th note delay setting at 100 BPM (100BMP means you are playing quarter notes every 600ms and the delay is occurring in between the beats or every 300ms). OK, now, if you pick twice as fast then you will play right on top of the delay again. WHY, because YOU HAVE CLANGED THE TEMPO, NOT THE DELAY SETTING. You are now you are playing at 200 BPM.

Here is where it gets a little confusing based on how your delay works. If you set your Axe-Fx to a tempo of 100 BPM and the delay set to an 8th note, then you will get repeats in between your quarter note picks (pick one note for each time the tempo light blinks). In this case, if you double the picking speed, THEN you are playing at twice the speed of the tempo light on the Axe or you have manually moved to 200 BPM, but the Axe is set at an 8th note (300ms if played with the 100 BPM tap light). But doubling your picking speed, the 8th note delay is now really a quarter note delay because if you play at 200 BPM, not the 100 BPM that the Axe is set for.

If you have a delay with no tap tempo and you set it for 300ms, and you start playing such that the repeats are in between your picking, then you are playing at 100 BPM (quarter note ever 600 ms with repeats in between). But if you double up your tempo and play on top of the delay, then you are now at 200 BPM and the delay is still set at 300 ms - BUT the 300ms delay is now an IMPLIED QUARTER NOTE because you are picking original notes at 300ms each (4 times per measure).

This seems a little circular, but it matters what setting you start with. If you start with tempo, then set the type of note and play to the tempo, not the delay setting. If you start with the delay setting (ms), then you need to find the tempo (quarter note beat) that dictates the type of delay note required for the song (e.g., 8th note).

What do you start with? Delay time or BPM. Well you can start with either. I like to set BPM in my Axe-FX and set the delay to 8th note (using above example). I watch the tempo light and count off (1-2-3-4) the light. The 8th note will occur right in between my picking notes (assuming I play quarter notes). BUT, you can also just set the delay to 300 ms and THEN figure out how to hit the quarter notes so that the delay occurs right in between the notes (THIS IS WHAT PEOPLE ON THIS BOARD MEAN BY FINDING THE GROOVE - YOU HAVE TO FIND THE TEMPO THAT FITS THE TYPE OF DELAY NOTE - KEEP THIS IN MIND FOR "BAD" DISCUSSION BELOW). So if you set the delay to 300ms and play such that the delayed notes come right in between your picked notes, then YOU ARE PLAYING AT 100 BPM.

STEP 3

(the Bad tutorial - my humble opinion)

Micks tutorial is excellent and it helped me learn the song. But I have also listened to loops of the delay many times. Here is my take on it. Please keep in mind the concepts above.

Bad uses a dotted 8th note. What is this? Well, it's an amount of time that falls right in between a quarter note and an 8th note (or 3/4 of a beat or 3/16 of a whole measure). Per above:

1 quarter note beat = every 600ms (1 beat)
1 8th note beat = every 300ms (1/2 a beat) (the & in 1&2&3&4&)
1 dotted 8th note = every 450ms (3/4 of a beat)

Again, let's assume for simplicity that Bad it at 100 BPM (I think the original is 99 and live is 107, based on MixMiester, so close enough).

Here is where my adjustment to Mick's tutorial comes in. 100 BMP is set, we all agree to the TEMPO of the song that the drummer will keep for us (or the tempo light on our delay). And we all know that the delay is a dotted 8th. 100 BPM implies that the beat (or every quarter note) occurs every 600ms. Then the dotted 8th will occur 450ms after any picked note. Here is the problem - if you set your tempo (1-2-3-4) to the delay time, then you are not playing at 100BPM, you are playing at about 133 BPM (quarter note = 450ms).

So this is why Bad is a little difficult to get used to. You have to start just as Mick says. Play simple quarter notes (1-2-3-4), BUT PLAY THEM AT 100 BPM or 600ms apart (I like to follow the tempo light on my Axe). Then double up and play 8th notes (300ms apart). THEN LET THE DELAY OCCUR EVERY 450ms. DONT SET YOUR TEMPO TO THE DELAY TIME.

YOU PLAY:

Original note (beat 1) —> second picked note (first 8th note) 300ms later —> third picked note (beat #2) —> fourth pick (2nd 8th note).

The delay will fall in between:

Original note (beat one) —> second picked note (first 8th note) 300 ms later —> DELAY OCCURS HERE AT 450ms —> third picked note (beat #2)….. etc. etc.

If you set your quarter and 8th note picking with the delay, then the delay would repeat right on top of your picking. So when Mick says in his tutorial to set the (1-2-3-4) with the delay, I don't believe this is correct.

Then the question is why does Mick's tutorial work. My opinion is that while Mick is starting with the tempo equal to the delay time, when he actually gets into the "groove" (REMEMBER ANALYSIS ABOVE), he is really changing the tempo back to what makes the delay note a dotted 8th and not a quarter note. It is very subtle and tricky, but I believe this is what happens in the tutorial. Mick's tempo is actually not the delay time. It's can't be if the delay note is a dotted 8th note and the song is in 4/4 time.

What Mick points out (and is very important), is that the high E note definitely occurs on the 8th note beat after the 3rd beat.

1   &   2   &   3   &   4   &

The numbers should be 600ms apart and the time between the numbers and the "&s" should be 300ms apart (beat and 8th note picking). But the delay will occur 450 ms after ever pick, so it will land right between the 8th notes.

What I also figured out is that the note change from D to C# on the D (4th string) (move from 12th to 11th fret) occurs on the "&" after the 2nd beat. If you listen carefully it is definitely not 4 picks for each note. It's 3 8th note picks for the D and 5 8th notes picks for the C#.

1   &   2   &   3   &   4   &
D   D   D   C#  C#  C#  C#  C#
                    E

Accent the 1 beat and the & after the 2nd beat and you get the amazing Bad groove with a dotted 8th note.

I hope this provides a practical example for understanding the relationship between BPM and delay times.

Michael

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