Tutorial #5: Vibrato, Pitch Slide and More Arpeggios


Getting Started With NTRQ
-------------------------

This info is correct as of NTRQ V1.3.

Part 4: Vibrato, Pitch Slide and More Arpeggios
-----------------------------------------------

With the V1.3 release of NTRQ, I included a .sav file, "ntrq-example.sav". We'll be using this to take a look at a few advanced features with this tutorial. Generally you'll have to rename the .sav to "ntrq.sav" and put it in the correct place. Also make sure that your ROM name matches the .sav name (i.e. "ntrq.nes").

Right, load up NTRQ and let's go. Bonus points to whoever recognises where the tune is from...

We'll look at Track A first so get the song playing and then mute Track B for the time being. How? Put the cursor on Track B either in the Song or Pattern window, hold SELECT and tap A....you should know this by now :)

Arpeggios/Pitch Table
---------------------

Track A is using an arpeggio sound to play "chords" for the backing. Move down to Instrument 00 and you'll see that it has "01" for the PT entry. Jump to entry 01 of the Pitch Table and you'll see;

01:00 F0
02:04 F0
03:0C F0
04:FF 01

All very straight forward, the arpeggio cycles around offset 0, 4 and C at the fastest speed. We're going to play with the arpeggio speed but first we need to change the Gate (GT) parameter so we can hear more of what we're doing. Initially it will be set to "03" but increase this to, say, 08 or 10. You should hear how you can drastically affect the way the ADSR settings shape the sound just by altering the gate time.

Now we can hear more of the "chords", jump back to the Pitch Table at entry 01 and change all the "F0" (in entry 01, 02 and 03) to "F1" or "F2" and you'll hear the arpeggio speed slow down. You might also have spotted that you can set independent timing for each entry in your arpeggio. It's sometimes creatively useful.

Something else you can do is create a kind of "strum" effect by stopping the arpeggio from cycling back to the first entry. Set the 3 speeds to "F2" and then where entry 04 reads "FF 01", change the 01 to 03. You should now be able to hear that you hear the 3 notes but that the pitch is left "held" on the last one until a new note is played.

So, you might be wondering what the left-hand digit of the speeds are? This is the volume scaling for each note in your arpeggio. "F" means it's not scaled at all, "8" will be about half volume, "0" will be silent. Go ahead and change one of the "F"s (in entries 01,02 and 03 only - the FF in step 4 is the command to loop the arpeggio so leave that one alone) to "8" e.g.

01:00 F2
02:04 F2
03:0C 82
04:FF 01

You should hear that note (offset "0C" on entry 03) become less prominent in the chord. Experiment with the numbers a bit and you'll get the idea. Using a volume scale of "0" is handy for making "stutter"-like effects, for example.

Duty Modulation
---------------

Fix the Pitch Table entries to something like what they were when we started and I'll talk about what's going on with the Duty Modulation for this instrument.

If you select the DT parameter in the instrument and then, in the usual way, hold SELECT and tap RIGHT, you'll end up at the relevant point in the Duty Table. The entries for this instrument are:

04:23 05
05:63 06
06:A5 04

As discussed before, the left-hand number sets the duty and a counter while the right-hand number tells NTRQ which table entry to jump to next. So on the first line, "23 05" means set duty "20" with a delay of 3, then jump to entry 05. However, there's more to the "23" than meets the eye. Remember that the only valid duty settings are "00", "40", "80" and "C0" in the hardware? In the Duty Table, if you add "20" to the duty value you want to set, it tells NTRQ that you want to use the "Note Count" modulation method. So, still using "23" as an example, instead of counting 3 ticks before moving to the next table entry, NTRQ will count 3 NOTES instead. So, what "23 05" is actually saying is, set a duty of "00", wait for 3 notes and then jump to entry 05. So, the next entry, 05, reads "63 06", which is saying, set duty of "40", wait for 3 notes and then jump to entry 06. For completeness, the entry at 06 reads "A5 04" which tells NTRQ to set a duty of "80" (because in HEX, 80+20=A0), wait 5 notes and then jump to entry 04.

Just remember, to use the Note Count mode, add "20" to the duty value.

If you listen closely you'll hear the duty changing every few notes. If you want to hear the difference between Note Counter and Tick Counter (or Frame Counter as I describe it in the manual), change the entries to:

04:03 05
05:43 06
06:85 04

or actually it might be better if you speed it up a bit:

04:01 05
05:41 06
06:83 04

you should then hear a constant modulation of the duty during each note.

OK, set the Duty Table entries back to what they were and we'll look at what's going on with Track B.

Using Vibrato
-------------

Unmute Track B and play the track. You should be able to hear that it uses Auto Echo, Vibrato, Pitch Slide and Duty Modulation. Stop it for the time being and have a look at the first Pattern on Track B, "02". Move down to the Pattern Editor, if you're not already there and have a look at the first couple of lines:

F 4 03
--- 42

So, the 03 should be pretty obvious (Instrument 03). The "42" in the second row is telling NTRQ to apply the Pitch Effect 42 to the Track. If you put the cursor on this number and hold SELECT then tap DOWN, you'll end up in the Pitch Table at entry 42 which is an Auto Echo command, "B3 41". We've covered Auto Echo before so I won't go any further into it here.

Jump back to the Pattern Editor and scroll down to row 07. Here you'll see another Pitch Effect command, "43". Once again, with the cursor on the "43" hold SELECT and tap DOWN. You're taken to the Pitch Table again but this time the entry is a Vibrato command. This is telling NTRQ that at the point in the Pattern where the command occurs, to apply the Vibrato at entry 43 to any notes that are playing. Because we have no Vibrato set up in the instrument itself (Instrument 03, if you want to have a look), what happens is that on the next note after the command, the Vibrato is stopped again. This way you can selectively apply the vibrato exactly where you want it in the melody. If it's too subtle for you, jump to entry 43 of the Pitch Table and change the "62" to, say, "64". If it's still too subtle for you, jump back to the Song Arranger and change the transpose for the two Patterns on Track B by an octave. How? Put the cursor in the Track B column, hold B and when the display changes, tap RIGHT. Do this on both steps of the song. You should end up with a tranpose value of "4E" for both of the patterns on Track B.

Using Pitch Slide
-----------------

Now, while in the Song Arranger (jump back there if you're not already there), move the cursor down to the second Song step and then move down to Pattern Editor. There are two Pitch Slides in pattern "08", the first is around step 0E:

C 4 --
--- --
D 4 3B ;the "D4" is in dark grey, this is significant
-- 43
-- --
OFF --

So, first of all, NTRQ plays the C4 note, then two ticks later, there is a "tie" note "D4" (dark grey indicates that the note is a tie note i.e. like hammer-on or pull-off on guitar). The "3B" to the side of the "D4" is the Pitch Slide command. Values range from "21" to "3F", slow to fast, so this is quite a fast slide. NTRQ works out the direction for you, you just have to tell it what note you want to reach. Then the "43" on the following tick, again tells NTRQ to apply vibrato at that point. The "OFF" command, performs a "key off" on the note. This is not necessary, I just did it to add a bit of space in the melody so that the auto echo would fill in the gaps :)

The second Pitch Slide is down at step 16

G 3 --
--- --
--- 43
--- --
--- --
D 3 33 ;the "D3" is a tie note and so is dark grey
F 3 --
--- --

This time the vibrato command "43" comes before the Pitch Slide. This is just to show you that you can do that :) The note is longer this time and it slides down towards "D 3" just before the melody plays the "F 3".

More Duty Table Stuff
---------------------

Might be better to mute Track A for this bit, just so you can hear more of what's going on.

Go to the DT parameter of this instrument (instrument 03) and hold SELECT then tap RIGHT to jump to the Duty Table entry:

07:04 08
08:84 08

What we're telling NTRQ here is to use a duty setting of 00 for 4 ticks, then change to duty 80 and hold that value until the note is finished. Using this trick you can get some interesting attacks to your instruments. You can experiement with these numbers. Try:

07:85 08
08:01 08

This time we start the note with duty 80 for 5 ticks then hold the duty at 00 for the remainder of the note. With this technique, because the duty is held on the second value, the number of ticks for the second duty is not important.

Have fun!

Neil

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