How to create samples with Modplug Tracker

I found this small tutorial, written by LP Chip. It's very nice and though may seem simple, it does give enough basis to start you off.
http://lpchip.com/modplug/viewtopic.php?t=786

Also, I've been recently visiting www.pouet.net and there found a really nice musicdisc by SandS called PostMODism. What's interesting about this album is that they made acoustic stuff and managed to squeeze it into mod files. And here I literally mean 'mod', ProTracker modules. One of their limitations is that you can have not more than 31 samples. If you look into the mods, supplied with the album, you can learn many clever ways to make your music smaller in filesize.
Here is the link directly to the album page at pouet: http://www.pouet.net/prod.php?which=21005

Techniques of Chipping

I've found this great tutorial by Vhiiula/Analogik on chip basics. Great stuff! Here's the URL:
http://www.modarchive.com/db/boards2/viewtopic.php?t=45
The tutorial covers the volume slides which I planned to cover here, including the Kxx effect, which is really very useful. Since all of it is very well described in the above mentioned tutorial, I decided not to clone it, so go check that link out.

However, I am ready to tell you about tuning samples. With some help from LPChip, I started playing with samples which needed tuning.
Funny how things might seem difficult when you don't have all the information. The thing you need to do here turned out to be very easy.
Let's say we have Sample 1 and Sample 2. Sample 2 needs to be in tune with Sample 1. There are 2 steps in the tuning process.
Step 1. The frequency.
In the sample window (I'm using Modplug Tracker, but every other tracker has same options, maybe just in other menus) there is that field Freq. (Hz). Copy Sample 1 frequency from that field and paste it to the freq. field in the Sample 2 window. That would transpose Sample 2 to the same note as Sample 1. Try it out. In some cases that would be enough, as samples may have just been "starting out" from different notes. However, in my previous blog entry I had mentioned a case when this did not give the desired result - samples were still out of tune. If that is so, let's proceed to the second step.
Step 2. Sample length.
This was what LPChip pointed out to me - the shorter the loop length, the higher the pitch of the sample. So if you want samples to be in tune, you'll have to adjust their loop lengths in such a way that both values would be divisible by one number. It may sound complex, but it is really very simple, let's just continue with our imaginary sample tuning.
So after you transposed Sample 2 to the same note as Sample 1, you'll have to look into the loop lengths. (I'm assuming we are working with samples, which have a loop starting from position zero. In other cases the situation is different, I'll cover that afterwards.)
Say, Sample 1 has a loop beginning at 0 and ending at 62. Sample 2 has a loop which also begins at zero, but ends at 150.
So what you have to do here is either put the end loop position of Sample 2 at precisely 62 or any number, divisible by 62. Once that is done, samples are tuned!

Let's theorize what we might have in our example. If we put end loop position of Sample 2 from 150 to 62, that will make the sample very high pitched. Perhaps, this is not what we want. We would like to keep the sound of the sample lower and closer to it's original sound of loop end 150. In that case it would be better to set loop end position to 124, which is 62x2. If the original sample had data after 150, you could set the loop to 186, which is 62x3 and that would also work.

Since chip tunes usually use samples of very short lengths, all of these loop position changes won't affect the sound. Of course, when you have more distinctive stuff, like strings or piano, you would need to have "perfect loops" and that makes the tuning process much harder. However, chip music, and we are speaking of chip music here, is very forgiving even to distinctive instruments. For instance, Purple Motion's track "Aquaphobia" has a string with a loop far from perfect, but it still works, especially on higher notes. (By the way, be sure to get as much good chip music as possible. Music by Future Crew's Purple Motion and Skaven is a very good starting point.)

Now let's talk about samples which have loops that do not start from zero position.
In that case changing the loop length is somewhat useless, as the sample before the loop would be out of tune, while the looped part would be okay. This weird situation may be fun and even useful at times, but generally it is no good and I personally don't yet know what to do. But I'll keep you updated!

My first chip tune.

I started this blog to share my experience in learning to track chip tunes.

Of course, first of all, you may ask a question: why would anyone want to compose exactly chip music?
Well, because chip music is the kind of genre that is 100% compatible with tracker software.
Actually, it wouldn't be a mistake to say that trackers were created with the intention of producing such tunes. Or, even more correctly, chip music is the kind of music that uses the possibilities of a tracker to the limits. Um. Probably both. Well, you get the point :)
The second reason is because I never really mastered that part. When tracking was the only way to produce music, I was absolutely uninterested in chips and was mostly aiming to produce 'pop music' type stuff. That pushed me away from things like Jxx or Gxx effects and thus all the possibilities it gives for expression.
Last year I came upon Purple Motion's music and fell in love with it instantly. I was truly amazed by the originality and freshness of it and later enjoyed music from http://www.chiptune.com It was obvious to me that music from Elwood, Hunz, Vibrants and other wonderful tracker composers startles us not only because it has an unresistable appeal musically, but because it was made with trackers. Tracking software created a unique style, due to both it's advantages and limitations - tracked music. The fact that you can produce a tune out of a couple of sine waves simply fascinates.

And now, in May 2006, I decided to make my first real attempt at chip music.

Of course, it is difficult. Actually, I felt like crap. I put down several tunes and they were awful. With chip music you can't fool a listener by playing an imaginative pad - you have to deliver a melody, original enough for him not to turn your 8 bit tune off the first 30 seconds it plays.

-My first chip tune-
I started with samples. Got several tunes from www.chiptune.com and extracted a dozen of sine, square and triangle waves. To a modern musician who uses an advanced sequencer, those samples are generally a bunch of weird sounds, suitable for sound effects at best.
Indeed, without processing those samples sound nothing like music. But since I am not a total lamer, I got one of them and applied Jxx effect on it.

Jxx is probably the most notable feature of chip music. It is usually used to produce chords. At first this thingy may seem mysterious, but once you know how to use it, it becomes very simple.
Jxx effect is an arpeggiator. It plays three notes at a very high speed repeatedly and this creates that funny chip sound. How do you know what three notes it plays?
Well, the first note is the one you've applied the effect on. The second and third are defined in the effect column.
Example:
If you have a C-5 note and you want to produce a Cmaj chord (C-E-G), you apply J47. Here digits are counting the needed notes from the base note, C-5 in our example. So you can see that E-5 is the fourth note from C-5: C#, D, D#, E. And G-5 is the seventh. Hence, J47. If you'd want to produce a C-E-A chord, you would use J49, since A-5 is the ninth note from C-5.

Jxx effect was probably created when all tracked music was limited to 4 channels. To produce a chord like C-E-G you'd need three channels, which was unacceptable. Jxx made it possible to produce chords and yet use only 1 channel.

Now that I had the Jxx theme, I could start writing the lead melody.
The amazing moment here is that you can use the same sample for that. Jxx effect changes the sound of the sample so significantly that it sounds very different. Also, using those sine waves on different octaves produces quite different sounds. So you would usually use lower octaves of the sample for bass, middle - for arpeggiator and higher - for leads.

But I decided to choose a different sample for that and bumped into the most annoying problem, something that turns away many newbies from chip music - I had two different sines and they were not properly tuned.
All my attempts to tune them through modplug tracker features, such as transpose note and frequency, resulted in even more difference. It is quite puzzling, since the frequency of the sines was then equal, yet they didn't work together. This still needs figuring out.

So I ended up taking two samples from virt's mod which were properly tuned. Using those two tiny samples I created the whole melodic basis of the tune - bass, leads, support themes, chords. In the end this was amazing even to me, a person composing the tune :)

Lead Melody.
Usually you think - well, I've put down this melody, but it sounds so dull with that sine, even annoying. And indeed - what can you expect from a sine wave, which is basically a beep?
Well, that's what trackers are! To make good stuff out of those beeps! All you have to do is apply different effects, which are functions that do different things with the sample. You can actually make the lead melody very-very interesting and expressive by applying those simple effects:
Hxx - Vibrato.
Gxx - Portameno.
SDx - Note delay.

Vibrato.
I haven't figured out exactly how vibrato works. But the usual values used by other musicians range from H81-H86. The higher the number, the more the vibrating. Values like H51 or H32 produce weird effects that sound like very slow vibrating. So perhaps the first digit indicates the speed of vibration, while the second - it's range.
I also noticed that different samples react to vibrato differently. Some whirl like a police siren at H81, some start vibrating significantly only starting from H84. The latter is prefferable, since it gives you more control over the effect and you can make the note vibrate at first slightly and then increase the effect which adds to expression. It is yet to be figured out why some samples react to vibrato like that, since if a sample whirls wildly at H81 it can not be vibrated at all. I tried lower values, even H11, but it didn't help.

Portamento.
Portamento in simple words is note sliding. So you need to have an intial note and apply an effect to the one after it. The effect will slide it from the first and the speed of the slide is defined by the digits in the effect. For example, G13 would slide it real fast, while G01 would create a slow slide. The effect usually takes place several rows, so you should duplicate it further down, like this:
C-5
...
...
D-5 G03
... G00
... G00

There is no need to copy the value, since G00 means that the above mentioned value is used. If you don't put the needed amount of G00 rows, the slide may not be completed and may end up somewhere in between. If there is no possibility to do that, increase the speed untill the slide is completed in the amount of available space.
Like with the vibrato effect, portamento works differently for different samples. Why - it is yet to be found. I think that the reason may be the same as with vibrato. Probably some sound property of the sample.

Note delay.
This can simply be used for ornaments. <-- that's a link in case you don't know what ornaments are or want more info on it. SDx, where x are digits from 1 to F, simply delays the note, so that it sounds slightly later then it should've been: F-6 SD3 G-6 In the above example F-6 would be an ornament to G-6. The value of the delay is easily defined by several tries and, as far as I understood, depends on the tempo and/or speed of the tune.

The result.
The result of my ordeal is surprisingly not that bad. Here is the link to the page where you can get the tune. Just push the download button: A Trip To Netherlands.
I think it's not bad for a first chip tune. I had previously tried making a chip, of course, but it was long ago and it was crap. But maybe that experience also helped. After all, how can you become a master without first being crap? :)

Summing up my first experience:
-you can produce the tune using few samples. A sine wave produces very different sounds on different octaves. Thus, you can use lower octaves for bass, middle and high octaves for arpeggiator and leads.
-Jxx is a simple effect to produce chords.
-Hxx,Gxx and SDx are the basic effects to make your lead theme interesting and expressive.

Well, I quess that's all for my first entry. In the next entry I plan to tell more about effects, like Kxx and volume slides.

Cheers!