Tutorial #4 - The Basic Patch : Pitch Manipulation Overview -------- One of the things we typically expect a synthesizer to do is allow us to change pitches. Although some music groups (mostly comprised of monks) are quite happy with only a single pitch, most musicians want the full spectrum of notes. Additionally, we synthesists tend to want access to the notes "between" pitches, for slides, microtones and miscellaneous warbles. This tutorial examines the K2000 pitch handling. The "Patch Run" section of this tutorial will utilize patches from the file TUTOR_04.KRZ (sometimes called DDGT0004.KRZ, available at an FTP site, WWW site or mailserver near you. Technical Discussion -------------------- The ability to change pitch is taken for granted. We hit a key and expect a note. Hit a different key, expect a different note. Hit middle C, expect a middle C tone. Nothing could be simpler, right? Not so fast, grasshopper! Sometimes, I'd like the same tone regardless of the key hit - like with a percussion sample. Sometimes I want to hit a key, and hear the tone rise or fall. And sometimes, I want two octaves on the keyboard to represent one octave of notes. I mean, I bought a synthesizer in order to have some flexibility, didn't I? As Western musicians, our ears are tuned to specific note values. If one note is double the frequency of another, the first note is an octave above the second. There is some fancy-pants formula that allows us to have twelve notes in an octave, with 100 "cents" between each note. Hitting a C-E-G combination gives us a simple C chord, and hitting G- C-E gives us the same chord in another inversion. A note on the left side of the keyboard is lower than one on the right... Well, there is nothing that intrinsically forces us to abide by any of these rules. By default, the K2000 assumes that we want 100 cents between each note, and that the left side of the keyboard is lower (in pitch) than the right. But we also have the ability to change this. But why? We may want to use non-tonal samples - samples that don't have a base tone, so are not normally useful when tone shifted. We may want to experiment with different octave scaling -- 17 or 24 notes per octave, rather than 12. We may want to try some "whacked" ideas, like a reversed keyboard or a velocity-based pitch. We may be using non-standard MIDI controllers, which may not follow strict tonal handling. We may want the sound to have many tonalities, not just one. In the Patch Runs, we will check out each of these types of sounds, and open some doors for your experimentation. But first, there are a few details to discuss. Pitch vs. Key-tracking ---------------------- There are two different pitch parameters at work in the K2000: the base pitch and keyboard tracking. The base pitch means: I have a sample or an waveform generated by an oscillator. If I hit a middle C key, how close to (or far from) a middle C pitch will I hear? Now, this is overly simplified, since the sample you are using may not be "middle C" based. However, you can think of the base pitch adjustment as a tuning factor, allowing you to change the relationship between which note you play, and which note you hear. Conversely, the key-tracking parameters represent the following: I have a sample or an waveform generated by an oscillator. If I hit a note, then hit a second note, how much difference is there in the pitch of the two notes? Therefore, the key-tracking parameters are used to determine if we change pitch, and by how much. In most typical Western music, you will either use 100 cents/key (standard 12-note octave scales) or 0 cents/key (no tonal change - typical for exact playback of samples). But we've just got to try some of the other options... Limitations of sample playback ------------------------------ Because the K2000 is typically used to play back recorded samples, we need to be aware of the limitations to the sample playback engine. Basically, the K2000 changes the pitch of a sample by altering the speed that the recorded sound is played. This works fine, but surely there must be a "speed limit"? Oh, yeah -- there is. The manual, and posts by on the Internet, detail the technology behind it; we'll just say there is an upper limit around one octave over the recorded sample pitch - give or take a few notes, based on the sample rate used. Well, what if we need samples that are accurate, and that sound good, over the entire range of the keyboard? This is where multi-sampling comes into play. A multi-sample is a collection of closely spaced samples that represent the full range of the recorded instrument. For example, if we were sampling a flute, we could take a recording of each note and assign it to a key. Or, we could sample every third note, and let the K2000 handle the pitch changes required for "in between" notes. All multi-sampling parameters are handled in the creation of a KEYMAP, and therefore become transparent to us algorithm programmers. Suffice to say, most of the internal samples of the K2000 are high-quality multisamples of their respective instruments. More about the Modulation Matrix -------------------------------- In the Patch Runs, we will also look at using controllers (MIDI controllers, envelopes and velocity) to adjust pitch. Since we are increasing the use of modulation options, I want to cover the concept of the modulation matrix in more depth. This is becoming more important, since we are starting to have more modulation destinations, and are using more modulation sources. I like to "visualize" a modulation matrix as a spreadsheet-like grid, with the destinations on the vertical plane, and the sources on the horizontal. So far, we've been using the following grid: A E E M D M N N O A P V V D T E A N 1 2 W V H _________________________ Tone Volume | A - - - - Filter Cutoff | - - - - - Filter Resonance | - - - - - In this grid, an "A" represents that a source always controls a destination - like the AMPENV always controls the tone volume. A "-" stands for "not in use," while an "X" will stand for "in use." Hence, a patch where ENV 1 controls the cutoff frequency, and the Mod Wheel controls the filter resonance, would look like: A E E M D M N N O A P V V D T E A N 1 2 W V H _________________________ Tone Volume | A - - - - Filter Cutoff | - X - - - Filter Resonance | - - - X - Using the above as a basic grid system, you should notice that there is no limitation to the number of destinations a modulation source can affect. So, for example, you could use the AMPENV to control the filter cutoff as well as the tone volume. In this tutorial, we will be adding some new sources and destinations. Our new grid will look like this: A E E K V B M D M N N E E E O A P V V Y L N D T E T C D A N 1 2 R T E W V K Y R _________________________ Tone Volume | A - - - - - - - Filter Cutoff | - - - - - - - - Cutoff SRC2 Depth | - - - - - - - - Filter Resonance | - - - - - - - - Pitch | - - - - - A - - Pitch SRC2 Depth | - - - - - - - - In this case, I've added the KEYTRK, Velocity and Bender modulators to the source set. We've used KEYTRK and Velocity before, and they will become more important as we go. The Bender was added, since it is an important part of pitch manipulation. The Pitch was added to the Destination column, since that is what we will be changing. You will notice that the Bender is, by default, "A"lways connected to the Pitch. While the bender can be programmed to not change the pitch, it is always connected to the pitch destination. I've also added the cutoff and pitch SRC2 Depth destinations, since these are values that can be modulated. In the upcoming patch runs, I will include a modulation matrix chart if the modulation sources are relevant. I will use a partial modulation matrix - a matrix containing only those values that are actually "wired". As we add modulation sources and destinations, I will also include an updated matrix listing - to help you coordinate modulator usage for your own patches. Well, that's a pile of discussion ... LET'S DO SOME MORE PATCHES!!! Patch Run #1 - Base Pitch and Key-tracking Options This "Patch Run" will utilize the first three patches, each prefixed with "[ddg]04/01". You should load the patches into your K2000 (typically in the 200's bank) in order to work along with this tutorial. The first patch is "[ddg]04/01 pitch", a bright, lightly chorused electric piano - the type of electric piano often used in a heavy studio mix. We are going to use this patch to explore the base pitch options. Enter the patch editor, and start by selecting the [KEYMAP] soft key. Although we are not going to dwell on the KEYMAP options at this time, there are a few options on this page that deal with how pitch is utilized in the K2000. The K2000 KEYMAP page ties a Keymap (a set of samples) to a programmed patch. The changes you make in the KEYMAP area are "global" to the patch layer you are working on - and are typically used to "tune" the samples to your playing style and the keyboard. In this case, I've created a Keymap featuring electric piano samples. There is one "base pitch" parameter that we need to examine on this page: KEYMAP XPOSE: This allows you to put in a transposition amount - in semitones. You would normally use this to move samples into a "playable" range based on the keyboard controller you are using. I often use it to "warp" sounds by massively transposing them. To experiment, change this value both up and down. When you are done, reset it to zero. Select the PITCH page by hitting the [PITCH] soft key. There are two fields that affect the base patch here, the COARSE and FINE parameters. The COARSE field allows you to adjust the pitch by semitones, while the FINE field allows you to adjust it by cents (100ths of a semitone). These are the parameters you would use to tune a patch to another patch, another synthesizer, or an acoustic instrument. Adjust the parameters, and check out the effect of various range options on the sound of the patch. Move to the SRC1: field, and change it to MWHEEL, and change the depth to 300cts. Now, play a note while adjusting the Mod Wheel. We've just changed the Mod Wheel to be a pitch modulator. Change the depth to -300cts and check out the difference. When you are "checking out" a modulation source, pitch modulation is the easiest way to hear the change! Return the SRC1: field to OFF, and move to the COMMON page by hitting the [MORE>] soft key until you see [COMMON], then hitting that soft key. You will notice that the pitch bend range is located in this area. It is part of the COMMON page, rather than the PITCH page, since it will affect all layers of a patch (a concept we will be exploring soon) identically. Adjust this parameter, then play keys while moving the pitch wheel. When you are setting up a patch, make sure that you set the pitch bend parameter suitably for the patch sound and playing style desired. When you are done, you can exit the patch editor. The second patch "[ddg]04/01 ptch2" will be used for experimenting with key-tracking. It is an ARP-like patch, with only a single note sounding. I've got a light filter modulation on it - check out the filter pages if you are interested. Again, start the pitch examination by looking at the KEYMAP page. You will notice that I'm using a standard keymap (#157 Buzzy Square), but I have set the KEYTRK: field to 0ct/key. KEYMAP KEYTRK: This determines the default amount of change, key-to-key, that a sample set will sound. Again, for typical use, this will either be set to 100 ct/key (standard Western tuning) or to 0 ct/key (no pitch change). Experiment with this setting, then return it to 100 ct/key. This means that, by default, the played sample will not change pitch. Regardless of which key I play, the base sample note will be sounded. Great for loops, not so great for grand pianos... Again, move to the PITCH page. Notice that there is no modulation here at all. Since the KEYMAP KEYTRK field is set to 0ct/key, and the PITCH KEYTRK is set the same, there is absolutely no change in pitch regardless of the note played. Change the PITCH KEYTRK field to 100ct/key, then play notes across the keyboard. Over the low end of the keyboard, the notes sound fine. However, at the high end of the keyboard, the notes will all sound the same. Why??? Well, this is the limitation of sample playback that we talked of earlier. Because we set the KEYMAP KEYTRK to 0ct/key, the same sample note plays, regardless of the note we hit. The PITCH KEYTRK is set to modulate the pitch, but can only change it to the extent that the sample is transposable. Since the K2000 cannot transpose the sample above an F#5 (in this case), no amount of modulation will affect the pitch. To correct this situation, set the PITCH KEYTRK to 0ct/key, then move back to the KEYTRK page. Set the KEYTRK field to 100ct/key, and play a broad range of notes. You should now notice that the notes sound correctly across the keyboard. The reason is that the KEYMAP KEYTRK is allowing the appropriate sample to be sounded, and the PITCH KEYTRK is not modulating pitch at all. Finally, let's experiment with some oddball pitch settings. First, return the KEYMAP KEYTRK field to zero, and set the PITCH KEYTRK to 50ct/key. Hit lower notes two octaves apart. They are only one octave apart! The setting of 50ct/key represents that individual keys are "half-a-note" apart - hence there are 24 keys in each octave. Play your favorite lead run using this scale. After you stop gagging, try some different PITCH KEYTRK options - you are in microtonal world! When you are finished experimenting, return the PITCH KEYTRK field to 0ct/key. Finally, we are going to try an old Josef Zawinul trick - the reversed keyboard. He wired up an ARP 2600 for the trick, we'll use our trusty K2000. Change the PITCH KEYTRK value to -100ct/key. This means that each key will be 1 semitone _lower_ than the key below it. Play some chromatic keyboard runs - weird!!! This is a great trick for innovative melody and solo ideas - try it in your next sequence. Again, the pitch stops changing at the very lowest played (highest sounding) keys. To allow the multisamples to play properly, you can also have the PITCH KEYTRK set to zero, and the KEYMAP KEYTRK set to -100ct/key. NOTE: The way NOT to do this is to set the KEYMAP KEYTRK to 100ct/key, and the PITCH KEYTRK to -200ct/key. Although this will set up a cumulative result of -100ct/key, the lowest played (highest sounding) keys will go crazy as samples are swapped out improperly. Try it and see - it just isn't pretty! Patch "[ddg]04/01 ptch3", the third patch for this run, will be used for some quick velocity testing. Play sixteenth notes at widely varying velocities - instant sci/fi. Jump into the editor to see what's happening. On the KEYMAP page, I've set up the system to use no pitch change based on note value (KEYTRK: 0ct/key), but a high VELTRK value of 7200 ct. This means that the velocity of each note will be measured, and the pitch will be determined by this velocity value. On the PITCH page, there is also a VELTRK value. I decided to use the KEYMAP VELTRK, since I want the K2000 to determine the correct multisample to use - which will prevent me from running out of transposition range. The same could be done at the PITCH VELTRK value, but the same sample would be transposed, and the upper limit of this single sample's range could easily be reached. I normally determine which parameter to change based on the amount of transposition I expect - if it is slight (like a drum's pitch change as it is hit harder), I will most likely use the PITCH VELTRK parameter. If the effect is extreme, like it is here, I would use the KEYMAP VELTRK value. While these keymap-based modulation options allow a great amount of flexibility, I would caution about overusing them. There are many places within the K2000 modulation matrix where these parameters can be affected. I suggest, again, that the KEYMAP parameters generally be used for tuning the samples that you are using -- and that effects and modulations be added in the PITCH page. The only alteration in this rule would be based on sample transposition. You can try both approaches to determine which is best for a specific instance. That's all for Patch Run #1 Patch Run #2: Envelope Modulations Select the patch labeled "[ddg]04/02 mod 1". Hit a ninth chord, hold it, then release it. This is a sound familiar to us old studio cats: the reel-to-reel machine cycling from rewind to playback mode. In today's digital world, you don't get to hear it enough, so I thought I should synthesize it... The simplified modulation matrix for this patch is: A E B M N E P V N E D N 2 E V R __________ Layer Volume | A - - Pitch | - X A I've attached ENV2 to pitch modulation SRC1, and set the depth to 1200ct. This means that envelope #2 will change the pitch +/- 1200 cents, or one octave. Take a look at ENV2. The parameters force the pitch to jump high (to 100%), fall low (to -100%) then rise back to 0%. This means that the pitch will rise by an octave (100% of 1200 cts), drop two octaves (to -100% of 1200 cts), then return to the original pitch (0% of 1200 cts). To test this, make changes to the duration and amount of the various ENV2 parameters, or to the depth control of the PITCH SRC1 field. The use of pitch modulation in this way give you a number of possibilities for both effects and accents to sampled sounds. Patch "[ddg]04/02 mod 2" is virtually the same patch, but with one simple addition - when you release the note, I'm emulating the reel-to-reel deck stopping, with the pitch dropping accordingly. First, examine the PITCH page. You will notice that I am using two different envelopes - ENV2 as SRC1, and ENV3 as SRC2. In this case, I am using a unique SRC2 depth modulation - the "Always ON" option. Anytime you set a modulation depth to be ON, it is the same as always setting a modulation source to 100% of its value. I've set the MaxDpt to 2400 cts, since the sound is most convincing when the pitch drops heavily. Next, take a look at ENV3. You will notice that the envelope is steady at 0% throughout the attack and decay sections. That prevents any pitch modulation while the key is being held down. However, this envelope drops to -100% rapidly on key release, and does so over .32 seconds. This gives the illusion of the tape machine rapidly stopping. Now, jump to the AMPENV page. You will notice that I've also added a release section to the AMPENV, and am allowing the output to drop only slightly during the first .32 seconds, then dropping it to zero. If there were no release values, you would not hear the release effect - because the AMPENV would have shut off the volume. However, since we are keeping the AMPENV open during the time frame of the ENV3 release section, you are able to hear the entire effect of the dropping pitch. For illustration purposes, here is the modulation matrix for "[ddg]04/02 mod 2": A E E B O M N N E N P V V N E D N 1 2 E V R ________________ Tone Volume | A - - - - Pitch | - X X A - Pitch SRC2 Depth | - - - - X "[ddg]04/02 mod 3" uses a complex envelope to play a simple melody. While this isn't generally too useful, it shows the power that is available using the advanced envelopes of the K2000. First, take a look at the PITCH page. Notice that I've used ENV2 as the SRC1 modulator, with a depth of 2400 cts. This gives me a +/- two octave range for envelope control. Now, move to the ENV2 page. Notice that I'm using the attack stage of the envelope to perform the initial slide and drop part of the phase, am holding steady at 30% during the decay and sustain phase, then do a little slide melody on release. This type of extensive pitch modulation is often used for demo patches, where small segments of a melody are programmed into each envelope, then combined into a larger "song". That is the end of Tutorial #4. You should have a pile of ideas to experiment, and should be able to produce some great effects on you own. Feel free to share these with your friends on the net, and with me at: ddg@wi.rr.com Thanks, and see you next week!