Windows or Mac?
If your intention is to use windows to develop and linux to perform, your patches should be portable between windows and linux. In fact going from windows to linux should be easier since the latter has certain pd features the former doesn't.
But watch out for case insensitive filesystems. In windows and mac the filesystem is case preserving but not sensitive, while linux has mostly case sensitive filesystems. For PD this means that under linux you can have two distinct patches, ex: Not.pd and not.pd while in windows this would not be allowed. Porting from windows to linux this example shouldn't be a problem, but you might have an abstraction patch saved as not.pd and use it as "NOT" in another patch. Under windows this will work since "NOT" will be matched to not.pd, but under linux it won't work since it will be looking for NOT.pd
Arduino and pure data
Hello. I'm trying to use Arduino with Puredata using the Firmata Library. I downloaded Firmata and installed the library as instructed in the readme, and then loaded 'AnalogFirmata' from the library examples. When I try to compile this example (or any of the others) I receive a string of error statements. Code and errors listed below. Any suggestions?
Code:
/* This firmware supports as many analog ports as possible, all analog inputs,
* four PWM outputs, and two with servo support.
*
* This example code is in the public domain.
*/
#include <Firmata.h>
#include <Servo.h>
/*==============================================================================
* GLOBAL VARIABLES
*============================================================================*/
/* servos */
Servo servo9, servo10; // one instance per pin
/* analog inputs */
int analogInputsToReport = 0; // bitwise array to store pin reporting
int analogPin = 0; // counter for reading analog pins
/* timer variables */
extern volatile unsigned long timer0_overflow_count; // timer0 from wiring.c
unsigned long nextExecuteTime; // for comparison with timer0_overflow_count
/*==============================================================================
* FUNCTIONS
*============================================================================*/
void analogWriteCallback(byte pin, int value)
{
switch(pin) {
case 9: servo9.write(value); break;
case 10: servo10.write(value); break;
case 3:
case 5:
case 6:
case 11: // PWM pins
analogWrite(pin, value);
break;
}
}
// -----------------------------------------------------------------------------
// sets bits in a bit array (int) to toggle the reporting of the analogIns
void reportAnalogCallback(byte pin, int value)
{
if(value == 0) {
analogInputsToReport = analogInputsToReport &~ (1 << pin);
}
else { // everything but 0 enables reporting of that pin
analogInputsToReport = analogInputsToReport | (1 << pin);
}
// TODO: save status to EEPROM here, if changed
}
/*==============================================================================
* SETUP()
*============================================================================*/
void setup()
{
Firmata.setFirmwareVersion(0, 2);
Firmata.attach(ANALOG_MESSAGE, analogWriteCallback);
Firmata.attach(REPORT_ANALOG, reportAnalogCallback);
servo9.attach(9);
servo10.attach(10);
Firmata.begin();
}
/*==============================================================================
* LOOP()
*============================================================================*/
void loop()
{
while(Firmata.available())
Firmata.processInput();
if(timer0_overflow_count > nextExecuteTime) {
nextExecuteTime = timer0_overflow_count + 19; // run this every 20ms
for(analogPin=0;analogPin<TOTAL_ANALOG_PINS;analogPin++) {
if( analogInputsToReport & (1 << analogPin) )
Firmata.sendAnalog(analogPin, analogRead(analogPin));
}
}
}
Error Statements:
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:61: error: typedef 'callbackFunction' is initialized (use __typeof__ instead)
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:61: error: 'byte' was not declared in this scope
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:61: error: expected primary-expression before 'int'
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:64: error: typedef 'sysexCallbackFunction' is initialized (use __typeof__ instead)
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:64: error: 'byte' was not declared in this scope
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:64: error: 'byte' was not declared in this scope
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:64: error: 'byte' was not declared in this scope
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:64: error: 'argv' was not declared in this scope
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:81: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:81: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:86: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:87: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:88: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:90: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:91: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:91: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:91: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:95: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:95: error: 'callbackFunction' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:96: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:97: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:98: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:98: error: 'sysexCallbackFunction' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:98: error: 'void FirmataClass::attach(int, int)' cannot be overloaded
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:95: error: with 'void FirmataClass::attach(int, int)'
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:99: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:104: error: 'byte' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:105: error: ISO C++ forbids declaration of 'byte' with no type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:105: error: expected ';' before '*' token
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:107: error: 'byte' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:108: error: 'byte' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:109: error: 'byte' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:110: error: 'byte' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:112: error: 'boolean' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:115: error: 'callbackFunction' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:116: error: 'callbackFunction' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:117: error: 'callbackFunction' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:118: error: 'callbackFunction' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:119: error: 'callbackFunction' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:122: error: 'sysexCallbackFunction' does not name a type
In function 'void setup()':
Interfacing PD with the Arduino ... how?
i got a problem in uploading the file to the board. ( I have press play, same error found. When I press upload to I/O, below error found)
anyone can help?
thx
////////////////////////////
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:61: error: typedef 'callbackFunction' is initialized (use __typeof__ instead)
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:61: error: 'byte' was not declared in this scope
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:61: error: expected primary-expression before 'int'
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:64: error: typedef 'sysexCallbackFunction' is initialized (use __typeof__ instead)
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:64: error: 'byte' was not declared in this scope
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:64: error: 'byte' was not declared in this scope
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:64: error: 'byte' was not declared in this scope
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:64: error: 'argv' was not declared in this scope
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:81: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:81: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:86: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:87: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:88: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:90: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:91: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:91: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:91: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:95: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:95: error: 'callbackFunction' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:96: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:97: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:98: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:98: error: 'sysexCallbackFunction' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:98: error: 'void FirmataClass::attach(int, int)' cannot be overloaded
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:95: error: with 'void FirmataClass::attach(int, int)'
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:99: error: 'byte' has not been declared
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:104: error: 'byte' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:105: error: ISO C++ forbids declaration of 'byte' with no type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:105: error: expected ';' before '*' token
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:107: error: 'byte' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:108: error: 'byte' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:109: error: 'byte' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:110: error: 'byte' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:112: error: 'boolean' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:115: error: 'callbackFunction' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:116: error: 'callbackFunction' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:117: error: 'callbackFunction' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:118: error: 'callbackFunction' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:119: error: 'callbackFunction' does not name a type
/Applications/arduino-0012/hardware/libraries/Firmata/Firmata.h:122: error: 'sysexCallbackFunction' does not name a type
In function 'void setup()':
Error: tabsend~: $O-hann: no such array
- To cross synthesise two voices you must ensure that two speakers make exactly the same utterances which are phonetically aligned. This is hard as I can tell you from experience of recording many voice artists. Even the same person will not speak a phrase the same way twice.
<< This is not possible in my experiment, as I am supposed to morph the actual conversation, so it is upto subjects what ever they want to speak. There is some work done by (Oytun Türk , Levent M.Arslan) who conducted experiment in passive enviornment (not at real time).
- The result is not a "timbral morph" between the two speakers. The human voice is very complex. Most likely the experiment will be invalidated by distracting artifacts.
Here's some suggestions.
- Don't "morph" the voices, simply crossfade/mix them.
<< yes I also want to do this, crossfading and mix, as I just want to create illusion, so that listner start thinking whether it is B's voice or A's voice>>
- For repeatable results (essential to an experiment) a real-time solution is probably no good. Real time processing is very sensitive to initial conditions. I would prepare all the material beforehand and carefully screen it to make sure each set of subjects hears exactly the same signals.
<<Yes, I agree, but it is demand of experiment, I can not control the environment, but to create some good illusion (or to distract listner, I may add noise in the siganl at real time, it would challange the listner brain in identification, so I may use such kind of tricks for the sucess factor)
- If you want a hybrid voice (somewhere between A and then vocoding is not the best way. There are many tools that would be better than Puredata which are open source and possible to integrate into a wider system.
<<Actually now I have a little familarity with pure data, so it is more good for me to stick with it for a while (due to short time), yes if i continue my phD in this domain, I would explore other tools as well. for the time being it is a kind of pilot study>>
Question :
Is VoCoder alone is sufficient for morph/mix/crossfade among two voices?
or I should also add the pitch shifting module with VoCoder to get some more qualitative results.
Question 2:
I already tried this VoCoder example, but could not change it according to my requirements. In my requirements, I have a target voice (the target voice is phonetically rich) and now source speaker is speaking (what ever he want to speak) and source voice is changing into target voice. (illusion/crossfade/mix)
The (changetimbre1.pd ) file that I attached first, give you an idea of what kind of operational interface I am looking for.
Question 3:
what should be the ideal length of target wave file?
Before the start of experiment, I would collect the voice sample of all participants.
I am highly oblige for your earlier help and looking for more (greedy). Meanwhile I would once again study this vocoder example to change it according to my requiement. ( though i doubt I may change it).
Thanks.
Problem compiling external on Windows
Hey,
thanks to everyone who responded to my posts both here and in the mailing list. Since then, I've figured out how to compile externals written in C using Microsoft Visual C++ 2005. There's more to document, however, such as how to compile externals using some of the other Windows compilers (Borland, djgpp, etc.), and also how to compile externals written in C++ in Windows. But one thing at a time.
one little thing to note... steps 4 and 7 may seem a little roundabout, but they account for the fact that MSVC sometimes has trouble with spaces in directory names (eg. C://Program Files/). If anyone knows how to override this behavior, post a reply, and I'll try to simplify the steps accordingly.
Updated June 29, 2007:
use [b]C://Progra~1/[/b] instead of [b]C://Program Files/[/b],
use [b]C://Docume~1/[/b] instead of [b]C://Documents and Settings/[/b], etc.
So, without further ado...
How to compile a pd external written in C using Microsoft Visual C++ 2005:
Compared to Windows, linux offers a much more user-friendly environment for compiling pd externals. However, with a little patience, a usable environment can be set up in Windows, and the good news is that everything you need is available for free. There are several reputable Windows-compatible C/C++ compilers out there, but here I'll discuss compiling externals with Microsoft Visual C++ 2005 (MSVC for short).
1. Download and Install Microsoft Visual C++ 2005 Express Edition.
a. Click the link above, then click Go! in the Visual C++ box.
b. Run vcsetup.exe to install the program
(the setup wizard should guide you through the process).
2. Download [url=http://download.microsoft.com/download/7/7/3/7737290f-98e8-45bf-9075-85cc6ae34bf1/VS80sp1-KB9267
]Visual C++ 2005 Express Service Pack 1.
a. Click the link above to download the Service Pack.
b. Run VS80sp1-KB926748-X86-INTL.exe to install the program.
3. Create a new project:
a. Open Visual C++.
b. Open the New Project window (Ctrl+Shift+N).
c. In the Project Types pane, select Visual C++.
d. In the Templates pane, select emptyproj.
e. Enter object name (helloworld).
f. Leave Create directory for solution unchecked, and click OK.
4. Import the pd header file:
a. Get m_pd.h here, or, using pd-vanilla (not pd-extended):
1. Open Windows Explorer or My Computer.
2. Navigate to the pd/src/ directory on your system.
3. Open m_pd.h in a text editor (file type is: C/C++ header).
b. Select all (Ctrl+A).
c. Copy selection to the clipboard (Ctrl+C).
d. Back in Visual C++, open the New File window (Ctrl+N).
e. In the Categories pane, select General.
f. In the Templates pane, select Text File, and click Open.
g. Copy the contents of m_pd.h into the editor window (Ctrl+V).
h. Open the Save File As Window (Ctrl+S).
i. Save as m_pd.h.
j. From the File Menu, select Move m_pd.h into; select helloworld.
5. Write the source code for the external in C.
a. Open the New File window (Ctrl+N).
b. In the Categories pane, select General.
c. In the Templates pane, select Text File, and click Open.
d. Write your source code in the editor window.
The following example is taken from the tutorial by Johannes M. Zmoelnig.
#include "m_pd.h"
static t_class *helloworld_class;
typedef struct _helloworld {
t_object x_obj;
} t_helloworld;
void helloworld_bang(t_helloworld *x)
{
post("Hello world !!");
}
void *helloworld_new(void)
{
t_helloworld *x = (t_helloworld *)pd_new(helloworld_class);
return (void *)x;
}
void helloworld_setup(void) {
helloworld_class = class_new(gensym("helloworld"),
(t_newmethod)helloworld_new,
0, sizeof(t_helloworld),
CLASS_DEFAULT, 0);
class_addbang(helloworld_class, helloworld_bang);
}
6. Save and import the source code into the project:
a. Open the Save File As Window (Ctrl+S).
b. Save as helloworld.c.
c. From the File Menu, select Move helloworld.c into; select helloworld.
7. Access the pd library file:
a. Open Windows Explorer or My Computer.
b. Navigate to the pd/bin/ directory on your system.
c. Right-click on pd.lib (file type is: Object File Library) and select Copy.
d. Navigate to the C://TEMP/ directory on your system.
e. Paste the copy of pd.lib in the C://TEMP/ directory (right-click or Ctrl-V).
8. Set configuration properties:
a. Set configuration type to .dll:
1. Back in Visual C++, open the helloworld Property Pages window (Alt+F7).
2. In the left pane, select Configuration Properties >> General.
3. In the right pane, under Project Defaults, click on
Configuration Type, and select Dynamic Library (.dll)
(using the arrow on the right).
b. Add MSW to preprocessor definitions:
1. In the left pane, select
Configuration Properties >> C/C++ >> Preprocessor.
2. In the right pane, type MSW in the Preprocessor Definitions field.
c. Tell compiler which language to use:
1. In the left pane, select
Configuration Properties >> C/C++ >> Advanced.
2. In the right pane, select Compile As.
3. Select Compile as C Code (/TC) by clicking the arrow on the right.
d. Tell linker where to find pd.lib:
1. In the left pane, select Configuration Properties >> Linker >> Input.
2. In the right pane, select Additional Dependencies and enter
C://TEMP/pd.lib.
e. Tell linker to export the setup function:
1. In the left pane, select
Configuration Properties >> Linker >> Command Line.
2. In the right pane, type
/export:helloworld_setup in the Additional options field.
3. Click OK.
9. Compile and link:
a. Use the Build Solution command (F7).
10. Copy the new helloworld.dll file into pd.
a. Open Windows Explorer or My Computer.
b. Navigate to the
My Documents/Visual Studio 2005/Projects/helloworld/Debug/
directory on your system.
c. Right-click on helloworld.dll (file type is: Application Extension)
and select Copy.
d. Navigate to the pd/extra directory on your system.
e. Paste the copy of helloworld.dll in the pd/extra directory
(right-click or Ctrl-V).
11. Test the external in pd.
a. the external should now be a useable object in pd.
b. open a new pd patch and try to create a helloworld object.
c. add a bang to the left inlet and test it out.
d. if the main pd console window displays "Hello world !!",
the external has succeeded.
Hope this helps!
-- middlepedal
Best way to do this tree...
Thanks obiwannabe. Before you posted, I had just found a way to get things working. It's messy and probably not the most efficient way of doing things though, but again it works how I need it. Right now, I'm using routeing, moses, and some send/receives. I'll take a look at lists since they seem like that may have been a better route to go.
I'm sorry, I probably didn't explain well what I am trying to achieve. Every 8 notes, I wanted a pattern (algorithmic) to go back to Note 1 and find a new pattern (which may be the same as the previous one). Looking at the diagram, each box is the option(s) that can be chosen by the random generator. A 1/2 = 500ms, 1 = 1000ms, 2 = 2000ms, and 4 = 4000ms. At note 1, if a 2 is chosen, the next one can only be a 2, and the next only a 1, next a 3, next a 4, 3, or 1. If a 1 is chosen for note 5, then the next note must be a 4, next a 1/2, and last a 1/2, then back to note 1 again ( 4 or 2). There is no direct link between step and note length other then the fact that the order of note lengths reach an even point at the end of every 4 and 8 notes.
Basically, I originally had an algorithmic note generator, where the notes were picked from moses divide/split points. The problem is, with 4 instruments playing simultaneously, the rhythms were too random. So, I wanted to line them up every 4 and 8 notes. With the diagram setup, every 4 notes and 8 notes, the notes start together, while in between they can deviate randomly in their rhythm (note length).
I hope that makes more sense. I'm a student, and learning PD for the first time. So I'm sure my way isn't the most efficient, but it's all I could think of. =) The patch is almost completed, and I can upload it once finished if interested.
Best way to do this tree...
I'm making an algorithmic based program and I just thought of a new way that I'd like to generate length of notes. I'm still new to pd and programming in general, so I was wondering what the best and easiest way would be to go about making something like my chart below:
4 = note lengths of 4000ms (4 seconds), 2 = 2 seconds, 1 = 1 second, 1/2 = half second. So similar to whole, half, quarter, and eight notes. If the first note (when banged from a random 50/50 chance) is a 4, then the second note can be a 1 or a 2. If the second note is a 1, the third note must be a 2 and so on. I hope the diagram explains what I am trying to accomplish. The goal in doing this is so that on every 4 and 8 notes, the notes line up again (since I have 4 parts to this music generation).
I originally was doing something else to get note lengths, using a route 8 and a random note was triggered by a metronome, and then the metronome (received this length and) didn't choose another until the length of the first note finished. I'm having a hard time switching over to this new concept.
This notelength, is passed to a random note chooser using route 8.
Any help would be great! =)
Escher-esque chord progressions
I've been getting into writing patches that generate music all by themselves, using mathematical
rules that apply quite nicely to music theory. I've made a few rhythm patches that make nice cross
rhythms using metronome division and delays (with values derived from multiples of the master
metronome), and i'll post these too if anyone is interested.
In this thread I'm showing off my "Mauritz Escher like Chord progressions" patch.
Screenshot:
Mp3: http://responsible7.googlepages.com/zenpho_escher_pd.mp3
Patch: http://responsible7.googlepages.com/zenpho_escher.pd
First some basic music theory:
(skip this if you're comfortable with chords, 7ths, and inversions)
A major scale is constructed of 8 notes, with the "root" note doubled at the 8th note.
For the key of C major (all the "white" notes on a piano) the names and numbers of the notes in
the scale of C-major are:
Name, Number:
C, 1st (root)
D, 2nd
E, 3rd
F, 4th
G, 5th
A, 6th
B, 7th
C, 8th (remember the root is doubled at the octave)
A triad is constructed of the 1st, the 3rd, and the 5th notes in the scale.
A SEVENTH chord is constructed of a triad (notes 1,3 and 5) PLUS the 7th note in the
scale. So a C major 7th is note 1,3,5,7 or C,E,G,B.
Up until now we've been describing "standard" voicings of the chords, in other words, the notes
are played so that the root is the lowest pitched note, the 3rd is higher, the 5th is higher
still, and the 7th is the note just below the octave of the root.
At the risk of sounding redundant, "octave numbers" after the note name help clarify which octave
the note is to be played in. To play a C major 7th on the third octave, we would write:
C3,E3,G3,B3. To play it an octave higher we would write: C4,E4,G4,B4.
"Inversions" of chords re-order the pitches of the notes, but still play notes with the same
"name" as the 3rd, 5th, 7th etc. For example:
C3,E3,G3,B3 is a standard C major 7th...
...and G2,C3,E3,B3 is an inversion. All the notes are there (C,E,G,B) but they are in a different
order to the normal "Root, Third, Fifth, Seventh" arrangement. In this case, we say that "the
fifth is in the root".
Okay so now we know what a major 7th chord is. Lets deal with chord progressions.
Now imagine playing C3,E3,G3,B3 and removing the "root" (the C3) from the notes played,
we have a chord that reads "E3,G3,B3" - we were playing C major 7th and now we're playing E minor.
*THIS IS A VERY IMPORTANT STEP* Moving from C major 7 to E minor sounds "natrual" because the
notes that occour in C major 7 ALSO occour in the E minor.
Now lets make this E minor chord a 7th...
We've said before that a 7th chord can be constructed by playing the 1st, 3rd, and 5th notes, PLUS
the 7th note in the scale.
The scale of E minor (a flavour of minor) is:
Name, Number
E, 1st (root)
F#, 2nd
G, 3rd
E, 4th
B, 5th
C, 6th
D, 7th
E, 8th (octave)
The 7th note is "D" so we add the D note to our E minor triad to make E minor 7th.
E minor 7th is therefore: "E3,G3,B3,D4".
We can extend this E minor again, removing the root, working out the new scale for G major, adding
the 7th to make G major 7th, and again, and again, and again... but if we do - we keep moving
*UP IN PITCH* and spiral off the end of the keyboard.
HOW THE PATCH WORKS
Okay, so what my patch does is to take the idea of generating new 7th chords over and over,
but to play inversions of these chords so that the notes stay inside a single octave. If the
"root" note is in the 3rd octave, C3 for example. Then when I move to E minor, the D4 is
transposed to be a D3, to keep within this octave range.
Due to the fact that there are 12 semitones in an octave, and notes that fall outside the octave
range will wrap around to be an octave lower. The maths for generating the new chords basically
involves taking each note in the current major 7th chord and adding two semitones to each note in
turn.
Now our terminology could cause confusion here, because there are "notes in a scale" and "notes in a chord"... So I'm going to define some notation to show when i'm talking about the notes in a
chord.
For example:
A C major 7th has the notes C3,E3,G3,B3.
Note-1-in-the-chord is to be defined as chord_note_1.
Note-2-in-the-chord is defined as chord_note_2.
Note-3-in-the-chord is defined as chord_note_3.
Note-4-in-the-chord is defined as chord_note_4.
chord_note_1 has the pitch C3.
chord_note_2 has the pitch E3.
chord_note_3 has the pitch G3.
chord_note_4 has the pitch B3.
It is important to be clear about the idea of "pitch", "chord_notes" and "scale_notes" because
because chord_note_3 has the pitch "G3" and scale_note_3 of C major which is the pitch "E3".
Back to the procedure for generating new seventh chords.
We generate a major 7th to begin with.
C3,E3,G3,B3.
We add 2 semitones to chord_note_1 to get "D3", and we leave the other notes alone.
Our chord now reads: D3,E3,G3,B3.
Which is an "inversion" of E minor 7th.
This time we add 2 semitones to chord_note_2 to get "F#3", and we leave the other notes alone as
before.
Our chord now reads: D3,F#3,G3,B3
This is an inversion of G major 7th.
This time we add 2 semitones to chord_note_3 to get "A3", we leave the other notes.
Our chord now reads: D3,F#3,A3,B3
This is an inversion of B minor 7th.
This time we add 2 semitones to chord_note_4 to get C#4...
*BUT C#4 IS OUTSIDE THE OCTAVE 3! So we TRANSPOSE it down to C#3*
Our chord now reads: D#3,F#3,A3,C#3
This is an inversion of D major 7th.
After my patch modifies all 4 chord_notes, it moves back to chord_note_1, and adds another
2 semitones... over and over.
Eventually we get back to C major 7th again, but on the way we move through a variety of different
chords that evokes very interesting changes of moods.
Want to try playing with it?
Mp3: http://responsible7.googlepages.com/zenpho_escher_pd.mp3
Patch: http://responsible7.googlepages.com/zenpho_escher.pd