El Tramo | Music

Basic Music Theory in Haskell

2008-06-19T00:00:00+02:00

While doing some spring cleaning around my hard disk, I found a little Haskell program I wrote several years ago in an attempt to learn the basics of music theory. Now, I'm not a pro at writing Haskell, and I know even less about music theory, but I'm hoping that what I wrote down back then is a bit accurate. The program seems to summarize the basics quite consisely: by just having a glance at the program, I'm rediscovering some things I totally forgot about scales and chords. For example, this is what it says about the sus4 chord:

chordNotes Five = [(ScaleNote Major 1), (ScaleNote Major 5)] chordNotes Sus4 = (chordNotes Five) ++ [(ScaleNote Major 4)]

So, sus4 is a power (5) chord (consisting of the first and the fifth of the major scale), added with the 4th note of the major scale. So, for Esus4, the program tells me:

Main> scale2notes $ Scale (read "E") Major [E,F#,G#,A,B,C#,D#]
Main> chord2notes $ Chord (read "E") Sus4

[E,A,B]

Something else I forgot is:

intervals Ionian = [2,2,1,2,2,2,1] intervals Major = Ionian intervals scale = shift (intervals Ionian) (rank scale) where rank ...

So, every scale is really a shift of the major (well, any) scale, which is actually called the Ionian scale. This program might come in handy as a summary of music theory in case I forget these things again :)

Keeping your best music on multiple discs with iTunes

2008-02-24T00:00:00+01:00

Like most of us, I like to listen to music when I'm in my car. Since the radio doesn't always play what I want, I always keep a few compilations from my own library handy to put in my car's MP3/CD player (no, I don't have an iPod dock yet). However, I always found it very hard to keep track of the songs I had already burnt to a disc for my car, and I eventually lost the courage to burn new discs with more recent library additions. However, over time, most of the discs I did create went on a journey to CD heaven, and so now I found myself having to compile new MP3 discs all over again. Luckily, iTunes turns out to make the task of creating and managing compilation discs a breeze.

Some of the problems I wanted to solve when burning my music library to discs were:

Because of the size of my music library, writing my whole music collection is not really a good idea. I therefore have to limit the discs I want to write to my best songs only. But ...
Not all my music in iTunes is rated (yet). Whenever I rate new songs as 'good', or I import new albums, I would eventually like them written to a new disc.
I don't want the discs to have duplicate songs, I already have to use a lot of discs to write everything as it is.
Discs in my car tend to have a short lifespan, because of the varying weather conditions, and the way I handle my discs (I always find myself too busy watching the road to put CD's in pockets etc.). So, whenever one of my disc dies, I would like to replace it with a new one.

To solve these problems, these are the steps I use to create my music compilation discs with iTunes:

Create a smart playlist containing only your best songs. If you have other criteria for music destined for car usage, add them to this playlist. Limit the playlist to the size of 1 CD (i.e. 704 Mb). Let's call this playlist `New Car Disc'.
To create our first compilation disc, we create a new (regular) playlist `Car Disc 1', and drag the complete song list from the `New Car Disc' playlist into it.
Since we don't want any of the songs from `Car Disc 1' in our second compilation disc, we modify our `New Car Disc' playlist to exclude all music from `Car Disc 1'.
At this point, `New Car Disc' contains a new batch of songs, which make up `Car Disc 2'. Repeat step 2 and 3 to divide all the best songs of your library into discs, until the `New Car Disc' playlist contains less than 704 Mb of songs.
Now, you can burn all (or some of) your `Car Disc' playlists. I always use an Export Playlist script, which makes sure that the alphabetical order of the exported files is the same order as those in the playlist. This tends to work with most MP3 disc players. Simply copy this script to your Library/iTunes/Scripts folder, and invoke it from within iTunes.

By using the scheme described above, whenever new songs get rated, they are automatically added to the `New Car Disc' playlist, allowing you to incrementally write new discs as you rate your library. Anytime you have enough music to fill another cd, just randomize the `New Car Disc' playlist (by deleting all songs in the playlist, which regenerates the playlist), and create a new disc. Another plus of keeping the playlists of your written discs around is that you can easily create new copies of a disc whenever you didn't handle it as you supposed to.

A downside of this approach is that you still have to manually create playlists, drag the songs into the playlist, and adapt the smart playlist to exclude the new one. I would have liked to automate this process using AppleScript, but unfortunately AppleScript does not support the creation of smart playlists yet :( Let's hope Apple adds this to a future version of iTunes.

Sampling away with the SPD-S

2006-03-18T00:00:00+01:00

Lately, I have been searching for ways to trigger loops and samples from behind my drum kit. After playing around with a less than ideal setup involving many cables and devices (see below), I decided to buy myself a Roland SPD-S sampling pad. Turned out to be a pretty good move ! About a year ago, I bought myself a Roland SPD-6 to start experimenting with loops. I connected it via MIDI to my Edirol UA-25 interface, which in turn was connected to my laptop. On the laptop, I used Ableton Live to trigger the loops. To stay in sync with the loops, I started one measure of cowbell hits on my Roland DR-770 rhythm box, sent it to one channel of my mini Behringer UB502 mixer, and connected the monitor mix of all other instruments (including the UA-25) to another channel, outputting the UB502's output to my headphones. Although this setup worked for rehearsals, it should be obvious by now that this wasn't very handy. Not only did this require a lot of connections and devices, it was also very hard to keep the tempo in sync. Syncing the tempo between the DR-770 and Ableton (with another MIDI cable) at least gave me a central point where i could manage my tempo, but because of the way the MIDI sync worked, it was hard to control just the rhythm box without interfering with the loops. The SPD-6 also gave me a bit of trouble, in that it was hard to program, and that it sometimes triggers if you hit its rim. On top of these major inconveniences, I was a bit reluctant to start gigging with my PowerBook, fearing that it probably wouldn't take long until some guy spilled beer all over it, and of course that things would start crashing mid-gig (I have faith in OS X, but not in Ableton and/or the UA-25 drivers). I considered buying a Roland SP-404 rhythm sampler as a replacement for the Laptop/Ableton/UA-25 combo. After some testing, this seemed like a very cool device indeed, but the on-screen display didn't seem enough (I like to see preset names on my display), it had a sequencer i didn't really need, and I still would be left with an extra device I had to drag around and connect. At just the extra 100 euros over the SP-404, I decided to buy an SPD-S. After unpacking, the first thing I did was reset the memory. The few sounds I heard sounded pretty decent, but you don't buy a sampling pad to play someone else's samples ;) Importing my existing sample wave files through the CompactFlash interface of the SPD-S was a breeze. I imported them directly to CompactFlash memory, because the internal memory was full after importing the samples of 3 songs. I also had to experiment with the three resolution settings (long, standard, fine) to find out that long suffers from a good deal of quality loss, whereas standard is nearly as good as fine (at half the space requirements). The SPD-S gave me all the control I wanted to make performances using the samples. I could even pan all the samples/loops to the left and pan a metronome loop completely to the right, such that I could send one channel to my headphones and the other to the mixing table. So, no need for an external metronome anymore, nor entering the tempo manually (it's saved with the performance). On top of that, I could create a 'panic' pad, which turns off all the loops except the metronome, resulting in a perfect situation for live performance. If you try this at home, don't forget to turn the ambience off, or your metronome will leak through to your other channel. The sampling process itself also seems decent. Using the 'auto-record' function (which starts recording based on input level) and the ability to synchronize the end of the recording by entering the tempo in advance, it gives a pretty handy interface to record loops. One thing I am missing though is the ability to enter the number of measures to record, to have full automatic stop. I'm also not able to stop recording with a foot switch (although you can do it for phrase recording). I don't really use the begin/end marking features (yet): for more complex sampling, I use software, and upload the loops afterwards. In conclusion of this review, the SPD-S gives me all the features I need to trigger loops from behind my drums, perfect for on stage performance, and it brings them all in one device. With some pan trickery, I even obsoleted my external metronome (although I lost the ability to use stereo samples this way, but this doesn't seem like a problem on stage). Two thumbs up !