10 Channel Concert

Supported by the Danish Composers Society, I recently acquired a compact 10 channel speaker setup, for composing (and performing!) multi channel concerts...
The system consists of 10 small active studio monitors with a 5" kevlar membrane and a 1" dome tweeter. The monitors are bi-amped with a 40W amp for the bass and a 30W amp for the tweeter. It's not a big powerful system, but it's effective, precise and well suited for smaller venues of 60-90m2.

I have composed music for 4, 5 12 and 16 channels before, and it's really something different, than a regular stereo setup. But the problem is often that you won't have much time with the multi channel system. You often have to compose in blind, and try to guess how it will be, and then try to save the worst misassumptions during a short rehearsal before the concert. And even more unfortunate; you never have time to experiment and explore the compositorial possibilities of the system. For instance using sample delays for creating advanced phasing effects, algorithmic ways of panning, diffusing, distributing and moving the sounds etc. So that is basically the reason for this project; to actually be able to work with the setup and compose with it instead of for it.

Sound localization
Sound localization is a big subject of research, and here are just a few key concepts. When we localize a sound source, we use a combination of three main indicators.
ILD (Interaural Level Difference)
A sound source will always be closer to one ear than the other (on less the source is on-axis). Since sound level decays with distance the sound level perceived by the first ear hit by the wavefront, will be louder than what is perceived by the second. And the head will also shadow away some of the higher frequencies. This level difference is used to determine the direction of a sound source.
ITD (Interaural Time Difference)
When a sounds wavefront approaches the ears, it will reach the ears with a small time delay, which creates a phase difference. This phase difference is detected by the brain and is used to calculate the direction. We can detect an ITD in the magnitude of tens of microseconds, which gives a directional precision of down to 2 degrees under the right circumstances.
ILD becomes close to useless with wavelengths longer that ear distance times 4, because the head isn't big enough to shade off the wave front at the second ear. ITD becomes useless at wavelengths shorter than ear distance times 2 because the phase difference gets so big that the brain can't calculate if the phase difference is 1/4 wavelength or 5/4 wavelength og 9/4 wavelength or more.

HRTF (Head Related Transfer Function)
The head related transfer function is the frequency "coloration" that happens when a wavefront hits the head, torso, pinnae, hair etc. from a certain angle. The coloration is different depending on th angle so from registering which frequencies are boosted and which are attenuated, the brain leans the directional fingerprint imbedded in the sounds perceived.

So since localizing sound sources are one of the core competences of the auditory system, it is if course, interesting to work with this in a artistic way. Deciding to go with 10 speakers is more of a practical and financial decision rather than an artistic decision, but it still radically expands the possibilities over a stereo or a 5.1 setup. And I found that it is just enough speakers to make an acceptably smooth circular panning. But if I could have had 1000 speakers sphericially distributed around the audience, I would prefer that:-)

Sound material

The first thing I did when I had the system set up, was to record and test a lot of different sounds, both synthetic and acoustic, and se how they were acting when being diffused and panned in different gestural movements and abrupt patterns. Some sounds were recorded in a old gym hall, with a lot of reverb. Stuff was thrown, hit, bowed, strung, spun, etc. make rich, vibrant, gestural sounds.
Other sounds were made up from very simple basic synthetic waveforms (sines, saws, squares). A rather obvious finding is that sounds that has energy distributed over a broad spectrum, are much easier to locate than sounds with narrow spectral energy. A sine wave, for instance, that per definition only has energy at one frequency, is very hard to source locate. Almost all the spectral cues are gone, so you only have vague cues from ILD and/or ITD depending on the frequency.

On the other hand, short broad spectrum bursts are quite easy and fast to locate.

The patch below is a 10ch panning interface that can be automated for different predicitable or unpredictable patterns.

To be continued...

Roland CR-68 external trigger mod

I just finished this mod on the Roland CR-68 drum machine. I bought it several years ago, and always liked the sound of it, but never really used it, since it only features preprogrammed rythms. But now it has external trigger in for nine of it's eleven analog voices. The mod is based on Andrew Kilpatrick's cool MIDI-solution for the machine, and he has been very helpful with this much simpler mod. The trigger signal for each voice is simply a 5 v pulse of 15-20ms. Andrew Kilpatrick suggests connecting each trigger through a resistor of 47k. So far I haven't done that, since I need to test the implementation with different setups. I tested it with an Arduino board (which outputs 5v on it's digital pins), but I also need to test if I can trig the sounds with my MOTU audio interface (with DC-coupled outputs for CV control) and my PAIA MIDI-to-CV converter.

 Anyway, here's pics!
Here's the row of the nine extra trigger inputs, underneath the five existing in/outputs.

From the left:
-Bass Drum
-Snare Drum
-Rim Shot
-Low Conga
-Low Bongo
-Hi Hat
-Maracas
-Cymbal
-Claves

(there are two more voices, but for now I couldn't fit the trigger input plugs properly. It's Cow Bell and Hi Bongo)

Sonic Boom

I googled sonic boom and found an article on the subject. It is quite good and easy to understand. Among other things it explains that the sonic boom only happens as an aircraft hits the exact speed of sound. However, at the end af the article, this proclamation is made:

"Our ships are beyond the speed of your supersonic planes, from the moment they determine to move. Its as simple as that, we skip the sonic boom period."

Then I saw it was from ZetaTalk.com:-)

From today I'm 28

It's my birthday and I started the day with a burger and a photoshoot in the living room so I can remember how I looked on my 28th birthday.

Live at "Train"

Yesterday I did a concert at Train in Århus. I was supporting Hjaltalin.

These pictures is by David Bust, a good friend and a good photographer!

Acoustic Occurences Live at Trinitatis Kirke in Copenhagen

Yesterday I played the first concert with all 24 mechanical devices with the "Acoustic Occurences" project. It was quite OK and there was a lot of people. Maybe 300-400. Here are some pictures of the setup in the beautiful church.

Acoustic events

I have spent some time during the summer building a new system for composing music. It is a bunch of stands that holds solenoids (electromagnetic pistons with a lever attached) and an object that makes a sound when the lever hits it. The solenoids can be controlled from maxMSP, using an arduino as interface. Here are the first prototypes I made.

Here I am building and playing around with 9 psc. of the final design in the apartment.

An Arduino Mega board works as interface to communicate with the Solenoids from maxMSP.

And here, the first concert at Musikhuset Aarhus on July 24. 2010 in the café area where people (mostly +60) enjoys salmon and expensive cake. It is a wonderful place to play concerts and the reverb of the big foyer really worked it's magic on the quite crappy objects, on which the solenoids knocked. It was cheap wine glasses and metal brackets and an old cookie jar.

here is a small video sample

Cassette tapes to the Queen

Yesterday (05.06.2010) Morten Riis and I played a concert at the Queens coach trip trough Aarhus. We had 7 cassette tape walkmen and played back a lot of danish old music. It was sort of a collage of hits from the last 50 years. At first we thought that we were actually going to play for the queen herself but later we found out that our concert had the purpose of entertaining the people waiting to wave at the Queen as she passed trough the city streets.

The concert lasted 45 minutes and ended as the Queen approached. It went very well but due to some misunderstanding a youth march orchestra was playing to the same audience at the same time as us.

To those who wanted to hear the youth orchestra it was ofcourse disturbing that we were playing at the same time. So a few older people asked us to turn it down or turn of the noise. Some were actually quite offensive.

But all in all it was ok and the interesting thing for us was ofcourse to see the reactions of the ones who were not prepared to hear a cassette collage of evergreens. And we also believe that most of the people enjoyed the old songs and had a interesting experience after all.

Manned spacecrafts

I found this nice little book from 1968 with the title "manned spacecrafts".

It's really interesting to read. First of all because it is about the rocket race between USA and Sovjet and the early years of the cold war and it's about H-bombs and spy reconnaissance planes and the first satellites.

Secondly because it gives a sense of the level of the technology at this time and how the voyages into space must have expanded every little boys fantasy with strange planets and advanced zivilizations.

Besides this it has fantastic graphics in it.

Invention of the speaker

I just read this autobiography by Peter L. Jensen (1886), called "Jensen, højttalerens opfinder" (1948). The history about the invention of the speaker varies depending on the source The earliest small speakers used in telephones was invented in 1860-1880, but the use of speakers to amplify the voice so that a speech could be heard by thousands at the same time, seems to be realised by Jensen in 1915. The speaker was based on the moving coil principle, which was already known, so he didn't get a patent. Some guys from AT&T got it almost 10 years later due to some improvements and more specific descriptions.

The book describes Jensen's work with Valdemar Poulsen on the first radio transmissions and the race against the spark transmitter of Marconi. And how he moves to U.S.A. in 1909 and experiences really loud feedback for the first time when testing the loudspeaker prototype. There are also stories about the invention of the electrical turntable cartridge and the radio tube. So the book is both a 1st person story about the early days of electrified media and a really interesting adventure of the son of a fisherman who became an important inventor. I borrowed it from this guy who got it from his father.

Wien Bridge Oscillator

This morning I just HAD to do a sine wave oscillator!

And so far it works... It is a Wein Bridge circuit. I don't know exactly what that means, but it is based on feedback in an op-amp, and and instead of a thermistor, a small lightbulb is used to stabilize the feedback. Charming solution, I think... I'm using one of the most crappy opamps, the LM741. It is old and noisy but even with this one the waveform seems quite OK.

And the spectrum analyzis confirms it. It's actually very pure!

... and clean up the breadboard... I always make a mess...

Touch represented at Spor-festival 2010

BJNielsen, Mike Harding and Jana Winderen

The label "touch" was represented at spor-festival with a concert by Jakob Kirkegaard, BJ Nielsen and Jana Winderen and a seminar led by Mike Harding, director of the label.

At the seminar Mike talked about the history of the label, which was founded in 1982. He also talked about the physicality of the media on which the music is released. The importance of the paper for the digipack and the colours, fonts and size of the booklet and all that. This was very interesting. All these things that music consists of, that is not the actual music, he refered to as "the other" and said that you should never forget "the other". I agree.

Headphone festival

The Headphone festival was good!

There were live concerts by Simon Roy, vectral, Morten Riis, Jonas Olesen and me. Also compositions by other artists were presented, including Rune Søchting, André Falsig, Stormhat and Karsten Pflum.

Simon Roy

Vectral

Me

Relaxed audience

A guy who wasn't allowed to borrow headphones, but participated the best he could anyway.

A pair of really ok dudes

...and the one dude smiling on an orange-furniture-device... Who wouldn't:-)

The concert was held in the foyer at Musikhuset Aarhus. Not the most charming place in town but quite many people came by and listened. The good thing was that many of the guests were people not used to this kind of experimental, electronic music and it is allways interesting to witness the different reactions. This 10 weeks old guy responded with a smile...

Headphone Concert preparation

Tomorrow I will be playing a concert at the Spor-Festival in Århus, Denmark. It will be a headphone concert afternoon and many artists have made works for the event and some will play live concerts, including me.

So, as usually, I'm interested in the transition between digital and acoustical representation of music; the convertion that gives the music physical, percievable attributes. I like to think of is as a birth.

For generating sound material to this 21 minute long head-phone-composition, I made this setup.

It's a metal plate (from a stove) hanging in a vertical position, with four speakers placed on it. The four speakers ar connected to an amplifier. From a very simple max patch I send sines or squarewaves at individual frequencies to the speakers. This way the speakers appears as vibrating, electromechanical objects, rather than as a media interface, which is the role that they normally have.

The metal plate resonates and the mix of speaker sound and resonating metal plate is recorded. It gives some really nice drones.

The mic is placed as close to the plate as possible to catch the small modulations emitted from the plate.

This is the proto type and me...

I will upload some sound from this soon.

The mail man just brought me this from China.

It's a backlit display for a Arduino project. But more about that later...