Sometime ago, I was inspired by the article How to Use Transeint Designers in Your Mixes at audio tuts+. I ended up creating a crude Max/MSP patch that loosely approximated what I took away from the article. Over the weekend, I reimplemented this patch in Csound, creating a drum transient processor.

Source Code: drum_transient_processor.csd

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And once again, I use a sample from the BT sample pack from the OLPC sample library. Download it here.

So how does it work? Audio from a sample is played through a user-defined opcode transient detector, called Transient. Transient works by running the audio through the built-in opcode rms. The yielded rms value is divided by the previous rms value. If the ratio is greater than or equal to a user-set threshold, then the output is 1, else 0.

The output of Transient is then used to trigger (or not trigger) a built-in envelope generator. Basically, a trigger causes the envelope to be reset to 1. The envelope value decays over time until it reaches 0; The decay is set by the user. This envelope is multiplied by a copy of the original sample audio signal and an amplitude value set with pfield 6. The original audio and transient audio are mixed together, based on the value specified at pfield 5, and then sent to the output

One other feature built into this example is that user’s can set a value that determines the minimum amount of time that must pass before the envelope can be triggered again.

As for the audio example. The tempo of the sample is originally 110, though I play it at 165 BPM. It is played 8 times, with various transient settings. These settings are as follows:

1. Original audio unmodified.
2. Transients only.
3. Original audio mixed with transients.
4. Original audio mixed with transients, with emphasis on transients.
5. Transients only, with the RMS threshold and minimum delta time settings modified so that less transients are detected.
6. Same as 5, with a little of the original audio mixed in.
7. Original audio mixed with transients, except transients have been given a negative amplitude value, so that it is now 180 degrees out of phase, which cancels out the transient.
8. Same as 7, though with subtle changes to the numbers.

Because I’m lazy and didn’t feel like creating an audio montage in a wave editor, I created a Csound utility that plays multiple audio files in a row, much like a playlist in iTunes. And it automates much of the grunt work, so one doesn’t have to type in and keep track of a bunch of start and stop times.

Source Code: sample_linker.csd

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First, about the music. The drum loops aren’t mine; They belong to BT. These samples are released under Creative Commons, and are part of the OLPC Sample Library. You’ll need to download the BT sample pack to run today’s file without modification.

Let’s get a look look at the relevant portion of the score:

i $Sample 0 1 "120 Scratchim.wav"
i $Sample 0 1 "120 KarmaTonic.wav"
i $Sample 0 1 "120 Fast Satellite.wav"
i $Sample 0 1 "120 KarmaTonic.wav"
i $Sample 0 1 "120 Fast Satellite.wav"
i $Sample 0 1 "120 Scratchim.wav"
i $Sample 0 1 "120 Drive the Bouncer.wav"
i $Sample 0 1 "120 Drive the Bouncer.wav"

Notice that the start times for each loop is set to zero. Though when you listen to the example, the loops are played serially, rather than mixed together. And even though the durations are set to 1 second, each sample runs its course. This is because the instruments use a bit of logic to automatically arrange the samples so they play one after the other, in the order which they are listed in the score, with their full durations.

TRON is my favorite movie of all time. I’ve been toying with recreating some of the classic sounds from the film on my analog synth. Though I really want to get some of these things happening in the digital domain. So this is my first Csound attempt at the recognizer.

Download: recognizer_v2.csd

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The first version of my recognizer was done on my analog modular synth. Truth be told, I can get a much better sound out of my modular than Csound. Though my Csound one is coming along. I think the secret lies in the filters, so I’ll have to do many more trial and errors before I get it sounding right.

According to wikia, the original recognizer sound was realized on a Prophet-5 synthesizer by sound designer Frank Serafine; He modified the “helicopter” preset.

Flynn Lives!

I am in need of big sounds. So I created Oscil Omega, a user-defined opcode that generates one or more detuned table oscillators. The number of oscillators is up to the user; Need 1000? Not a problem. Depending on the amount of oscillators, detuning value, and waveform, one can get everything from super digital flange-like sounds to massive tone clusters out of Oscil Omega.

Download: oscil_omega.csd

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Looking forward to plugging this into my modular synth.

Message From Another Planet is my third completed Csound piece, finished and released in the spring of 1999.

Download: message_from_another_planet.csd

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Perhaps it was the beautiful Boston weather that inspired me to take a walk down by the river that day. I eventually found myself in front of the Museum of Science, where I had once attended a Nine Inch Nails laser show in their planetarium. I am quite fond of planetariums, with or without the industrial music. So I bought a ticket, and watched a show that featured the SETI Institute and signals from space. After the show, I walked back to my apartment and started coding, completing Message From Another Planet within six hours time. Days later, SETI@Home was launched.