video tutorial

Why don’t DAWs let you do this?

I was teaching recently and one of my students had a patch with lots of effects in it. They were all routed to a central matrix~ object. It was really powerful but let down by the fact that controlling the matrix~ can be quite confusing esp when performing live. Personally I don’t like having to think in rows and columns when I just want to put the delay after the gate instead of before it.

This is the solution I came up with in Max/MSP, Have a look at Mr Matrix in action…

Lots of fun, I really wish I could do this in Logic Pro!

Download the patch

If you don’t have Max/MSP you can still play with Mr Matrix by installing Max/MSP runtime. Just make sure you put the Mr Matrix folder within the runtime patches folder!

Creative Commons Licence
Mr Matrix by Leafcutter John is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
Based on a work at

Music using Inductive Pickups.

Sunday, October 30th, 2011 | Building Things, Electronics, Music!, video tutorial | 5 Comments

After making this video I received an email asking if I’d make a couple of pickups for a gentleman in Norway.

I decided that it would be a nice thing to do, so I made these two little beauties.

commercial inductor with 1/4" (guitar type) jack.

Handwound coil with stereo 1/8" (headphone) jack - it's wired as mono

I was actually quite nervous making these things and having someone pay for them. Thankfully the recipient was delighted with his pickups and sent me this piece he made with them.

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You can hear more of Mads Lund Kolding’s fascinating music HERE!

Take care,



Weekly Music Thing No. 2 : Inductive Pickup

This week I’ll show you how to make a pick up that will let you eavesdrop on the internal sound-world of electronic devices.

The inductive pickup is simply a coil of wire, really that’s all there is to it. Connect that to an amplifier and begin probing your: Laptop, mobile phone, local transport network (London underground tube trains sound amazing!)

As last week, a video follows….


NEXT WEEK: either ‘How to make really good contact mics’ or ‘Messing about with CMOS chips to make a horrid noise” or something altogether different, you decide!

Other Weekly Music Things

Weekly Music Thing No. 1 : Laser Microphone

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Weekly Music Thing No. 1 : Laser Microphone

Here is the first ‘Weekly Music Thing’! In the video I take a look at how a cheap laser pointer and a solar cell can be turned into a remarkable optical microphone. I say microphone, but I think that might not actually be the correct description as a microphone converts sound into electricity where as  the laser mic turns light into electricity via the solar cell. It’s more of a Phosophone! Watch the following video for what you’ll need to build it, and I show a few ways it can be used too. I particularly like the fact that you can create sound bouncing the laser off a vibrating or moving surface. Used like this patterns of light and dark create audible tones. It’s supremely simple, fun and cheap which makes it a winner in my book. Have fun and don’t point the laser in your (or anybody’s) eye holes!

Let me know if you find this at all interesting and I’ll do some more….

Some sound highlights from the video

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Real Sound Cookery – Make a contact mic with baking soda and cream of tartar.

home made Potassium sodium tartrate "Rochelle Salt" crystals chunk in top right is aprox 5mm long

I’ve been into contact mics for a very long time, and have used them to record sounds for my records since 1999. There is something magical about how an innocuous little brass disc covered in ceramic piezo crystals can act as a sonic microscope, revealing tiny sound-worlds easily and cheaply. For a bit more info on contact pickups have a look at some of my previous posts: Shit I’m a Geek / The joy of Piezoelectricity and Leafcutter’s DIY Steel Can Hydrophone & Preamp. Step-by-step guide *schematic link fixed!*

I recently stumbled on a great video tutorial by Collin’s Lab entitled  ‘Homebrew Piezo’ in it he shows how to make Potassium sodium tartrate  crystals also known as “Rochelle Salt”. These crystals are fairly amazing in that they are made from ingredients available cheaply from your local grocery store or supermarket. I suggest you watch it as it shows the process really clearly. Later in this post I’ll show my experience of following Collin’s method and do something Collin didn’t – Made some sound with it!

If you want to make your own crystals you’ll need:

  • 200 g / 7 oz Cream of Tartar (aka Potassium Bitartrate, aka potassium hydrogen tartrate) from the grocer/supermarket
  • about 120 g / 4 oz Sodium Carbonate  (aka soda ash) OR same amount of baking soda (Sodium Bicarbonate) if you cant find the Sodium Carbonate.
  • Pyrex jug or bowl
  • Pan big enough to fit the bowl inside
  • Filter paper or Kitchen towel
  • Thermometer useful but not essential
  • Clean Baking tray and Oven if you are using Baking Soda instead of Sodium Carbonate

The Method is pretty simple, follow Collin’s Video to the letter! If you cant see the video for some reason here are the basic steps:

Collin asks for Sodium Carbonate  (soda ash) in the video, I could not find this but luckily you can make it very easily. Get hold of some Sodium Bicarbonate from the chemist or supermarket and spread it thinly on a clean baking tray. Now bake this for an hour or so at about 150 deg C / 300 deg F stirring the powder every 15 mins or so. Doing this will give of water vapor and Carbon Dioxide (open a window maybe) and after an hour your Sodium Bicarbonate will have turned into Sodium Carbonate!

  1. Using your Pyrex jug Dissolve 200 gr / 7oz Cream of Tartar (Potassium Bitartrate) into 1 cup cold water. Stir.
  2. Pop the jug into a pan of water, turn on the heat until the water bath reaches about 82 C / 180 F. If you don’t have a thermometer the water will start simmering at this point so keep an eye out for little bubbles in the pan.
  3. When the water bath is at 82 C / 180 F put half a teaspoon of Sodium Carbonate into the Pyrex jug and stir, it’ll bubble up and then subside.
  4. When the bubbling subsides repeat step 3. until the milky mixture goes clear (slight yellow tint).
  5. Your mixture is now ready to filter, while still hot pour into another heat proof container (a clean jam jar is good) through filter paper or kitchen towel to get rid of any solids. Don’t mess about here as crystals will form as soon as the mixture cools and you don’t want that happening in the filter.
  6. Place the container in a coolish spot cover loosely and wait for the crystals to form!

This is my solution just after pouring:


tiny crystal forming at the botom of the jam jar


after 2-3 hours

after sitting overnight

loose crystals fished out of the jar dried and viewed X50

So I seem to have generated thousands of tiny crystals as opposed to a few big ones like Collin managed – not sure why this happened but maybe linked to a fairly short cooling time. I wanted to see if the crystals were in fact piezo electric so I arranged the following rig to hold the tiny crystal against two contacts which were connected to a little battery powered guitar amp.


Holding a music box against the clamp I was able to record this sound

Not quite as good as the stuff in my mic drawer but it’s amazing considering it’s made from cookery ingredients!

I’m going to let the crystals in the jars carry on growing and I’ll add another post when I’ve managed to grow a bigger crystal.

Give it a go and let me know how you get on!

J x.

UPDATE – Check out my larger crystals.

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Boxing Day Java Script in Max/MSP

Monday, December 27th, 2010 | Building Things, Max/MSP, Software News, video, video tutorial | 3 Comments

Hope you are having a good Crimbo. I’ve been thinking about making some video tutorials covering Generative and Algorithmic music in Max/MSP. Have been sidetracked somewhat by learning Javascript within the JS Max object, which as it happens is very useful for Generative music making. So far I have made a patch which essentially documents me learning JS. I’ll be making this available soon with an accompanying video. Then I’ll be moving on to a comprehensive Algorithmic Music Tutorial.



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