The new Quantize Hot Filter is a powerful tool for discovering fresh sounding harmonies and grooves. In this tutorial, we take the picture made by analyzing a few sung notes and create a 'techno' style groove.

Step 1. Doing the analysis

In this step, we start by singing a little theme. Before performing the analysis, we have to adjust the duration of the picture to match the sample's so that looping will be seamless.

A) Open the sound file "Tut6_eric voice " or record something yourself.

B) Double-click the Tempo/Duration icon  to invoke the dialog box, and click on "Fit duration to current sample". This will set the current picture's duration to that of the currently loaded sound.

C) Type 'n' to perform an analysis of the current sound. Typing 'n' is the equivalent of choosing Analyse current sample from the Image Synth's file popup menu. (preset#1)

Step 2. Preparing the Picture

In this step, we take the picture created in Step 1 and prepare it for quantizing. When using the Quantize Hot Filter, it is often helpful to adjust the picture's density. If pictures are too dense, the results may be unmusical (though that may be just what you need!) We use a few techniques to reduce the image's density. We increase the contrast slightly to make dim pixels even dimmer, and MetaSynth's new option-Quantize command removes isolated pixels. (In this case, these pixel "islands" are artifacts of the frequency analysis process).
The Quantize Hot Filter maximizes pixels across the sections of the grid which exaggerates the effect of isolated pixels. Option-Quantize removes isolated pixels.

A) Adjust the contrast: Press the shift key and click and hold the mouse button over the Brightness & Contrast tool . Drag the the mouse to the right. You will notice some of the lines becoming dim or disappearing.

TIP: Pressing the shift key constrains the tool to Contrast adjustments.

B) Option-Quantize : Click on the grid field  and type 3 to set the quantization size in pixels. Press the option key and click  in the Hot Filter list. Note how clusters less than 2 pixels wide are removed.
 
 

Step 3. Quantizing the Image.

In this step, the Quantize Hot Filter is applied and the new Option-Shorten feature is used to disconnect connected notes.

A) Click on the grid field  and type 16. This sets the quantization size in pixels.

B) Click  in the Hot Filter list. Note how most notes collide with the adjacent one.

C) Press the option-key and press . Most connected notes are separated from each other.

NOTE: If the adjacent notes have the same brightness, they are not separated from each other.

D) Click  to preview the sound.

When the picture is played with the default semitone mapping, it sounds a bit dissonant which we will fix in the next step by using a custom scale.

Step 4. Adjusting the Harmonic Mapping and Tempo.

In this step, we use a Custom Scale to give the groove a more pleasing timbre and adjust its tempo.

A) Click on the scale pop-up menu . and choose the Custom Scales... option. The Custom Scales dialog appears.

In MetaSynth 2.5, it is now possible to save and import Custom Scales.

B) Click on the Import Scale icon .
Find the file "harmonic32.scl" which is found in MetaSynth's Custom Scales folder and press the Open button. This scale is composed of the first thirty-two harmonics of the harmonic series. This scale is great for synthesizing almost any picture, including pictures that have clumps of pixels that are dissonant with other scales.

C) Click  to preview the sound. To add a little percussiveness to the picture, press a few times and play the sound.

IDEAS FOR FURTHER EXPLORATION

The tutorial preset library provides several pictures created using similar techniques. Presets#8-12 were created choosing the custom scale prior the analysis step. General envelope shaping functions like 'pulse', 'shorten', 'smooth right' can be used in any order to further shape the result. (Preset# 7) To tune the final sound to a piece on which you are working, you can simply adjust the reference pitch of the picture. To adjust the tempo, double-click  and enter a new tempo in the Tempo and Duration dialog.