Filter Sweep Playground

Filter Sweep Playground is an interactive tool that visualizes filter sweep frequency responses. It allow you to both hear and see how various audio filters alter a sound source.

With it you can move the survey pin around with your mouse on the chart or with greater accuracy via keys on your computer keyboard to adjust parameters. It plots math behind the filters into a visual representation, then dynamically redraws that map each time you modify its settings.

How to Use the Filter Tool

On the main map, the horizontal axis is frequency and the vertical axis is resonance. By moving the pin left and right, you’re changing the cutoff frequency, aka the place where it starts to cut out what’s passing through. Up and down controls the Q value, or how gradually versus sharp it cuts off. You can see exactly what those values are at any given moment in the upper-right-hand corner of the screen: That’s your Q factor and precise kilohertz value.

You do not need a mouse to move through map. You can use arrow keys instead. Up/down arrows change resonance; Left/Right arrow keys nudge the cutoff frequency up/down slightly. For bigger jumps along the axis, simply hold Shift and press one of the arrow keys. With that keyboard control, you can both sweep quickly through a range or zero in on a particular frequency with ease.

Topology stamps provides toggles for different filter types. These include notch, band-pass, high-pass and low-pass filters, each of which will shape the signal in its own way. Three other preset stamps below these feature common scenarios. There’s the hum notch for removing mains hum from your signal, and the telephone midband for isolating only those frequencies used by voices.

This is where you choose what passes through filter and what does not. You can choose from a triangle, noise, square wave, or sawtooth wave. Depending on how aggressively you filter this sound the harmonic content will become more apparent.

A slider adjusts overall volume of the output so that as you experiment with filtering the sound remain at a reasonable volume for comfort.

The field expedition controls let you program and automate your exploring. When you open up signal beacon, you’ll hear the audio to monitor how filters are affecting it in real-time. You can then pin current response as a ghost trace so you can compare it against new settings. The overlay allows you to see how changes to the cutoff or Q will affect the overall curve.

For example, with whole band button, you can hear the whole sweep of low to high frequencies on any single filter type. It makes an automatic sweep that is handy when you want to know what one of your filters would sound like all the way across the spectrum. As you move the pin around map you will see the progress bar indicate where you are in the sweep and then hear it as it crosses over each point. To get most out of this, pin a resonant low-pass filter before loading a different topology and you’ll see what energy is left and what’s thrown away by each filter type at each frequency.

The fullscreen button will also come in handy as it gives the map some extra space on your screen for you to get a closer look at response curve detail.

Beginning with the drag of a pin, pick a frequency you want to explore. Next adjust filters to hear what happens on different ground. There is also some handy presets which will take you straight to areas of interest. Pinning down your favourate responses lets you examine form in more detail.

This is an experiment, so go ahead and play around with the controls as you wish, listening out for the effects. You should of tried it all.