TILT!Audio the new audio experience for your pinball

Welcome to TILT!Audio. TILT!Audio is an alternative sound system that offers much better sound experience than original sound hardware. Its build based on a Raspberry Pi and a small shield that helps decoding sound commands coming from the main cpu.

TILT!Audio is the successor of RasPiSound so don’t get confused when in some forums or on my youtube channel it is called RasPiSound.

Wanna see it in action? Check out my youtube channel.

TILT!Audio is not a ready to use product that offers simple plug’n’play by simply replacing the old sound card. However you can easily build it for yourself (see Quick Start).

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You do not even need to buy every little piece of hardware on your own, instead you can simply order kits on my shop, that makes assembly very easy.

You can even take a look at the schematics and the latest pcb or export gerbers to build the shield on your own. Everything you need is hosted on EasyEDA.

New Revision 3.5

What’s new

The most important change since the latest release: the annoying “sound interface error” with some WPC machines (TAF, STTNG, …) is now gone!

The old discrete decoder hardware build based on 3 smd logic chips was replaced by a STM32F4 micro controller module. This way the micro controller can talk to the game, avoiding the “sound interface error” and also takes over the command decoding.

There some more advantages with this new design:

  • no more jumper. Data east input or wpc input is recognized automatically
  • no more smd soldering. The new mcu module is normal through hole.
  • no need for analog digital converter (for old style data east pot). The STM32 takes over this task as well.
  • no need for pull up resistors networks. The STM32 has internal pull ups.
  • no decoupling caps for smd needed.

All in all there are 10 pieces less to solder and replaced by one STM32 module (plus one resistor).

Other improvements

Additionally there is an extended connector for the OLED display (was already on rev 3.1) that can be used with both types of OLEDs (either GND left or Vcc left). Depending on your OLED type you need to use the upper or lower row to connect.

More changes

The HF filtering at the amplifier outputs are now optional. Only a very few user were ever effected by that. So you could still assemble the 6 impedance filter and caps if you like, but the parts will no longer be included in the kits. Instead you need to bridge the L1 – L6 with a wire (or solder jumper).

OLED with reversed Gnd/Vdd

There’s a lot of OLED displays on the market, that have reversed Vdd / Gnd connectors compared to the TILT!Audio PCB. This can be fixed with a simple workaround.

Just cut the normal Vdd pin and bend the GND pin to left:

GND bend to the left Vdd with flexible wire

Vdd instead of using a pin, will be connected using a short isolated wire:

A word on sound

Many questions these days are about sounds and the fine grained setup you can do with TILT!Audio.

First of all there are 2 types of sound packs:

  • Old style in directories
  • Altsound: all in one directory together with a csv table.

Features of both formats are slightly different, but mostly one can categorize sound effects in:

  • background music (or simply music)
  • voice callouts (or just voice)
  • special effects (or just sfx)
  • jingles (play over a music and music continues)
  • singles (play once and terminate the playing music)

In addition to that there’s volume control that balanced the volume of music, sfx, voice, jingle and single.


First there is a gain, that allows to raise or lower volume level for each sound effect. Normal level is 50, but it can be adjusted from 1 to 100.

So if some sound effect seem to be too low, you can just go to the web UI and raise the gain.

Here is one difference between directory sound packs and altsound packs:

While in both cases each sound effect has its individual gain, the directory style also has a default for a category: gain by type!

So if you want to raise volume level for voice in general, just use the sliders GainByType in the webUI

Change default gain for a category


Second volume control concept is ducking. Ducking means volume of background music is lowered while some other effect is playing to make it more hearable.

Ducking can also controlled individually on each sound effect. Ducking ranges between 100 .. 0 where a value of 70 means music is lower to a value of 70% relative to normal volume. If more than one effect with ducking is played at the same time the lower ducking wins.

Ducking can also be adjusted in the web UI for each sound effect:

Ducking set to 80%

Again there is a small difference between altsound and directory sound packs: directory sound packs have a default per category duckingByType. So if nothing special was adjusted, a sound effect gets its ducking value from the category. This way you can lower music for all voice callouts at once:

Change ducking for each category

Note: if you change the DuckingByType value, while a sound effect has its individual ducking value set, it will not change for that sound effect.

Try it in the game!

With TILT!Audio you can try all these tweaking of sounds and volumes IN THE GAME! Not only the adjustment can be done, but you can also listen how it will work out in the actual game. All changes you are applying to one of the sliders (ducking / gain, …ByType) are changing the playback directly, so you can hear directly. This is a big advantage as sound in the machine with real speakers always sounds completely different from the computer.

There are two ways to do this:

PLAY from the UI

Just use the “Play” buttons in the web UI to play arbitrary sound effects, that you want to prelisten and adjust. The different effect type will behave like in the normal game play: a voice callout will be played over the background music, a single will play and stop the background track, etc.

PLAYBACK a recording

With TILT!Audio you can record a gameplay (the sound command it produces) and playback them later, just use the “Recording” and “Playback” pages in the web UI. While playback is running you can online tweak the sound adjustments, and hear them live while tweaking.

Browser audio

If you happen not have the game near by or don’t have speakers installed or just don’t want to make noise, us can switch to browser playback:

Browser playback button

If “Browser” is selected an emulated TILT!Audio sound engine is used in the browser and you can hear the sound from your computer and can use headphones if you like. As already said above this is only a weak replacement compared to the real game, but it works.

Audio editing

If all the volume adjustments with ducking and gain does not help as the sound is simply to long or there is a bad crackling in the beginning, you can finally open the sound editor:

Audio editor button

Clicking the button opens another browser window, where you can really edit the sound second by second:

Example: cropping a sound effect

If you don’t want to change something just close the window, if you’re done press Save & Close. Don’t worry the actual sound effect will not be overridden in the first place but a new variant will be stored instead. You can keep them both or decide which one you want to keep.