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Sound Fx Like Never Before!

Anyone familiar with model trains equipped with sound modules will appreciate the amazing effect it has. Models are instantly brought to life with the addition of sound. The PFx Brick brings the magic of sound Fx to your LEGO® creations. Unlike many toy or model sound effects modules, the PFx Brick works with your sound effects! Using the PFx App, you can easily copy your sound files to the PFx Brick. You can choose these sound files from our default sound library, download sound files from many freely available libraries on the internet, or record your own sound effects!

The PFx Brick's advanced digital audio processing natively supports 4 channel polyphonic playback. This means up to 4 sound effects can be playing simultaneously. The audio processor ensures the levels between all 4 channels are automatically balanced to avoid clipping distortion with maximum dynamic range.
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HiFi Quality Audio

The PFx Brick was designed to offer the very best audio quality possible. It uses the latest Digital Signal Processing (DSP) audio processor technology coupled with 24-bit HiFi grade Digital to Analog Conversion (DAC). The DSP processor allows for automatic dynamic range levelling for consistent audio output quality, realtime EQ adjustment of bass and treble, and realtime mixing of multiple audio streams at different sampling rates and quantization.
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Make It Loud!

High quality audio is of no use if it can’t be heard! The PFx Brick has a built-in 2W audio amplifier ready to power up the largest of speakers. We’ve tested the PFx Brick with the smallest cell phone speaker up to massive home audio speakers! In all cases, we’ve been blown away with its power—your only limitation is finding space in your model to fit the biggest speaker!

There are many speaker options available—in fact, there are too many! Another issue is how to fit and secure a speaker in a LEGO model. To address these issues, we’ve designed special speaker bricks. These bricks have two advantages:
  • It provides the speaker cone with the necessary sound box chamber for optimum acoustic performance and sound projection.
  • Its size and shape is made to LEGO system geometry and includes anti-stud mounting tubes.
Now you can securely mount a speaker in your model and benefit from the acoustic quality of an engineered speaker sound box! We’ve designed two speaker brick models to start: the 2x3 stud M Speaker and the 4x6 XL Speaker. Our intention is to offer a family of speaker bricks of different shapes and sizes to suit many different applications.

Compare Speakers

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6 x 4 studs x 6 plates

2 x 3 studs x 4 plates

Size (mm)

32 x 48 x 19.2 (L x W x H)

16 x 24 x 12.8 (L x W x H)


100 mm w/2-pin connector

128 mm w/2-pin connector


Power handling

3 W continuous, 4 W max

1 W continuous, 1.2 W max

Freq. response

200 Hz — 20 kHz (nominal)

320 Hz — 14 kHz (nominal)

Useful for…
When you have the space or you want it loud, the XL Speaker is the one to choose! Its superior frequency response and high power handling give outstanding audio performance.
The perfect balance of modest size with superb audio quality. Its size allows easy installation into most LEGO® models. It combines good power handling with excellent dynamic range. Its difficult to believe a speaker this small has such great performance!
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Playback Flexibility

Your sound Fx might be short one-time sounds like a horn or bell, or longer duration sounds such as repetitive machinery noises or entire songs. Whatever the sound, you can choose from a variety of playback modes to get the effect you want. You can choose any one of the following playback modes:
  • Play one time
Toggles the playback of a sound from start to finish
  • Play multiple times
Toggles sound playback from start to finish for a specified number of times (1–100)
  • Play duration
Plays a sound file for a specified time duration. If the file is shorter than the duration, then it is repeated as many times as necessary to reach the duration. If the file is longer, playback is truncated to match the duration.
  • Play continuously
Toggles continuous playback of a sound file. Playback will continue indefinitely by repeating playback until stopped.
  • Play with motor modulated volume
Playback a sound file with its volume proportional to the speed of a specified motor channel. This can be useful for simulating machinery noises which get louder with increased speed.
  • Play with motor modulated duty cycle
Playback a sound file with gaps of silence between repetition. The duration of silence gaps is proportional to the speed of a specified motor channel. This can be useful for simulating “chuffing” sounds whose rate increases with speed.
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Storage Flexibility

The PFx Brick is fitted with up to 16 Mbytes of flash memory to store audio files. For most applications, this represents an abundant amount of space to store sounds. However, for very demanding applications requiring a lot of audio file storage, the PFx Brick allows you to trade-off sound quality vs. storage space. Audio files are stored as uncompressed WAV files. These WAV files can store audio with 8 or 16 bits of sample resolution and can represent samples at either 11.025 kSamples/sec or 22.050 kSamples/sec. Depending on the format, the same file can occupy more or less memory. The table below shows the trade-off between storage space and WAV file format expressed as maximum playback time:


4 MB

8 MB

16 MB

11.025 kHz / 8-bit

06 : 20

12 : 40

25 : 20

11.025 kHz / 16-bit
22.050 kHz / 8-bit

03 : 10

06 : 20

12 : 40

22.050 kHz / 16-bit

01 : 35

03 : 10

06 : 20

Sometimes, using 8-bits or storing low-frequency sound files at 11 kHz can use half the memory space yet compromise very little in audible sound quality. The following is an example audio file reproduced in each of the different formats:
22 kHz, 16-bits, size: 137 kB
22 kHz, 8-bits, size: 69 kB
11 kHz, 16-bits, size: 69 kB
11 kHz, 8-bits, size: 34 kB
The PFx Brick lets you store any combination of WAV file formats. During playback, the DSP processor automatically resamples and rescales the audio to a nominal 22.050 kHz 16-bits in realtime. The PFx App makes the process of importing audio files and selecting WAV format easy! Simply choose any audio file on your PC (.wav, .ogg, .gsm, .au, etc.), and the PFx App will automatically convert it to the desired WAV file format!
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