Custom Sound Device

Custom Sound Device

The Custom Sound device is an electronic airsoft accessory with the main function of emitting a loud simulated gunshot sound effect when triggered by the muzzle sensor. The “custom” part is that it can play any sound effect you want – e.g sci-fi gun effects, or alternative gunshot sounds to the original built-in one. The device is more audible and obvious on the battlefield from much further away than any normal AEG. In close quarters you can use it to scare the pants off your opponents as you breach and clear a room!

The system comprises of a PEQ-box style main unit, and the muzzle sensor adapter. See below for information on each part, and the features they provide.

Showcase of the capability to play Custom Sounds via SD Card


Main PEQ Box Unit


The features of the main PEQ box unit are as follows:

  • 2″ full range 15W loudspeaker, 60W peak power handling,
  • Metal mesh grid to protect speaker from BB impacts,
  • Red laser pointer module with on/off slide switch,
  • Rail-mount to any picatinny/MIL-STD/RIS 20mm rail system,
  • Onboard high-efficiency power conversion – accepts any battery from 7.4V Lipo up to 11.1V Lipo (and all Ni-Mh/NiCad in between),
  • High performance embedded processor – reads the SD card, plays the sounds, and interfaces with sensors,
  • High-efficiency class D amplifier, plus all onboard power circuitry is high-efficiency,
  • External battery connector to give more options and to keep weight and size of unit down,
  • On/Off toggle switch to disconnect device from battery input,
  • Automatic Lipo protection cut-off for 2-cells by default (~6.1V), jumper available to change for 3-cell Lipo (~9.1V),
  • Injection moulded plastic (or cast resin) for a smooth, high quality casing,
  • Connector  for sensor cable or other trigger mechanism

Because the CSD needs an external battery to operate, users have a few options for this – see the Battery Recommendations section at the bottom of this page.


CLEARANCE HEIGHT NOTE: The top surface of the CSD sits about  31mm above the rail surface, with the speaker grill making a total height of 35mm above the rail. Most people will required 1/4 inch rail risers for their scopes/sights to clear the top of the CSD. Most iron sights will NOT clear the CSD when mounted on the top rails. If you don’t have a rail riser, mount the CSD on a side rail!


How Loud Is It?

It’s “loud” but not “too loud”. This topic is a little subjective, and also heavily depends on how it is mounted (facing you or not) and the environment you are in. The sound carries significantly farther than a normal AEG shot sound, and you can be quite far away in a forest and still hear the shots distinctively.

In terms of raw numbers, the speaker has a sensitivity spec of 80db for 1 Watt of power measured at 1 metre. The onboard amplifier in the CSD drives the speaker with short bursts of up to ~25W, making the perceived volume up at around 94dB to someone 1m away from the speaker, directly pointed at them.  This is only the peak however, and is maximum possible output power. While playing a sound effect, the device is going to be more in the average range of  ~85-90dB when 1m away, possibly less depending on the frequency components of the audio track.

This is fortunate because any louder and you’d want hearing protection 100% of the time as the user of the equipment. People around you will not need hearing protection.

Sensor Adapter

The features of the muzzle sensor adapter are as follows:

  • Anodised machined aluminium for light weight and durability,
  • 14mm CCW (left hand) threaded female-to-male pass-through so you can re-attach original flash hider or other muzzle attachments,
  • Light-based detection of BB passing through barrel,
  • Triggers LED flash to act as a Tracer Unit!
  • Connector for small flexible cable to provide power and signal return to PEQ box unit.

Tracer Unit feature

After field-testing and feedback from observers/commentators, it become clear that the sensor adapter was a perfect platform to add a “tracer unit” functionality to it. This makes the product even more multipurpose (along with the laser pointer added to the PEQ sound unit). The sensor will provide an LED flash, triggered as the BB comes past, to light up the tracer BB chemical coating.

Threads and Adapters

The sensor for the CSD comes with 14mm CCW (‘left hand’) threads, which is standard for most airsoft guns however we realise this is not exactly a ‘standard’ and you may need an adapter to mount the muzzle sensor. There is 14mm CCW female threads to connect to your outer barrel’s external male threads (typically your flash hider or silencer would go on that thread), and the sensor presents a new male 14mm threaded section for your flash hider/accessories to re-attach to.


Battery Input Requirements/Recommendations

From field testing, a 2-cell 610mAh Lithium Ion battery lasted a whole day – mostly CQB but some out-door action with full-auto. Therefore a huge battery is not required, and there is a very real option of wiring the CSD to the main gun’s battery if it’s an AEG.

Battery requirements and recommendations are as follows:

  • Voltage greater than 6V, less than 14V. 2-cell (7.4V), 3-cell (11.1V) lithium batteries recommended. works with NiMH and NiCad such as 8.4 and 9.6V packs will work well too.
  • Integrated battery protection cuts off at 6V, can be changed with jumper on the circuitboard to allow a 9V cut-off (for protecting 3-cell lithium batteries).
  • Capacity of  >600mAh recommended, however the real amount needed depends on usage and how often you want to change batteries.
  • Current draw from battery during a shot will reach about 5A when operating on as low as 6V. Higher voltages lead to less current required.