The core of all LokSound decoders is an extremely capable processor. This is complemented by a sound storage, which contains the sounds, and an extremely powerful audio amplifier. Lastly, the sound is reproduced through especially developed high-performance speakers.
All LokSound decoders are based upon a sound-technology with exceptional key-values: A flash-memory records up to 65 seconds of sound data, which is transferred via a polyphonic, four channel mixer with an active filter, to the last stage amplifier.
But much more important than the fact that beside the actual prime mover sound, up to three more sounds, such as bell, whistle or brake squeal can be reproduced, is the unique sequence-choice of the sound decoders:
Steam engines, Diesel electrics.- Diesel hydraulics,-Electro-Locos, or Locos with a transmission (e.g. Rail bus, Doodlebug) can be reproduced. Depending on the type, sound sequences do differ, but are always faithful to the prototype:
Steam locomotives reproduce changing chuffs. Those are coupled to motor control and are load-dependant. When accelerating, chuffs sound harsh, while, when the throttle is closed, only rod-clatter is discernible. The reproduction hereby is so faithful that you can differentiate between the rhythms of a two-.three, or four cylinder loco. The rhythm can either be triggered by an external sensor, absolutely r.p.m.- synchronous, or via back E.M.F ( load compensation ),speed step dependant.
Diesel engines come in various designs, which are all correctly reproduced: Diesel hydraulic Locos first rev up, before they start moving. Engine r.p.m.-sound is in ratio to speed. LokSound decoders allow your loco, prototype like, to move only when engine r.p.m is high enough. This is only possible through the entity of sound module and decoder. When accelerating or straining, the sound is more intensive, while, when you close the throttle, the prime mover revs down to idle. Diesel-electrical locos keep their prime mover r.p.m nearly constant, but you hear the soft whine of the electro motors.
But even Electric locomotives are a treat for the ears: Beside the fan noise, the compressors, or the oil coolers, you hear the whine of the electro motors, the cracks of main switches, or gear noises.
Beside these sound variations, you can activate sounds anytime per function key. Thus you can whistle, sound the horn or bell to your heart’s content, in front of railroad crossings, or tunnels. Length of sound is up to you.
In the background you hear, coincidentally, the fireman shovelling coal, and the release of compressed air, or steam, by the safety valve. The decoder can couple all this to the function outputs, so that the fire in the firebox really flickers, when the fireman adds coal. LokSound decoders create real station atmosphere. 
