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DigitraxDMU Class 108 #108955 Diesel Sound scheme. Copright (c) Digitrax Inc. July 8th 2007

(C) General Notes

This sound recording courtesy of Swanage Heritage Railway, Dorset,UK, and very helpful Driver (Engineer) Nick Lanham. Recorded by AJ Ireland, June 2007.

Note: This DMU class 108 prime mover has significant low-frequency components at idle and low throttle settings, so the speaker enclosures should be as large as possible behind the diaphragm to extend adequate frequency response below e.g. 300Hz. This will ensure a more "full" sound that does not appear thin or "tinny".

Each engine recorded has a distinct 'personality', so a particular locomotive example may sound slightly different due to unique e.g. tappet, crank-rate shell vibrations and exhaust-stack differences. Horns and bells are often moved between locomotives, and some roads may change/upgrade prime-movers, or change a normally aspirated engine with turbo-chargers etc.

Recording microphone aspect and location reverberation also significantly affect the final sound scheme.

This first Class 108 DMU (Diesel Multiple Unit, similar to US RDC, Rail Diesel Car) sound scheme is configured for our British cousins, so note that this first SDF may not be strictly prototypical for UK railway practices!

For example, the F7 crossing horn-blow is not the UK practice, and these locos do not have an F2/bell. To skip bell, simply set CV141/bell volume to 0, or remove assigned wav file for diesel_bell using a PR2 to modify the scheme.

The DMU dual-diesel governors do not have notches. UK carriage (car) brakes employ a vacuum, unlike the US practice of the Westinghouse pressure driven brake cylinders. (UK Brake-stands make "sucking" instead of 'blowing' sounds)