From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
The unsatisfactory testing of two makes of vibration type electric horns.
| Identifier | ExFiles\Box 59\3\ Scan062 | |
| Date | 6th July 1929 | |
| To R.{Sir Henry Royce} Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} By.{R.W. Bailey - Chief Engineer} C. to E.E.C. X6075 Hs{Lord Ernest Hives - Chair}/AJL/MJ6.7.29 Vibration Type Electric Horns. X4278. We have tested two makes of the above type of electric horns and both were proved unsatisfactory. Spartan S.O.S. Horn. This horn gave a very coarse note, and when working the vibration could be felt throughout the chassis. Although loud enough for all purposes, the quality and tone of the sound emitted was considered much too coarse and blatant. Klaxon two note horn. The sound emitted by this horn was somewhat similar to that given byy the German Bosch horn, though by no means so pure and inoffensive. The quantity of sound was found to be very much too small, both on the loud and on the soft note. It was impossible to make oneself heard on the open road when attempting to overtake vehicles. Hs{Lord Ernest Hives - Chair}/A.J.Lidsey. | ||