And the answer is… The Lumiere Gramophone (HMV Model 460). Well done to those of you who answered correctly!
The Lumiere Gramophones were a great novelty of 1924, making a highly successful debut at the Piccadilly Hotel, London, on Wednesday 22nd October an esteemed audience.The HMV Model 460 was introduced in early 1925, and is unique by virtue of its Lumiere pleated diaphragm instead of a conventional horn. This enabled the tone arm and sound box to be eliminated and in theory would have been cheaper to make (the price tag didn’t reflect this). The sound produced was less directional than a horn, but as the diaphragm was fragile and easily damaged, the 460 was removed from the catalogue after about a year. The cabinets were then used for the Model 461 which used a conventional internal horn and soundbox. It originally cost £22 in Oak, and £25 in mahogany.