They say the presidential petition would underscore the White House's commitment to campaign finance reform at a time when the president and the Democratic Party are under fire for improper fund-raising activities involving soft money last year.
Karl Hoffman, who lived in the flat, told jurors he had tried to put out the fire with a cup of water and a bottle of soft drink before a neighbour dialled 999.
The technology would enable a person talking to someone with a loud, high-pitched, rapid-fire voice to sound similar even if his actual voice was soft, low and slow, for instance.