Study finds new FM signal poor

By ROB STEIN, UPI Science Writer

CAMBRIDGE, Mass. -- A new type of FM radio system touted as offering a clearer, stronger signal and a new standard for the broadcast industry actually produces a poorer, more distorted sound, researchers said Wednesday.

Amar Bose, chairman of the board of the Bose Corp., and an engineer at Bose's Framinghman, Mass., loud speaker company presented the results of several studies that found the FMX system was inferior to standard FM.


'In my opinion, if the system is accepted all of us will experience a lower quality level of FM reception,' said Bose at the conclusion of a two-hour presentation at the Massachusetts Institute of Technology.

The findings were immediately disputed by Emil Torick, president of Broadcast Technology Partners of Greenwich, Conn., which is developing and marketing the new system.

'We feel there is grossly misleading information being presented here which is not a represenation of the real world,' said Torick, who was among the students, faculty, reporters and radio industry representatives at the presentation.


Bose said Torick's company threatened to sue him if he presented his findings. Torick refused comment on Bose's claim but suggested the presentation was supported by a receiver manufacturer who opposed the new technology.

Bose, a professor of electrical engineering and computer science at MIT, denied that charge, claiming FMX would have no commercial impact on his company and that he did the research out of personal interest.

The FMX technology was developed about four years ago to improve the quality and strength of FM stereo radio transmissions by adding additional signals.

By the end of 1988, more than 100 of the nation's 6,000 commercial and educational FM stations had begun broadcasting in FMX and two companies have begun producing FMX receivers, according to Torick's company.

Michael Rau of the National Association of Broadcasters said the broadcast industry is evaluating the technology, which potentially could become an industry standard.

Rau said he could not evaluate Bose's research without seeing it. But he said there has been no previous significant criticism of the FMX system and he had not heard any complaints from stations using the technology.

'What we know about FMX is that making FMX work well requires a every carefully controlled environment,' said Rau in a telephone interview. 'Many of our stations have installed it with no adverse effects.'


Bose outlined a complex mathematical evaluation of the system he said demonstrated the FMX system was inferior to standard FM because it exacerbates a problem in normal FM called 'multipath.'

Bose and William Short, a Bose engineer, said they conducted laboratory simulations of the FMX signal and field studies in which they compared FMX to standard FM. They played music that had been transmitted in FMX, which sounded distorted whem compared with its transmission in FM.

'The results of modeling, simulation and objective field testing at 15,000 locations lead us inescapably to the following conclusions,' said Short. 'Broadcast station coverage, instead of being increased as origianlly hoped, is actually decreased by the FMX system. FMX transmission degrades reception on existing FM stereo receivers. FMX receivers are inferior to existing FM stereo receivers for receiving FMX transmissions.'

Latest Headlines