ought surely to be regarded as the normal condition and avoidable departures from this state, while justified upon occasion, should not be allowed to become a permanent feature of the system. In designing a loudspeaker, the BBC established the compromise that had to be established between size, weight and cost considerations. Two-way designs were preferred due to the inherently simpler crossover network, but were subject to the limitations of speaker driver technology at the time – there were few high-frequency units available at the time that functioned down to 1.5 kHz, meaning that the woofer must operate in a predictable manner up to about 2 kHz. The BBC developed a two-way studio monitor in 1959, the LS5/1, using a 58mm Celestion tweeter and 380mm Goodmans bass unit, but continually had problems with consistency of the bass units. The successful testing of a 305mm bass cone made with new thermoplastics led to development and deployment of the LS5/5 and LS5/6 monitors that occupied only 60% volume of its predecessor. As recording became less and less "live" and multi-tracking and overdubbing became the norm, the studio monitor became far more crucial to the recording process. When there was no original performance outside what existed on the tape, the monitor became the touchstone of all engineering and production decisions. As a result, accuracy and transparency became paramount and the conservatism evident in the retention of the 604 as the standard for over twenty years began to give way to fresh technological development. Despite this, the 604 continued to be widely used - mainly because many engineers and producers were so familiar with their sonic signature that they were reluctant to change. 1960s and 1970s In a BBC white paper published in January 1963, the authors explored two-channel stereophony, and remarked that it was at a disadvantage compared with multi-channel stereophony that was already available in cinemas in that "the full intended effects is apparent only to observers located within in a restricted area in front of the loudspeakers". The authors expressed reservations about dispersion and directionality in 2-channel systems, noting that the "face-to-face listening arrangement" was not able to give an acceptable presentation for a centrally-located observer in a domestic setting. The paper concluded: The achievement of suitable directional characteristics within the aesthetic and economic limitations applying to domestic equipment will however require a much greater research effort than either the corporation or