[a repost for my much larger audience so they may learn the history of some of tools of the trade.]

The mult box has its origins in a 1938 invention by Fox Movietone’s Warren McGrath and Paramount News’ Marshall McCarroll. Though in those days, it was christened the “Mike Spider Box” instead of its current appellation.

From the pen of soundman Warren McGrath:

“Ever since the newsreels took unto themselves their step-child, sound, the poor mechanical ear that we have pleased to dub “microphone” has been a bone of contention. It might be likened to the highly fictionalized robot – that mysterious assembly of gadgets that does the bidding of a master. Unfortunately (or maybe fortunately) the robot is unable to distinguish intelligently which parts of the job to do and which to avoid. And so too is the lowly microphone cursed. Inherently it has the faculty of picking up extraneous noise with the same fidelity as desired sound.

It has been the lot of the small army of motion picture soundmen to figuratively take their robot by its duraluminum ear and force it to obey the strict requirements essential for the illusion of audible realism on the screen. This perhaps overzealous performance of this has been the cause of much weeping and gnashing of teeth by their co-workers, the cameramen. With a view to improving the general results of sound newsreel coverage, on the basis of both sight and sound, newsreel sound technicians have devised and constructed apparatus which recently has gone a long way towards solving the constant problem of camera angle vs. microphone location.

In the limited budgets of most newsreel producing companies, there is little place for costs incurred by field experimentation in the interest of sound. It is to the great credit of the soundmen that they willingly shoulder the cost of many improvements in order that sound equipment might be used to best advantage in the field. Due in no small measure to this fact, newsreel field recording has kept pace with the demand for better and still better quality.

For purpose of comparison let us take a quick look at the technique employed in a newsreel interview, vintage of 1930. At times there were as many as four sound cameras with attendant sound apparatus shooting the same scene. Cameramen, accustomed to artistic composition, were confronted with a picture of the rear side of four ugly looking microphones surmounted by the head and shoulders of the subject. Small wonder that wordy battles ensued between cameraman and soundman. Yet each was trying to do his part of the job in a manner guaranteeing the best possible results from their separate viewpoints. In time, however, the soundman and cameraman learned to grant concessions to each other. Microphones were placed to one side and lenses and angles were chosen which would frame out the mikes, but the result was neither fish nor fowl. In the majority of cases it was neither good pick-up nor the best to be desired photographically.

This, of course, was an impossible situation and its solution seemed to be in a device which would enable all newsreels to operate from a common microphone. To M. G. McCarroll goes the lion’s share of credit for working out the extremely flexible system now in use by the newsreel producing companies operating in Southern California.

The first microphone distribution system was in itself a highly satisfactory device. It was greeted with enthusiasm by the men in the field and promptly christened “The Mike Spider Box.” Subsequent improvements resulted in the present ten pound affair, entirely self-contained and capable of working one dynamic microphone or a maximum of two crystal microphones into as many as five recording amplifiers. Today the Mike Spider Box is deemed as important on jobs were all newsreels are working as the microphone itself.”