Radio today (Jan-Dec 1938)

kk CONTACT MIKE" OPENS NEW FIELDS Picks up vibrations direct from instrument. New commercial opportunities * XEW possibilities in musical reproduction and "sound selling" are opened up by the "contact microphone," which reproduces the vibrations of any instrument or object on which it is placed. This reproduction is accomplished, moreover, without introducing any annoying peaks, and life-like results are given throughout the entire frequency range, explains Sam Ruttenberg of Amperite. An idea of the reproduction quality of the new contact mike can he gained from the fact that it was used recently by the Philadelphia Symphony Orchestra to reinforce a mandolin solo. The unit is flat within ± '2 db from 40 to 9,000 cycles per second. Its operating principle is magnetic. Although the violin is one of the most versatile instruments, its use has been reduced to practically large symphony orchestras where enough violins to give the necessary dynamic power can be afforded. Violinists therefore learned to play the more demanded saxophones. The reason for the unpopularity of the violin in dance orchestras is due to its limited power output. Sound engineers removed this objection by giving the violinist amplification — and yet he must he pushed to try it — to experiment with it. Patience and tact must therefore be exercised by the sound man in dealing with musicians. Stokowski compares this lack of interest in sound amplification on the part of musicians, as follows: "If a gold mine were found or a subterranean sea of petroleum discovered, it would be quickly developed. But a means whereby every man can hear music with overwhelming beauty and elegance is neglected and left unused." N h )lin< ew magic tor violins With the aid of the new contact microphone a $50 violin can be given the tone and volume of one costing several thousand dollars. It also gives the violin the dynamic power of the brasses. A few violins can give a small orchestra the effect of a symphony. A "hot" violinist can obtain effects unobtainable by any other instrument. Instead of decreasing, the use of amplification will increase the employment of violinists — their more powerful instruments will increase their usefulness and field. Classical guitar players find it difficult to obtain volume. Their power of interpretation is limited. The contact mike gives the guitar the volume and depth of a piano. And incidentally a small piano can be made to sound like a concert grand. When the contact unit is attached to the piano of a dance band, the piano becomes more audible and gives the band more fullness — especially when the floor noise level is high. An unusual and fortunate use of the contact microphone is in helping the deaf to enjoy playing or hearing musical instruments. This is accomplished by attaching a contact unit to pactically any musical instrument, feeding it into a low gain amplifier or radio set and then to an ear phone or "bone-conductor." Another rather unusual use that was accidentally discovered is in making sound effects for radio and movie studios. Granulated sugar dropped on a piece of paper placed over the contact mike, will give the effect of rain. Talking very close and into the unit was found to be the best and easiest way to obtain a "telephone voice." Pounding the chest with the contact unit against it, gives the illusion of galloping horses's hoofs, etc. Recording of a piano has always been difficult — especially when special rooms are not available. By putting a single contact microphone on the sound board of the piano, better recording can be obtained than with any regular type of microphone. Of course outside noises will not be picked up. Home applications Not limited to the professional field, servicemen will find the contact unit a very easy sale in any home where an instrument is played. Attach the unit to a musical instrument such as a violin, ukulele, piano, etc., connect it to the radio and request the musician to play with the contact unit connected. The better tone and volume of the instrument will be immediately noticeable. A demonstration is all that is usually necessary to close the sale. It is an extra sale since it does not compete with anything else the serviceman sells. When the unit is taken off, the instrument will sound rather flat. Practically any number of contact mikes can be connected in parallel and fed into one input. In other words, a unit can be attached to each of twenty-five instruments and all fed into one amplifier. In many cases, the musician prefers to have a separate amplifier for his own instrument. A compact low-gain amplifier with a speaker on it is placed next to the musician, giving a perfect illusion of the music coming only from the instrument.