A harmonica is a musical instrument having a number of reeds over a surface of which air is passed to cause the reed to vibrate and emit a musical sound, or note.

In most harmonicas the air may be blown over the surface of the reed, or sucked over the surface of another closely adjacent reed to produce a sound of different pitch. Such harmonicas have been well-known for many years and have lately been developed to produce music of various styles. The sounds produced may have to be amplified if used in a performance so that the volume of sound may carry from e. g. a stage area to an audience.

In one type of amplifying system, a conventional moving coil dynamic microphone is held in the musician's hand behind the harmonica. This has been found to be very bulky and restrict the free area behind the harmonica which reduces the effect of the sound expanding out of the instrument.

Such microphones are also prone to substantial feedback problems and are well-known to amplify other unwanted sounds such as breath noise.

According to the invention there is provided a harmonica having a main body with a plurality of box-like cavities therein, for each box-like cavity at least one reed fast at one end to the body and free at its other end, holes formed in a front edge of the body with each hole being in communication with a respective one of the box-like cavities whereby passage of air along one surface of the reed causes the reed to vibrate and produce a musical sound, the rear of the harmonica being open to allow the sound of the reeds vibrating to pass outwardly, and a microphone mounted on the body at the rear thereof.

Preferably the microphone is provided in a recess in the rear of the main body.

Such a harmonica having a microphone can be connected to an amplifying device. The microphone can be so located with respect to the instrument that it does not pick up extraneous noises and is not of a bulky construction.

Advantageously the microphone is so mounted that it has a sensitive face

facing away from the reeds and in the same direction that the sound travels.

Preferably there is at least one further microphone, each microphone having a frequency range closely related to that of the part of the instrument on which it is mounted.

The invention is diagrammatically illustrated by way of example with reference to the accompanying drawings, in which:- Figure 1 is a front elevation of a harmonica according to the invention; Figure 2 is a corresponding rear elevation ; Figure 3 is a sectional view taken on the line III-III of Figure 2; and Figure 4 is a sectional view taken on the line IV-IV of Figure 3.

As seen in the drawings a harmonica 2 comprises a main body 4 of moulded thermoplastics material having a plurality, for example ten, of slots 5 extending therethrough from top to bottom and positioned between upper and lower reed plates 6 and 7. The slots 5 and the reed plates 6 and 7 create box-like cavities. Reeds 8 are secured e. g. each by a respective rivet 10 to the upper reed plate 6 and further reeds 9 are similarly secured to the lower reed plate 7, The reeds 8 are each located beneath a respective slot 12 formed in the reed plate 6, and the reeds 9 are each located beneath a similar respective slot 14 in the reed plate 7.

Upper and lower cover plates 15 are secured by screws 17, which screws 17 also act to secure the reed plates 6,7 to the main body 4, and create cavities over the reed plates 6 and 7, the cavities being open to the rear of the harmonica.

As seen in Figure 1, the front face of the body 4 is formed with holes 16, each communicating with a respective one of the slots 5, through which holes 16 air may be induced by blowing or drawing (sucking) through the vertical slots 5 in the body 4. As is usual in harmonicas, blown air causes a reed 8 to vibrate to produce certain musical tones, and drawn or sucked air causes a reed 9 to produce a different range of tone from that produced by the corresponding reed vertically above it. It is well-known that the length of each reed determines the pitch or key produced, and different lengths of reeds are provided along the length of the harmonica. Thus, as is well-known in the art, by blowing or sucking through different ones of the holes 16 in varying sequences a pleasing tune can be played on the instrument.

Although the direction of flow of air over the reeds is in opposite directions according to whether it is blown or sucked, the direction of flow of the sound is consistently outwardly towards the rear of the instrument as indicated by the arrows A. Being open backed, the volume and tone of the musical emission can be controlled by enclosing the exit space by suitable manual cupping to a greater or lesser degree.

In present day performances on the harmonica. it is not unusual to find a need to amplify the emitted sound by the use of one or more microphones and it has hitherto been the practice to hold a microphone in one hand in which the harmonica is cupped.

This system leads to difficulties in amplifying the true sound of the instrument and is known to cause feedback noise and the capture and amplification of breath noise.

Such difficulties can be avoided by providing a miniature microphone 20 secured to the body of the instrument, preferably mounted in a recess 21 in the rear face 22 of the main body 4, and within the flow route of the sounds.

Thus a sensitive face 20a of the microphone 20 preferably faces away from the reeds 8,9 and in the direction in which the sound travels.

More than one miniature microphone 20 may be provided each in a respective recess 21, each microphone having a frequency range which is closely related to that part of the instrument to which it is secured.

The microphone or microphones 20 may be wired to a socket incorporated within an end portion of the body 4, either left hand end or right hand end or even one at each end from where it may be connected to a convenient pre-amplifier within the stage or band electronics gear.

Although the specific embodiment describes and shows reed plates of a standard design with the reeds riveted over a gap formed in the plates, a further embodiment (not shown) includes a reed plate and reed made from one sheet of metal. A laser cutting technique or other suitable technique, e. g. spark erosion is used to avoid the use of rivets which are known to introduce stress in the reed which badly affects the tuning of the reed. Tuning is achieved by the removal of precise amounts of metal during machining resulting in a precision reed of the exact weight and alignment.