The present invention relates to an audio reproduction desk comprising a table with a tabletop lying at a height and a listening position and listening height which are associated with the table and lie in a central perpendicular plane of the tabletop, and a left-hand loudspeaker panel and a right-hand loudspeaker panel which extend upward substantially mirrored relative to the central perpendicular plane of the tabletop and each comprise at least one loudspeaker with a reproduction range in a first, relatively high frequency range, wherein the at least one loudspeaker comprises an acoustic membrane and is mounted therewith parallel to a main surface of the relevant loudspeaker panel in a loudspeaker opening provided therein, wherein the loudspeaker panels are oriented at an angle relative to the central perpendicular plane such that corresponding central perpendicular lines through the membrane of the at least one loudspeaker of each of the two panels intersect each other in the central perpendicular plane at least substantially at the sitting position, and wherein the loudspeaker panels are oriented at substantially the same incline relative to the tabletop, such that the central perpendicular lines intersect each other in the central perpendicular plane at least substantially at the listening height.

Such a device is intended particularly for sound engineers and similar professionals who will benefit from a precise definition and editing in the reproduction of recorded audio clips. The fixed, precisely determined configuration of the at least one loudspeaker in the two (stereo) loudspeaker panels provides here for a fixed reference, wherein ambient factors of any walls in a studio are shut out to great extent, particularly in that the sound image created by the two loudspeaker panels is radiated directly toward the listening position.

A known device of the type described in the preamble was introduced by applicant under the name Sphere. This known device comprises in each of the two loudspeaker panels both a loudspeaker for high-pitched tones (tweeter) and a reproducer for a lower, middle and low range of the frequency domain (mid-range or woofer). This already provided a highly fixed reference in respect of a high-fidelity reproduction and definition of a recorded audio clip or composition. What should be noted here is the localization of the maximum acoustic sound pressure around the listening height of the listening position, keeping the intensity for the surrounding area limited.

The present invention has for its object, among others, to further improve the known device by also providing a similar definition and concentration around the listening position at the outermost layer of the frequency domain.

In order to achieve the stated object an audio reproduction desk of the type stated in the preamble has the feature according to the invention that at least a first and a second further loudspeaker are provided with a reproduction range in a second relatively low frequency range below the first, relatively high frequency range, that the first and second further loudspeaker each comprise an acoustic membrane and are oriented parallel to the central perpendicular plane therewith, that on a side of the table remote from the listening position the first and second further loudspeaker are accommodated in a housing placed centrally relative to the listening position, that the housing comprises in a wall thereof at least one sound opening for allowing sound waves of the first and a second further loudspeaker to escape and is otherwise at least substantially closed, and that the at least one sound opening extends transversely of the central perpendicular plane.

A set of reproducers for low-pitched tones is thus provided in a substantially closed housing behind both panels, and here suspended with their acoustic membrane parallel to the central perpendicular plane. The loudspeakers will hereby produce substantially transversely of the central perpendicular plane a sound pressure which is received in the substantially closed housing and can escape at least substantially only via the localized sound opening(s). Because the at least one sound opening lies transversely of the central perpendicular plane, the sound escaping from the first and a second further loudspeaker for low-pitched tones will be received in a relatively flat imaginary cylinder with an imaginary cylinder axis which coincides with a central axis transversely through (the acoustic membranes of) the first and second further loudspeaker. Located in this cylinder is the listening position, which is thus radiated toward in relatively concentrated manner. The housing is closed parallel to the central perpendicular plane, particularly on the outward directed side of the first and second further loudspeaker. The sound pressure is thus intercepted and repressed on this side so that a noise impact on the surrounding area caused by these bass reproducers remains relatively small, not least owing to a phase difference with the cylindrical pressure wave via the at least one sound opening.

In order to enhance a balanced sound distribution on the left-hand side and on the right-hand side of the listening position, a preferred embodiment of the audio reproduction desk has the feature according to the invention that the first and second further loudspeaker are oriented mirrored in relation to each other relative to the central perpendicular plane, particularly back-to-back, and close the housing on their side remote from the central perpendicular plane. The mirrored configuration enhances here the intended balance in a stereo image, while the back-to-back suspension provides more openness in the low-range reproduction.

With a view to a direct bass reproduction to the listening position a further particular embodiment of the audio reproduction desk has the feature according to the invention that the desk comprises a panel extending above the tabletop centrally between the two loudspeaker panels, and that the panel provides at least substantially equidistantly on either side of the central perpendicular plane an opening which allows the sound waves to pass substantially parallel to the central perpendicular plane. The housing thus opens with a set of sound openings toward the front between the two loudspeaker panels so that this part of the bass reproduction will reach the listening position more or less simultaneously to the reproduction by the at least one loudspeaker from both loudspeaker panels. In order also to enhance a fuller and thereby more complete bass reproduction a preferred embodiment of the audio reproduction desk has the feature according to the invention that the housing provides in a roof thereof a first further sound opening for allowing the sound waves to escape in an upward direction substantially parallel to the central perpendicular plane, and that the housing provides in a bottom thereof a second further sound opening for allowing the sound waves to escape in downward direction substantially parallel to the central perpendicular plane. The bass waves thus escaping from the housing on an upper and lower side thereof as it were fill the above stated imaginary cylinder. The direction, substantially parallel to the central perpendicular plane, imparted thereby to the bass waves keeps this cylinder relatively flat, whereby the bass will reach the listening position mainly from above and from below and there merges into a spatial bass image.

What is important for an optimal reproduction and definition of the sound image is a good frequency separation between the different loudspeakers. In this respect good experiences have been had with a particular embodiment of the audio reproduction desk according to the invention which is characterized in that the first and second further loudspeaker comprise at least substantially identical subwoofers which are electronically controlled under a turnover frequency in the order of 200 Hz.

In the same way, an excellent reproduction is achieved with a further particular embodiment of the audio reproduction desk according to the invention which is characterized in that the at least one loudspeaker comprises a reproducer for high- pitched tones and a reproducer for midtones, which are electronically controlled with a mutual turnover frequency in the order of 800 Hz. In order for the high-pitched tones to be expressed to a greater degree in passive manner here a further preferred embodiment has the feature here that the reproducer for high-pitched tones is mounted in the loudspeaker opening with interposing of an acoustic horn.

With a view to a clear, unstrained reproduction by the at least one loudspeaker in each of the loudspeaker panels, a further preferred embodiment of an audio reproduction desk has the feature according to the invention that the at least one loudspeaker is mounted in the loudspeaker panel free of any further enclosure.

The invention will be further elucidated hereinbelow with reference to an exemplary embodiment and an accompanying drawing. In the drawing:

Figure 1 is a front view of an exemplary embodiment of an audio reproduction desk according to the invention;

Figure 2 is a rear view of the audio reproduction desk of figure 1;

Figure 3 is a top view of the audio reproduction desk of figure 1;

Figure 4 is a left-hand side view of the audio reproduction desk of figure 1; and Figure 5 is a right-hand side view of the audio reproduction desk of figure 1 .

It is otherwise noted here that the figures are purely schematic and not always drawn to (the same) scale. Some dimensions in particular may be exaggerated to greater or lesser extent for the sake of clarity. Corresponding parts are designated in the figures with the same reference numeral. The device shown from different angles of view in the figures comprises essentially a table 100 with a tabletop 110 which lies at a height in the order of 700-800 millimetres. The table supports on the ground surface here with a set of wings 120 arranged on either side and the width between the two wings lies in the order of 2500-2800 millimetres. Located centrally behind the tabletop 110 is a listening position 200, see figure 3, with a shelf surface 130 for a user where he/she can for instance set up a laptop computer. The shelf surface 130 typically has a width in the order of 1000-1100 millimetres, with a greatest depth in the order of 450-500 millimetres. The whole desk fits inside a rectangular outline of 2500-2800 millimetres by 1300-1400 millimetres. More space is not required, while an audio reproduction rivalling the best studios is nevertheless realized. On either side of shelf surface 130 the desk comprises a left-hand loudspeaker panel 1401 and a right-hand loudspeaker panel MOR, which are here oriented mirrored relative to the central perpendicular plane through the desk and through the listening position 200. Use is made for both the tabletop and the panels 140L/R connecting thereto of a solid core plastic or composite sheet material with a thickness of 15-20 millimetres. The tabletop and the wings are moreover adhered to a base of solid hardwood, such as wenge, with a thickness of 30-50 millimetres, which is not only attractive from an aesthetic viewpoint but furthermore imparts additional stability and tone colour to the desk.

Incorporated in each of the loudspeaker panels is an identical set of loudspeakers which are placed in loudspeaker openings provided for this purpose. Each set of loudspeakers comprises a tweeter 310 for reproducing high-pitched tones and a mid- range speaker 320 or woofer for reproducing a midtone range. The tweeter 310 is here received in the loudspeaker opening with interposing of a horn 315, which imparts a passive amplification to the tweeter. In the example use is made for the tweeters 310L/R of a matched pair of high-grade BlieSMa T34A-4 Aluminium-Magnesium reproducers, this because of their exceptionally clear and rich reproduction. The midrange speaker or woofer 320 is placed directly in the loudspeaker opening. As is clearly visible in figure 2, the loudspeakers 310L/R, 320L/R are preferably placed in completely open manner, meaning that the loudspeakers are not encased in a casing on their rear side. The relevant acoustic membranes (cones) of the loudspeakers can thereby vibrate freely in the space and are not damped therein.

A frequency separation between the two speakers is imposed by an electronic separating filter (not shown) with a turnover frequency of around 800 Hz. For control, each stereo channel comprises a separate amplifier, in this example a Hypex FA253 Fusion Amp which has a separate tweeter channel and is placed in the foot 500 of the desk. On a front side the desk has on each side a standard 19-inch rack in which any further audio equipment or network equipment can be accommodated.

The loudspeaker panels 1401, MOR mutually enclose an angle of about 110-130 degrees, whereby the central axes through the respective acoustic membranes of the loudspeakers 310L, 320L on the left-hand side and those through the respective acoustic membranes of the loudspeakers 31 OR, 320R on the right-hand side intersect each other at least substantially at the listening position 200 in the central perpendicular plane ML. The two panels MOL, MOR furthermore have a rearward incline of about 115 degrees relative to the shelf surface 130, so that the relevant central axes furthermore intersect each other roughly at the listening height, see also figure 5. The reproduction by the loudspeakers 310L/R, 320L/R is thus focused particularly accurately toward the listener 200. This same incline of the two loudspeaker panels MOL, MOR furthermore limits or even eliminates interference of the outgoing sound waves by the tabletop.

The tabletop extends from shelf surface 130 into flanks 150 on the left-hand side and right-hand side, these following the same angle here as the loudspeaker panels M0. On a rear side the flanks 150 are bounded by an upright wall 160 which is formed on the adjacent loudspeaker panel M0L/R in the manner of a wing. These wings 160 contribute to a focusing of the sound toward the listening position 200. The desk 100 supports on a rear side thereof on the ground surface with a column 500, which will be discussed in further detail below.

The column 500 provides support to a housing 550 in which a set of further loudspeaker 330 is accommodated. The further loudspeakers each comprise a reproducer for low-pitched tones, a so-called subwoofer, and are accommodated in the housing back to back, mirrored in relation to each other relative to the central perpendicular plane MLV, see figure 2. In this example a set of Dayton Audio RSS315HF-4 Reference HF reproducers has been opted for for the subwoofers 330. The housing 550 around the subwoofers 330 is substantially closed, although some sound openings 560, 570, 580 through which sound can escape are provided locally in a wall thereof. Two sound openings 560 open directly forward here in a further panel 180 which extends between the two loudspeaker panels 140L/R, see figure 1. These openings 560 are here positioned mirrored relative to the central perpendicular plane MLV to support the two other loudspeakers 310L/R, 320L/R on either side. The housing further comprises a first sound opening 570 in a roof thereof, see figure 3, in order to allow sound waves to escape in upward direction as well, and likewise provided in a bottom of the housing is a second sound opening 580, see figure 4, so that the same bass waves can also escape in downward direction.

What is important is that the loudspeakers 330 are enclosed laterally in outward direction by an acoustically damping wall 590 of the housing, see figures 4 and 5, so that the escaping of the bass waves in this direction is preferably damped as far as possible. For the lowest frequencies a sound image is thus formed inside a relatively flat cylinder C, which is shown schematically in top view in figure 3 and is shown in a partial side view in figure 5. This contributes to a focusing of even the bass reproduction around the listener 200. Each of the two subwoofers 330 is provided with its own amplifier, which is accommodated in the column of the pillar 500. An electronic separating filter provides for a frequency separation relative to the woofers 320 in the loudspeaker panels. A turnover frequency of 200 Hz or less is applied here.

Although the invention has been further elucidated above with reference to only a single exemplary embodiment, it will be apparent that the invention is by no means limited thereto. On the contrary, many variations and embodiments are still possible within the scope of the invention for a person with ordinary skill in the art.