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Model 2018. A line array speaker with built-in amplifiers.
Dimensions: 120 x 26 x 11 cm
Documentation can be found here.
DFX drawings acrylic panels:
The design of the standard loudspeaker sold in stores differs in at least four respects. The standard speaker is usually a two-way or three-way system with a bass reflex port and no amplifiers are built in. This model is a two-way system in which the mid and high frequencies are reproduced by nine broadband speakers in an open box and a bass speaker in a completely closed box. Amplifiers with filters are built into the cabinet. The cabinet has been kept as flat and narrow as possible to be placed in the living room.
Each of the following four features contribute to quality enhancement:
When a speaker is enclosed in a cabinet, resonances of the air in the cabinet will occur. Those resonances gradually disappear through the speaker and cabinet panels. This seriously 'colors' the sound image. The cabinet continuously stores sound energy that is released in a delayed manner. However, a closed box is not necessary for mid and high tones. That is why the broadband speakers are mounted in an open cabinet. This results in an uncolored sound. Voices sound more natural. For this reason, electrostatic speakers also sound so good because they are never mounted in a closed cabinet.
A line array system consists of a column of identical loudspeakers. This system is used in large spaces (e.g. concert halls, churches) due to its high efficiency. The efficiency is due to the vertical bundling of the sound. For a living room, efficiency is not important, but vertical bundling is. This ensures that less sound reaches the listener through reflection from the floor and ceiling. To the listener, it seems as if he is closer to the speaker. Almost as if he is listening through headphones.
An open cabinet for the bass is impractical because it would require a very large panel. With standard loudspeaker systems, a bass reflex port is needed to get more lower frequencies. However, the bass reflex port is based on resonance. And at resonance, sound energy is released in a delayed manner. For this reason, a closed cabinet was chosen. The cabinet is so small that standing waves (resonance) cannot arise. To compensate for the lack of bass, which a small box entails, correction amplifiers are built in. In this way, the bass sounds quieter than a bass reflex system.
There are a number of reasons why amps are built in. As mentioned before, correction amplifiers are needed for the low end. The treble is also slightly corrected. In addition, there is an electronic crossover filter. This is more accurate than a passive filter as used in standard loudspeaker systems. Separate power amplifiers (LM3886T) are built in for the low and high frequencies. This means that the speaker is directly connected to the amplifier, without the intervention of cables, coils, capacitors and resistors. In that way, the speaker is better controlled by the amplifier.
There is a circuit ("audio switch") that automatically turns on the power of the amplifiers when the music starts. When the music has stopped, the power will be turned off after a few minutes.
The "active" speaker can be directly connected to a preamplifier or media player. The loudspeaker can be connected to an existing power amplifier via a resistance attenuator (1:20).
Model 2017. A speaker with built-in amplifiers.
Dimensions: 128 x 30. Depths: 8 and 20 cm
Documentation can be found here.
|Model 2014. Designed for a puppet show.
Just very cheap speakers, but due to the
line array gives an excellent performance
Model 2007. A three-way active speaker.
|Model 2011. For people that are hearing impaired.
Designed together with my daughter.
To be used in combination with a TV.
In order to gain a better understandability, room reflections
must be reduced. Also, frequencies below voices frequencies
do not help and therefore are not reproduced.
Model 2009. A speaker with built-in amplifiers.
I have a set of empty cabinets in the garage I want to get rid off.
When I was about 17 years old, I heard the Quad ESL 57 for the
I can recommend a visit to:
Model 1990. A passive three-way speaker.
I probably build another 8 speakers before this model.