|
|
Loudspeaker Box for Laboratory Measurements of Loudspeaker Impedance
Nevole, Tomáš ; Káňa, Ladislav (referee) ; Schimmel, Jiří (advisor)
In this thesis there are solved problems of design and construction of a universal modular loudspeaker box, which should serve for laboratory measurements of broadband electro-magnetic loudspeaker’s impedance. These measurements should demonstrate how the electric parameters are changed by changing the acoustic impedance of surrounding into which the speaker transmits. In the first part there is explained necessary theory for solving the task, such as way of sound’s transmission in the environment, variable sorts of speakers and their characteristics. A special focus is given to description of the electro-magnetic speaker’s parameters and construction that was used for the loudspeaker box. Then there are introduced needed mathematical formulas for algebraic design of the loudspeaker box, various types of the loudspeaker boxes (open, closed, vented) and their parameters. In this thesis there is also solved the problem with leaks and settled the matter, if it is better to build one modular box or 2 or 3 separate boxes. Most important characteristics are the impedance characteristics for this thesis but the SPL characteristics are also included. Unfortunately the simulating programs couldn’t generate the hodographs of impedance. After the algebraic calculations, in the thesis there are presented outputs from simulation programs Unibox 408 and WinISD 0.6. The outputs also are compared with the algebraic calculations. In the last part of the thesis there is already described the own construction of the loudspeaker box and presented results from the box’s measuring in the anechoic chamber (in the laboratory of electro-acoustic). The measuring of the modular impedance characteristic was realized on the single speaker and all the boxes. The measuring of the SPL (sound pressure level) characteristic was realized on the boxes only. All these results are compared with the calculations and simulations and the inaccuracies are substantiated in the end. The comparing of the manufacturer’s characteristics with the measured characteristics is also included.
|
|
| |
|
| |
|
|
Loudspeaker Box for Laboratory Measurements of Loudspeaker Impedance
Nevole, Tomáš ; Káňa, Ladislav (referee) ; Schimmel, Jiří (advisor)
In this thesis there are solved problems of design and construction of a universal modular loudspeaker box, which should serve for laboratory measurements of broadband electro-magnetic loudspeaker’s impedance. These measurements should demonstrate how the electric parameters are changed by changing the acoustic impedance of surrounding into which the speaker transmits. In the first part there is explained necessary theory for solving the task, such as way of sound’s transmission in the environment, variable sorts of speakers and their characteristics. A special focus is given to description of the electro-magnetic speaker’s parameters and construction that was used for the loudspeaker box. Then there are introduced needed mathematical formulas for algebraic design of the loudspeaker box, various types of the loudspeaker boxes (open, closed, vented) and their parameters. In this thesis there is also solved the problem with leaks and settled the matter, if it is better to build one modular box or 2 or 3 separate boxes. Most important characteristics are the impedance characteristics for this thesis but the SPL characteristics are also included. Unfortunately the simulating programs couldn’t generate the hodographs of impedance. After the algebraic calculations, in the thesis there are presented outputs from simulation programs Unibox 408 and WinISD 0.6. The outputs also are compared with the algebraic calculations. In the last part of the thesis there is already described the own construction of the loudspeaker box and presented results from the box’s measuring in the anechoic chamber (in the laboratory of electro-acoustic). The measuring of the modular impedance characteristic was realized on the single speaker and all the boxes. The measuring of the SPL (sound pressure level) characteristic was realized on the boxes only. All these results are compared with the calculations and simulations and the inaccuracies are substantiated in the end. The comparing of the manufacturer’s characteristics with the measured characteristics is also included.
|
guest ::
