Speaker system

• US 6,259,799 B1
• Filed: 04/16/1998
• Issued: 07/10/2001
• Est. Priority Date: 11/11/1997
• Status: Expired due to Term

• Current Assignee: Mitsubishi Electric Engineering Co Ltd (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Suzuki, Seiki, Kyouno, Noboru
• Primary Examiner(s): Mei, Xu
• Application Number:
  US09/060,711
• Time in Patent Office: 1,181 Days
• Field of Search: 381/182, 381/99, 381/400, 381/401, 381/89, 381/332, 381/333, 381/334, 381/335, 381/336, 381/59, 381/186, 381/111, 381/117
• US Class Current: 381/401
• CPC Class Codes: H04R 2209/041 Voice coil arrangements comprising more than one voice coil unit on the same bobbin
• CPC Class Codes: H04R 3/08 of electromagnetic transducers
• CPC Class Codes: H04R 9/063 using a plurality of acoustic drivers H04R1/24 and H04R1/403 take precedence

Abstract

A speaker system includes a plurality of double-voice-coil speaker units fitted to a closed type cabinet and connected in parallel with each other so that first voice coils are connected to each other at the same polarities, and second voice coils are connected to each other at the same polarities, and a single impedance compensating circuit is connected in series to the second voice coils for making the input impedance as the speaker system constant.

Claims

1. A speaker system, comprising:

a closed type cabinet in which a rear space relative to a speaker disposed face is closed;

a plurality of double-voice-coil speaker units, each having a first voice coil and a second voice coil and being fixed to said closed type cabinet, each said first voice coil and second voice coil having a connection of a first polarity and a connection of a second polarity; and

an impedance compensating circuit that makes the impedance of said speaker system constant;

wherein

the first voice coils of said plurality of double-voice-coil speaker units are connected in parallel to each other so that the respective same polarities are connected to each other, the second voice coils of said plurality of double-voice-coil speaker units are connected in parallel to each other so that the respective same polarities are connected to each other, an input signal is directly applied to said first voice coils of said plurality of double-voice-coil speaker units, and the input signal is applied to said second voice coils of said plurality of double-voice-coil speaker units through said impedance compensating circuit,

said impedance compensating circuit is made up of a series circuit that includes an inductor and a capacitor, and

said double-voice-coil speaker units are designed so that a resistance R_v2 of said second voice coils and element constants L, C of said impedance compensating circuit satisfy the following expressions, under the condition that said second voice coils are opened, assuming that a resonance angular frequency is ω

_o, an equivalent mass is m_o, a mechanical sharpness is Q_m, a ratio of the force factor of said second voice coil to said first voice coil is α

, an air compliance due to a volume within said closed type cabinet viewed from a single unit as disposed is C_b, a mechanical resistance is r_b, an inductance of said impedance compensating circuit is L, a capacitance of said impedance compensating circuit is C, the resistances of said first and second voice coils are R_v1 and R_v2, respectively, and the number of said plurality double-voice-coil speaker units is n;

$R_{\mathrm{V2}}=R_{\mathrm{V1}}<br><br>\left(\frac{Q_0<br><br>Q_m}{Q_m-Q_0}\right)<br><br>\left\{\left(\frac{1}{Q_0}+\frac{n}{Q_b}\right)-2<br><br>\mathrm{\alpha <br><br>}<br><br>\left(\frac{Q_m-Q_0}{Q_m<br><br>Q_0}\right)\right\};<br><br>$$L=\frac{R_{\mathrm{V1}}}{{\mathrm{\omega <br><br>}}_0}<br><br>\left(\frac{Q_0<br><br>Q_m}{Q_m-Q_0}\right);<br><br>\mathrm{and}$$C=\frac{1}{R_{\mathrm{V1}}<br><br>{\mathrm{\omega <br><br>}}_0}<br><br>\left(\frac{Q_m-Q_0}{Q_0<br><br>Q_m}\right)<br><br>\frac{{\mathrm{\gamma <br><br>}}_b}{n+{\mathrm{\gamma <br><br>}}_b},\mathrm{where}$${\mathrm{\gamma <br><br>}}_b=\frac{C_b}{C_0}<br><br>\text{\hspace{1em}<br><br>}<br><br>Q_b=\frac{{\mathrm{\omega <br><br>}}_0<br><br>m_0}{r_b}.$

2. The speaker system as claimed in claim 1, wherein said plurality of double-voice-coil speaker units have the same specifications.