US1841101A - Loud speaker - Google Patents

Loud speaker Download PDF

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Publication number
US1841101A
US1841101A US433590A US43359030A US1841101A US 1841101 A US1841101 A US 1841101A US 433590 A US433590 A US 433590A US 43359030 A US43359030 A US 43359030A US 1841101 A US1841101 A US 1841101A
Authority
US
United States
Prior art keywords
diaphragm
air
resistance
box
waves
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US433590A
Other languages
English (en)
Inventor
Paul B Flanders
Henry C Harrison
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AT&T Inc
Original Assignee
Bell Telephone Laboratories Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US433590A priority Critical patent/US1841101A/en
Priority to DEE40550D priority patent/DE593202C/de
Priority to GB5528/31A priority patent/GB373268A/en
Priority to FR712387D priority patent/FR712387A/fr
Application granted granted Critical
Publication of US1841101A publication Critical patent/US1841101A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
    • H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
    • H04R1/2807—Enclosures comprising vibrating or resonating arrangements
    • H04R1/2815—Enclosures comprising vibrating or resonating arrangements of the bass reflex type
    • H04R1/2819—Enclosures comprising vibrating or resonating arrangements of the bass reflex type for loudspeaker transducers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 

Definitions

  • This invention relates to loud speakers of the direct radiating diaphragm type and more particularly to mountings for inertia controlled speakers having piston dia- 5 phragms of the cone or stiff plate type.
  • the air confined within the box acts as an elastic reactance tending to retard the diaphragm and since this effect is inversely roportional to frequency the response is und uIy decreased at low frequencies.
  • the variation of velocit of vibration with frequency is such that 2hr constant energy input the'sound output, (VR) is also substantially constant over the range of interest.
  • Fig. 1 is a cross-section of a cone type loud speaker mounted in a baflie box with the back resistance added in accordance with the present invention
  • Fig. 2 is a detail of the acoustic resistance material employed
  • Fig. 3 is a representation of the analogs of the mechanical elements of the loud speaker of Fig. 1 in the elements of a corresponding electrical network
  • Fig. 4 is a vector representation of the air velocities set up by the arrangement of Fig. 1.
  • a resistance consists of a thin sheet of metal containing narrow slits 6 such as those described in French Patent 665,237 ranted to P. B. Flanders May 6, 1929.
  • This system like any othermechanical system may be considered for the sake of convenience as a mechanical transmission line as indicated in Fig.
  • F is the driving force in dynes applied to the cone by the unit 1,717, is the mass of the cone in grams, 1-, is theradiation resistance due to the air on the front side of the cone, S is the stiffness of the air enclosed in the box, 7' is the radiation resistance at the back of the cone and R is the added resistance of the material 5.
  • the velocities imparted to the air at the front and rear sides of the cone are represented by i and 77 respectively as indicated. Under these conditions the actual sound emitted is proportional to the vector sum. of i and i Obviously the ideal condition would be to have 2': alone effective.
  • a mechanical ohm is defined as the impedance of a system which when acted on by a force of l dyne, moves with a velocity of 1 cm. per sec.
  • the added resistance is equal to the air reactance of 4115 ohms at cycles and is large compared with the radiation resistances r, and n, which are about 66 ohms at 60 cycles, i will be approximately equalto 11,, i. e. substantially the air displaced by the diaphragm will pass through the membrane while the other half will be compressed within the box. While this value may be varied somewhat in any particular case-it is found in general that if more than about of the displaced air passes through the membrane the transient effect is not sufficiently eliminated while if much more than 1/ the displaced air is confined the response is unduly reduced.

Landscapes

  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
  • Transducers For Ultrasonic Waves (AREA)
  • Devices Affording Protection Of Roads Or Walls For Sound Insulation (AREA)
US433590A 1930-03-06 1930-03-06 Loud speaker Expired - Lifetime US1841101A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US433590A US1841101A (en) 1930-03-06 1930-03-06 Loud speaker
DEE40550D DE593202C (de) 1930-03-06 1931-01-24 Direkt wirkender Schallausstrahler
GB5528/31A GB373268A (en) 1930-03-06 1931-02-21 Improvements in or relating to loud speakers
FR712387D FR712387A (fr) 1930-03-06 1931-03-02 Perfectionnements aux haut-parleurs

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US433590A US1841101A (en) 1930-03-06 1930-03-06 Loud speaker

Publications (1)

Publication Number Publication Date
US1841101A true US1841101A (en) 1932-01-12

Family

ID=23720713

Family Applications (1)

Application Number Title Priority Date Filing Date
US433590A Expired - Lifetime US1841101A (en) 1930-03-06 1930-03-06 Loud speaker

Country Status (4)

Country Link
US (1) US1841101A (de)
DE (1) DE593202C (de)
FR (1) FR712387A (de)
GB (1) GB373268A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2713396A (en) * 1950-05-24 1955-07-19 Ernest A Tavares Novel, small, extended low frequency response, loudspeaker enclosure
US2766839A (en) * 1953-03-16 1956-10-16 Research Corp Loudspeaker system
US2885024A (en) * 1959-05-05 Loudspeaker cabinets
US2971597A (en) * 1941-09-05 1961-02-14 Henry Heinrich & Co Electro-acoustic devices

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI823540A0 (fi) * 1982-10-18 1982-10-18 Polarpro Oy Hoegtalare
FR2552610A1 (fr) * 1983-09-23 1985-03-29 Bresteau Paul Henri Simulateur de charge infinie pour haut-parleur

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2885024A (en) * 1959-05-05 Loudspeaker cabinets
US2971597A (en) * 1941-09-05 1961-02-14 Henry Heinrich & Co Electro-acoustic devices
US2713396A (en) * 1950-05-24 1955-07-19 Ernest A Tavares Novel, small, extended low frequency response, loudspeaker enclosure
US2766839A (en) * 1953-03-16 1956-10-16 Research Corp Loudspeaker system

Also Published As

Publication number Publication date
GB373268A (en) 1932-05-23
DE593202C (de) 1934-02-24
FR712387A (fr) 1931-10-01

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