GB2148074A - Loudspeaker circuit - Google Patents

Loudspeaker circuit Download PDF

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Publication number
GB2148074A
GB2148074A GB08412663A GB8412663A GB2148074A GB 2148074 A GB2148074 A GB 2148074A GB 08412663 A GB08412663 A GB 08412663A GB 8412663 A GB8412663 A GB 8412663A GB 2148074 A GB2148074 A GB 2148074A
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GB
United Kingdom
Prior art keywords
tweeter
capacitance
rating
capacitors
circuit
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.)
Granted
Application number
GB08412663A
Other versions
GB8412663D0 (en
GB2148074B (en
Inventor
Michael Emile Telford-Miller
Valerie Patrici Telford-Miller
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.)
TELFORD MILLER MICHAEL EMILE
TELFORD MILLER VALERIE PATRICI
Original Assignee
TELFORD MILLER MICHAEL EMILE
TELFORD MILLER VALERIE PATRICI
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 TELFORD MILLER MICHAEL EMILE, TELFORD MILLER VALERIE PATRICI filed Critical TELFORD MILLER MICHAEL EMILE
Priority to GB08412663A priority Critical patent/GB2148074B/en
Publication of GB8412663D0 publication Critical patent/GB8412663D0/en
Publication of GB2148074A publication Critical patent/GB2148074A/en
Application granted granted Critical
Publication of GB2148074B publication Critical patent/GB2148074B/en
Expired 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; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones
    • H04R3/02—Circuits for transducers, loudspeakers or microphones for preventing acoustic reaction, i.e. acoustic oscillatory feedback

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  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Circuit For Audible Band Transducer (AREA)

Abstract

Feedback inhibition apparatus (3) suitable for equipment used in "live" performances is provided comprising a plurality of tweeters (5, 6, 7, and 8), each having differing capacitance ratings, at least one of such ratings being provided by a plurality of capacitors connected between an amplifier (2) and a tweeter, the arrangement being such that the capacitors inhibit feedback. <IMAGE>

Description

SPECIFICATION Feedback inhibitor apparatus This invention relates to apparatus for inhibiting feedback in audio systems such as those used for "live" performances.
One type of feedback occurs when an amplifier is placed near to a microphone and loudspeakers, as is typically the case in a "live" performance on a stage.
Although it is known to incorporate anti-feedback circuitry within the amplifier, nevertheless this can be inconvenient in terms of cost and may not always be satisfactory.
It is an object of the present invention to provide feedback inhibition apparatus in which the foregoing disadvantages are obviated.
According to the invention there is provided feedback inhibition apparatus for a plurality of tweeters having differing capacitance ratings, at least one of such ratings being provided by a plurality of capacitors connected between an amplifier and a tweeter, the arrangement being such that the capacitors combine to provide a resistance within the circuit which acts to inhibit feedback.
Preferably, four tweeters are provided, the first having a relatively high capacitance rating, the second and third having intermediate capacitance ratings and the fourth having a relatively low capacitance rating. Conveniently, the relatively low capacitance rating of the fourth tweeter may be provided by a set of capacitors arranged in series in the circuit such that in combination they provide a relatively low capacitance rating but also act to provide a resistance in the circuit. The capacitance rating in the intermediate tweeters may also be provided by a plurality of capacitors connected in series in the circuit. The capacitance rating in the first tweeter may be provided by one or more capacitors connected in series in the circuit.
The invention will now be described, by way of example only, with reference to the accompanying drawing which shows schematically the arrangement of one circuit operable to provide feedback inhibition according to the invention.
Referring to the drawing, an audio system suitable for "live" performances is shown which comprises a microphone 1 an amplifier 2 and a loudspeaker system shown generally at 3. The system 3 comprises a relatively low frequency loudspeaker 4, known as a "woofer", connected conventionally to the amplifier 2. A first tweeter loudspeaker 5, second tweeter loudspeaker 6, third tweeter loudspeaker 7 and fourth tweeter loudspeaker 8 are each connected to the amplifier 2 through a main capacitor 9 having a rating of 8 micro Farad and a voltage of 312 v. The first tweeter 5 is connected directly to the main capacitor 8 and thus has an identical capacitance rating of 8 micro Farad.
Between the second tweeter 6 and the main capacitor 9 is connected in series a secondary capacitor 10 having a capacitance rating of 8 micro Farad and a voltage of 275v. The combined capacitance provided by the main capacitor 9 and the secondary capaciter 10 is approximately 4.0.
Micro Farad.
Between the third tweeter 7 and the main capacitor 8 is connected in series a secondary capacitor 11 having a capacitance rating of 8 micro Farad. Connected in series between the secondary capacitor 11 and the tweeter 7 are a set of five tertiary capacitors 12, each having a capacitance rating of 4.7 micro Farad. The combined capacitance rating for the third tweeter 7 is thus 0.8 micro Farad.
Between the fourth tweeter 8 and the main capacitor 9 is connected a secondary capacitor 13 having a capacitance rating of 33 micro. Farad.
Connected in series between the secondary capacitor 13 and the tweeter 8 are a set of four tertiary capacitors 14, each having a capacitance rating of 2.2 micro Farad, and a set of two quaternary capacitors 15, each having a capacitance rating of 4.7 micro Farad. The combined capacitance rating for the fourth tweeter 8 is thus 0.4 micro Farad.
The combination of the tweeters 5,6,7 and 8 together with the capacitors provides a circuit which is suitable for reproduction of the human voice but which also acts to inhibit feedback from the microphone or from the amplifier. Ordinarily, in a conventional system, a single tweeter is used having e.g. a capacitance rating of 8 micro. Farad.
However, in such a system there is little or no resistance and, additionally, the tweeter itself is only suitable for a single limited range of frequencies.
However, in the present system according to the invention the use of, say, four tweeters, each having a different frequency range, makes it possible to reproduce and even improve the frequency range produced by a performer using the equipment.
Since feedback within the system is essentially eliminated there is a marked improvement in the audio system compared with a conventionsl audio system having a single tweeter.
1. Feedback inhibition apparatus for a plurality of tweeters having differing capacitance ratings, at least one of such ratings being provided by a plurality of capacitors connected between an amplifier and a tweeter, the arrangment being such that the capacitors combine to provide a resistance within the circuit which acts to inhibit feedback.
2. Apparatus according to claim 1 in which four tweeters are provided, the first having a relatively high capacitance rating, the second and third having intermediate capacitance ratings and the fourth having a relatively low capacitance rating 3. Apparatus according to claim 2 in which the relatively low capacitance rating of the fourth tweeter is provided by a set of capacitors arranged in series in the circuit such that in combination they provide a relatively low capacitance rating but also act to provide a resistance in the circuit.
4. Apparatus according to claim 2 or claim 3 in which the capacitance rating in intermediate tweeters is provided by a plurality of capacitors
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Feedback inhibitor apparatus This invention relates to apparatus for inhibiting feedback in audio systems such as those used for "live" performances. One type of feedback occurs when an amplifier is placed near to a microphone and loudspeakers, as is typically the case in a "live" performance on a stage. Although it is known to incorporate anti-feedback circuitry within the amplifier, nevertheless this can be inconvenient in terms of cost and may not always be satisfactory. It is an object of the present invention to provide feedback inhibition apparatus in which the foregoing disadvantages are obviated. According to the invention there is provided feedback inhibition apparatus for a plurality of tweeters having differing capacitance ratings, at least one of such ratings being provided by a plurality of capacitors connected between an amplifier and a tweeter, the arrangement being such that the capacitors combine to provide a resistance within the circuit which acts to inhibit feedback. Preferably, four tweeters are provided, the first having a relatively high capacitance rating, the second and third having intermediate capacitance ratings and the fourth having a relatively low capacitance rating. Conveniently, the relatively low capacitance rating of the fourth tweeter may be provided by a set of capacitors arranged in series in the circuit such that in combination they provide a relatively low capacitance rating but also act to provide a resistance in the circuit. The capacitance rating in the intermediate tweeters may also be provided by a plurality of capacitors connected in series in the circuit. The capacitance rating in the first tweeter may be provided by one or more capacitors connected in series in the circuit. The invention will now be described, by way of example only, with reference to the accompanying drawing which shows schematically the arrangement of one circuit operable to provide feedback inhibition according to the invention. Referring to the drawing, an audio system suitable for "live" performances is shown which comprises a microphone 1 an amplifier 2 and a loudspeaker system shown generally at 3. The system 3 comprises a relatively low frequency loudspeaker 4, known as a "woofer", connected conventionally to the amplifier 2. A first tweeter loudspeaker 5, second tweeter loudspeaker 6, third tweeter loudspeaker 7 and fourth tweeter loudspeaker 8 are each connected to the amplifier 2 through a main capacitor 9 having a rating of 8 micro Farad and a voltage of 312 v. The first tweeter 5 is connected directly to the main capacitor 8 and thus has an identical capacitance rating of 8 micro Farad. Between the second tweeter 6 and the main capacitor 9 is connected in series a secondary capacitor 10 having a capacitance rating of 8 micro Farad and a voltage of 275v. The combined capacitance provided by the main capacitor 9 and the secondary capaciter 10 is approximately 4.0. Micro Farad. Between the third tweeter 7 and the main capacitor 8 is connected in series a secondary capacitor 11 having a capacitance rating of 8 micro Farad. Connected in series between the secondary capacitor 11 and the tweeter 7 are a set of five tertiary capacitors 12, each having a capacitance rating of 4.7 micro Farad. The combined capacitance rating for the third tweeter 7 is thus 0.8 micro Farad. Between the fourth tweeter 8 and the main capacitor 9 is connected a secondary capacitor 13 having a capacitance rating of 33 micro. Farad. Connected in series between the secondary capacitor 13 and the tweeter 8 are a set of four tertiary capacitors 14, each having a capacitance rating of 2.2 micro Farad, and a set of two quaternary capacitors 15, each having a capacitance rating of 4.7 micro Farad. The combined capacitance rating for the fourth tweeter 8 is thus 0.4 micro Farad. The combination of the tweeters 5,6,7 and 8 together with the capacitors provides a circuit which is suitable for reproduction of the human voice but which also acts to inhibit feedback from the microphone or from the amplifier. Ordinarily, in a conventional system, a single tweeter is used having e.g. a capacitance rating of 8 micro. Farad. However, in such a system there is little or no resistance and, additionally, the tweeter itself is only suitable for a single limited range of frequencies. However, in the present system according to the invention the use of, say, four tweeters, each having a different frequency range, makes it possible to reproduce and even improve the frequency range produced by a performer using the equipment. Since feedback within the system is essentially eliminated there is a marked improvement in the audio system compared with a conventionsl audio system having a single tweeter. CLAIMS
1. Feedback inhibition apparatus for a plurality of tweeters having differing capacitance ratings, at least one of such ratings being provided by a plurality of capacitors connected between an amplifier and a tweeter, the arrangment being such that the capacitors combine to provide a resistance within the circuit which acts to inhibit feedback.
2. Apparatus according to claim 1 in which four tweeters are provided, the first having a relatively high capacitance rating, the second and third having intermediate capacitance ratings and the fourth having a relatively low capacitance rating
3. Apparatus according to claim 2 in which the relatively low capacitance rating of the fourth tweeter is provided by a set of capacitors arranged in series in the circuit such that in combination they provide a relatively low capacitance rating but also act to provide a resistance in the circuit.
4. Apparatus according to claim 2 or claim 3 in which the capacitance rating in intermediate tweeters is provided by a plurality of capacitors connected in series in the circuit.
5. Apparatus according to claim 2,3 or 4 in which the capacitance rating in the first tweeter is provided by one or more capacitors connected in series in the circuit.
6. Apparatus substantially as hereinbefore described with reference to and as shown in the accompanying drawing.
GB08412663A 1984-05-18 1984-05-18 Loudspeaker circuit Expired GB2148074B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08412663A GB2148074B (en) 1984-05-18 1984-05-18 Loudspeaker circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08412663A GB2148074B (en) 1984-05-18 1984-05-18 Loudspeaker circuit

Publications (3)

Publication Number Publication Date
GB8412663D0 GB8412663D0 (en) 1984-06-27
GB2148074A true GB2148074A (en) 1985-05-22
GB2148074B GB2148074B (en) 1987-08-05

Family

ID=10561125

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08412663A Expired GB2148074B (en) 1984-05-18 1984-05-18 Loudspeaker circuit

Country Status (1)

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Also Published As

Publication number Publication date
GB8412663D0 (en) 1984-06-27
GB2148074B (en) 1987-08-05

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19930518