US2403232A

US2403232A - Reverberation modulator for echo effect

Info

Publication number: US2403232A
Application number: US524037A
Authority: US
Inventors: Parisier Maurice
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-02-26
Filing date: 1944-02-26
Publication date: 1946-07-02
Anticipated expiration: 1963-07-02

Description

July 2, 1946. M. PARISIER REVERBERATION MODULATOR FUR ECHO EFFECT Filed Feb. 26, 1944 EHTDE KNEW-Es;

FmEImSE EEEE' 'L wK a mu-M Mamas PARIS/El? INVENTOR ATTORNEY Patented July" 2,

UNITED STATES I Prim-10m REVERBERATION MODfiLATOB FOR EGHO EFFECT Maurice Parisier, New York, N. Y. Application February 26, 1944, Serial No. 524,037

My invention relates to reverberation modulators for echo efiect and has particular reference to devices for sound conditioning and for obtaining special sound effect for radio broadcasting and recording.

In my patent application, Serial No. 517,321, filed January 7, 1944, of which this application is a continuation-in-part, I disclosed a reverberation chamber in which sound is electrically reproduced, conditioned as to its reverberation and other properties, and again converted into elec trical impulses for further broadcasting or recording. I further disclosed means by which the volume of the chamber and the type of its walls can be" changed or modified for varying the reverberation and other sound effects.

For certain purposes it is also desired to produce an echo eiiect when broadcasting or record- .4 Claims." (01. Iva-4).

. whiching music, speech, singing, etc. My invention has for its object, therefore; to provide a chamber or chambers by means-of which echo efiect can be obtained. I

It is a well known fact that velocity of sound propagation varies with the density of a'medium through which the sound is transmitted. In dense mediums such as water, velocity of sound is greatly increased, and in a rarefied air it is correspondingly reduced. According to my invention, therefore, it is possible to divide the sound impulses into several frequency bands or several channels with sound conditioning charg r hers, certain of these chambers transmitting the sound at a normal or increased velocity, the other chambers beingadapted to retard the sound velocity. This may be accomplished by using air at normal pressure or-compressing the air in high velocity chambers and exhausting the air to a desired degree in low velocity chambers, or by using other 7 gases. By combining the sound impulses received from the difierent chambers and modulating Fig. 1 is a diagrammatic view of my system in which several channels or tracks are employed with various acoustic chambers, showing means for modulating the sound and for combining the tracks into a single channel;

Fig. 2 is a sectional elevational view of my echo chamber;

Fig. 3 is a sectional plan view of the same.

My reverberation chamber or enclosure for producing echo effect is shown in Figs. 2 and 3 and consists of an outer shell I of a tubular shape, preferably made of a material having poor resonance properties such as a plastic or fibrous composition, suitably impregnated to make it airtight. The shell has flanges 2 at the end to which end covers 3 and 4 are secured by screws or other suitable means. A tube 5 of a small diameter is fitted in the cover 3 with a valve 6 for exhausting the air from the space inside the shell or, if desired, for compressing the air or for filling the chamber inside with a suitable gas or vapor.

A loud speaker I is placed at one end of the chamber for converting electric impulses received through leads 8 into sound, and a microphone I0 their relative intensities; it is possible to obtain loud principal sound with more or less weakened echoes in the form of sounds from the low velocity chambers.

Another object of my invention is to prevent the sound in the low velocity chamber irom passing through the walls of the chamber, which for this purpose are lined with a soundproofing material and otherwise so constructed as to inhibit the sound transmission. The sound transmitters and receivers in the .chamber are for this purpose suspended on threads, wires, etc., so as to prevent direct transmission of the sound to the walls or the chamber, restricting the sound transmission II is placed at the other end of the chamber for converting the sound again into electric impulses.

To prevent direct transmission of sound through the walls of the chamber, the loud speaker and the microphone are suspended on wires or cords l2, IS. The walls for the same purpose are lined inside with a soundproofing material M such as rock wool, cotton, asbestos, etc., with a thin inner shell [5 preferably made also of a soundproofing material such as fabric, leather, rubber, etc.

The enclosure or shell I may be of any suitable dimensions but need not be very large so that several such enclosures can, be placed in a studio where the sound is produced or transmitted.

To obtain the echo efl'ect, the sound must be divided into several channels as shown in Fig.

1. Electric impulses from microphones 20 placed in a broadcasting or recording! studio pass through switches II and through a common mixing amplifier 29 through regulating potentiometers 30, ill. These amplifiers transmit the sound directly, without my sound conditioning chambers.

The second set of the transmitting amplifiers 28 and filters I8 are connected by lines 33 with loud speakers 1 in echo chambers or enclosures l, which may be tuned to different frequencies. The tuning may be accomplished by varying dimensions of the chambers, by varying the relative angles of the loud speakers in addition to providing special filters 28 in the lines leading to the loud speakers. Potentiometers 26 or similar de-- vices are provided for regulating the relative intensities of the impulses for different loud speakers.

Microphones H are placed in front of the loud speakers and are connected to receiving bus bars II by leads 4! at one side, and through regulating potentiometers 445, and leads 48 at the other side, the potentiometers being preferably placed at a common point of control.

Supplementary reverberation chambers may be also provided of a type disclosed in my foregoing patent application, with provision for varying the volume of the chambers or the type of their walls.

The bus bars 4| are connected to a first mixing amplifier 80 which is in turn connected to the second or main mixing amplifier 29 through the potentiometer 3|.

With my system it is possible to obtain various echo eflects. Thus, for instance, it is possible to direct the low frequencies only through the first or direct channel, while sending the high frequencies through the echo chambers. By varying the relative intensities of the sound through these channels, a more or less strong echo effect may be obtained in connection with sounds of higher lpitch. Or it may be possible to direct all frequencies through the echo chambers, thereby obtaining echo efi'ect for all sounds. Usually it is preferred to have for every frequency band one direct and one echo channel so as to obtain direct sound transmitted with a distinct accompanying echo.

It will be understood that various features and principles of each of the embodiments of the invention above described or referred to may be utilized or substituted in the other embodiments.

While the invention has been described in detail with respect to certain particular preferred 4 examples, it will be understood by those sl llled in the art after understanding the invention, that various changes and further modifications may be made without departing from the spirit and scope of the invention, and it is intended therefore in the appended claims to cover all such changes and. modifications.

What is claimed as new and desired to be secured by Letters Patent is:

1. Means to obtain echo effect in sound transmission by radio comprising means to separate electric impulses corresponding to the sounds to be transmitted into several channels of diiferent frequencies; means to connect one channel directly to a receiver; means to individually regulate the impulses of the other channels; means to convert the impulses of the other channels into secondary sounds; reverberation chambers in the paths of the secondary sounds; means to com vert the sounds of the second channel into secondary impulses; means ,to individually regulate the secondary impulses; means to combine the secondary impulses; means to regulate the combined secondary impulses; means to combine the secondary and primary impulses; and means to regulate the combined primary and secondary impulses.

2. A method of obtaining an echo effect in sound transmission by radio consisting in separating electric impulses produced by a sound to be transmitted into groups of channels of different frequencies, transmitting the impulses of the first group of channels directly; individually regulating the impulses oi. the channels of the second group; converting the impulses of the second group of channels into secondary sounds; modifying the reverberation properties of the secondary sounds; reconverting the secondary sounds into secondary electric impulses; regulating the secondary impulses, combining the secondary impulses into one channel; regulating the combined secondary impulses; and-combining the impulses of the first group of channels with the combined impulses of the second group.

3; A reverberation modulator comprising an air-tight enclosure containing a rarefied gas, means to produce sound in the enclosure, and means to receive sound within the enclosure and to convert it into electrical impulses.

4. A reverberation modulator comprising an air-tight enclosure containing a rarefied gas, means to produce sound in the enclosure, means to receive sound within the enclosure and to convert it into electrical impulses, and means for supporting at least one of the aforesaid means for angular adJustment to modify the sound effect within the enclosure.

MAURICE PARISIER.