DE342591C - - Google Patents
Info
- Publication number
- DE342591C DE342591C DENDAT342591D DE342591DA DE342591C DE 342591 C DE342591 C DE 342591C DE NDAT342591 D DENDAT342591 D DE NDAT342591D DE 342591D A DE342591D A DE 342591DA DE 342591 C DE342591 C DE 342591C
- Authority
- DE
- Germany
- Prior art keywords
- mouthpiece
- megaphone
- message
- wall
- opening
- 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.)
- Active
Links
- 230000003287 optical effect Effects 0.000 claims description 3
- 239000011521 glass Substances 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/18—Methods or devices for transmitting, conducting or directing sound
- G10K11/26—Sound-focusing or directing, e.g. scanning
- G10K11/28—Sound-focusing or directing, e.g. scanning using reflection, e.g. parabolic reflectors
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Telescopes (AREA)
Publications (1)
| Publication Number | Publication Date |
|---|---|
| DE342591C true DE342591C (cg-RX-API-DMAC7.html) |
Family
ID=572293
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DENDAT342591D Active DE342591C (cg-RX-API-DMAC7.html) |
Country Status (1)
| Country | Link |
|---|---|
| DE (1) | DE342591C (cg-RX-API-DMAC7.html) |
-
0
- DE DENDAT342591D patent/DE342591C/de active Active
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