586:
These circuits prevent cross modulation of low frequencies with high frequencies, suppress tape saturation when large signal transients are present, and increase the effective headroom of the cassette tape system. As a result, recordings are cleaner and crisper with a much improved high-frequency response that the cassette medium heretofore lacked. With a good quality tape, the Dolby C response could be flat to 20 kHz at the 0 dB recording level, a previously unattainable result. An A-weighted signal-to-noise ratio of 72 dB (re 3% THD at 400 Hz) with no unwanted "breathing" effects, even on difficult-to-record passages, was possible.
690:
420:. It was much simpler than Dolby A and therefore much less expensive to implement in consumer products. Dolby B recordings are acceptable when played back on equipment that does not possess a Dolby B decoder, such as many inexpensive portable and car cassette players. Without the de-emphasis effect of the decoder, the sound will be perceived as brighter as high frequencies are emphasized, which can be used to offset "dull" high-frequency response in inexpensive equipment. However, Dolby B provides less effective noise reduction than Dolby A, generally by an amount of more than 3 dB.
440:
651:
563:
253:
574:) in the 2 kHz to 8 kHz region where the ear is highly sensitive and most tape hiss is concentrated. Its noise reduction effect results from the dual-level (consisting of a high-level stage and a low-level stage) staggered action arrangement of series-connected compressors and expanders, with an extension to lower frequencies than with Dolby B. As in Dolby B, a "sliding band" technique (operating frequency varies with signal level) helps to suppress undesirable
555:
297:, receive no signal modification at all. Between the two limits, a varying level of pre-emphasis is applied. On playback, the opposite process is applied (de-emphasis), based on the relative signal component above 1 kHz. Thus, as this portion of the signal decreases in amplitude, the higher frequencies are progressively increasingly attenuated, which also reduces in level the constant background noise on the tape when and where it would be most noticeable.
520:
387:
379:
273:. The signal-to-noise ratio is simply how large the music signal is compared to the low level of tape noise with no signal. When the music is loud, the low background hiss level is not noticeable, but when the music is soft or in silence, most or all of what can be heard is the noise. If the recording level is adjusted so that the music is always loud, then the low-level noise would not be audible.
29:
277:
the same amount on playback so that the signal returns to the original volume levels. When the volume is reduced on playback, the noise level is reduced by the same amount. This basic concept, increasing the volume to overwhelm inherent noise, is known as pre-emphasis, and is found in a number of products.
581:
As a result of the extra signal processing, Dolby C-type recordings will sound distorted when played back on equipment that does not have the required Dolby C decoding circuitry. Some of this harshness can be mitigated by using Dolby B on playback, which serves to reduce the strength of the
468:
system, used in place of Dolby B on earlier JVC cassette decks, is considered compatible with Dolby B. JVC eventually abandoned the ANRS standard in favor of official Dolby B support; some JVC decks exist whose noise-reduction toggles have a combined "ANRS / Dolby B" setting.
276:
One cannot simply increase the volume of the recording to achieve this end; tapes have a maximum volume they can record, so already-loud sounds will become distorted. The idea is to increase the volume of the recording only when the original material is not already loud, and then reduce the volume by
674:
Dolby S is much more resistant to playback problems caused by noise from the tape transport mechanism than Dolby C. Likewise, Dolby S was also claimed to have playback compatibility with Dolby B in that a Dolby S recording could be played back on older Dolby B equipment
585:
With Dolby C-type processing, noise reduction begins two octaves lower in frequency in an attempt to maintain a psychoacoustically-uniform noise floor. In the region above 8 kHz, where the ear is less sensitive to noise, special spectral-skewing and anti-saturation networks come into play.
450:
Prior to the introduction of later consumer variants (Dolby C being the first), cassette hardware supporting Dolby B and cassettes encoded with it would be labeled simply "Dolby System," "Dolby NR", or wordlessly with the Dolby symbol. This continued in some record labels and hardware
423:
The Dolby B system is effective from approximately 1 kHz upwards; the noise reduction that is provided is 3 dB at 600 Hz, 6 dB at 1.2 kHz, 8 dB at 2.4 kHz, and 10 dB at 5 kHz. The width of the noise reduction band is variable, as it is designed to be
362:
As with the Dolby B-type system, correct matching of the compression and expansion processes is important. The calibration of the expansion (decoding) unit for magnetic tape uses a flux level of 185 nWb/m, which is the level used on industry calibration tapes such as those from Ampex; this
358:
circuit has a threshold of −40 dB, with a ratio of 2:1 for a compression/expansion of 10 dB. This provides about 10 dB of noise reduction increasing to a possible 15 dB at 15 kHz, according to articles written by Ray Dolby and published by the Audio
Engineering Society
300:
The two processes (pre- and de-emphasis) are intended to cancel each other out as far as the actual recorded program material is concerned. During playback, only de-emphasis is applied to the incoming off-tape signal and noise. After playback de-emphasis is complete, the apparent noise in the output
733:
HX-Pro only applies during the recording process. The improved signal-to-noise ratio is available no matter which tape deck the tape is played back on, and therefore HX-Pro is not a noise-reduction system in the same way as Dolby A, B, C, and S, although it does help to improve noise reduction
316:
On some high-end consumer equipment, a Dolby calibration control is included. For recording, a reference tone at Dolby Level may be recorded for accurate playback level calibration on another transport. At playback, the same recorded tone should produce the identical output, as indicated by a Dolby
729:
continued work in the same direction, which resulted in a 1981 patent (EP 0046410) by Jørgen Selmer Jensen. Bang & Olufsen immediately licensed HX-Pro to Dolby
Laboratories, stipulating a priority period of several years for use in consumer products, to protect their own Beocord 9000 cassette
619:
The Dolby SR (Spectral
Recording) system, introduced in 1986, was the company's second professional noise reduction system. It is a much more aggressive noise reduction approach than Dolby A. It attempts to maximize the recorded signal at all times using a complex series of filters that
363:
is set to 0 VU on the tape recorder playback and to Dolby Level on the noise reduction unit. In the record (compression or encoding) mode, a characteristic tone (Dolby Tone) generated inside the noise reduction unit is set to 0 VU on the tape recorder and to 185 nWb/m on the tape.
202:
When recording a signal on magnetic tape, there is a low level of noise in the background which sounds like hissing. One solution to this issue is to use low-noise tape, which records more signal, and less noise. Other solutions are to run the tape at a higher speed or use a wider tape. Cassette
285:
to certain frequencies, the total amount of distortion of the original signal can be reduced and focused only on the problematic frequencies. The differences in the various Dolby products are largely evident in the precise set of frequencies that they use and the amount of modification of the
321:, and calibration tapes were available to assist with the task of correct level setting. For accurate off-the-tape monitoring during recording on 3-head tape decks, both processes must be employed at once, and circuitry provided to accomplish this is marketed under the "Double Dolby" label.
280:
On top of this basic concept, Dolby noise reduction systems add another improvement. This takes into account the fact that tape noise is largely heard at frequencies above 1,000 Hz. It is the lower-frequency sounds that are often loud, like drum beats, so by only applying the
620:
change according to the input signal. As a result, Dolby SR is much more expensive to implement than Dolby B or C, but Dolby SR is capable of providing up to 25 dB of noise reduction in the high-frequency range. It is only found on professional recording equipment.
675:
with some benefit being realized. It is basically a cut-down version of Dolby SR and uses many of the same noise reduction techniques. Dolby S is capable of 10 dB of noise reduction at low frequencies and up to 24 dB of noise reduction at high frequencies.
304:
The correct calibration of the recording and playback circuitry is critical in order to ensure faithful reproduction of the original program content. The calibration can easily be upset by poor-quality tape, dirty or misaligned recording/playback heads, or using inappropriate
485:
started to transmit programs with Dolby NR, and soon some 17 stations broadcast with noise reduction, but by 1974 it was already on the decline. Dolby FM was based on Dolby B, but used a modified 25 μs pre-emphasis time constant and a frequency-selective
710:. To overcome this, a high-frequency signal, known as bias, is mixed in with the recorded signal, which "pushes" the envelope of the signal into the linear region. If the audio signal contains strong high-frequency content (in particular from percussion instruments such as
670:
as the dominant mass market music format. Dolby Labs claimed that most members of the general public could not differentiate between the sound of a CD and a Dolby S encoded cassette. Dolby S mostly appeared on high-end audio equipment and was never widely used.
424:
responsive to both the amplitude and the frequency distribution of the signal. It is thus possible to obtain significant amounts of noise reduction down to quite low frequencies without causing audible modulation of the noise by the signal ("breathing").
156:, which used a relatively noisy tape size and speed. It is common on high-fidelity stereo tape players and recorders to the present day, although Dolby has as of 2016 ceased licensing the technology for new cassette decks. Of the noise reduction systems,
714:), this adds to the constant bias causing magnetic saturation on the tape. Dynamic, or adaptive, biasing automatically reduces the bias signal in the presence of strong high-frequency signals, making it possible to record at a higher signal level.
329:
Dolby A-type noise reduction was the Dolby company's first noise reduction system, presented in 1965. It was intended for use in professional recording studios, where it became commonplace, gaining widespread acceptance at the same time that
1360:
1315:
256:
Encoding characteristics for Dolby B-type and C-type noise reduction systems for a −60 dB input signal level. The decoding curves used in playback are the exact inverse and thus the overall record/replay frequency response is
427:
From the mid-1970s, Dolby B became standard on commercially pre-recorded music cassettes even though some low-end equipment lacked decoding circuitry, although it allows for acceptable playback on such equipment. Most pre-recorded
661:
Dolby S was introduced in 1989. It was intended that Dolby S would become standard on commercial pre-recorded music cassettes in much the same way that Dolby B had in the 1970s, but it came to market when the
301:
signal is reduced, and this process should not produce any other effect noticeable to the listener other than reduced background noise. However, playback without noise reduction produces a noticeably brighter sound.
693:
The Dolby HX circuitry driven by the industry-standard NEC uPC1297 integrated circuit. It modulates the incoming bias current and injects it into the two channels of the stereo recording head via two ferrite
1367:
1322:
412:
Dolby B-type noise reduction was developed after Dolby A, and it was introduced in 1968. It consisted of a single sliding band system providing about 9 dB of noise reduction (
481:
broadcasts and some tuners and amplifiers were manufactured with decoding circuitry; there were also some tape recorders with a Dolby B "pass-through" mode. In 1971
566:
Comparison of noise and frequency response characteristics of Dolby B-type and Dolby C-type noise reduction systems, from a
Nakamichi ZX-7 high-performance cassette deck
289:
Within each band, the amount of pre-emphasis applied depends on the original signal volume. For instance, in Dolby B, a low-level signal will be boosted by 10
734:
encode/decode tracking accuracy by reducing tape non-linearity. Some record companies issued HX-Pro pre-recorded cassette tapes during the late 1980s and early 1990s.
730:
tape deck. By the middle of the 1980s the Bang & Olufsen system, marketed through Dolby
Laboratories, became an industry standard under the name of Dolby HX Pro.
1290:
999:
963:
1446:
1138:
523:
A typical consumer cassette deck from the late 1980s, featuring automatic reverse, electronic transport controls, and Dolby B and C, among other features
1518:
309:
levels/frequency for the tape formulation, as well as tape speed when recording or duplicating. This can manifest itself as muffled-sounding playback, or "
1717:
203:
tapes were originally designed to trade off fidelity for the convenience of recording voice by using a very narrow tape running at a very slow speed of
804:
1384:
1200:
589:
Dolby C first appeared on higher-end cassette decks in the 1980s. The first commercially available cassette deck with Dolby C was the
605:. Cassette decks with Dolby C also included Dolby B for backward compatibility, and were usually labeled as having "Dolby B-C NR".
392:
834:
354:
at 9 kHz. (The stacking of contributions from the two high-pass bands allows greater noise reduction in the upper frequencies.) The
689:
390:
Three different music cassettes encoded with Dolby B, showing the various ways in which the use of the system could be indicated.
593:
6150C, which came onto the market around 1981. Dolby C was also used on professional video equipment for the audio tracks of the
1491:
953:"Audio Noise Reduction: Some Practical Aspects – Part 1: Operating principles and details of a professional noise-reduction system"
439:
1702:
1511:
404:
382:
Noise and frequency response analysis of a
Nakamichi 580M high-performance cassette deck with Dolby B-type noise reduction system
451:
manufacturers even after Dolby C had been introduced, during the period when the new standard was relatively little-known.
1182:
1104:
623:
In the motion picture industry, as far as it concerns distribution prints of movies, the Dolby A and SR markings refer to
498:
880:
1181:
Prüfung eines modifizierten HIGH COM-Kompanders für den
Einsatz bei der RF-Übertragung im UKW-Hörfunk (Report) (in German).
634:
SR prints are fairly well backward compatible with old Dolby A equipment. The Dolby SR-D marking refers to both analog
1437:(in German). Vol. 36, no. 8. Heidelberg, Germany: Dr. Alfred Hüthig Verlag GmbH. August 1981. pp. 269–271.
627:
which is not just a method of noise reduction, but more importantly encodes two additional audio channels on the standard
725:, was invented in 1979 by Kenneth Gundry of Dolby Laboratories, and was rejected by the industry for its inherent flaws.
1712:
334:
became standard. The input signal is split into frequency bands by four filters with 12 dB per octave slopes, with
317:
logo marking at approximately +3 VU on the VU meter(s). In consumer equipment, Dolby Level is defined as 200
1697:
1504:
1279:
1163:
988:
952:
310:
1402:
1427:
1119:
650:
245: in/s (9.5 cm/s) was of lower fidelity. As a result of their narrow tracks and slow speed, cassettes make
537:
402:
uses a Dolby logo with "B NR" (also with "HX PRO" to indicate the complementary use of that technology);
570:
The Dolby C-type noise reduction system was developed in 1980. It provides about 15 dB noise reduction (
152:(introduced in 1968), a sliding band system for the consumer market, which helped make high fidelity practical on
1722:
1707:
508:
broadband compander system, but never introduced commercially in FM broadcasting. Another competing system was
859:
1388:
1095:
Mielke, E.-Jürgen (1977). "Einfluß des Dolby-B-Verfahrens auf die Übertragungsqualität im UKW-Hörrundfunk".
758:, but Dolby's analog noise reduction systems are still widely used in niche analog production environments.
812:
754:, music streaming) has made analog audio production less prevalent and therefore changed Dolby's focus on
429:
1083:
1039:
773:
270:
146:
noise reduction system for recording studios that was first demonstrated in 1965, but the best-known is
129:
1339:
1196:
1044:
706:
were recorded directly onto magnetic tape, its reproduction would be extremely distorted due to this
331:
767:
562:
252:
1601:
1566:
841:
747:
509:
443:
133:
50:
16:
A line of noise reduction systems for reel-to-reel, compact cassette, and videocassette recorders
217: in/s (4.8 cm/s) housed in a simple plastic shell when 15 in/s (38 cm/s) or
601:
videocassette formats. In Japan, the first cassette deck with Dolby C was the AD-FF5 from
1438:
1130:
874:
726:
1060:
684:
663:
519:
417:
398:
335:
558:
Encoding characteristics of Dolby C-type noise reduction for a range of input signal levels
1586:
1576:
1129:(in German). Vol. 38, no. 12. Dr. Alfred Hüthig Verlag GmbH. pp. 494–497 .
1065:
590:
386:
1222:
925:
751:
711:
624:
554:
378:
1691:
1676:
1561:
743:
707:
703:
654:
639:
628:
533:
367:
191:
153:
83:
1611:
1606:
1596:
1556:
755:
667:
366:
The Dolby A-type system also saw some use as the method of noise reduction in
318:
78:
1626:
1616:
1541:
1479:
1249:
1127:
Funk-Technik - Fachzeitschrift für Funk-Elektroniker und Radio-Fernseh-Techniker
895:
494:
262:
1120:"Rundfunk für Europa - Pressekolloqium Rundfunktechnik während der IFA 83"
1644:
1639:
699:
571:
513:
502:
487:
413:
355:
282:
266:
187:
1442:
1134:
1660:
1634:
1428:"Hi-Fi-Cassettenrekorder: Bessere Höhenaufzeichnung mit dem Dolby-HX-System"
598:
351:
347:
343:
306:
246:
143:
102:
1167:
1406:
1361:"Dolby B, C, and S Noise Reduction Systems: Making Cassettes Sound Better"
933:. 33rd Audio Engineering Society Convention, Paper Number 543. Los Angeles
1591:
1551:
1546:
779:
635:
614:
532:
A fully Dolby B-compatible compander was developed and used on many
505:
478:
339:
294:
1230:. 70th Audio Engineering Society Convention, Paper Number 1850. New York
657:
Dolby S tape deck, released 1991 and also incorporating HX Pro
1571:
770:(DNR), a playback-only noise reduction system often confused with Dolby
594:
290:
286:
original signal volume that is applied to each of the frequency bands.
1435:
1496:
1250:"A 20 dB Audio Noise Reduction System for Consumer Applications"
477:
In the early 1970s, some expected Dolby NR to become normal in
28:
1224:
A 20 dB Audio Noise
Reduction System for Consumer Applications
1527:
688:
578:, which is often a problem with other noise reduction techniques.
553:
518:
438:
377:
231: in/s (19 cm/s) tape speeds were for high fidelity, and
1492:
Overview of Dolby and other noise reduction systems, Richard Hess
463:
436:
video recorders used Dolby B on linear stereo audio tracks.
194:
of the sound during recording, and expanding it during playback.
860:"Dolby Laboratories Awarded International Honour for Excellence"
602:
497:
was evaluated in
Germany between July 1979 and December 1981 by
482:
458:
1500:
313:" of the noise level as the volume level of the signal varies.
454:
433:
446:
tape recorder with Dolby noise-reduction system (ca. 1972)
269:
used during playback, which work in tandem to improve the
1027:. Audio Engineering Society Convention. Cologne, Germany.
112:
1474:
698:
Magnetic tape is inherently non-linear in nature due to
835:"A Chronology of Dolby Laboratories: May 1965–May 1998"
136:
for use in analog audio tape recording. The first was
1025:
A noise reduction system for consumer tape recording
501:, and field-trialed up to 1984. It was based on the
1669:
1653:
1625:
1534:
108:
98:
90:
74:
66:
56:
46:
38:
265:employed during recording, plus a form of dynamic
182:were designed for the consumer market. Aside from
750:and consumer applications (e.g., compact discs,
293:, while signals at the "Dolby Level", +3
1512:
8:
989:"Audio Noise Reduction: Part 2 (Conclusion)"
631:, giving left, center, right, and surround.
541:
21:
1387:(in Danish). jollyjokers.dk. Archived from
798:
796:
359:(October 1967) and Audio (June/July 1968).
261:Dolby noise reduction is a form of dynamic
1519:
1505:
1497:
1481:Some Not Well Known Aspects of Analog Tape
1405:(in Danish). Datamuseum.dk. Archived from
1185:(IRT). 1981-12-30. Technical Report 55/81.
27:
20:
1254:Journal of the Audio Engineering Society
900:Journal of the Audio Engineering Society
649:
561:
385:
251:
792:
33:Dolby 361 A-type noise reduction module
872:
546:, English: "Noise reduction system").
540:in the 1980s. It was called RMS (from
408:uses a Dolby logo with "Dolby System."
1587:Dolby Surround/Pro Logic/Pro Logic II
1084:Popular Science, February 1974, p. 50
166:were developed for professional use.
7:
1487:, AES 1990 March, Arndt Klingelnberg
1316:"Dolby SR: Dolby Spectral Recording"
338:(3 dB down points) as follows:
183:
14:
1718:Audiovisual introductions in 1965
1403:"B&O/Beocord 9000 - DDHFwiki"
1059:Gilmore, C. P. (September 1971).
896:"An Audio Noise Reduction System"
346:from 80 Hz to 3 kHz; a
186:, all the Dolby variants work by
742:The widespread proliferation of
702:of the magnetic material. If an
1452:from the original on 2021-07-10
1296:from the original on 2022-10-09
1203:from the original on 2021-05-09
1144:from the original on 2021-04-25
1118:Reuber, Claus (December 1983).
1097:Rundfunktechnische Mitteilungen
1023:Dolby, Ray (16–18 March 1971).
1005:from the original on 2022-10-09
969:from the original on 2022-10-09
927:An Audio Noise Reduction System
1280:"Dolby C-Type Noise Reduction"
1:
717:The original Dolby HX, where
490:arrangement to reduce noise.
350:from 3 kHz; and another
162:
1582:Dolby noise-reduction system
1183:Institut für Rundfunktechnik
1105:Institut für Rundfunktechnik
858:Foster, Alana (2017-09-06).
803:White, Paul (January 1996).
178:
172:
148:
138:
122:Dolby noise-reduction system
22:Dolby noise-reduction system
1359:Dolby Laboratories (2004).
1314:Dolby Laboratories (1987).
987:Dolby, Ray M. (July 1968).
951:Dolby, Ray M. (June 1968).
924:Dolby, Ray (October 1967).
894:Dolby, Ray (October 1967).
1739:
1038:Woram, John (1976-12-04).
879:: CS1 maint: url-status (
682:
666:was being replaced by the
642:soundtracks on one print.
612:
538:German Democratic Republic
416:), primarily for use with
396:uses a simple Dolby logo;
393:You Don't Bring Me Flowers
1535:Technologies and products
1433:. Produkt-Informationen.
1278:Hull, Joseph (May 1981).
1248:Dolby, Ray (March 1983).
1040:"Update: Noise Reduction"
26:
1475:Dolby Laboratories, Inc.
1162:Schröder, Ernst F.
1125:. Systeme und Konzepte.
128:, is one of a series of
1703:Noise reduction systems
1164:"The Story of HIGH COM"
768:Dynamic Noise Reduction
493:A similar system named
249:a very severe problem.
1385:"Jørgen Selmer Jensen"
1340:"Harman Kardon TD4800"
805:"Tape Noise Reduction"
695:
658:
567:
559:
543:Rauschminderungssystem
542:
524:
447:
409:
383:
258:
113:Dolby official website
1079:Free, John R. (1974)
774:dbx (noise reduction)
692:
683:Further information:
653:
565:
557:
522:
512:, which was based on
442:
389:
381:
370:for motion pictures.
271:signal-to-noise ratio
255:
132:systems developed by
833:Dolby Laboratories.
782:, a competing system
776:, a competing system
332:multitrack recording
1713:American inventions
1221:Dolby, Ray (1981).
190:: compressing the
23:
1698:Dolby Laboratories
1602:Dolby Surround 7.1
1567:Dolby Digital Plus
1528:Dolby Laboratories
727:Bang & Olufsen
723:Headroom eXtension
696:
659:
629:optical soundtrack
582:high frequencies.
568:
560:
525:
448:
444:Advent Corporation
432:use this variant.
410:
384:
336:cutoff frequencies
259:
134:Dolby Laboratories
51:Dolby Laboratories
1685:
1684:
1061:"Look and Listen"
142:, a professional
118:
117:
1730:
1521:
1514:
1507:
1498:
1462:
1460:
1458:
1457:
1451:
1432:
1424:
1418:
1417:
1415:
1414:
1399:
1393:
1392:
1381:
1375:
1374:
1372:
1366:. Archived from
1365:
1356:
1350:
1349:
1347:
1346:
1336:
1330:
1329:
1327:
1321:. Archived from
1320:
1311:
1305:
1304:
1302:
1301:
1295:
1284:
1275:
1269:
1268:
1266:
1265:
1245:
1239:
1238:
1236:
1235:
1229:
1218:
1212:
1211:
1209:
1208:
1193:
1187:
1186:
1178:
1172:
1171:
1166:. Archived from
1159:
1153:
1152:
1150:
1149:
1143:
1124:
1115:
1109:
1108:
1092:
1086:
1077:
1071:
1070:
1056:
1050:
1049:
1035:
1029:
1028:
1020:
1014:
1013:
1011:
1010:
1004:
993:
984:
978:
977:
975:
974:
968:
957:
948:
942:
941:
939:
938:
932:
921:
915:
914:
912:
911:
891:
885:
884:
878:
870:
868:
867:
855:
849:
848:
846:
840:. Archived from
839:
830:
824:
823:
821:
820:
811:. Archived from
800:
685:Adaptive biasing
664:Compact Cassette
545:
467:
244:
243:
239:
236:
230:
229:
225:
222:
216:
215:
211:
208:
42:Audio technology
31:
24:
1738:
1737:
1733:
1732:
1731:
1729:
1728:
1727:
1723:American brands
1708:Sound recording
1688:
1687:
1686:
1681:
1665:
1649:
1621:
1577:Dolby Headphone
1530:
1525:
1485:Dolby-HX/HX-Pro
1471:
1466:
1465:
1455:
1453:
1449:
1430:
1426:
1425:
1421:
1412:
1410:
1401:
1400:
1396:
1383:
1382:
1378:
1370:
1363:
1358:
1357:
1353:
1344:
1342:
1338:
1337:
1333:
1325:
1318:
1313:
1312:
1308:
1299:
1297:
1293:
1282:
1277:
1276:
1272:
1263:
1261:
1247:
1246:
1242:
1233:
1231:
1227:
1220:
1219:
1215:
1206:
1204:
1195:
1194:
1190:
1180:
1179:
1175:
1161:
1160:
1156:
1147:
1145:
1141:
1122:
1117:
1116:
1112:
1107:(IRT): 222–228.
1094:
1093:
1089:
1081:Look and Listen
1078:
1074:
1066:Popular Science
1058:
1057:
1053:
1037:
1036:
1032:
1022:
1021:
1017:
1008:
1006:
1002:
991:
986:
985:
981:
972:
970:
966:
955:
950:
949:
945:
936:
934:
930:
923:
922:
918:
909:
907:
893:
892:
888:
871:
865:
863:
857:
856:
852:
844:
837:
832:
831:
827:
818:
816:
802:
801:
794:
789:
764:
740:
687:
681:
679:Dolby HX/HX-Pro
648:
617:
611:
552:
530:
475:
461:
376:
342:at 80 Hz;
327:
241:
237:
234:
232:
227:
223:
220:
218:
213:
209:
206:
204:
200:
130:noise reduction
99:Previous owners
82:
61:
34:
17:
12:
11:
5:
1736:
1734:
1726:
1725:
1720:
1715:
1710:
1705:
1700:
1690:
1689:
1683:
1682:
1680:
1679:
1673:
1671:
1667:
1666:
1664:
1663:
1657:
1655:
1651:
1650:
1648:
1647:
1642:
1637:
1631:
1629:
1623:
1622:
1620:
1619:
1614:
1609:
1604:
1599:
1594:
1589:
1584:
1579:
1574:
1569:
1564:
1559:
1554:
1549:
1544:
1538:
1536:
1532:
1531:
1526:
1524:
1523:
1516:
1509:
1501:
1495:
1494:
1489:
1483:-- concerning
1477:
1470:
1469:External links
1467:
1464:
1463:
1419:
1394:
1391:on 2013-09-14.
1376:
1373:on 2012-10-21.
1351:
1331:
1328:on 2012-10-02.
1306:
1270:
1240:
1213:
1188:
1173:
1170:on 2016-04-16.
1154:
1110:
1087:
1072:
1051:
1030:
1015:
979:
943:
916:
886:
850:
847:on 2024-04-23.
825:
809:Sound On Sound
791:
790:
788:
785:
784:
783:
777:
771:
763:
760:
752:music download
739:
736:
712:hi-hat cymbals
680:
677:
647:
644:
625:Dolby Surround
613:Main article:
610:
607:
551:
548:
536:in the former
534:tape recorders
529:
526:
474:
471:
418:cassette tapes
375:
372:
326:
323:
199:
196:
154:cassette tapes
116:
115:
110:
106:
105:
100:
96:
95:
92:
88:
87:
86:(1986-present)
81:(1976-present)
76:
75:Related brands
72:
71:
68:
64:
63:
60:United Kingdom
58:
54:
53:
48:
44:
43:
40:
36:
35:
32:
15:
13:
10:
9:
6:
4:
3:
2:
1735:
1724:
1721:
1719:
1716:
1714:
1711:
1709:
1706:
1704:
1701:
1699:
1696:
1695:
1693:
1678:
1677:Dolby Theatre
1675:
1674:
1672:
1668:
1662:
1659:
1658:
1656:
1652:
1646:
1643:
1641:
1638:
1636:
1633:
1632:
1630:
1628:
1624:
1618:
1615:
1613:
1610:
1608:
1605:
1603:
1600:
1598:
1595:
1593:
1590:
1588:
1585:
1583:
1580:
1578:
1575:
1573:
1570:
1568:
1565:
1563:
1562:Dolby Digital
1560:
1558:
1555:
1553:
1550:
1548:
1545:
1543:
1540:
1539:
1537:
1533:
1529:
1522:
1517:
1515:
1510:
1508:
1503:
1502:
1499:
1493:
1490:
1488:
1486:
1482:
1478:
1476:
1473:
1472:
1468:
1448:
1444:
1440:
1436:
1429:
1423:
1420:
1409:on 2021-08-04
1408:
1404:
1398:
1395:
1390:
1386:
1380:
1377:
1369:
1362:
1355:
1352:
1341:
1335:
1332:
1324:
1317:
1310:
1307:
1292:
1288:
1281:
1274:
1271:
1259:
1255:
1251:
1244:
1241:
1226:
1225:
1217:
1214:
1202:
1199:(in German).
1198:
1192:
1189:
1184:
1177:
1174:
1169:
1165:
1158:
1155:
1140:
1136:
1132:
1128:
1121:
1114:
1111:
1106:
1102:
1099:(in German).
1098:
1091:
1088:
1085:
1082:
1076:
1073:
1068:
1067:
1062:
1055:
1052:
1048:. p. 30.
1047:
1046:
1041:
1034:
1031:
1026:
1019:
1016:
1001:
997:
990:
983:
980:
965:
962:: 19–22, 55.
961:
954:
947:
944:
929:
928:
920:
917:
905:
901:
897:
890:
887:
882:
876:
861:
854:
851:
843:
836:
829:
826:
815:on 2016-06-04
814:
810:
806:
799:
797:
793:
786:
781:
778:
775:
772:
769:
766:
765:
761:
759:
757:
753:
749:
745:
744:digital audio
737:
735:
731:
728:
724:
720:
715:
713:
709:
708:non-linearity
705:
704:analog signal
701:
694:transformers.
691:
686:
678:
676:
672:
669:
665:
656:
655:Harman/Kardon
652:
645:
643:
641:
640:Dolby Digital
637:
636:Dolby SR
632:
630:
626:
621:
616:
608:
606:
604:
600:
596:
592:
587:
583:
579:
577:
573:
564:
556:
549:
547:
544:
539:
535:
527:
521:
517:
515:
511:
507:
504:
500:
496:
491:
489:
484:
480:
472:
470:
465:
460:
456:
452:
445:
441:
437:
435:
431:
425:
421:
419:
415:
407:
406:
405:Tour De Force
401:
400:
395:
394:
388:
380:
373:
371:
369:
368:optical sound
364:
360:
357:
353:
349:
345:
341:
337:
333:
324:
322:
320:
314:
312:
308:
302:
298:
296:
292:
287:
284:
278:
274:
272:
268:
264:
254:
250:
248:
197:
195:
193:
192:dynamic range
189:
185:
184:Dolby HX
181:
180:
175:
174:
169:
165:
164:
163:Dolby SR
159:
155:
151:
150:
145:
141:
140:
135:
131:
127:
126:Dolby NR
123:
114:
111:
107:
104:
101:
97:
93:
89:
85:
84:Dolby Digital
80:
77:
73:
69:
65:
62:United States
59:
55:
52:
49:
45:
41:
37:
30:
25:
19:
1612:Dolby Vision
1607:Dolby TrueHD
1597:Dolby Stereo
1581:
1557:Dolby Cinema
1484:
1480:
1454:. Retrieved
1434:
1422:
1411:. Retrieved
1407:the original
1397:
1389:the original
1379:
1368:the original
1354:
1343:. Retrieved
1334:
1323:the original
1309:
1298:. Retrieved
1286:
1273:
1262:. Retrieved
1257:
1253:
1243:
1232:. Retrieved
1223:
1216:
1205:. Retrieved
1191:
1176:
1168:the original
1157:
1146:. Retrieved
1126:
1113:
1100:
1096:
1090:
1080:
1075:
1064:
1054:
1043:
1033:
1024:
1018:
1007:. Retrieved
995:
982:
971:. Retrieved
959:
946:
935:. Retrieved
926:
919:
908:. Retrieved
906:(4): 383–388
903:
899:
889:
864:. Retrieved
853:
842:the original
828:
817:. Retrieved
813:the original
808:
756:Dolby Vision
748:professional
741:
732:
722:
718:
716:
697:
673:
668:compact disc
660:
638:and digital
633:
622:
618:
588:
584:
580:
575:
569:
531:
492:
476:
453:
449:
426:
422:
411:
403:
397:
391:
365:
361:
328:
315:
303:
299:
288:
279:
275:
263:pre-emphasis
260:
201:
177:
171:
168:Dolby B
167:
161:
158:Dolby A
157:
149:Dolby B
147:
139:Dolby A
137:
125:
121:
119:
79:Dolby Stereo
39:Product type
18:
1627:Doremi Labs
1617:Dolby Voice
1542:Dolby Atmos
1260:(3): 98–113
721:stands for
495:High Com FM
462: [
267:de-emphasis
1692:Categories
1645:CinePlayer
1640:CineExport
1456:2021-07-10
1413:2020-11-09
1345:2023-09-02
1300:2020-11-11
1264:2023-08-27
1234:2023-08-27
1207:2021-05-09
1148:2021-04-25
1009:2020-11-09
973:2020-11-09
937:2020-11-09
910:2023-09-02
866:2024-09-09
819:2023-09-02
787:References
700:hysteresis
572:A-weighted
503:Telefunken
488:companding
414:A-weighted
283:companding
188:companding
67:Introduced
1661:Ray Dolby
1635:CineAsset
1461:(3 pages)
1443:0016-2825
1289:: 20–25.
1135:0016-2825
1045:Billboard
998:: 26–30.
599:Umatic SP
576:breathing
430:cassettes
356:compander
352:high-pass
348:high-pass
344:band-pass
311:breathing
247:tape hiss
144:broadband
103:Ray Dolby
94:Worldwide
1592:Dolby SR
1552:Dolby 3D
1547:Dialnorm
1447:Archived
1291:Archived
1201:Archived
1197:"SK 900"
1139:Archived
1000:Archived
964:Archived
875:cite web
780:High Com
762:See also
615:Dolby SR
609:Dolby SR
506:High Com
479:FM radio
473:Dolby FM
399:Apurimac
340:low-pass
1572:Dolby E
646:Dolby S
595:Betacam
550:Dolby C
374:Dolby B
325:Dolby A
240:⁄
226:⁄
212:⁄
198:Process
109:Website
91:Markets
57:Country
1654:People
1441:
1133:
176:, and
1670:Other
1450:(PDF)
1431:(PDF)
1371:(PDF)
1364:(PDF)
1326:(PDF)
1319:(PDF)
1294:(PDF)
1287:Audio
1283:(PDF)
1228:(PDF)
1142:(PDF)
1123:(PDF)
1069:: 38.
1003:(PDF)
996:Audio
992:(PDF)
967:(PDF)
960:Audio
956:(PDF)
931:(PDF)
862:. IBC
845:(PDF)
838:(PDF)
738:Today
466:]
319:nWb/m
124:, or
47:Owner
1439:ISSN
1131:ISSN
881:link
603:Aiwa
597:and
483:WFMT
459:ANRS
307:bias
257:flat
160:and
70:1965
746:in
591:NAD
528:RMS
510:FMX
499:IRT
457:'s
455:JVC
434:VHS
1694::
1445:.
1285:.
1258:31
1256:.
1252:.
1137:.
1103:.
1101:21
1063:.
1042:.
994:.
958:.
904:15
902:.
898:.
877:}}
873:{{
807:.
795:^
719:HX
516:.
514:CX
464:ja
295:VU
291:dB
170:,
120:A
1520:e
1513:t
1506:v
1459:.
1416:.
1348:.
1303:.
1267:.
1237:.
1210:.
1151:.
1012:.
976:.
940:.
913:.
883:)
869:.
822:.
242:4
238:3
235:+
233:3
228:2
224:1
221:+
219:7
214:8
210:7
207:+
205:1
179:S
173:C
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
