Sound

Survey of Broadcasting: Assignment 1, Question 1: Describe the five general steps of signal processing–Videos

Posted on June 21, 2011. Filed under: Audio, Broadcasting, Communications, Digital Communication, Radio, Signal Processors, Sound, Television | Tags: , , , , , , |

1. Describe the five general steps of signal processing.

Roger Waters – Radio KAOS – Radio Waves

    The five general steps in signal processing are as follows:

  1. Signal generation
  2. Signal amplification and processing
  3. Signal transmission
  4. Signal reception
  5. Signal storage.

Step 1 Signal Generation: Signal generation is the conversion or transduction of the sound or light waves from the source into electrical energy which corresponds to the frequency of the original source. The audio signal may be generated  mechanically using a microphone or turntable to create an analog of the original sound signal such as a phonograph record or audio cassette.  Microphones are used to transduce the physical energy of music and voice into electrical energy.The audio signal may be generated electromagnetically using tape recorders.The audio signal may also be generated digitally by using laser optics to create a binary or digital equivalent of the original sound.  Television signal generation requires electronic line-by-line scanning of an image using an electron beam to scan each element of the picture. The image is subsequently retraced by the television receiver.

Step 2 Signal Amplification and Processing: Audio and video signals are amplified and mixed using audio consoles and video switchers. After the audio signal has been converted from a physical sound wave into an electrical or digital facsimile, the audio signal must be amplified to boost the signal and processed including the mixing, combining and routing for broadcast transmission and/or recording. Sound sources are combined at the mixing board. The amplified sound may be fine tuned using equalizers and special effects. The switcher is used to mix TV signals and put the desired picture on the air. A special effect generator is used to add transitions, split screen and keying. Digital video editing and effects can also be produced using computer software such as Adobe Premiere Pro and After Effects.

Step 3 Signal Transmission: The electronic signal is superimposed  by a modulation process on a carrier wave  generated or propagated by the radio station on its assigned frequency. The generated sound wave may travel by ground, sky and direct waves. Radio waves occupy a segment of the electromagnetic spectrum. AM radio channel frequencies are divided into three main types: clear channels, regional channels and local channels. FM channel frequencies are classified by antenna height and power. Stereo broadcasting and other nonbroadcast services are accomplished with the wide bandwidth of the FM channel. Digital radio is satellite-based  or in-band on channel. Television signal transmission includes over-the-air broadcasting using the electromagnetic radiation on the VHF and UHF portions of the spectrum or by wire through a cable system using coaxial cable that can carry programming on more than 100 channels.. New transmission technologies used for transmission and distribution include satellite and fiber optics for digital signals.

Step 4 Signal Reception: After the radio signal has been transduced, modulated and transmitted, the radio waves are picked up on a radio receiver where they are transduced or converted by the speaker system back into sound waves. The characteristics of the electromagnetic spectrum and modulation  method used in transmission determine the type of radio receiver needed to convert the signal back into sound waves.There are several types of radio receivers including AM, AM stereo, FM, shortwave, and multiband. These receivers can be equipped with either analog tuners or a digital system. For moving images both large and small-screen TVs are now receiving high-definition television vision signals. 

Step 5 Signal Storage: Both audio and video technology is used in the storage and retrieval of sounds and moving images.  Audio or video signals are transduced or converted for storage and eventual playback or rebroadcast. The storage medium have included glass discs, wire, vinyl, magnetic type, compact disc, video tapes, digital storage media such as digital versatile discs (DVDs) and computer hard drives including high-capacity disc drives.

Roger Waters – Radio KAOS – Tide Is Turning

Background Articles and Videos

 

Amplitude modulation tutorial & AM radio transmitter circuit 

 

The Professor – How does a radio work?

 

AM Modulation and Demodulation Part 1

 

Introduction to Radio Waves Training Course

 

High Definition Television (HDTV) : Difference Between High & Standard

 

Roger Waters – Radio KAOS – Intro

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Producing Dialogue–Videos

Posted on October 15, 2010. Filed under: Audio, Microphones, Radio, Sound, Speech | Tags: , , , , , , |

ADR. What is ADR? Automated Dialogue Replacement

Automated Dialogue Replacement

EXTRAORDINARY Webdoc 10: POSTPRODUCTION – ADR Voice Overs

Post Synchronization

1. Influences of nonverbal speech on meaning include accent, pace, patterns, emphasis, inflection and mood.

2. The principal challenge during production is recording dialogue that is clear, intelligible, and as noise-free as possible.

3. Dramatizations on radio involve creating a “theater of the mind,” using sound to impel the listener to “see” the action.

4. To create perspective using one microphone n radio dramatization, performers are positioned at appropriate distances relative to the mic and to one another, as the dramatic action dictates.

5. Using the multimicrophone technique in radio dramatization, perspective is created in the postproduction mix.

6. For stereo radio dramatizations, coincident or near-coincident microphone arrays are usually employed. Coincident miking positions two microphones, usually directional (or s stereo mic), in virtually the same space, with their diaphragms located vertically on the same axis. Near-coincident miking positions two mics, usually directional, horizontally on the same plane, angled a few inches apart.

7. A main difference and advantages of surround-sound miking radio dramatizations is being able to position performers much as they would be on a stage and recording them from those perspectives or recording them conventionally and creating those perspectives in postproduction.

8. Recording dialogue on the set of a multi- or single-camera production usually means employing a boom, body-mounted wireless, or plant microphone, or a combination of the three. The microphones of choice are usually the mini- and shotgun capacitor mics.

9. The main sonic difference between the boom and body-mounted microphones is perspective. The boom better reproduces the mic-to-source distances that are relative to the shots’ fields of view. This helps maintain acoustic perspective between sound and picture. on the other hand, the body-mounted mic always picks up dialogue that is clear and present with a minimum of background sound, but sonic perspective remains the same regardless of a shot’s focal length.

10. Miking decisions are made in preproduction planning during blocking, when the movements of performers and cameras are worked out.

11. The challenge in operating a boom is to maintain aural perspective while simultaneously keeping the performers in the mic’s pickup pattern and, of course, the mic out of the frame.

12. Care must be taken when using a body mic to ensure that it is inconspicuous and that it does not pick up the sound of clothes rustling. Cotton does not make as much rustling sound as do synthetic fabrics.

13. Plant, or fixed, microphones are positioned around a set to cover action that cannot easily be picked up with a boom or body mic.

14. Preproduction planning is essential in any production, but especially so when working in the field, away from security and resources of the studio. Preproduction planning involves selecting a location; determining how to deal with unwanted sound; preparing, in advance, prerecorded material; and anticipating all the main and backup equipment needs.

15. In production, recording the clearest, most intelligible noise-free dialogue is the primary challenge of the production recordist, regardless of a director’s intention to use it or redo it in postproduction.

16. Dealing with unwanted sound on the set is an ever-present challenge to the audio crew. But being aware of problems is not enough–ou have to know what, if anything, to do about them.

17. Be wary of employing signal processing during production recording. It affects the dialogue audio throughout postproduction.

18. The value of noise reduction throughout the production process cannot be overemphasized, especially in relation to dialogue and field recording.

19. If the director enlightens the entire picture-producing team on how to avoid or minimize audio problems, it goes a long way toward audio efficiency and economy, not only in production but in postproduction as well.

20. Production recordists can be of considerable help in giving sound editors flexibility by how they record dialogue on the set.

21. In automated dialogue replacement, dialogue is recorded or rerecorded in postproduction so there is complete control over the acoustic environment in which the dialogue sits. Any background sound, ambience, or sound effects are added to the dialogue track(s) later.

22. ADR is done in a dialogue recording studio, a relatively dry room with a screen and a microphone.

23. ADR frees picture from sound and gives the director more flexibility and control. On the other hand, it involves re-creating a performance, which is not as natural or as authentic as the real thing.

24. The five elements generally considered to be most important in ADR are pitch, tone, rhythm, emotion, and syn.

25. In scenes calling fo background voices, called walla, loop groups are used.

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Producing Talk And Voice-Overs–Videos

Posted on October 15, 2010. Filed under: Acoustics, Audio, Communications, Digital Communication, Loudspeakers, Radio, Recordings, Sound, Speech, Television | Tags: , , , , , , , , , , |

How to Set Up PA Systems : Basic Microphone Placement for PA System Setup

School radio studio tour

How a Radio Station Works : Radio DJ Microphone Placement

Audio-Technica Studio Recording Microphones w/ AVGIANT at NAMM

1. The production chain (in non-music production) generally begins with the talking performer and therefore involves considerations that relate to producing speech.

2. How speech is produced depends on (1) the type of program or production; (2) the medium–radio, TV, film–and, in TV and film, whether the production technique is single– or multicamera; (3) whether it is done in the studio ori n the field; and (4) whether it is live, live-on-tape, or produced for later release.

3. The frequency range of the human voice is not wide compared with that of other instruments. The adult male’s fundamental voicing frequencies are from roughly 80 to 240 Hz; for the adult female, they are from roughly 140 to 500 Hz. Harmonics and overtones carry theses ranges somewhat higher. (Ranges for the singing voice are significantly wider).

4. Speech intelligibilty is at a maximum when levels are about 70 to 90 dB-SP. Certain frequencies, particularly in the midrange, are also more critical to speech intelligibility than others.

5. Acoustical phase refers to the time relationship between two (or more) sound waves at a given point in their cycles. Electrical phase refers to the relative electrical polarity of two signals n the same circuit. When these waves or polarities are in phase–roughly coincident in time–their amplitudes are additive. When these waves or polarities are out of phase–not coincident in time–their amplitudes are reduced.

6. Evaluation of a microphone for speech includes at least four criteria: clarity, presence, richness, and versatility.

7. The closer a microphone is placed to a sound sources, the closer to the audience the sound source is perceived to be and the warmer, denser, bassier, drier, more intimate, and more detailed is the perceived sound.

8. The farther a microphone is placed from a sound source, the farther from the audience the sound source is perceived to be and the more distant, diffused, open, spacious, reverberant, and detached, and the less detailed is the perceived sound.

9. In selecting and positioning a mic, keep excessive sound that is reflected from room surfaces, furniture, and equipment from reaching the mic, or comb filtering can result. Choose a mic and position it to avoid sibilance, plosives, and breath sounds.

10. In monaural sound aural space is one-dimensional–measured in terms of depth–so perspective is near-to-far.

11. In stereo sound aural space is two-dimensional–measured in terms of depth and breadth–so perspectives are near-to-far and side-t0-side.

12. In stereo miking the angle or distance between the two microphones (or microphone capsules) determines side-to-side perspective. The smaller the angle or distance between the mics, the narrower the left-to-right stereo image; the larger the angle or distance, the wider the left-to-right image.

13. In disc jockey, interview, and panel programs, the participants should sound as though they are coming from the front and center of the aural space. With more than one participant, using individual microphones, the loudness levels for the participants must be similar if the sound is to be perceived as coming from the front and center of the aural space.

14. The overall sound of a radio station involves the particular music or talk format, the announcer’s delivery style, the production style of the spot announcements and jingles, and how tightly presented they all are.

15. The techniques used to mike speech for picture in television and film (and to produce sound, in general) may depend on whether the production is broadcast live, or live-on-tape, or is taped/filmed for showing at a later date.

16. In radio microphones can be placed anywhere without regard for appearance so long as the participants are comfortable and the mics do not get in their way. If the radio program is also televised, some care for appearance should be taken. In television, if a mic is in the picture, it should be good-looking and positioned so that it does not obscure the performer;s face. If it is not in the picture, it must be positioned close enough to the performer so that the sound is on-mic.

17. Generally, for optimal sound pickup the recommended placement for a mini-mic is in the area of the performer’s sternum, about 6 to 8 inches below the chin.

18. Hiding a mini-mic under clothing requires that the mic and mic cable are or can be made insensitive to rustling sounds and that the clothing be made of material that is less likely to make those sounds.

19. In television a desk mic is often used as a prop. If the desk mic is live, make sure it does not block the performer’s face, interfere with the performer’s frontal working space, pr pick up studio noises.

20.The handheld mic allows the host to control audience questioning and mic-to-source distance and, like the desk mic, helps generate a closer psychological rapport with the audience.

21. The boom microphone, like the mini-mic hidden under clothing, is used when mics must be out of the picture. Often one boom mic covers more than one performer. To provide adequate sound pickup, and to move the boom at the right time to the right place, the boom operator must anticipate when one performer is about to stop talking and another is to start.

22. Different techniques are used in controlling levels, leakage, and feedback of mic feeds from multiple sound sources: following the three-t0-one rule, moderate limiting or compression noise gating, or using an automatic microphone mixer.

23. If an audience is present, it must be miked to achieve an overall sound blend and to prevent one voice or group of voices from predominating.

24. Increasing audience laugher or applause, or both, by using recorded laugher or applause tracks adds to a program’s spontaneity and excitement.

25. Recording speech begins with good acoustics. Mediocre acoustics can make speech sound boxy, oppressive, lifeless, ringy, or hollow.

26. Recording speech generally involves either the voiceover–recording copy to which other sonic material is added–or dialogue. Voice-over material includes short-form material, such as spot announcements, and long-form material, such as documentaries and audiobooks.

27. Recording a solo performer and a microphone is a considerable challenge: there is no place to hide.

28. Among the things to avoid in recording speech are plosives, sibilance, breathiness, and tongue and lip smacks.

29. Three types of narration are direct, indirect, and contrapuntal.

30. It is often not so much what is said, but how is said that conveys the overall meaning of a message.

31. Voice acting involves “taking the words off the page” and making them believable and memorable.

32. Among the considerations a voice actor comes to grips with in bringing the appropriate delivery to copy are voice quality, message, audience, word values, and character.

33. Studio intercommunication systems are vital in coordinating the functions of the production team. Three types of studio intercom systems are the private line or phone line–PL; studio address–SA: and interruptible foldback–IFB.

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News Journal: Number 26, October 15, 2010: Printing More Money (Quantitative Easing) and The Coming Currency War and Decline In The Purchasing Power of The U.S. Dollar–Robbing The American People–Videos

Posted on October 15, 2010. Filed under: Audio, Books, Communications, Digital Communication, Issues, Law, Magazines, Mass Media, News, Newspapers, Politics, Print Media, Recordings, Society, Sound, Television | Tags: , , , , , , , , |

“True, governments can reduce the rate of interest in the short run. They can issue additional paper money. They can open the way to credit expansion by the banks. They can thus create an artificial boom and the appearance of prosperity. But such a boom is bound to collapse soon or late and to bring about a depression.”

“The gold standard alone makes the determination of moneys purchasing power independent of the ambitions and machinations of governments, of dictators, of political parties, and of pressure groups.”

~Ludwig von Mises

Jim Rogers Currency Wars

“IMF Meeting Stokes Fear of Currency War”

Grant Says Quantitative Easing Is Just Money Printing: Video

Global Currency War Brewing

Is The World On The Verge Of A Currency War?

Daniel Rosen: Currency War

IMF Meeting Stokes Fear of Currency War

Webster Tarpley: “There’s a currency war!”

Heller Says `Very Difficult’ for Fed to Boost Growth: Video

Feldstein Predicts Dollar to Weaken, Boosting Exports: Video

Japan cooperates with US on international currency issues – NHK 101010

US House committee approves China currency bill – NHK 100925

US criticizes China, Japan over currency interventions – NHK 100917

Clyde Prestowitz discusses valuation of Chinese currency

Mar 24 10 Hearing on China’s Exchange Rate Policy, C. Fred Bergsten Opening Statement

Mar 24 10 Hearing on China’s Exchange Rate Policy, Clyde Prestowitz Opening Statement

The Truth About The Economy: Total Collapse

Ron Paul in September 14, 2007

The Federal Reserve System is a banking cartel that benefits the large banks at the expense of the American people.

Cartel economists and so-called experts cannot replace the market by attempting to fix the price of money or the dollar.

Abolish the Federal Reserve System.

Abolish fiat paper currency.

Establish a new United States currency backed by gold.

Milton Friedman on Monetary Policy – 1/3

Milton Friedman on Monetary Policy – 2/3

Milton Friedman on Monetary Policy – 3/3

This is necessary to stop the financing of massive Federal Government deficits by the Federal Reserve that is purchasing U. S. Treasury bills and notes with Federal Reserve Notes by printing money or the monetarization of government debt.

Money printing or quantitative easing decreases the purchasing power of the money supply–debasing of the currency– robbing the American people.

Will the Federal Reserve System and fiat paper money be abolished?

Not any time soon.

The result will first be a longer and deeper recession lasting well into 2013.

In 2013 the Federal Reserve System will be 100 years old.

The Federal Reserves System will celebrate by achieving by then the devaluation of the dollar by 99%.

In other words one dollar in 1913 will be worth 1 cent in 2013.

If this is monetary stability, one wonders what inflation really is.

Time to do away the Federal Reserve System for incompetence.

I do not expect the unemployment rate to fall below 8% for U-3 until 2013 at the earliest.

As unemployment slowly declines in 2011 and 2012, there will be at first a gradual increase in the general price level that will accelerate in 2013.

This will be due the inability of the Federal Reserve to reverse quickly enough its very aggressive expansive monetary policy.

In 2011 and 2012 import prices will rise as the Federal Reserve attempts to devalue the dollar compared with other national currencies in an attempt to expand exports by making them cheaper.

The price of a gallon gasoline in the United States will first rise above $3 in 2011 and $4 in 2012 mainly due to the devaluation of the U.S. dollar.

As Communist China gradually lets the value of its currency rise in value relative to the U.S. dollar, exports from China will rise in price. This means higher prices for goods imported into the U.S. from China.

The decline in the value or purchasing power of the dollar in 2011 and 2012 combined with unemployment rates exceeding 8% will mean further losses for the Democratic Party in 2012 including the Presidency.

The American people are rightfully mad as hell at the ruling class and political elites in Washington D.C.

Power of the Market – How to Cure Inflation 1

 

 

Power of the Market – How to Cure Inflation 2

 

Power of the Market – How to Cure Inflation 3

 

Ron Paul on the Federal Reserve and Government Deficit Spending

The Gold Standard in Theory and Myth by Joseph Salerno

“The gold standard has one tremendous virtue: the quantity of the money supply, under the gold standard, is independent of the policies of governments and political parties. This is its advantage. It is a form of protection against spendthrift governments.”

“Inflationism, however, is not an isolated phenomenon. It is only one piece in the total framework of politico-economic and socio-philosophical ideas of our time. Just as the sound money policy of gold standard advocates went hand in hand with liberalism, free trade, capitalism and peace, so is inflationism part and parcel of imperialism, militarism, protectionism, statism and socialism.”

~Ludwig von Mises

9. Consolidated Statement of Condition of All Federal Reserve Banks

Millions of dollars
Assets, liabilities, and capital Eliminations from
consolidation
Wednesday
Oct 6, 2010
Change since
Wednesday
Sep 29, 2010
Wednesday
Oct 7, 2009
Assets  
Gold certificate account   11,037 0 0
Special drawing rights certificate account   5,200 0 0
Coin   2,114 + 3 + 124
Securities, repurchase agreements, term auction
credit, and other loans
  2,101,199 + 7,113 + 216,329
Securities held outright 1   2,051,716 + 7,403 + 456,429
U.S. Treasury securities   819,072 + 7,403 + 49,887
Bills 2   18,423 0 0
Notes and bonds, nominal 2   752,832 + 7,390 + 52,364
Notes and bonds, inflation-indexed 2   42,318 0 – 2,270
Inflation compensation 3   5,499 + 13 – 207
Federal agency debt securities 2   154,105 0 + 20,294
Mortgage-backed securities 4   1,078,539 0 + 386,248
Repurchase agreements 5   0 0 0
Term auction credit   0 0 – 178,379
Other loans   49,483 – 290 – 61,721
Net portfolio holdings of Commercial Paper
Funding Facility LLC 6
  0 0 – 41,059
Net portfolio holdings of Maiden Lane LLC 7   28,510 + 40 + 2,206
Net portfolio holdings of Maiden Lane II LLC 8   15,674 – 201 + 1,213
Net portfolio holdings of Maiden Lane III LLC 9   22,782 – 258 + 2,616
Net portfolio holdings of TALF LLC 10   601 0 + 601
Preferred interests in AIA Aurora LLC and ALICO
Holdings LLC 11
  26,057 + 324 + 26,057
Items in process of collection (84) 463 + 98 + 310
Bank premises   2,222 – 7 + 1
Central bank liquidity swaps 12   61 0 – 49,770
Other assets 13   95,313 + 2,248 + 11,389
 
Total assets (84) 2,311,231 + 9,358 + 170,016

Note: Components may not sum to totals because of rounding. Footnotes appear at the end of the table. 9. Consolidated Statement of Condition of All Federal Reserve Banks (continued)

Millions of dollars
Assets, liabilities, and capital Eliminations from
consolidation
Wednesday
Oct 6, 2010
Change since
Wednesday
Sep 29, 2010
Wednesday
Oct 7, 2009
Liabilities
Federal Reserve notes, net of F.R. Bank holdings 918,609 + 4,849 + 42,489
Reverse repurchase agreements 14 64,440 – 2,930 + 1,540
Deposits (0) 1,253,413 + 6,593 + 113,645
Term deposits held by depository institutions 2,119 0 + 2,119
Other deposits held by depository institutions 1,000,014 + 15,875 + 33,477
U.S. Treasury, general account 49,530 – 8,299 + 18,525
U.S. Treasury, supplementary financing account 199,962 + 1 + 70,006
Foreign official 1,345 – 1,066 – 540
Other (0) 444 + 84 – 9,940
Deferred availability cash items (84) 2,598 + 410 – 182
Other liabilities and accrued dividends 15 15,029 + 91 + 6,468
Total liabilities (84) 2,254,089 + 9,014 + 163,961
Capital accounts
Capital paid in 26,687 + 1 + 1,798
Surplus 25,881 + 6 + 4,500
Other capital accounts 4,575 + 338 – 242
Total capital 57,142 + 344 + 6,055

Note: Components may not sum to totals because of rounding.

1. Includes securities lent to dealers under the overnight and term securities lending facilities; refer to table 1A.

2.Face value of the securities.

3. Compensation that adjusts for the effect of inflation on the original face value of inflation-indexed securities.

4. Guaranteed by Fannie Mae, Freddie Mac, and Ginnie Mae. Current face value of the securities, which is the remaining principal balance of the underlying mortgages.

5.Cash value of agreements, which are collateralized by U.S. Treasury and federal agency securities.

6. Includes the book value of the commercial paper, net of amortized costs and related fees, and other investments held by the Commercial Paper Funding Facility LLC.

7. Refer to table 4 and the note on consolidation accompanying table 10.

8. Refer to table 5 and the note on consolidation accompanying table 10.

9. Refer to table 6 and the note on consolidation accompanying table 10.

10. Refer to table 7 and the note on consolidation accompanying table 10.

11. Refer to table 8.

12. Dollar value of foreign currency held under these agreements valued at the exchange rate to be used when the foreign currency is returned to the foreign central bank. This exchange rate equals the market exchange rate used when the foreign currency was acquired from the foreign central bank.

13. Includes other assets denominated in foreign currencies, which are revalued daily at market exchange rates, accrued dividends on the Federal Reserve Bank of New York’s (FRBNY) preferred interests in AIA Aurora LLC and ALICO Holdings LLC, and the fair value adjustment to credit extended by the FRBNY to eligible borrowers through the Term Asset-Backed Securities Loan Facility.

14. Cash value of agreements, which are collateralized by U.S. Treasury securities, federal agency debt securities, and mortgage-backed securities.

15. Includes the liabilities of Maiden Lane LLC, Maiden Lane II LLC, Maiden Lane III LLC, and TALF LLC to entities other than the Federal Reserve Bank of New York, including liabilities that have recourse only to the portfolio holdings of these LLCs. Refer to table 4 through table 7 and the note on consolidation accompanying table 10.

Minutes of the Federal Open Market Committee September 21, 2010″…At the conclusion of the discussion, the Committee voted to authorize and direct the Federal Reserve Bank of New York, until it was instructed otherwise, to execute transactions in the System Account in accordance with the following domestic policy directive:

“The Federal Open Market Committee seeks monetary and financial conditions that will foster price stability and promote sustainable growth in output. To further its long-run objectives, the Committee seeks conditions in reserve markets consistent with federal funds trading in a range from 0 to 1/4 percent. The Committee directs the Desk to maintain the total face value of domestic securities held in the System Open Market Account at approximately $2 trillion by reinvesting principal payments from agency debt and agency mortgage-backed securities in longer-term Treasury securities. The System Open Market Account Manager and the Secretary will keep the Committee informed of ongoing developments regarding the System’s balance sheet that could affect the attainment over time of the Committee’s objectives of maximum employment and price stability.”

The vote encompassed approval of the statement below to be released at 2:15 p.m.:

“Information received since the Federal Open Market Committee met in August indicates that the pace of recovery in output and employment has slowed in recent months. Household spending is increasing gradually, but remains constrained by high unemployment, modest income growth, lower housing wealth, and tight credit. Business spending on equipment and software is rising, though less rapidly than earlier in the year, while investment in nonresidential structures continues to be weak. Employers remain reluctant to add to payrolls. Housing starts are at a depressed level. Bank lending has continued to contract, but at a reduced rate in recent months. The Committee anticipates a gradual return to higher levels of resource utilization in a context of price stability, although the pace of economic recovery is likely to be modest in the near term.Measures of underlying inflation are currently at levels somewhat below those the Committee judges most consistent, over the longer run, with its mandate to promote maximum employment and price stability. With substantial resource slack continuing to restrain cost pressures and longer-term inflation expectations stable, inflation is likely to remain subdued for some time before rising to levels the Committee considers consistent with its mandate.The Committee will maintain the target range for the federal funds rate at 0 to 1/4 percent and continues to anticipate that economic conditions, including low rates of resource utilization, subdued inflation trends, and stable inflation expectations, are likely to warrant exceptionally low levels for the federal funds rate for an extended period. The Committee also will maintain its existing policy of reinvesting principal payments from its securities holdings.The Committee will continue to monitor the economic outlook and financial developments and is prepared to provide additional accommodation if needed to support the economic recovery and to return inflation, over time, to levels consistent with its mandate.”

Voting for this action: Ben Bernanke, William C. Dudley, James Bullard, Elizabeth Duke, Sandra Pianalto, Eric Rosengren, Daniel K. Tarullo, and Kevin Warsh.Voting against this action: Thomas M. Hoenig.Mr. Hoenig dissented, emphasizing that the economy was entering the second year of moderate recovery and that, while the zero interest rate policy and “extended period” language were appropriate during the crisis and its immediate aftermath, they were no longer appropriate with the recovery under way. Mr. Hoenig also emphasized that, in his view, the current high levels of unemployment were not caused by high interest rates but by an extended period of exceptionally low rates earlier in the decade that contributed to the housing bubble and subsequent collapse and recession. He believed that holding rates artificially low would invite the development of new imbalances and undermine long-run growth. He would prefer removing the “extended period” language and thereafter moving the federal funds rate upward, consistent with his views at past meetings that it approach 1 percent, before pausing to determine what further policy actions were needed. Also, given current economic and financial conditions, Mr. Hoenig did not believe that continuing to reinvest principal payments from SOMA securities holdings was required to support the Committee’s policy objectives.It was agreed that the next meeting of the Committee would be held on Tuesday-Wednesday, November 2-3, 2010. The meeting adjourned at 1:10 p.m. on September 21, 2010. …”

http://www.federalreserve.gov/monetarypolicy/fomcminutes20100921.htm

Background Articles and Videos

Marc-Faber– FedsPrinting to Create Final Crisis 8-3-2010

Quantitative easing

Marc Faber Sees Fed Introducing `Massive’ Quantitative Easing

Ron Paul: If You Care About The Poor You Have To Look At Monetary Policy

The Gold Standard Before the Civil War | Murray N. Rothbard

Monetary Policy, Deflation, And Quantitative Easing

“…Aren’t the excess bank reserves inflationary?

Potentially yes, but currently no. Even though banks are earning a meager 25 basis points on their reserves, that is not sufficient incentive to keep large quantities of excess reserves uninvested or unloaned. As they were in the mid-1930s, massive excess reserves are the result of banker fear and uncertainty. The banking system has been saved, but it hasn’t been made whole yet. Bankers continue to worry about reserve levels and liquidity levels and capital levels. They are willing to lend, but only very conservatively to credit-worthy borrowers. Also, much of the slowdown in bank lending comes from low demand for loans by highly qualified borrowers.

The idea that the excess reserves held on banks’ balance sheets should be “mopped up” to prevent them being used in inflationary ways later is a very dangerous idea. They are there voluntarily because bankers feel they are needed. To remove them would cause further bank retrenchment, as it did in the 1930s when the Fed decided to “mop up” the excess reserves of that time.

As the economy and confidence improves, banks will begin using their excess reserves more aggressively. At that point, the Fed will have to be very careful not to stifle that desirable activity on the one hand or let it get out of hand and become inflationary on the other hand. Since they have lots of good, two-handed economists, I think they can pull it off. ..”

http://www.dailymarkets.com/economy/2010/07/30/monetary-policy-deflation-and-quantitative-easing/

The Founding of the Federal Reserve | Murray N. Rothbard

If you work to earn money you need to watch this

Quantitative Easing

“…The term quantitative easing (QE) describes a monetary policy used by central banks to increase the supply of money by increasing the excess reserves of the banking system. This policy is usually invoked when the normal methods to control the money supply have failed, i.e the bank interest rate, discount rate and/or interbank interest rate are either at, or close to, zero.

A central bank implements QE by first crediting its own account with money it creates ex nihilo (“out of nothing”).[1] It then purchases financial assets, including government bonds, agency debt, mortgage-backed securities and corporate bonds, from banks and other financial institutions in a process referred to as open market operations. The purchases, by way of account deposits, give banks the excess reserves required for them to create new money, and thus hopefully induce a stimulation of the economy, by the process of deposit multiplication from increased lending in the fractional reserve banking system.

Risks include the policy being more effective than intended, spurring hyperinflation, or the risk of not being effective enough, if banks opt simply to sit on the additional cash in order to increase their capital reserves in a climate of increasing defaults in their present loan portfolio.[1]

“Quantitative” refers to the fact that a specific quantity of money is being created; “easing” refers to reducing the pressure on banks.[2] However, another explanation is that the name comes from the Japanese-language expression for “stimulatory monetary policy”, which uses the term “easing”.[3] Quantitative easing is sometimes colloquially described as “printing money” although in reality the money is simply created by electronically adding a number to an account. Examples of economies where this policy has been used include Japan during the early 2000s, and the United States, the United Kingdom and the Eurozone during the global financial crisis of 2008–the present, since the programme is suitable for economies where the bank interest rate, discount rate and/or interbank interest rate are either at, or close to, zero.

Concept

Ordinarily, the central bank uses its control of interest rates, or sometimes reserve requirements, to indirectly influence the supply of money.[1] In some situations, such as very low inflation or deflation, setting a low interest rate is not enough to maintain the level of money supply desired by the central bank, and so quantitative easing is employed to further boost the amount of money in the financial system.[1] This is often considered a “last resort” to increase the money supply.[4][5] The first step is for the bank to create more money ex nihilo (“out of nothing”) by crediting its own account. It can then use these funds to buy investments like government bonds from financial firms such as banks, insurance companies and pension funds,[1] in a process known as “monetising the debt“.

For example, in introducing its QE programme, the Bank of England bought gilts from financial institutions, along with a smaller amount of relatively high-quality debt issued by private companies.[6] The banks, insurance companies and pension funds can then use the money they have received for lending or even to buy back more bonds from the bank. The central bank can also lend the new money to private banks or buy assets from banks in exchange for currency.[citation needed] These have the effect of depressing interest yields on government bonds and similar investments, making it cheaper for business to raise capital.[7] Another side effect is that investors will switch to other investments, such as shares, boosting their price and thus creating the illusion of increasing wealth in the economy.[6] QE can reduce interbank overnight interest rates, and thereby encourage banks to loan money to higher interest-paying and financially weaker bodies.

More specifically, the lending undertaken by commercial banks is subject to fractional-reserve banking: they are subject to a regulatory reserve requirement, which requires them to keep a percentage of deposits in “reserve”,[citation needed]: these can only be used to settle transactions between them and the central bank.[7] The remainder, called “excess reserves”, can (but does not have to be) be used as a basis for lending. When, under QE, a central bank buys from an institution, the institution’s bank account is credited directly and their bank gains reserves.[6] The increase in deposits from the quantitative easing process causes an excess in reserves and private banks can then, if they wish, create even more new money out of “thin air” by increasing debt (lending) through a process known as deposit multiplication and thus increase the country’s money supply. The reserve requirement limits the amount of new money. For example a 10% reserve requirement means that for every $10,000 created by quantitative easing the total new money created is potentially $100,000. The US Federal Reserve‘s now out-of-print booklet Modern Money Mechanics explains the process.

A state must be in control of its own currency and monetary policy if it is to unilaterally employ quantitative easing. Countries in the eurozone (for example) cannot unilaterally use this policy tool, but must rely on the European Central Bank to implement it.[citation needed] There may also be other policy considerations. For example, under Article 123 of the Treaty on the Functioning of the European Union[7] and later the Maastricht Treaty, EU member states are not allowed to finance their public deficits (debts) by simply printing the money required to fill the hole, as happened, for example, in Weimar Germany and more recently in Zimbabwe.[1] Banks using QE, such as the Bank of England, have argued that they are increasing the supply of money not to fund government debt but to prevent deflation, and will choose the financial products they buy accordingly, for example, by buying government bonds not straight from the government, but in secondary markets.[1][7]

HistoryQuantitative easing was used unsuccessfully[8] by the Bank of Japan (BOJ) to fight domestic deflation in the early 2000s.[9] During the global financial crisis of 2008–the present, policies announced by the US Federal Reserve under Ben Bernanke to counter the effects of the crisis are a form of quantitative easing. Its balance sheet expanded dramatically by adding new assets and new liabilities without “sterilizing” these by corresponding subtractions. In the same period the United Kingdom used quantitative easing as an additional arm of its monetary policy in order to alleviate its financial crisis.[10][11][12]

The European Central Bank (ECB) has used 12-month long-term refinancing operations (a form of quantitative easing without referring to it as such) through a process of expanding the assets that banks can use as collateral that can be posted to the ECB in return for Euros. This process has led to bonds being “structured for the ECB”[13]. By comparison the other central banks were very restrictive in terms of the collateral they accept: the US Federal Reserve used to accept primarily treasuries (in the first half of 2009 it bought almost any relatively safe dollar-denominated securities); the Bank of England applied a large haircut.

In Japan’s case, the BOJ had been maintaining short-term interest rates at close to their minimum attainable zero values since 1999. With quantitative easing, it flooded commercial banks with excess liquidity to promote private lending, leaving them with large stocks of excess reserves, and therefore little risk of a liquidity shortage.[14] The BOJ accomplished this by buying more government bonds than would be required to set the interest rate to zero. It also bought asset-backed securities and equities, and extended the terms of its commercial paper purchasing operation.[15]

RisksQuantitative easing is seen as a risky strategy that could trigger higher inflation than desired or even hyperinflation if it is improperly used and too much money is created.

Quantitative easing runs the risk of going too far. An increase in money supply to a system has an inflationary effect by diluting the value of a unit of currency. People who have saved money will find it is devalued by inflation; this combined with the associated low interest rates will put people who rely on their savings in difficulty. If devaluation of a currency is seen externally to the country it can affect the international credit rating of the country which in turn can lower the likelihood of foreign investment. Like old-fashioned money printing, Zimbabwe suffered an extreme case of a process that has the same risks as quantitative easing, printing money, making its currency virtually worthless.[1]

…”

http://en.wikipedia.org/wiki/Quantitative_easing

Federal Open Market Committee

“…About the FOMCThe term “monetary policy” refers to the actions undertaken by a central bank, such as the Federal Reserve, to influence the availability and cost of money and credit to help promote national economic goals. The Federal Reserve Act of 1913 gave the Federal Reserve responsibility for setting monetary policy.The Federal Reserve controls the three tools of monetary policy–open market operations, the discount rate, and reserve requirements. The Board of Governors of the Federal Reserve System is responsible for the discount rate and reserve requirements, and the Federal Open Market Committee is responsible for open market operations. Using the three tools, the Federal Reserve influences the demand for, and supply of, balances that depository institutions hold at Federal Reserve Banks and in this way alters the federal funds rate. The federal funds rate is the interest rate at which depository institutions lend balances at the Federal Reserve to other depository institutions overnight.Changes in the federal funds rate trigger a chain of events that affect other short-term interest rates, foreign exchange rates, long-term interest rates, the amount of money and credit, and, ultimately, a range of economic variables, including employment, output, and prices of goods and services.

Structure of the FOMC

The Federal Open Market Committee (FOMC) consists of twelve members–the seven members of the Board of Governors of the Federal Reserve System; the president of the Federal Reserve Bank of New York; and four of the remaining eleven Reserve Bank presidents, who serve one-year terms on a rotating basis. The rotating seats are filled from the following four groups of Banks, one Bank president from each group: Boston, Philadelphia, and Richmond; Cleveland and Chicago; Atlanta, St. Louis, and Dallas; and Minneapolis, Kansas City, and San Francisco. Nonvoting Reserve Bank presidents attend the meetings of the Committee, participate in the discussions, and contribute to the Committee’s assessment of the economy and policy options.The FOMC holds eight regularly scheduled meetings per year. At these meetings, the Committee reviews economic and financial conditions, determines the appropriate stance of monetary policy, and assesses the risks to its long-run goals of price stability and sustainable economic growth.For more detail on the FOMC and monetary policy, see section 2 of the brochure on the structure of the Federal Reserve System and chapter 2 of Purposes & Functions of the Federal Reserve System.

2010 Members of the FOMC

  • Members
    • Ben S. Bernanke, Board of Governors, Chairman
    • William C. Dudley, New York, Vice Chairman
    • James Bullard, St. Louis
    • Elizabeth A. Duke, Board of Governors
    • Thomas M. Hoenig, Kansas City
    • Sandra Pianalto, Cleveland
    • Sarah Bloom Raskin, Board of Governors
    • Eric S. Rosengren, Boston
    • Daniel K. Tarullo, Board of Governors
    • Kevin M. Warsh, Board of Governors
    • Janet L. Yellen, Board of Governors …”

http://www.federalreserve.gov/monetarypolicy/fomc.htm

FEDERAL RESERVE statistical release
H.4.1
Factors Affecting Reserve Balances of Depository Institutions and
Condition Statement of Federal Reserve Banks

Why Chinese Currency Manipulation Is America’s Fault by: Ian Fletcher April 15, 2010

“…Unfortunately, the token appreciation that is probably now in store won’t help very much. For one thing, Beijing has played this game before. China first started diversifying its currency reserves away from the dollar (which weakens currency manipulation) in July 2005, and from then until July 2008 allowed the yuan to rise from 8.28 to the dollar to 6.83, where it has since been held nearly steady. But this appreciation, while showcased by China, was purely nominal; after adjusting for inflation, the change was far smaller: about two percent.

How does China manipulate its currency? Mainly by preventing its exporters from using the dollars they earn as they wish. Instead, they are required to swap them for domestic currency at China’s central bank, which then “sterilizes” them by spending them on U.S. Treasury securities (and increasingly other, higher-yielding, investments) rather than U.S. goods. As a result, the price of dollars is propped up — which means the price of yuan is pushed down — by a demand for dollars which doesn’t involve buying American exports.

The amounts involved are astronomical: as of 2008, China’s accumulated dollar-denominated holdings amounted to $1.7 trillion, an astonishing 40 percent of China’s GDP. The China Currency Coalition estimated in 2005 that the yuan was undervalued by 40 percent; past scholarly estimates have ranged from 10 to 75 percent.

Why is this America’s fault? Because China’s currency is manipulated relative to our own only because we permit it, as there is no law requiring us to sell China our bonds and other assets. We could, in fact, end this manipulation at will. All we would need to do is bar China’s purchases, or just tax them to death.

This would be neither an extreme nor an unprecedented move. It is roughly what the Swiss did in 1972, when economic troubles elsewhere in the world generated an excessive flow of money seeking refuge in Swiss franc-denominated assets. This drove up the value of the franc and threatened to make Swiss manufacturing internationally uncompetitive. To prevent this, the Swiss government imposed a number of measures to dampen foreign investment demand for francs, including a ban on the sale of franc-denominated bonds, securities, and real estate to foreigners. Problem solved. (It did not even damage Switzerland’s standing as an international financial center, a key worry at the time.) …”

“…So the real underlying problem is that America doesn’t generate enough savings on its own to meet its voracious appetite for borrowing. China’s savings rate, thanks to deliberate suppression by the Chinese government of its people’s opportunities to spend what they earn, is an astonishing 50 percent. Ours was negative four percent in the last Federal Reserve report on the subject. We are—Oh, how Mao would have loved this!—decadent. …”

http://seekingalpha.com/article/198825-why-chinese-currency-manipulation-is-americas-fault


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Signal Processors–Videos

Posted on October 8, 2010. Filed under: Audio, Communications, Digital Communication, Signal Processors, Sound, Synchronization | Tags: , , , , , , , , , |

Sound Made Simple – Equalization – Definition

 

Adobe Audition 3.0 Introduction and New Features

Adobe Audition 3.0 Tutorial—-In English

Adobe Audition Editing and Effects

Main Points To Remember

1. Signal processors are used to alter some characteristics of a sound. They can be grouped into four categories; (1) spectrum, (2) time, (3) amplitude, or dynamics, and (4) noise.

2. The equalizer and filter are examples of spectrum processors because they alter the spectral balance of a signal. The equalizer increases or decreases level of a signal at a selected frequency by boost or cut (also known as peak and dip), or by shelving. The filter attenuates certain frequencies above, below, between, or at a preset point(s).

3. Two types of equalizers in common use are the fixed-frequency and the parametric.

4. The most common filters are high-pass (low-cut), low-pass (high-cut), band-pass, and notch.

5. Psychoacoustic processors add clarity, definition, and overall presence to sound.

6. Time signal processors affect the time relationships of signals. reverberation and delay ae two such effects.

7. The three  most common types of reverberation systems used today are digital, plate, and acoustic chamber.

8. Digital  reproduces electronically the sound of different acoustic environments.

9. An important feature of most digital reverb units is predelay–the amount of time between the onset of the direct sound and the appearance of the first reflections.

10. Delay is the time interval between a sound or signal and its repetition.

11. Delay effects, such as doubling, chorus, slap back echo, and prereverb delay, are usually produced electronically with a digital delay device.

12. Flanging and phasing split a signal and slightly delay one part to create controlled phase cancellations that generate a pulsating sound. Flanging uses a time delay; phasing uses a phase shifter.

13. Amplitude (dynamic) signal processors affect a sound’s dynamic range. These effects include compressing, limiting, de-essing, expanding, noise gating, and pitch shifting.

14. With compression, as the input level increases, the output level also increases but at a slower rate, reducing dynamic range. With limiting, the output level stays at or below a preset point regardless of its input level. With expansion, as the input level increases, th e output level also increases but at a greater rate, increasing dynamic range.

15. A de-esser is basically a fast-acting compressor that acts on high frequency sibilance by attenuating it.

16. A noise gate is used primarily to reduce or eliminate unwanted low-level noise, such as ambience and leakage. It is also used  creatively to produce dynamic special effects.

17. A pitch shifter uses both compression and expansion to change the pitch of a signal or the running time of a program.

18. Noise processors are designed to reduce or eliminate noise from an audio signal. Most are double-ended; they prevent noise from entering a signal. Single-ended noise processors reduce existing noise in the signal.

19. Noise reduction is also possible using the digital signal processing (DSP) in a hard-disk recording/editing system. Virtually any unwanted sound can be eliminated.

20. Multieffects signal processors combine several of the functions of individual signal processors in a single unit.

21. A voice, or vocal, processor can enhance, modify, pitch-correct, harmonize, and change completely the sound of a voice, even to the extent of gender.

22. Plug-ins incorporated in hard-disk recording/editing systems add to digital signal processing not only the familiar process tools,–EQ, compression and expansion, reverb, delaypitch shifting, and so on–but also an array of capabilities that place at the recordist’s fingertips a virtually limitless potential for creating entirely new effects and at comparatively little cost.

23. Plug-ins’ programs are available separately or in bundles. bundles include a number of different plug-in programs.

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Synchronization And Transfers–Videos

Posted on October 8, 2010. Filed under: Audio, Law, Radio, Recordings, Sound, Sound Effects, Speech, Synchronization, Web | Tags: , , , , , , |

 

Midi Time Code & SMPTE Synchronization for Midi Composers

How to Synchronize Audio and Video

How to Make a Good Basic YouTube Video

Cheap Wireless Radio Mics From eBay – any good?

Radio Mics & Alternatives for Low Budget Filmmaking?

Main Points To Remember

1. Synchronization allows the locking of two or more devices that have microprocessor intelligence so that they operate at precisely the same rate.

2. Accurate synchronization requires a system to code the recording media as well as a synchronizer to read the codes, compare them, and adjust the positions and speeds of machine transports so that they run at exactly the same rate.

3. There are three basic time codes: longitudinal time code and vertical interval time code, both of which are forms of  SMPTE time code; MIDI time codes; and the IEC standard.

4. SMPTE time code is a high-frequency electronic digital signal consisting of a stream of pulses produced by a time code generator. Its identifying code numbers are broken down into hours, minutes, seconds, and frames.

5. SMPTE longitudinal time code (LTC) is a digital signal converted to audio frequencies so it can be recorded on an audio track.

6. Vertical interval time code (VITC) carries the same information as SMPTE code, but it is used with video-tape and encodes the information vertically within the video signal, outside the visible picture area.

7. MIDI time code (MTC) translates SMPTE time code into MIDI messages.

8. The IEC (International Electrotechnical Commission) standard is the time code system used in digital audio-cassette recorders to ensure compatibility among all R-DAT equipment.

9. Because all time code readouts are in the same form, it is easy to confuse them if any numbers are duplicated on the same tape or on multiple tapes in a production. Two ways to avoid this confusion are to use the zero-start or the time-of-day logging method.

10. In recording SMPTE time code, be careful to record it at the recommended level. It the signal is recorded at too low a level, synchronization is adversely affected. If it is recorded  at too high a level, the time code signal will distort.

11. Every digital audio system has a signal, known as a word clock, generated inside the device that controls sampling frequency, or sampling rate. With digital audio, sampling rate is the determining syn factor.

12. A degradation in word-clock signals among the digital devices being interfaced can create jitter–a variation in time from sample to sample that causes changes in the shape of the audio waveform.

13. Five frame rate standards are used within SMPTE time code: 23.976, 24, 25, 29.97, and 30 frames per second (fps).

14. Frame rates for television are in either drop frame or non-drop frame format. Drop frame time code is time-accurate because it makes up for the error that results from the difference between the 29.97-fps and the 30-fps rate of video. Non-drop frame is the original video time code calculated at 30 fps. The two modes are not interchangeable.

15. In double-system recording, sound and picture are recorded separately and in syn; the camera records the picture, and an audio recorder handles the sound.

16. In single-system recording, both sound and picture are recorded on the same medium.

17. Two methods used to synchronize the film camera and the audio recorder in double-system recording are crystal synchronization and time code synchronization.

18. In double-system recording, a clapslate is used to make a visible and an audible syn mark on the film and audio recording, respectively. This helps identify and synchronize scenes during their transfer from the audio recoding to magnetic film, or more common, hard disk, and in editing.

19. Time code permits the accurate interlocking of two or more recorders, but a synchronizer is necessary to ensure that their transports run together simultaneously.

20. Copying sound (or picture) from one audio film or video device to another is usually called a transfer. Dub is another often-used term to describe this process.

21. Common audio transfers are analog to analog, analog to digital, and digital to digital.

22. In transferring audio, the sound can be altered for special effects.

23. The process of transferring a double-system film recording for postproduction to align the audio and the film is called resolving.

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Physics and Psychophysics of Sound–Videos

Posted on October 7, 2010. Filed under: Audio, Radio, Sound, Web | Tags: , , , , , , , , , , , |

 

Sound Waves and their Sources (1933)

Episode 1 – Sound behaviour part 1

Episode 2 – Sound behaviour part 2

Episode 3 – Microphone types and characteristics

Hertz and frequency response

Phase

Capturing audio

Sample rate

Bit depth

Audio file formats

The waveform

Mastering – Decibels Explained – Warbeats Tutorial

 

Main Points To Remember

1. A sound wave is a vibrational disturbance the involves mechanical motion of molecules transmitting energy from one place to another.

2. A sound wave is caused when a body vibrates and sets into motion the molecules nearest to it; the initial motion the molecules nearest to it; the initial motion starts a chain reaction. This chain reaction creates pressure waves through the air, which are perceived as sound when they reach the ear and brain.

3. The pressure wave compresses molecules as it moves outward, increasing pressure, and pulls the molecules farther apart as it moves inward, creating a rarefaction by decreasing pressure.

4. The components that make up a sound wave are frequency, amplitude, velocity, wavelength, and phase.

5. Sound acts according to physical principles, but it also has a psychological effect on humans.

6. The number of times a sound wave vibrates determines its frequency, or pitch. Humans can hear frequencies between roughly 20 and 20,000 HZ–A RANGE OF 10 octaves. Each octave has a unique sound in the frequency spectrum.

7. The size of a sound wave determines its amplitude, or loudness. Loudness is measured in decibels.

8. The decibel (db) is a dimensionless unit used to compare the ratio of two quantities usually in relation to acoustic energy, such as sound-pressure level (SPL), and electric energy, such as power–dBm–and voltage, such as dBv) and dBV.

9. Impedance is that property of a circuit, or an element, that restricts the flow of alternating current (AC). Impedance is measured in ohms, a unit of resistance of current flow.

10. Humans can hear from 0 dB-SPL, the threshold of hearing to 120 dB-SPL, the threshold of feeling; to 140 dB-SPL, the threshold of pain, and beyond. The scale is logarithmic, which means that adding two sounds each with a loudness of 100 dB-SPL, would bring it to 103 dB-SPL. The range of difference in decibels between the loudest and quietest sound a vibrating object makes is called dynamic range.

11. The ear does not perceive all frequencies at the same time loudness even if their amplitudes are the same. This is the equal loudness principle. Humans do not hear lower-and higher-pitched sounds as well as they hear midrange sounds.

12. Masking–covering a weaker sound with a stronger sound when each is a different frequency and both vibrate simultaneously–is another perceptual response dependent on the relationship between frequency and loudness.

13. Velocity, the speed of a sound wave, is 1,130 feet per second at sea level and 70 degrees F. Sound increases or decreases in velocity by 1.1 feet per second for each change of 1 degree F.

14.  Each frequency has a wavelength, determined by the distance a sound wave travels to complete one cycle of compression and rarefaction. The length of one cycle is equal to the velocity of sound divided by the frequency of sound. The lower a sound’s frequency, the longer its wavelength; the higher a sound’s frequency, the shorter its wavelength.

15. Acoustical phase refers to the time relationship between two or more sound waves at a given point in their cycles. If two waves begin their excursions ate the same time, their degree intervals will coincide and the waves will be in phase. If two waves begin their excursions at different times, their degree intervals will not coincide and their waves will be out of phase, weakening each other and decreasing amplitude.

16. Timbre is the tone quality, or tone color, of a sound.

17. A sounds envelope refers to its changes in loudness over time. It has four stages: attack, initial decay, sustain, and release (ADSR).

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Ears–Videos

Posted on October 7, 2010. Filed under: Audio, Communications, Ear, Radio, Sound, Television, Web | Tags: , , , |

Ear

 

Colour of Sound

Science of Sound

How Ear Works

Sound Waves and their Sources (1933)

Hertz and frequency response

Phase

Capturing audio

Audio file formats

The waveform

 

Key Main Points To Remember

1. Sound is elemental. It is integral to much of what we know and feel. It provides all sorts of cognitive and affective information.

2. Sound is a force: emotional, perceptual, and physical.

3. Sound is omnidirectional; it is everywhere. The human eye can focus on only one view at a time.

4. Sound, paradoxically, has a visual component; it can create pictures in the “theater of the mind.”

5. In the parlance of audio, having “ears” means having healthy hearing and the ability to listen perceptively.

6. The human ear is divided into three parts: the outer ear, the middle ear, and the inner ear.

7. In the basilar membrane of the inner ear are bundles of microscopic hairlike projections called cilia attached to each sensory hair cell. They quiver at the approach of sound and begin the process of transforming mechanical vibrations into electrical and chemical signals, which are then sent to the brain.

8. Temporary threshold shift (TTS), or auditory fatigue, is a reversible desensitization in hearing caused by exposure to loud sound over a few hours.

9. Prolonged exposure to loud sounds can bring on tinnitus, a ringing, whistling, or buzzing in the ears.

10. Exposure to loud sound for extended periods of time can cause permanent threshold shift–a deterioration of the auditory nerve endings in the inner ear. In the presence of loud sound, use an ear filter (hearing-protection device)designed to reduce loudness.

11. Humans have the potential to hear an extremely wide range of loudness between the threshold of hearing and the threshold of pain.

12. Having educated ears means the ability to listen with careful discrimination to style, interpretation, nuance, and technical quality in evaluating the content, function, characteristics, and fidelity of sound.

13. Learning how to listen begins with paying attention to sound wherever and whenever it occurs.

14. Analytical listening is the evaluation of the content and function of sound.

15. Critical listening is the evaluation of the characteristics of the sound itself.

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