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#41
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FM recording on Audio Cassettes
In , on 01/05/04
at 01:22 PM, "bg" said: Rumor has it that a record amp broke into oscillation thus adding a bias to the audio. I've heard that this "accident" was discovered by B&K. Interesting, that would add another country to the list of possible inventors. It also sounds like a reasonable "accident", given that no one understood the fine points of feedback in the 1920's. ----------------------------------------------------------- spam: wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15 13 (Barry Mann) [sorry about the puzzle, spammers are ruining my mailbox] ----------------------------------------------------------- |
#42
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FM recording on Audio Cassettes
In , on 01/05/04
at 01:22 PM, "bg" said: Rumor has it that a record amp broke into oscillation thus adding a bias to the audio. I've heard that this "accident" was discovered by B&K. Interesting, that would add another country to the list of possible inventors. It also sounds like a reasonable "accident", given that no one understood the fine points of feedback in the 1920's. ----------------------------------------------------------- spam: wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15 13 (Barry Mann) [sorry about the puzzle, spammers are ruining my mailbox] ----------------------------------------------------------- |
#43
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FM recording on Audio Cassettes
In , on 01/05/04
at 01:22 PM, "bg" said: Rumor has it that a record amp broke into oscillation thus adding a bias to the audio. I've heard that this "accident" was discovered by B&K. Interesting, that would add another country to the list of possible inventors. It also sounds like a reasonable "accident", given that no one understood the fine points of feedback in the 1920's. ----------------------------------------------------------- spam: wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15 13 (Barry Mann) [sorry about the puzzle, spammers are ruining my mailbox] ----------------------------------------------------------- |
#44
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FM recording on Audio Cassettes
bg wrote:
Rumor has it that a record amp broke into oscillation thus adding a bias to the audio. That was what happened for the germans, they were initially using Poulsen style DC bias. I've heard that this "accident" was discovered by B&K. Undefined abbreviation .... Valdemar Poulsen did invent the tape recorder in principle, but as a wire recorder. There is only one country of invention. big snip ------------ -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#45
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FM recording on Audio Cassettes
bg wrote:
Rumor has it that a record amp broke into oscillation thus adding a bias to the audio. That was what happened for the germans, they were initially using Poulsen style DC bias. I've heard that this "accident" was discovered by B&K. Undefined abbreviation .... Valdemar Poulsen did invent the tape recorder in principle, but as a wire recorder. There is only one country of invention. big snip ------------ -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#46
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FM recording on Audio Cassettes
bg wrote:
Rumor has it that a record amp broke into oscillation thus adding a bias to the audio. That was what happened for the germans, they were initially using Poulsen style DC bias. I've heard that this "accident" was discovered by B&K. Undefined abbreviation .... Valdemar Poulsen did invent the tape recorder in principle, but as a wire recorder. There is only one country of invention. big snip ------------ -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#47
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FM recording on Audio Cassettes
Barry Mann wrote:
Interesting, that would add another country to the list of possible inventors. It also sounds like a reasonable "accident", given that no one understood the fine points of feedback in the 1920's. Poulsens problem and thus limitation was that amplifiers, feedback or no feedback, weren't invented yet. -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#48
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FM recording on Audio Cassettes
Barry Mann wrote:
Interesting, that would add another country to the list of possible inventors. It also sounds like a reasonable "accident", given that no one understood the fine points of feedback in the 1920's. Poulsens problem and thus limitation was that amplifiers, feedback or no feedback, weren't invented yet. -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#49
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FM recording on Audio Cassettes
Barry Mann wrote:
Interesting, that would add another country to the list of possible inventors. It also sounds like a reasonable "accident", given that no one understood the fine points of feedback in the 1920's. Poulsens problem and thus limitation was that amplifiers, feedback or no feedback, weren't invented yet. -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
#50
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FM recording on Audio Cassettes
"Richard Crowley" wrote in message ...
Some might even say that it is worse because of the nature of FM demodulation when no carrier is present (i.e. "inter-station hiss") Would heterodynes affect the audio in "AM cassettes"? |
#51
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FM recording on Audio Cassettes
"Richard Crowley" wrote in message ...
Some might even say that it is worse because of the nature of FM demodulation when no carrier is present (i.e. "inter-station hiss") Would heterodynes affect the audio in "AM cassettes"? |
#52
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FM recording on Audio Cassettes
"Richard Crowley" wrote in message ...
Some might even say that it is worse because of the nature of FM demodulation when no carrier is present (i.e. "inter-station hiss") Would heterodynes affect the audio in "AM cassettes"? |
#53
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FM recording on Audio Cassettes
"Richard Crowley" wrote in message ...
Some might even say that it is worse because of the nature of FM demodulation when no carrier is present (i.e. "inter-station hiss") Would heterodynes affect the audio in "AM cassettes"? |
#55
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FM recording on Audio Cassettes
In , on 01/06/04
at 06:56 PM, (Curious) said: Would heterodynes affect the audio in "AM cassettes"? "AM" should not be associated with the cassette tape process. Are you thinking that AM implies noise and FM does not; therefore, since cassettes are noisy, they must be AM? This is incorrect thinking. Answering your question: Heterodynes can be an issue with cassette decks. The bias oscillator can mix with the music you are trying to record, leakage from the FM Stereo subcarriers, or leakage from the AM tuner in your receiver. (Some combination radio/cassette units have a switch that will shift the tape bias frequency slightly to avoid heterodynes with the AM radio section) It's not a heterodyne problem, but most cassette decks that include Dolby will include a filter to remove the FM Stereo pilot tone. --- Home cassettes use a direct recording process. Air pressure changes (sound) generate a changing current in the microphone. This current is amplified and passed through the record head (a coil of wire wound on a c-shaped metal core), which impresses a magnetic pattern on the tape that is an analog of the air pressure changes. Records also use a direct process, but the result is a mechanical analog cut into the surface of the master recording. Direct processes are simple and useful, but are not always adequate. For example, if you are running a logging operation, it is usually not practical to launch a tree directly into a remote saw mill, you enlist the aid of a "carrier". This carrier could be a river, team of mules, or possibly a truck. Ultimately you will throw away the carrier and use the log. Sound waves don't travel well in the air over long distances, but radio waves do. If we could somehow attach sound to a radio wave, we could send the sound great distances. This is where "AM" and "FM" enter the picture. They are methods of attaching the sound to the radio frequency carrier. The AM method is similar to throwing our logs into the river. It's straight forward and inexpensive, but the log might pick-up some pollutants along the way. FM is a bit more complicated, but is more robust with respect to noise. (Think of shipping our logs in a boat.) Yes, there are other applications for AM and FM. Yes, there are a relatively few tape recorders that use an FM process in industrial applications, but home audio cassettes are recorded by a direct process. ----------------------------------------------------------- spam: wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15 13 (Barry Mann) [sorry about the puzzle, spammers are ruining my mailbox] ----------------------------------------------------------- |
#56
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FM recording on Audio Cassettes
In , on 01/06/04
at 06:56 PM, (Curious) said: Would heterodynes affect the audio in "AM cassettes"? "AM" should not be associated with the cassette tape process. Are you thinking that AM implies noise and FM does not; therefore, since cassettes are noisy, they must be AM? This is incorrect thinking. Answering your question: Heterodynes can be an issue with cassette decks. The bias oscillator can mix with the music you are trying to record, leakage from the FM Stereo subcarriers, or leakage from the AM tuner in your receiver. (Some combination radio/cassette units have a switch that will shift the tape bias frequency slightly to avoid heterodynes with the AM radio section) It's not a heterodyne problem, but most cassette decks that include Dolby will include a filter to remove the FM Stereo pilot tone. --- Home cassettes use a direct recording process. Air pressure changes (sound) generate a changing current in the microphone. This current is amplified and passed through the record head (a coil of wire wound on a c-shaped metal core), which impresses a magnetic pattern on the tape that is an analog of the air pressure changes. Records also use a direct process, but the result is a mechanical analog cut into the surface of the master recording. Direct processes are simple and useful, but are not always adequate. For example, if you are running a logging operation, it is usually not practical to launch a tree directly into a remote saw mill, you enlist the aid of a "carrier". This carrier could be a river, team of mules, or possibly a truck. Ultimately you will throw away the carrier and use the log. Sound waves don't travel well in the air over long distances, but radio waves do. If we could somehow attach sound to a radio wave, we could send the sound great distances. This is where "AM" and "FM" enter the picture. They are methods of attaching the sound to the radio frequency carrier. The AM method is similar to throwing our logs into the river. It's straight forward and inexpensive, but the log might pick-up some pollutants along the way. FM is a bit more complicated, but is more robust with respect to noise. (Think of shipping our logs in a boat.) Yes, there are other applications for AM and FM. Yes, there are a relatively few tape recorders that use an FM process in industrial applications, but home audio cassettes are recorded by a direct process. ----------------------------------------------------------- spam: wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15 13 (Barry Mann) [sorry about the puzzle, spammers are ruining my mailbox] ----------------------------------------------------------- |
#57
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FM recording on Audio Cassettes
In , on 01/06/04
at 06:56 PM, (Curious) said: Would heterodynes affect the audio in "AM cassettes"? "AM" should not be associated with the cassette tape process. Are you thinking that AM implies noise and FM does not; therefore, since cassettes are noisy, they must be AM? This is incorrect thinking. Answering your question: Heterodynes can be an issue with cassette decks. The bias oscillator can mix with the music you are trying to record, leakage from the FM Stereo subcarriers, or leakage from the AM tuner in your receiver. (Some combination radio/cassette units have a switch that will shift the tape bias frequency slightly to avoid heterodynes with the AM radio section) It's not a heterodyne problem, but most cassette decks that include Dolby will include a filter to remove the FM Stereo pilot tone. --- Home cassettes use a direct recording process. Air pressure changes (sound) generate a changing current in the microphone. This current is amplified and passed through the record head (a coil of wire wound on a c-shaped metal core), which impresses a magnetic pattern on the tape that is an analog of the air pressure changes. Records also use a direct process, but the result is a mechanical analog cut into the surface of the master recording. Direct processes are simple and useful, but are not always adequate. For example, if you are running a logging operation, it is usually not practical to launch a tree directly into a remote saw mill, you enlist the aid of a "carrier". This carrier could be a river, team of mules, or possibly a truck. Ultimately you will throw away the carrier and use the log. Sound waves don't travel well in the air over long distances, but radio waves do. If we could somehow attach sound to a radio wave, we could send the sound great distances. This is where "AM" and "FM" enter the picture. They are methods of attaching the sound to the radio frequency carrier. The AM method is similar to throwing our logs into the river. It's straight forward and inexpensive, but the log might pick-up some pollutants along the way. FM is a bit more complicated, but is more robust with respect to noise. (Think of shipping our logs in a boat.) Yes, there are other applications for AM and FM. Yes, there are a relatively few tape recorders that use an FM process in industrial applications, but home audio cassettes are recorded by a direct process. ----------------------------------------------------------- spam: wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15 13 (Barry Mann) [sorry about the puzzle, spammers are ruining my mailbox] ----------------------------------------------------------- |
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