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| == DI (box) == | | == DI (box) == |
| [[Image:DIbox.gif|right]]
| | {{:DI}} |
| Use a DI when you want to connect two devices and you have any of these issues:
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| * impedance mismatch
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| * line level mismatch
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| * differences in wiring or connectors (e.g. Balanced XLR to Unbalanced 1/4" Tip-Sleeve)
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| * noise - especially "hum" (ground loop)
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| ''A DI unit or DI box is an electronic device designed for connecting a piece of equipment with an electronic audio output to a standard microphone or line level input. It performs both level and impedance matching to minimise both noise and distortion. DI is variously claimed to stand for direct input, direct injection or direct interface. DI units are extensively used with professional and semi-professional PA systems and in sound recording studios.'' -- [http://en.wikipedia.org/wiki/DI_box Wikipedia]
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| You will also see the term DI used to refer to devices used to modify the tone as well as other properties of a signal. This is often in the context of Acoustic Guitar and Electric Bass. In the picture above the first two are passive DIs used for solving problems. The others are all sold as DIs that also shape the sound.
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| == Dual Mono == | | == Dual Mono == |
| This is amplifying the same sound source through two separate loudspeakers.
| | {{:Dual Mono}} |
| * [http://bose.infopop.cc/eve/forums/a/tpc/f/8766055944/m/217104153/r/656105263 Stereo vs. Mono in a Live Setting]]
| | <!-- do not edit this section directly - please edit the page call Dual Mono --> |
| * [http://bose.infopop.cc/eve/forums/a/tpc/f/3976055944/m/6461092581/r/8621086581#8621086581 Dual mono is usually not a good idea]
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| * [http://bose.infopop.cc/eve/ubb.x/a/tpc/f/301107819/m/7891072511 Can I use it as a PA?] (Cliff-at-Bose talks about Dual Mono)
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| == Equal Loudness Curves == | | == Equal Loudness Curves == |
| | | {{:Equal Loudness}} |
| (also known as Fletcher Munson curves)
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| [[Image:EqualLoudness.gif|Equal Loudness Curves|right]]
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| "You will see lots of references to equal loudness curves or equal loudness contours- these are based on the work of Fletcher and Munson at Bell labs in the 30s, or perhaps refinements made more recently by Robinson and Dadson. These were made by asking people to judge when pure tones of two different frequencies were the same loudness. This is a very difficult judgment to make, and the curves are the average results from many subjects, so they should be considered general indicators rather than a prescription as to what a single individual might hear"
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| - [http://arts.ucsc.edu/EMS/Music/tech_background/TE-02/AcNumbers/AcNumbers.html Numbers and Initials of Acoustics]
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| See also:
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| http://www.sfu.ca/sonic-studio/handbook/Equal_Loudness_Contours.html
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| http://hyperphysics.phy-astr.gsu.edu/hbase/sound/eqloud.html
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| == Fletcher Munson Curves == | | == Fletcher Munson Curves == |
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| == Gain Before Feedback == | | == Gain Before Feedback == |
| | | {{:Gain Before Feedback}} |
| Gain before feedback refers to the maximum sound pressure level that can be attained before the sound from a speaker enters the microphone and is amplified a second time, creating a loop that only builds on itself: feedback. | |
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| ''An often not very scientific measure of how loud a sound reinforcement system can be turned up before any open microphone(s) will feed back. The point at which feedback occurs is effected by numerous variables, including atmospheric conditions (temperature, humidity, etc.) so it's not something that anyone considers an objective measure of performance. Instead the phrase is used to state relative differences: "By adjusting the EQ I was able to get 'more' gain before feedback." '' -- [http://www.sweetwater.com/expert-center/glossary/t--GainBeforeFeedback Sweetwater]
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| == Inverse Square Law == | | == Inverse Square Law == |
| | {{:Inverse Square Law}} |
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| == Localization, Spaciousness and Reverberation == | | == Localization, Spaciousness and Reverberation == |
| | {{:Localization Spaciousness Reverberation}} |
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| == Nulls == | | == Nulls == |
| | {{:Nulls}} |
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| == Out of Phase (for Drum mics) == | | == Out of Phase (for Drum mics) == |
| See [[Instruments/Drums|Drums]]
| | {{:Instruments/Drums|Drums}} |
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| == Phase (cancellation, interference) == | | == Phase (cancellation, interference) == |