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The following two applications show the BCL20 inserted into an
individual channel. After processing, the signal is mixed with the
other channels. This is done because the BCL20 is used to
modify a sound, not to control its amplitude.

Bass Drum

Bass Drum

Vocal

Vocal

The next two applications show the BCL20 connected at the
output of the mixer. This is because if the BCL20 was inserted in
the Mix inserts the level would vary with the setting  Of the
Master fader.

Cassette Mastering

Cassette Mastering

FM Transmission

FM Transmission

Содержание BCL20

Страница 1: ...Dual Stereo Broadcast Compressor Limiter Operation Manual August 2004 ...

Страница 2: ... 2 2 2 Installation Installation Page 3 3 3 Warranty Warranty Page 5 4 4 Description of controls Description of controls Page 6 5 5 Applications Applications Page 8 6 6 Specifications Specifications Page 14 7 7 Front panel blanks Front panel blanks Page 16 ...

Страница 3: ...ristics A potentiometer allows mixing of RMS and Peak detectors to tailor the timing parameters to the program being processed The BCL20 takes advantage of a unique transformer distortion cancelling circuit reducing it an order of magnitude compared to conventional designs 2 bargraphs display the amount of compression and the input output level The de essing functions involves a slew rate sensitiv...

Страница 4: ...ld the unit be installed in an equipment rack ensure that the ambient temperature conforms to these levels 2 3 CE STANDARDS AND THE LOW VOLTAGE DIRECTIVE LVD 2 3 CE STANDARDS AND THE LOW VOLTAGE DIRECTIVE LVD The BCL20 has been designed to meet the latest Electromagnetic Compatibility EMC regulations However we recommend you do not operate the unit close to strong emitters of electromagnetic radia...

Страница 5: ...nging at any time please ensure the correct fuse is fitted An incorrect fuse could cause damage to the unit and may constitute a fire hazard If you carry your BCL20 from one country to another it is very important to ensure the voltage is compatible For your information the unit can be internally rewired for use in 230V or 110 125V countries contact your dealer for information A special 100V versi...

Страница 6: ...ng failure of the unit within one year of the date of original purchase we will agree to repair or at our discretion replace any defective item without charge for labour or parts To receive service under this warranty it is necessary to return the unit to an LA Audio authorised service centre or to the factory with a dated receipt as proof of purchase After repair the unit will be returned to you ...

Страница 7: ...utton instantly adds de essing capability to the BCL20 by adding a filter into the side chain This makes the compressor frequency conscious which means that it compresses more on the frequency chosen in this case the frequency where sibilance occurs RATIO RATIO This determines the ratio of compression applied This may be varied from 1 1 to LIMIT 20 1 The ratio of compression may be defined as the ...

Страница 8: ...low frequency signal being longer than the release time The low frequency waveform will be distorted by the initial release of gain reduction because the action is almost certain to occur mid waveform RECTIFIER RECTIFIER This controls the respective percentage of RMS detection and Peak detection that will be processed by the side chain In the extreme positions it uses only one of the rectifiers In...

Страница 9: ...lied as the signal rises or starts to be removed as the signal falls The Gain Reduction display will indicate when compression commences and then the threshold can be varied to obtain the desired effect Reducing the threshold point will give more compression effect than leaving it just below the input level Peak detection Peak detection It is closely related to the maximum electric amplitude of th...

Страница 10: ...nge of a recording or transmission system Compression Compression Compression describes conditions of gain reduction that are more or less continuous so that the original dynamics are compressed A low compression ratio is used when it is desirable to preserve a relationship with the original dynamics but higher ratios provide useful effects particularly in pop recording and the transmission of spe...

Страница 11: ...sion will increase the overall compression effect THE BCL20 AS A LOUDNESS LIMITER THE BCL20 AS A LOUDNESS LIMITER The perceived loudness SPL is not linear as a function of frequency The human ear is more sensitive to the mid frequencies than to very low or very high frequencies This phenomenon must be taken into account when using a limiter to control the maximum loudness in certain areas such as ...

Страница 12: ... the sound is produced Very often only certain low frequencies are transmitted in particular those which excite resonant modes of cavities walls or structures To achieve efficient limiting of those frequencies it is necessary to measure the noise transmission using a real time spectrum analyser preferrably 1 3ÿoctave When this is done one has to copy the frequency response to a graphic equalizer w...

Страница 13: ...ucing the background music accordingly To do this the music channels must be routed to separate groups which will be processed through the BCL20 and then reinjected to the Mix busses sub group The voice channels must be routed directly to Mix and to an auxiliary output whichs feeds the Side Chain insert Return The BCL20 must be in the Stereo mode The active front panel controls are those of the ch...

Страница 14: ...se the BCL20 is used to modify a sound not to control its amplitude Bass Drum Bass Drum Vocal Vocal The next two applications show the BCL20 connected at the output of the mixer This is because if the BCL20 was inserted in the Mix inserts the level would vary with the setting Of the Master fader Cassette Mastering Cassette Mastering FM Transmission FM Transmission ...

Страница 15: ...utput 1 kHz 10 dB compression 0 07 1 kHz by pass 0 01 Intermodulation Distortion Intermodulation Distortion 0 01 Compression Ratio Compression Ratio Continously variable from 2 1 to 20 1 Attack Time Peak Attack Time Peak Continously variable from 0 1 to 70 millisec Release Time Peak Release Time Peak Continously variable from 100 millisec to 3 sec Attack Time RMS Attack Time RMS Program dependant ...

Страница 16: ... W x 190mm D x 44 5mm H 19 W x 7 5 D x 1 75 H Weight Weight 3 9kg 8 6lbs Shipping Weight Shipping Weight 4 8kg 10 6lbs Temperature Range Temperature Range Operating Operating 0C to 50C Storage Storage 30C to 75198 C Note In these specifications 0 dBu is referenced to 0 775 V RMS LA Audio reserves the right to alter any feature or specification without prior notice E OE ...

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