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Summary of Contents for 2BX

Page 1: ...db X Model 2BX two band dynamic range enhancer INSTRUCTION MANUAL...

Page 2: ...WARNING TO PREVENT FIRE OR SHOCK S A A D vPi N0T OSE THIS APPLIANCE TO RAIN OR MOISTURE dbx is a Registered Trademark of dbx Inc...

Page 3: ...OPERATING INSTRUCTIONS INTRODUCTION CONNECTIONS OPERATION EXPANSION SIMPLE PRECAUTIONS WHEN USING ANY PROGRAM EXPANDER HOWdbx EXPANDERS WORK SPECIFICATIONS dbx PRODUCT WARRANTY FACTORY SERVICE SCHEMAT...

Page 4: ...r tape recorder POWER Push this switch once IN to turn the 2BX ON push again OUT for OFF EXPANSION Adjust this slide control for the desired amount of expansion A 1 4 setting means that an input signa...

Page 5: ...e Outputs of your receiver preamplifier or integrated amplifier to these inputs OUTPUTS Connect the cables from these outputs to the Tape Inputs or Monitor Inputs of your receiver pre amplifier or int...

Page 6: ...pe noise reduction system such as our 120 or 150 series lets you make tape copies of records FM broadcasts or other tapes that actually sound better than the original With these capabilities the 2BX w...

Page 7: ...is is the preferred hookup assuming a tape monitor loop is available LEFT x D LT 0 RT O f o 2 o h O SojJ o o o o PREAMP dfc LpH AH MAIN AMP I I LOCATION OF OPTIONAL REVERB OR GRAPHIC EQ I NOTE 2BX wil...

Page 8: ...Fig 3 How to Connect the 2BX in the Tape Monitor Loop of a Graphic Equalizer or Speaker Equalizer...

Page 9: ...is shown on the display 6 Slowly bring up your amplifier s master volume control to the desired listening level 7 Readjust the EXPANSION control for the desired amount of expansion This will depend on...

Page 10: ...he 2BX in TAPE mode TAPE button IN This Monitors the signal coming from the tape recorder s outputs without changing the expander s input to the tape recorder SIMPLE PRECAUTIONS WHEN USING ANY PROGRAM...

Page 11: ...Fig 4 Combining the 2BX with a dbx Tape Noise Reduction System...

Page 12: ...tricts the quietest sounds that can be recorded and tape Z h fn Z0r de f et f 3 Unit of We on for sound level or 1Z1ofs h ound ne decibel is usually described as the smallest detectable change m sound...

Page 13: ...sages and decreases the level of loud passages The COMPRESSION RATIO is the ratio in dB of the compressor s input dynamic range to its output dynamic range For example if the compression ratio is 2 1...

Page 14: ...All expanders have a level detection circuit This detection circuit is used to sense the input signal level and to determine whether it is above or below the threshold However the method used to dete...

Page 15: ...by a fixed amount the 2BX increases or decreases the level of the program on a linear decibel basis This means that the output dynamic range and the input dynamic range are linearly related by the ex...

Page 16: ...are using dbx professional tape noise reduction systems and dbx has become the new established leader in the field dbx II noise reduction systems such as our 120 series are available for use by the au...

Page 17: ...PEDANCE Low the 2BX is designed to feed a tape monitor input or tape deck with long cables MAXIMUM OUTPUT LEVEL 6 volts RMS at 1 kHz CONTROLS Interlocking Tape Source switches Interlocking Pre Post sw...

Page 18: ...10 Telex 92 2522 or write to dbx Inc 71 Chapel Street Newton MA 02195 Attn Customer Service Department Should it become necessary to have your equipment factory serviced 1 Please repack the unit inclu...

Page 19: ...SCHEMATIC 17 Other patents pending...

Page 20: ...NOTES...

Page 21: ...lay outputs Mic level or phono level signals are considerably lower in level than aux inputs approx 60 to 40dBV so they will not produce adequate volume when connected to an aux input Moreover phono c...

Page 22: ...d highest audio levels is squeezed into a smaller dynamic range A compressed signal has higher average level and therefore may have more apparent loudness than an uncompressed signal even though the p...

Page 23: ...times may cause moderate level program which follows high level program or pro gram peaks to be too low in level Decoder When a circuit restores an original program from a specially treated version o...

Page 24: ...have many controls each affecting one octave one half octave or one third octave of the audio spectrum An octave is the interval between a given tone and its repetition eight tones above or below on...

Page 25: ...armonic distortion are musical and not particularly objectionable most I M distortion is unpleasant to the ear Impulse Response Related to the rise time of a circuit the impulse response is a measurem...

Page 26: ...but when two signals are compared to one another one having a phase shift relative to the other the fi J5ft V6rV noticeable and not very desirable Excessive Phase shift can give a tunnel like quality...

Page 27: ...levels below a threshold point Some compander type noise reduction systems such as Dolby have upper and lower threshold between which the gain changes these systems require careful level calibration...

Page 28: ...uld become unstable and might even oscillate The gain amount of amplification in these traditional amplifiers would be adjusted by one of three methods 1 attenuat ing the audio signal fed to the input...

Page 29: ...1 NOTES...

Page 30: ...dbx 71 Chapel Street Newton MA 02194 Manufactured under one or more of the following U S patents 3 681 618 3 714 462 3 789 143 4 101 849 4 097 767 Other patents pending 1079 2M 600104 Printed in U S A...

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