background image

18

MULTICOM PRO MDX4400

5.2.1 Initial Settings For The Compressor Section

l

o

rt

n

o

C

g

n

it

t

e

S

h

c

ti

w

s

T

U

O

/

N

I

N

I

h

c

ti

w

s

E

V

I

T

C

A

R

E

T

N

I

N

I

h

c

ti

w

s

R

E

T

L

I

F

C

S

T

U

O

l

o

rt

n

o

c

D

L

O

H

S

E

R

H

T

B

d

0

2

+

l

o

rt

n

o

c

O

I

T

A

R

1

:

3

l

o

rt

n

o

c

T

U

P

T

U

O

B

d

0

Tab. 5.1: Initial settings for the compressor section

Rotate the THRESHOLD control counterclockwise until an appropriate amount of gain reduction is indicated on

the GAIN REDUCTION meter. This operation will be accompanied by an audible drop in output level. The

OUTPUT control should now be turned clockwise to reinstate the output level. The level of the unprocessed and

the processed signal can be compared by pressing the I/O METER switch and observing the INPUT/OUTPUT

LEVEL meter.
Final adjustments of the RATIO control can then be made to suit your particular requirements. The experi-

enced user will be in a position to specify parameters while in bypass mode and thus realize the effect before

the unit is actually switched into operation. This is important in live situations, where a signal needs to be

managed efficiently by the engineer, without the convenience of continual A/B comparison.

5.2.2 The MULTICOM PRO As A Sound Effects Unit

In the early 1960’s, musicians began looking at the recording process as a way to create new sounds. The

pumping effect which had been avoided by earlier engineers suddenly became fashionable and was utilized as

a creative tool, laying the groundwork for many of the sounds which are now considered indispensable in

contemporary music. The compressor is used in this role because you can hear it working, and control of the

dynamic range is of secondary importance.
The BEHRINGER MULTICOM PRO, with its extensive range of functions, is well suited to this application.

Sound effects of this kind can be achieved using “extreme” settings. To achieve this, set the THRESHOLD

control to a fairly low level, the RATIO control to almost maximum to obtain the desired effect. Experiment with

all the controls in order to get a feel of their function!

5.2.3 The “Muffling” Effect Of A Compressor

Quite often, compressors are sometimes accused of “muffling” the sound, whilst at the same time reducing the

dynamics. This fact should be investigated further. Bass frequencies contain most of the energy within music

and therefore cause the compressor to reduce the overall dynamics. If the music also contains high frequen-

cies along with the bass frequencies, these are also reduced in level. This is the reason why: in an extremely

compressed recording of drums, the cymbals and high-hats are acoustically swamped by the sound of the

snare or the bass drum. The same effect is experienced when processing reverberated or ambient sounds. The

solution commonly used to this basic problem is either to reduce the compression ratio or to slow down the

attack time, so that the increasing high frequency transients pass through the compressor unhindered before

the compressor takes effect.
The MULTICOM PRO MDX4400 offers a solution to this problem that is by much more elegant. The SC Filter

switch allows you to activate a highpass filter in the control signal path of the compressor. This filter makes

sure that midrange and treble range frequencies are taken into account to a greater extent, and that a low-

frequency signal triggers less compression than a midrange/treble signal of comparable level. A major advan-

tage of this design can be seen in the fact that the frequency response of the overall signal is not modified

below the threshold adjusted with the Threshold control.

5. APPLICATIONS

Summary of Contents for Multicom Pro MDX4400

Page 1: ...MULTICOM PRO MDX4400 www behringer com E User s Manual Version 1 3 April 2001 ENGLISH ...

Page 2: ... appliances including amplifiers that produce heat Power Source The appliance should be connected to a power supply only of the type described in the operating instructions or as marked on the appliance Grounding or Polarization Precautions should be taken so that the grounding or polarization means of an appliance is not defeated Power Cord Protection Power supply cords should be routed so that t...

Page 3: ...u because you are the most important member of the BEHRINGER family With your highly competent suggestions for new products you ve greatly contributed to shaping our company and making it successful In return we guarantee you uncompromising quality manufactured under the ISO9000 certified management system as well as excellent technical and audio properties at an extremely favorable price All of t...

Page 4: ...n IKA and hard knee characteristics s IGC Interactive Gain Control peak limiter combines clipper with program limiter circuits s Extremely low noise operational amplifiers and high grade VCA s s High quality detent potentiometers and backlit switches s Stereo Couple function for channels 1 2 and 3 4 selectable with real totaling of RMS output s Accurate 8 digit LED meters for input level output le...

Page 5: ...mpression Leveling Limiting Clipping 16 5 2 Compressor Section 17 5 2 1 Initial Settings For The Compressor Section 18 5 2 2 The MULTICOM PRO AsA Sound Effects Unit 18 5 2 3 The Muffling Effect OfACompressor 18 5 3 Peak Limiter Section 19 5 3 1 Initial Settings For The Peak Limiter Section 19 6 SPECIAL APPLICATIONS 20 6 1 Using The MULTICOM PRO For RecordingAnd Cassette Duplication 20 6 1 1 The MU...

Page 6: ...ining the audio properties as well as the circuit topology For the first time the MULTICOM PRO MDX 4400 uses SMD technology Surface Mounted Device These sub miniature components known from aerospace technology allow for an extreme packing density plus improve the unit s reliability IKA Interactive Knee Adaptation Compressor Our proven IKA Interactive Knee Adaptation circuit successfully combines t...

Page 7: ...ise cannot be avoided This effect is similar when replaying a tape The non directional magnetic particles passing the replay head can also cause uncontrolled currents and voltages The resulting sound of the various frequencies is heard as noise Even the best possible tape biasing can only provide signal to noise ratios of about 70 dB which is not acceptable today since the demands of listeners hav...

Page 8: ...passages the gain is reduced Of course it is fairly obvious that this kind of manual control is rather restrictive it is difficult to detect signal peaks and it is almost impossible to level them out Manual control is simply not fast enough to be satisfactory t P dB 20 0 20 40 60 80 Clipping Headroom Operating level Effective SNR Noise floor Fig 1 2 The interactive relationship between the operati...

Page 9: ...sors and limiters perform similar tasks one essential point makes them different limiters abruptly limit the signal above a certain level while compressors control the signal gently over a wider range A limiter continuously monitors the signal and intervenes as soon as the level exceeds a user adjustable threshold Any signal exceeding this threshold will be immediately returned to the adjusted lev...

Page 10: ...rst time the MULTICOM PRO MDX 4400 uses SMD technology Surface Mounted Device These sub miniature components known from aerospace technology allow for an extreme packing density plus the unit s reliability could be improved Additionally the unit is manufactured under ISO9000 certified management system 2 2 Inputs And Outputs 2 2 1 Balanced Inputs And Outputs As standard the BEHRINGER MULTICOM PRO ...

Page 11: ...vices such as power amplifiers etc to avoid overheating 3 2 Mains Voltage Before you connect your MULTICOM PRO to the mains please make sure that your local voltage matches the voltage required by the unit The fuse holder on the female mains connector has 3 triangular markers with two of these triangles opposing each other Your MULTICOM PRO is set to the operating voltage printed next to these mar...

Page 12: ...1 and pin 3 have to be bridged Fig 3 2 Different plug types Never use unbalanced XLR connections with microphone cables as this would short circuit any phantom power transmitted over these cables 3 4 Selecting The Operating Level With the Operating Level switch on the rear of the BEHRINGER MULTICOM PRO you can adjust the internal operating level of the unit Thus the MULTICOM PRO can be adapted per...

Page 13: ...can be adjusted from 1 1 to oo 1 3 The OUTPUT control allows for the increase or decrease of the output signal by a maximum of 20 dB Thus a level loss due to the compression or limiting process can be compensated for Please note when using the THRESHOLD control of the Peak Limiter section that the OUTPUT control of the Compressor section precedes the Peak Limiter section If the OUTPUT control is s...

Page 14: ...for about 1 second to avoid heavy and thus audible signal distortion When you use the peak limiter as a protective device against signal peaks the THRESHOLD control should be set in combination with the OUTPUT control in the compressor section so that the peak limiter responds rarely or not at all Thus only real signal peaks will activate the limiter circuit However to produce creative sound effec...

Page 15: ...e mains Please also note the instructions given in the INSTALLATION chapter 14 AUDIO IN These are the audio inputs of your MULTICOM PRO available both as balanced 1 4 jack and XLR connectors 15 AUDIO OUT These are the audio outputs of your MULTICOM PRO Matching phone jack and XLR connectors are wired in parallel 16 With the OPERATING LEVEL switch you can adapt the MULTICOM PRO to various operating...

Page 16: ...nges without affecting the short term dynamics Normally the threshold is set quite low in order to be able to increase low level signals Leveling requires slow attack and release times combined with a high ratio Because of the very slow response time leveling has no effect on signal peaks or short term changes in average level Limiting The limiting function requires a fast attack time and a high r...

Page 17: ...chieved by low threshold settings sounds less natural with higher ratio settings Ratio settings in the range of 4 1 and lower effect the dynamics of the program material less and are often used to compress the sound of a bass guitar a snare drum or a vocal Sensitive and moderate settings are generally used in mixing and for leveling of program material in broadcast Threshold Gain 0 dB Input Output...

Page 18: ...ance The BEHRINGER MULTICOM PRO with its extensive range of functions is well suited to this application Sound effects of this kind can be achieved using extreme settings To achieve this set the THRESHOLD control to a fairly low level the RATIO control to almost maximum to obtain the desired effect Experiment with all the controls in order to get a feel of their function 5 2 3 The Muffling Effect ...

Page 19: ...e solid graph represents the output signal while the dashed graph above shows the input signal response The areas between the graphs represent the amount of gain reduction bright areas are clipping areas i e signal peaks are radically cut off dark areas show the effect of the program limiter The limiter is activated when the adjusted threshold is exceeded for more than 20 ms so as to limit audible...

Page 20: ...ample a sampler As a result of this process a digital recording or a sampling event can be optimally set in level without any problem 6 1 2 The MULTICOM PRO In Mastering The mastering process is one of the most critical processing steps in recording In this production step it is the goal to achieve a maximum level copy of the recording without any noise or distortion In many applications it is fur...

Page 21: ...aradox as it may seem at first can be explained with the fact that especially low frequency signals with high amplitudes can overload the power supplies in the amplifier s The resulting clipping cutting off of signal peaks produces high energy distortion upper harmonics which is abruptly added to the midrange tweeter signals For this reason weak power amps in particular must be protected by a limi...

Page 22: ...o peak to peak level in response to amplitude and duration The higher the average level and the time it remains at a high level the louder the program material will be perceived by the listener If you want to run your broadcast station at maximum average volume proceed as mentioned in chapter 6 1 2 The MULTICOM PRO In Mastering Please make sure that the maximum peak level is below the threshold of...

Page 23: ...A Interactive Knee Adaptation Compressor Threshold variable 40 dB to 20 dB Ratio variable 1 1 to oo 1 Threshold characteristics variable Interactive or Hard Knee Auto characteristics Wave Adaptive Compressor Auto Attack Time typ 15 ms at 10 dB 5 ms at 20 dB 3 ms at 30 dB Auto Release Time program dependent typ 125 dB s Output variable 20 to 20 dB PEAK LIMITER SECTION Type IGC Interactive Gain Cont...

Page 24: ...50 Hz General Export Model 100 120 V 200 240 V 50 60 Hz Fuse 100 120 V T 630 mA H 200 240 V T 315 mA H Power Consumption max 32 W Mains Connection Standard IEC receptacle PHYSICAL Dimension 1 3 4 44 5 mm 19 482 6 mm 8 1 2 217 mm Net Weight 2 2 kg Shipping Weight 3 4 kg BEHRINGER is constantly striving to maintain the highest professional standards As a result of these efforts modifications may be ...

Page 25: ...of receipt of the product at BEHRINGER 2 If the product needs to be modified or adapted in order to comply with applicable technical or safety standards on a na tional or local level in any country which is not the country for which the product was originally developed and manufactured this modification adaptation shall not be considered a defect in materials or workmanship The warranty does not c...

Reviews: