Behringer MDX4400 ユーザーズマニュアル

MULTICOM PRO MDX4400

6. SPECIAL APPLICATIONS

6.1 Using The MULTICOM PRO For Recording And Cassette Duplication

In the recording and duplication field the goal should always be to achieve an optimum recording level onto the

recording media. Too low or too high recording levels lead to side effects such as noise, distortion etc. In

mastering and multitrack recording, as well as in duplication, one should always take care to utilize the full

dynamic range of the tape recorder, DAT recorder etc. Principally, it is possible to control the recording level by

riding faders, which means with low level signals, the gain is increased, whereas the amplitude of high level

signal is reduced. It is obvious that this method is insufficient because, especially in live recordings, the

expected signal levels cannot be anticipated correctly. Especially with multitrack recordings, which are run

under hectic circumstances, the signal level of all channels cannot be monitored and controlled at the same

time. Generally, with manual control, it is not possible to achieve satisfying recording results.
An automatic gain control system achieves better and more constant results. Use the MULTICOM PRO by

starting with the initial settings, and use its dynamic control functions in order to be able to drive an analogue,

as well as a digital recording, up to the limit of its maximum dynamic range while remaining noise- and

distortion-free.

6.1.1 The MULTICOM PRO In Digital Recording And Sampling
In an analogue recording, too low recording levels lead to an increased noise level, whereas too high levels will

cause a compressed and squashed sound. In extreme cases, it will cause distortion due to tape saturation.

In contrast to analogue, side effects in the digital field always become extremely audible: with decreasing level,

a tape previously recorded with insufficient level loses resolution: the recording sounds hard and loses

atmosphere. With excessive level, the recording sounds harsh and heavily distorted. In order to avoid these

effects, the Peak Limiter section of the MULTICOM PRO should be placed before for example 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 further required to produce a high average volume. In the field of commercial media for exam-

ple, this is apparent especially with records and cassettes which are processed with high average volumes.

Quite often in these cases, dynamics suffer drastically, because the program material has been compressed

and limited too heavily. Using the compressor and the Peak Limiter section of the MULTICOM PRO allows you

to drastically increase the overall volume, without audibly affecting the dynamics.
Proceed as follows:
1. Limit the dynamics of the program material by 6 dB using the Peak Limiter section. By softly clipping just

the transients, the real audio signal will not be limited, resulting in a higher headroom. The overall gain can

now be increased by 6 dB, which leads to a higher volume. More than 6 dB should not be limited, otherwise

side effects could become audible.

2. Therefore, in addition, you should also use compression. It is recommended that the compression is limited

to the first 6 dB of the dynamic range only. A high threshold level in addition to the auto mode will give good

results.

This effect is particularly noticeable with DAT recorders, whose level indicators achieve a response time of less

than 1 ms. Set the DAT recorder at unity and now reduce the LEVEL control of the peak limiter until the LIM

LED starts to illuminate. The cut signal peaks cause a reduced recording level of about 6 dB, which is visible

on the level indicators of the DAT recorder. Now increase the recording level of the recorder back to unity. The

result is a clearly louder recording without any loss of sound.

6.2 The MULTICOM PRO as a protective device

Sound system distortion is usually a result of amplifiers and loudspeakers being driven beyond their limitations

by signals clipping. The signal limitations that occur lead to unpleasant distortion that is dangerous to the speakers.

6. SPECIAL APPLICATIONS