User Manual

Appendix
Rocket User´s Manual 38
Low Pass Filter
Synthesizers are often equipped with a low pass filter. A
low pass filter dampens all frequencies above its cutoff
frequency. Frequencies below the cutoff point are not
affected.
MIDI
The acronym MIDI stands for "musical instrument digital
interface." It was developed in the early 1980s so that
diverse types of electronic musical instruments by diffe-
rent manufacturers could interact. At the time a commu-
nications standard for heterogeneous devices did not
exist, so MIDI was a significant advance. It made it pos-
sible to link all devices with one another through simple,
uniform connections.
Essentially, this is how MIDI works: One sender is
connected to one or several receivers. For instance, if
you want to use a computer to play the Rocket, then the
computer is the sender and the Rocket acts as the recei-
ver. With a few exceptions, the majority of MIDI devices
are equipped with two or three ports for this purpose:
MIDI In, MIDI Out and in some cases MIDI Thru. The
sender transfers data to the receiver via the MIDI Out
jack. Data are sent via a cable to the receiver's MIDI In
jack.
MIDI Thru has a special function. It allows the sender to
transmit to several receivers. It routes the incoming signal
to the next device without modifying it. Another device is
simply connected to this jack, thus creating a chain
through which the sender can address a number of recei-
vers. Of course it is desirable for the sender to be able to
address each device individually. Consequently, there is
a rule which is applied to ensure each device responds
accordingly.
MIDI Channel
This is a very important element of most messages. A
receiver can only respond to incoming messages if its
receive channel is set to the same channel as the one the
sender is using to transmit data. Subsequently, the sender
can address specific receivers individually. MIDI Chan-
nels 1 through 16 are available for this purpose.
MIDI Clock
The MIDI Clock message sets the tempo of a piece of
music. It serves to synchronize processes based on time.
Modulation
A modulation influences or changes a sound-shaping
component via a modulation source. Modulation sources
include envelopes, LFOs or MIDI messages. The modula-