Behringer DSP1200P - Manual (Page 27)

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3.6 Saving data via MIDI
The MODULIZER PRO’s MIDI implementation also allows for archiving one or several presets on an external
storage medium. Proceed as follows:
Connect the MIDI OUT jack of the MODULIZER PRO to the MIDI IN jack of a MIDI data recorder (e.g. se-
quencer). Press the STORE and IN/OUT keys simultaneously to enter MIDI mode. Set program change mode
to 0 and controller change mode to 3. Now quit MIDI mode by pressing the STORE key. Use the jog wheel to
select the preset whose data you wish to save. When the preset is activated its parameters are transmitted as
controller data and can be recorded on a sequencer or similar device. Repeat this routine until all presets of
your choice have been sent to the external data recorder.
To load archived data back into the MODULIZER PRO, you must enable controller reception in MIDI mode (see
2.5). Then, start the sequencer to automatically transmit each preset data set back to the MODULIZER PRO.
Press the STORE key, select a program location to store the data and then again press the STORE key. If you
want to automate MIDI store functions you must enable the store mode, to switch on the reception of controller
#28. This allows you to directly store any modification of the actual preset on the preset number that is
transmitted with the controller. You can also restore a complete preset that has previously been recorded with
a MIDI sequencer on the same location it had before.
4. TECHNICAL BACKGROUND
4.1 Digital audio processing
In order to convert an analog signal - e.g. music - into a series of digital words, a so-called “Analogue to Digital
Converter” or ADC is used. The converter functions by viewing the signal entering it a given number of times
over a period of time, e.g. 44,100 times per second, giving a rate of 44.1 kHz, and in each case measuring the
signal amplitude, and giving it a numerical value. This form of measuring the signal regularly over a period of
time is known as “sampling”, the conversion of the amplitude into a numerical value, quantizing. The two
actions together are referred to as digitizing.
In order to carry out the opposite - the conversion of a digitized signal into its original analogue form - a “Digital
to Analogue Converter” or DAC is used. In both cases the frequency at which the device operates is called the
sampling rate. The sampling rate determines the effective audio frequency range. The sampling rate must
always be more than twice the value of the highest frequency to be reproduced. Therefore, the well known CD
sampling rate of 44.1 kHz is slightly higher than twice the highest audible frequency of 20 kHz. The accuracy
at which quantization takes place is primarily dependent on the quality of the ADCs and DACs being used.
The resolution, or size of digital word used (expressed in bits), determines the theoretical Signal/Noise ratio (S/
N ratio) the audio system is capable of providing. The number of bits may be compared to the number of
decimal places used in a calculation - the greater the number of places, the more accurate the end result.
Theoretically, each extra bit of resolution should result in the S/N ratio increasing by 6 dB. Unfortunately, there
are a considerable number of other factors to be taken into account, which hinder the achievement of these
theoretical values.
If you picture an analog signal as a sinusoidal curve, then the sampling procedure may be thought of as a grid
superimposed on the curve. The higher the sampling rate (and the higher the number of bits), the finer the grid.
The analog signal traces a continuous curve, which very seldom coincides with the cross points of the grid. A
signal level at the sampling points will still be assigned a digital value, usually the one closest to the exact
representation. This limit to the resolution of the grid gives rise to errors, and these errors are the cause of
quantizing noise. Unfortunately, quantizing noise has the characteristic of being much more noticeable and
unpleasant to the ear than “natural” analog noise.
4. TECHNICAL BACKGROUND