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6 Calculation of Parameters
General
The loudspeaker parameter setup contains all
adjustments and informations of the internal di-
gital controller to obtain the desired frequency
and phase response plus all limiter and
protection functions for the O 500 C.
For every O 500 C an individual set of
parameters will be set at the factory. This set of
parameters contains far more information as it
is the case in any other digital or analog
controlled monitor on the market today.
Normally these functions are reduced to the
selection of crossover frequencies and gains in
every amplifier stage, an EQ of the frequency
response for a better linearisation and a setup
for the limiters.
The O 500 C is supplied with a complex
equalisation for every driver system. The EQ
is not only reduced to the frequency and
amplitude of the whole system, but also
includes the adjustment of the phase
response down to 40 Hz!
The adjustments contained in loudspeaker
parameter setup can be looked at in three
groups:
1.
Filter coefficients of the FIR filter
bandpasses (FIR = Finite Impulse Response)
2.
Limiter parameters
3.
Output scaling factors
The adjustments within a loudspeaker parameter
setup can not be influenced by the user, as any
change (if possible) would result in a loss of
quality of the transmission datas of the monitor.
In the FlashROM-memory of the built-in digital
controller a number of parameter settings are
stored as a standard. Each of them can contain
different acoustic results.
A change between the stored parameter settings
is made in the menu „
Monitor / Subwoofer
“ of
the MAIN menu and can be made while using
the monitor (see chapter 3.2, menu step 8).
Loading of loudspeaker parameter setups
Note:
New loudspeaker parameter setups can
only be downloaded into the system by erasing
the old, existing files. It is not possible to add
new settigs to the list!
- The serial interface (RS-232) socket of a PC
is linked to the serial connector of the
O 500 C by using a standard interface cable,
as described in chapter 4.2.
- Switch ON the O 500 C by the POWER
SWITCH and check if in menu
2 Midi Settings
of the System-Menu
„Baudrate“
the option
„RS232“
is activated,
see chapter 3.
- Now copy all new data files supplied by K+H
(on a FDD, by E-Mail or on a CD-R) into a file
of the HDD of the PC. Then the PC has to be
rebooted and started in the DOS-mode.
- After changing into the directory containing
the files just type in „
TXMATRX“
to start the
data transfer
- Wait until the display will show „
Input Gain“,
now the transfer is completed.
- Switch OFF the O 500 C and - after a few
seconds - ON again, wait for the notice:
„
Wrong Filter Setup
“ and press ENTER
- Now disconnect the O 500 C from the PC.
Room specific parameter settings
To compensate for room and positioning specific
unlinearities in the frequency response, it
alternatively is possible to make up a room
specific loudspeaker parameter setup instead of
using the Room- or PEQ sections described in
chapter 5.1 and 5.2. This will contain the
adjustments of the EQ’s but without the
characteristic influence on the phase response.
In order to do this it is neccessary to make a
complete measurement of the installed monitor
system in the relevant room or studio by using a
special measuring setup which is capable of
calculating the new filtersetups. In addition to this
it will be possible to also include a „individual
coloration“ of the response according to personal
preferences.
The measurements needed for this setup, plus
the neccessary calculations and corrections can
be carried out at extra cost by K+H or by a
subcontractor.
