Stereo filters inside a DSP
When using FIR filters, normally, the 4 outputs of one DSP are configured to feed sub, low, mid and
high paths of a speaker. The HD2 allows to use a stereo mode inside one DSP, that is, it can feed mid
and high 2 times or the coefficients for the high path 4 times. On a HD2 with 8 outputs, you can, then,
feed 4 two-way speakers or 8 one-way speakers. To accomplish that, use a FIR filter with coefficients
for mid and high path only (or high path only) and copy these to the other paths of one DSP. The wizard
automatically detects this possibility from the selected filters and shows 2 additional drop-down lists as
shown in the above picture.
If a 4x1->2 routing is selected, 4 two-way speakers can be fed from 4 different inputs.
4.6.4 Firmware Update
Note: after updating the firmware, all data stored in the HD2 is lost. To prevent loss of data, store the
HD2 configuration to hard disk by
Save Config
and upload it again after updating the firmware by
Load
Config
.
Note: the current software HD2Control requires at least firmware version 1071 to operate. You can
connect to HD2s with older firmware versions and do firmware updates but should not expect that the
software fully works with that version.
Upgrading the firmware of the HD2 to a newer version can be done via ethernet. You should have a
valid firmware file named „hd2_v####.$.fwu“ were #### denotes the 4 digit main version number and $
the sub-version number. The file size must be 122.144 bytes. To upgrade, simply push the
Update
Firmware
button in the Configuration group box at the bottom and select the firmware file in the file
selection dialog. The file will be transferred to the HD2 and copied internally. This takes about 45-50
seconds. After that, a reboot of the HD2 will occur and you should see the new version number
appearing in the display of the HD2.
The ethernet connection to the HD2 is getting lost during rebooting. Watch the messages in the log
window and wait until 'Trying to reconnect' occurs. If all goes well, a new connection is established
automatically. If that doesn't work, you have to connect manually by clicking the connect button.
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Fig. 11: Using a stereo setup inside a DSP