1.23
Operation Manual
© 2013 Prism Media Products Ltd
Revision 1.00Prism Sound Lyra
5.1.1.1 Overkiller
The analogue input channels include a switchable Prism Sound 'Overkiller' circuit. The Overkiller is
an instantaneous progressive limiter which protects against converter overload by a margin of up to
10dB, gently absorbing transients and allowing recording levels to be raised without risk. The
Overkillers in Lyra operate identically to those in other Prism Sound converters; they can be used
with any input mode (line, mic or instrument), and their operating thresholds are automatically
adjusted for any gain setting.
The Overkillers are switched on and off in the Inputs tab of the Lyra Control Panel app. A
per-channel indication of Overkiller activity is provided both on the front panel of the unit (below each
meter, if the meters are in 'Input' mode), and also in the Inputs tab. Note that these indicators are
dynamic, and show when the Overkiller is actually limiting.
5.1.1.2 High-pass filter
The analogue input channels have switchable high-pass 'impact filters', which roll off below 80Hz.
These are most useful in mic input mode, in removing unwanted low-frequency content. The filters
are also available in instrument and line modes, which can be useful if, for example, external
microphone pre-amplifiers without filters are used.
The filters are switched on and off in the Inputs tab of the Lyra Control Panel app.
Note that in Lyra 2 the filters can also provide an RIAA de-emphasis filter selectable as an alternative
to the high-pass filter, allowing them to be used with vinyl decks. The RIAA filter is aligned to have a
gain of 16dB at 1kHz, so that phono cartridges fall within the sensitivity range of the instrument
inputs, as described in the vinyl decks section.
5.1.1.3 MS matrix
In Lyra 2, the analogue input channels have a switchable MS matrix. This is intended for use with
'mid-side' stereo microphones, where sum and difference signals are derived from the two input
channels creating left and right output channels. The MS matrices are available when the analogue
inputs are in both mic or line modes, allowing external microphone preamplifiers without matrixing to
be used.
Note that there is no explicit stereo width control provided in the matrix; however width can be
adjusted by balancing the gains of the mid and side inputs - the gain steps of the Lyra microphone
preamplifiers are fine and precise. In line input mode, no fine gain adjustment is available, so if the
Lyra MS matrix is used with external preamplifiers, these must have fine and accurate gain control if
width adjustment is required.
The MS matrix is switched on and off in the Inputs tab of the Lyra Control Panel app.
5.1.2 Digital inputs
TOSLINK and RCA connectors accept two-channel digital audio signals in the S/PDIF format at any
standard sample rate between 44.1kHz and 192kHz. The RCA input can also automatically accept
digital audio in the AES3 (AES/EBU) format using the XLR-RCA adapter supplied. Note that RCA
connectors are only fitted to Lyra 2.
The Inputs tab of the Lyra Control Panel app contains the control for selecting the RCA or TOSLINK
connector for S/PDIF input, and also indicators to show that the S/PDIF input is unlocked (i.e. no
S/PDIF carrier is recognized) or asynchronous to the unit's sample clock. The unlock indicator is
To Next Page
Loading...