Using the SPA25
Front panel controls
Almost all the functions of the SPA25 Prisma Multi-Channel Processor can be accessed using the front panel controls, and information about its operation is displayed on the front panel display:
Switches the SPA25 to standby, or switches it on from standby.
Select the input.
Adjusts the volume.
Changing the volume
The SPA25 allows you to vary the volume from 0 (silence) to 99 (maximum), although by default the maximum volume is set at 70.
To change the volume
- Turn the VOLUME selector on the front panel, press + or – on the PRISMA remote, or press or on the PRISMA remote.
The current volume setting is shown on the front panel; for example:
To mute the sound
- Press on the PRISMA remote.
To restore the sound to its original volume
- Press again on the PRISMA remote, or adjust the volume.
Selecting a source
The SPA25 Prisma allows you to define up to 17 presets. Each preset can use one of the analogue or digital audio inputs, and any preset can be combined with one of the HDMI inputs. Alternatively, a multi-channel source can be defined using analog inputs A1 to A4.
When the SPA25 Prisma is first supplied the eight standard presets shown in the following table are already set up for you:
|1||HDMI 1||Video and digital audio on HDMI connector.|
|2||HDMI 2||Video and digital audio on HDMI connector.|
|3||A1||Analogue on RCA connectors.|
|4||A2||Analogue on RCA connectors.|
|5||D1 Coaxial||Digital coax on RCA connectors.|
|6||D2 Optical||Digital optical or analogue on a 3.5mm jack.|
|7||PC/MAC||Digital on a USB-B connector.|
By default only presets 1 and 2 include video.
To step between presets
- Press the or buttons on the front panel, or the or buttons on the PRISMA remote, to step between sources.
The display shows the current preset alias; for example:
To select a preset directly
- Press the number of the preset on the PRISMA remote.
To select a preset number greater than 9, long-press the first digit and then press the second digit.
You can disable any preset you don’t need. You can also change any preset to use different inputs, or configure your own presets with any name you choose and using any particular inputs as appropriate for the preset.
On Screen Display
An on-screen display is overlaid on your video image when you adjust settings on the SPA25:
- The current preset alias, and the signal.
- The video and audio inputs used by the preset.
- The volume.
You can choose how long the OSD stays on the display, and whether the background is transparent; see Setting up Sources: Video Settings.
Changing the display brightness
To change the front panel display brightness
- Press the DIM button on the PRISMA remote to step through the three brightness levels and blank.
If you blank the display it will be restored briefly when you operate any control.
The display automatically dims after ten minutes; you can adjust this delay in the settings menus; see Other Settings: General Settings.
Selecting the DSP mode
The DSP mode determines how the audio signal is processed to give the optimum surround sound through the particular configuration of speakers in your system.
The SPA25 lets you choose an appropriate DSP mode for each source preset. For example, Dolby Surround may be appropriate for movies, but 2 CH PCM may be more appropriate for classical music.
To change the DSP mode
- Press AUDIO on the PRISMA remote.
The on-screen display shows the DSP Mode menu with the current DSP mode highlighted:
The options available depend on the source you are listening to.
- Press or on the PRISMA remote to select the new DSP mode and press SELECT to select it.
Note that this adjustment is temporary, and the default setting is restored if you change preset. If you want to make a permanent change to a preset, edit its configuration using the Preset Settings menu; see Setting up sources: Preset Settings.
Blu-ray players provide three lossless audio formats: Dolby TrueHD, DTS-HD Master Audio, and Linear Pulse-Code Modulation (LPCM). These formats will all convey eight discrete channels (7.1) of lossless audio that exactly duplicate the original studio masters:
|Dolby||Dolby Prologic IIx|
|Dolby Digital||EX, Plus, TrueHD|
|DTS||DTS-ES, DTS-NEO:6, DTS 96/24, DTS-HD Master Audio, DTS-HD High Resolution Audio|
|PCM||2ch-PCM, Multi-PCM, LPCM|
For Dolby Digital or DTS sources only the following option is available:
|Auto||Automatically detects an incoming digital signal and locks onto it.|
The SPA25 Prisma automatically detects a Dolby Digital or DTS input and displays Dolby Digital on the front panel display.
If you are listening to a conventional two-channel analog or digital source, such as a CD, the following options are available:
|Auto||Automatically selects a DPS mode based on the incoming signal.|
|Bypass||The inputs are fed directly to the output, with no decoding for the most faithful possible reproduction of stereo or multi-channel sources.|
|Stereo||Conventional stereo, using just the main left and right loudspeakers.|
|Party||The same signal to the front left and right, surround left and right, and surround back left and right loudspeakers, if connected and enabled.|
|Dolby Surround Movie||A variant of Dolby Surround optimised for movie soundtracks.|
|Dolby Surround Music||A variant of Dolby Surround optimised for music sources.|
|Dolby Surround Night||A variant of Dolby Surround optimised for night listening|
|DTS Neural:X||Provides up to 6.1 channel surround sound from conventional stereo sources.|
Changing the levels
You can independently change the balance, center level, surround level, surround back level, and subwoofer level to alter the balance of sound in your surround system.
Changing the balance alters the level of both the left and right main loudspeakers to shift the position of the stereo image, keeping the overall level of the sound the same. The other adjustments change the level of the corresponding speaker(s) without affecting the remaining speakers in the surround system.
To change levels
- Press BAL on the PRISMA remote.
The display shows the first setting:
- Press or on the PRISMA remote to step between levels.
- Press or on the PRISMA remote to adjust the current level.
Note that these adjustments are temporary, and the default setting is restored if you change preset. If you want to make a permanent change to a preset, edit its configuration using the Preset Settings menu; see Setting up sources.
The settings are shown in the following table:
|AV Delay||0ms to 200ms||Delay audio to match video (lipsync).|
|FL||-12.0dB to +12.0dB||Front left level.|
|C||-12.0dB to +12.0dB||Centre level.|
|FR||-12.0dB to +12.0dB||Front right level.|
|SR||-12.0dB to +12.0dB||Side right level.|
|SBR||-12.0dB to +12.0dB||Surround back right level.|
|SBL||-12.0dB to +12.0dB||Surround back left level.|
|SL||-12.0dB to +12.0dB||Side left level.|
|Sub||-12.0dB to +12.0dB||Subwoofer level.|
|HL||-12.0dB to +12.0dB||Height left level.|
|HR||-12.0dB to +12.0dB||Height right level.|
|HRL||-12.0dB to +12.0dB||Height rear left level.|
|HRL||-12.0dB to +12.0dB||Height rear right level.|
The level adjustments go clockwise around the loudspeakers in your surround system, starting with the front left speaker.
The SPA25 Prisma allows you to make a recording of an analog source to the PRE/LINE audio output.
You can set the output to Pre, which gives a variable level output, or Line, which gives a fixed-level output, in the Audio Settings menu; see Setting up sources: Audio Settings.
Note that this option is not available if you are using the PRE/LINE outputs as part of a 7.1.4 speaker layout.