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Operations
UltraVoice Remote Interface (UVRI-B)
Federal Signal www.fedsig.com
Digital Voice Recording
When purchased, the Digital Voice option adds a microSD card that is capable of storing
up to 4,093 voice or tone messages that total up to 17 hours of total recording time.
File Format
The digital voice message format is 8000 samples per second, 8 bit, mono. Save these
messages with a DV#.wav naming format or the messages are not recognized. This
naming format results in messages DV1.wav through DV4093.wav.
Voice Levels Within Files
Voice sections of a recording should be “Normalized” so that the peaks are at the limits.
After Normalization, increase the gain by 6 dB (200%) to deliver full nominal output power
at the peeks and about 3.5 dB down on average during a word.
Tone Levels Within Files
Tone signals in the recording (such as, siren sounds, horn sounds, and music) should be
at no more than 36% of the maximum level (-9 dB) to prevent them from overdriving the
amplifiers and overpowering the drivers. These can be normalized to set them at the
maximum level and then reduced to 36% or -9 dB.
These levels assume that the attenuation is programmed for 0 dB and that the DV GAIN
on the control board is turned fully up. This delivers -1.8 dB compared to the square wave
siren tones or about 54 V
rms
. For UVRI-Bs, this delivers -2 dB compared to the square
wave siren tones.
Filtering Files
You need to filter the files to reduce content below 300 Hz. This prevents low-frequency
tones in a recording from saturating the output transformer and the speaker drivers.
SPEAKER DAMAGE: The speaker drivers can not reproduce these frequencies
and can be damaged by them.
Checking/Setting Control Board DV Levels
These levels assume that the attenuation is programmed for 0 dB and the DV GAIN on
the control board is turned fully up.
To check the control board DV levels, with the speakers un-plugged from the amplifiers:
1. Turn the DV GAIN pot fully (25 turns) counter clockwise.
2. Play the stored tone function.
3. Monitor the amplifiers output level.
4. Turn up the DV GAIN pot until 27 V
rms
is reached.
NOTE: It is important to start by turning the DV GAIN pot down to a low level and
work your way up to prevent overdriving the amplifiers.