Recordings have been made using an SDRPLAY receiver running SDR-CONSOLE V3 and captured using
"Audacity" on a Windows PC. 32 bit sampling at 48000Hz is employed (16000Hz from 18th May 2017) and
the finalised versions are converted to mp3 format at 192 kbits/second. #
Raw recordings are
more or less as received, but level as a whole is adjusted so that no
signal is greater than -3dB. I have removed very long periods of
silence and any obvious clicks or spikes. Users can check their
audio on different settings by listening to their overs. These
recordings give the audio at the receiver showing what listeners to the
repeater hear and you can compare levels together with sound quality
and white noise etc.. You can make comparisons of different
microphones or settings by changing them between overs.
have had most signigificant gaps removed and the relative levels for
each participant adjusted for ease of listening. The techniques
have varied. Where time is available I have adjusted each over
so the maximum level is set to -3dB for full scale. Where this
has resulted in significant background noise within an over I have sometimes applied
Audacity's built in noise reduction process to any
problematic overs and re-normalised.
[On some occasions I
have simply resorted to using "Chris's Compressor" Plug-in which brings
levels up to a target and compresses the recordings. At present
my settings for this technique are imperfect and the background noise
gets louder during long quiet periods.]
From 1st June, normalisation has included notch filtering at 214 Hz to remove the third harmonic of the CTCSS tone.
1st June normalised version prepared with standard method, followed
by a pass through my Sprachextractor and then compressed.