Recording Methods

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.

Normalised recordings 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.