This is what you see when you start Mono-a-Mono. There’s a section labelled “Input Files” where you create a list of all the files you want to clean up. When you click on “Add”, you get a standard file browsing dialogue and can select one or more files to add. If you make a mistake, you can remove files from the list, one at a time or all at once.
The various controls determine exactly what Mono-a-Mono will do with your recordings:
- Select only the “Centre” Output Signal to enhance those components of the original mono signal which are common to both channels, or deselect “Centre” and select both “Left” and “Right” to remove them. You can select any other combination of Output Signals, if you want to de-mix a stereo recording.
- Select “Vertical Cut” if the left and right channels of the recording you’re processing have opposite polarity (this can happen for a variety of reasons, but unless you’re dealing with very old recordings, or are using home-made equipment to digitise them, you should not normally select this option).
- Mono-a-Mono normally tries to optimise the amplitude of its output signals to get the best signal-to-noise ratio (SNR). However, in some cases, you may want to make sure that the amplitude is not significantly changed. In this case, select “Fixed Level”.
The other controls affect the more qualitative aspects of the processing: the sliders labelled “Click Remover”, “Silence Enhancer”, “Rejuvenator”, “Output Level”, “Rumble Filter”, “Hiss Filter”, “Bass Boost”, and “Treble Boost”. The default values are usually pretty good, but you can play with them a bit to get the best out of your particular recordings. To tune them to match your particular recording, you can try clicking on the “Wizard” button. To get a quick idea of what any chosen settings will sound like, use the “Preview” button – this will process the first few seconds of each file, and then play the output through your PC’s speakers.
There are some useful tips from a user of Mono-a-Mono on Ron Tipton’s archived web site. I’d recommend following both their advice and mine, below:
- If possible, take note of my tips regarding the digitisation of the audio.
- Increase “Click Remover” if you want to remove more (and less obvious) clicks, at the risk of making a quiet crackling sound during some vocal sections. See the FAQ for more information about this.
- Increase “Silence Enhancer” to remove more noise in quiet periods, at the risk of making the output audio sound more woolly (muffled).
- Increase “Rejuvenator” if there’s any distortion or ‘harshness’ during louder sections. Decrease it if the processed sound is muffled but your recordings are in good nick (i.e. neither distorted, badly worn, nor digitised with inappropriate equipment).
- If there’s any hum or rumble in your recordings, remove it by setting “Rumble Filter” to the highest frequency you want to remove. Take a look in the FAQ for more details.
- Set “Hiss Filter” to your best guess of the highest frequency of any important components in your audio. This will optimise the signal-to-noise ratio of the output audio. You can use free software such as “WaveSurfer”, “Spectrogram”, “Raven Lite”, or “Audacity” to examine the frequency content of your signals. If you aren’t sure what value to use, just set it high. There’s more information about this in the FAQ.
- The equaliser controls, “Bass Boost” and “Treble Boost” act like a tone control to help make the output sound more natural. They can be used to compensate for differences between the recording and playback equalisation curves used for old recordings (modern record reproduction equipment uses RIAA/CCIR equalisation, but older records were produced with a wide variety of equalisation curves). See the FAQ for some more detailed advice.
- Increase “Output Level” to make the audio louder, at the risk of clipping (distorting) the loudest sections.
- Conversely, if you think there’s some crackle, woolliness, or high-amplitude distortion in the processed audio, you can reduce the respective settings. There’s more advice on adjusting these settings in the FAQ section.
Mono-a-Mono puts all its output files in one folder, which you can specify by typing it into the box, or by browsing for it with a standard dialogue. Once this is done, you can click on “Go!” to start the processing.
You don’t need to worry if you hit “Go!” by mistake: Mono-a-Mono will never overwrite any files. If the output folder already contains a file with the same name as the input file, Mono-a-Mono will simply add a numerical suffix onto the name and try again.
It’s worth mentioning that you can cancel processing before it’s complete. If you do, the output file will still be playable – it’ll just be shorter than the input. In fact this is a good way of checking if the settings you’ve chosen are OK: just start processing, cancel after a few seconds, and then listen to the (incomplete) output file before processing again when you’re sure the settings are right.
The time taken to process the files depends on the CPU speed of your computer. On a modern PC, the processing it is usually a few times faster than “real-time” (so a three minute audio file should be processed in a minute or so – faster if you have a fast processor).