Frequently Asked Questions

Q. What do I need to make good digital copies of old records?
A. There are plenty of web sites giving advice on this. Some can be slightly misleading, or just plain wrong, so take what you read with a pinch of salt, but you can gleam something useful from almost all of them. If you want my opinions too, there’s a quick summary here.

Q. Audio processed with Mono-a-Mono can sound “woolly”, especially during quiet periods. What’s that all about?
A. The “Silence Enhancer” slider controls the amount of noise during (what should be) quiet periods, while the “Rejuvenator” slider reduces distortion (such as that created by wear-and-tear of old records). Unfortunately, removing such noise and/or distortion can make the recording sound muffled. If your recording is relatively unused (i.e. hasn’t been abused and has been digitised on good quality equipment), move the “Rejuvenator” slider towards zero. If you don’t mind a bit more noise when the audio should really be silent, move the “Silence Enhancer” slider towards zero. Most of the noise will still be removed, but the “woolliness” should disappear. If it still sounds muffled, try increasing the “Hiss Filter” slider towards full-scale.

Q. No matter what I do with the “Silence Enhancer” and “Rejuvenator” sliders, the audio sounds “thin” and “tinny”. What have I done wrong?
A. This is most often caused by having checked the “Vertical Cut” box, or not having checked the “Centre” Output Signal box, when it’s not appropriate. The “Vertical Cut” box should only be checked when processing (very) old vertical-cut discs on equipment designed for lateral-cut discs.

Q. So how do I estimate the highest frequency in my audio? I need this figure to set the “Hiss Filter” slider.
A. Ideally, use an audio analysis tool such as “WaveSurfer”, “Spectrogram”, “Raven Lite” or “Audacity” to examine your recording and see which frequencies stand out from the background noise. If you don’t know how to do this (or if you can’t be bothered), you can make a fair guess based on the type of media. The frequencies quoted below are based on published equalisation curves for American Victor recordings, but all the dates are approximate and will be different for different record companies – if in doubt, err on the side of higher frequencies:

  • for post-1952 78 rpm discs, modern vinyl, and high quality tape, use 16 kHz or more
  • for early vinyl, cheap-and-nasty tapes, and 1947-1952 78 rpm discs, 12 kHz is probably best
  • for 1936-1947 78 rpm discs, 8 kHz is most appropriate
  • for 1925-1936 78s, use 6 kHz
  • for pre-1925 78 rpm discs and cylinders, 4 kHz is a good guess

Q. How can I choose the right setting for the “Rumble Filter”?
A. Quite a few old records suffer from mains hum introduced during the recording – such low frequencies were often inaudible to the recording engineers because of the limited capabilities of their playback equipment. If you have a poor quality playback system or the record you’re working on is warped, more hum and / or rumble may have been introduced during the playback process. Whatever the cause, you can remove these low-frequency signals by setting “Rumble Filter” to the highest such frequency in the recording. The bulk of the mains hum usually occurs at 50 Hz in most of Europe, 60 Hz in the USA. Sometimes the harmonics of the mains frequency can also be audible (especially if the hum originates from a poorly regulated power supply). In that case, you’ll need to set the “Rumble Filter” to twice the respective mains frequency. If you don’t have much hum in your recordings, you can set it to the default value, 20 Hz, or even lower.

Q. I’ve set the “Rumble Filter”, “Hiss Filter”, “Bass Boost” and “Treble Boost” according to the best figures I could find, based on what I know about my recording, but it still doesn’t sound right. What can I do?
A. Well, to quote many other web sites, “trust your ears”. Early audio recordings were very much an art rather than a science. Both the equipment and the recording engineer’s personal preferences varied, resulting in a range of equalisation characteristics. Early recordings even changed the composition of the orchestra to compensate for the limitations of phonographic reproduction at the time (i.e. they increased the number of specific instruments which were not reproduced well).

Even if you know the manufacturer, recording location, and exact date of your records, you still can’t be sure of the “correct” settings. The only way to be sure is to try various settings and see which sounds best. My rules of thumb go like this…

  • if you can hear buzz, hum, or rumble in the recordings, increase the “Rumble Filter”.
  • if bass notes are inaudible, reduce the “Rumble Filter”.
  • if the sound is “boomy”, decrease the “Bass Boost”.
  • if it sounds “tinny”, reduce the “Treble Boost”.
  • if there’s too much hiss throughout the recording, reduce the “Hiss Filter”.
  • if the quiet sections sound “rougher” than the loud sections, increase the “Silence Enhancer” setting.
  • if the sound is “rough” during loud sections of the recording, increase the “Rejuvenator” setting. If roughness still remains, try reducing the “Hiss Filter”.
  • if it sounds “woolly”, increase the “Hiss Filter”, or if that fails, reduce the “Rejuvenator”.

Q. There are still some clearly audible clicks. Can I get rid of them?
A. Try increasing the “Click Remover” slider. It should make the clicks less audible, even if it doesn’t remove them completely.

Q. What types of input file can Mono-a-Mono handle?
A. Any uncompressed stereo Sun/NeXT, AIFF, or WAV/RIFF format. Compressed files do not contain enough detail to identify which components are noise and which are the “true” signal. Similarly, without stereo information, Mono-a-Mono can’t differentiate between signal and noise.

Q. What format are the output files?
A. The same as the inputs, but mono instead of stereo.

Q. What operating systems does Mono-a-Mono support?
A. It should work on any Win32 desktop operating system from Windows 95, up to and including Windows 7, 32 or 64 bit. However, it’s only been tested on Windows 98, ME, XP SP3, Vista and 7. If you find an operating system on which it doesn’t work, please let me know.

Q. Can I select the output folder to be the same as the input without typing the whole path?
A. Yes – just type a “.” (without the quotation marks) in the output folder box. The output files will then be in the same folder, and have the same name as the inputs, but with a numerical suffix (e.g. the input file “FredTheOyster.wav” will produce an output file “FredTheOyster-1.wav”).

 

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