Message for Dilwyn

[NormanDunbar]

Hi Dilwyn.

I wonder if you can advise here, given your past life at the BBC.

Some old comedy programs from the radio, Dad's Army and Hancocks Half Hour, still have excellent sound quality when heard again these days. Others, are apparently abysmal in that department.

What, would you know, would be the reason?

I'm having a chat online with a blind American who loves British comedy from the BBC and she is wondering. There is a hypothesis that tapes have been reused a few more times than might have been good for them, but I couldn't comment.

Any information gratefully received, thanks.

Cheers,
Norm.

[dilwyn]

Some will have been re-processed to improve sound quality. Modern software and hardware can work minor miracles. Others may not have been processed if the originals were of good enough quality.

Bear in mind that the original studio recordings may have been better quality than the broadcast medium of the time, so if you heard something on analogue radio (or on cassette or vinyl), you may remember them as poorer quality than they actually were recorded originally. Even in my time in broadcasting, analogue tape could store almost the full range of frequencies a human could hear, and listening to the original tapes on good quality speakers was clearly much better quality than hearing the same thing broadcast.

Older master audio tapes which might have deteriorated over time can sometimes be "oven baked" to make it safe to play them and bring them back to life for a while, especially if the tapes were kept in non-ideal conditions, e.g. a valuable old tape salvaged from someone's attic. Although often this temporary fix will lead to quick degradation after a while, it makes them sufficiently improved to be copied and processed in the short term before any new degradation sets in. Once digitised, there is less need to keep the original tapes. Or if you do keep them, less worry if they "die" before you next use them. I forget now how this "baking" works, but plenty of info out there on the interweb if you search.

This is of course a particular worry for libraries, archives and museums which keep old recordings - the tapes degrade over time, no matter what the original quality was. Broadcasters and archives try to keep old recordings under conditions as ideal as possible to try to extend the life of tapes. An interesting quirk is that reel-to-reel tapes may be stored wound back to front for less risk of magnetic print-through causing pre-echo.

Modern audio processing software and hardware can make a real and genuine difference to the quality of old audio tapes. And of course, since the lifetime of analogue tapes is finite as the tape itself degrades, everything has to be digitised to preserve it.

I have an extensive collection of old Welsh music recordings (cassette, vinyl and 78rpm's) and I try to digitise them as I get a chance while the media and my playback machines still work. I use Audacity software for the most part to do this, and it's remarkable how much you can achieve with fairly straightforward software like Audacity. Such as removing clicks from records and tape hiss and noise reduction (sample a piece of background noise, then use the software to follow and cancel out the noise). If I can achieve this sort of thing with fairly simple free software at home, imagine what professionals can achieve with modern software and hardware.

As a local Welsh language recording company (Sain) found in recent years, when they bowed to pressure to digitally re-release older Welsh recordings (a little streaming income from old material is better than none), the old multitrack audio tapes from the 1970s and earlier were usable after a bit of "baking". The real problem was that they no longer had the old analogue machines to play them and had to send the tapes away to be digitised to specialist retrieval companies which keep old multitrack and reel-to-reel machines going for this very purpose.

Bearing in mind it's over 20 years since I was a sound technician (unsound technician?), technology's moved on quite a bit and I'm sure AI will bring further advancements in the audio field.

[NormanDunbar]

I'm very much obliged Dilwyn, thank you.

Cheers,
Norm.

[Chr$]

Dilwyn, I find Vinyl Studio Pro very good for removing clicks and pops in vinyl. The automatic mode (there are several levels to select from) finds and removes the vast majority of issues. It never actually makes any changes to the original audio file and you can easily go through and manually remove any that it misses or put back any percussion clicks that were not actually defects. You can also remove the hiss from recordings of tapes, the rumble from vinyl and also the background noise by selecting a section of noise and then removing it from the rest of the file (similar to Audacity). It's very fast as I previously used Audacity and seems to involve a lot more manual work. I think there is a free trial version but for the time-saving I was more than happy to pay for the full version. I use it to digitise all my vinyl and the result it amazingly good digital audio files that I can put on real tapes, CDs, mp3 players etc.

[Cristian]

A fascinating story, Dilwyn

[RalfR]

Dilwyn, do you know if "telcom c4" for noise reduction was ever used in these studios for reel-to-reel machines? Or any others like Dolby A or dbx?

[dilwyn]

Dilwyn, do you know if "telcom c4" for noise reduction was ever used in these studios for reel-to-reel machines? Or any others like Dolby A or dbx?

I've been out of the business too long to really know, I'm afraid Ralf. Where I worked from the late 1970s to early 00s, we didn't use those noise reduction systems for audio tape recording , although I know some broadcasters did use them. I think C4, which I think was developed by Telefunken in the early 1970s, came a few years after Dolby A. Dolby noise reductions were sometimes used with cassette media, but in my time we didn't noise reduction systems for reel to reel audio tape, apart from occasionally doing work for outside companies who requested specific formats. As I was never involved with video, I don't know how much it was used there.

[RalfR]

Dilwyn, do you know if "telcom c4" for noise reduction was ever used in these studios for reel-to-reel machines? Or any others like Dolby A or dbx?

I've been out of the business too long to really know, I'm afraid Ralf. Where I worked from the late 1970s to early 00s, we didn't use those noise reduction systems for audio tape recording , although I know some broadcasters did use them. I think C4, which I think was developed by Telefunken in the early 1970s, came a few years after Dolby A. Dolby noise reductions were sometimes used with cassette media, but in my time we didn't noise reduction systems for reel to reel audio tape, apart from occasionally doing work for outside companies who requested specific formats. As I was never involved with video, I don't know how much it was used there.

"telcom c4" was indeed developed by Telefunken, produced and marketed by "ANT", still in use and very effective during copying from one tape to another.

There was also "High-Com" from Telefunken, based on c4 for home cassette recorders. Dolby A and c4 use similar methods, the frequency range is divided into four areas, which the compander then processes (High-Com just used two ranges). This prevents "pumping". High-Com was also very effective, but it also required High-Com to play the tapes and cassettes. Without it, it sounds awful, in contrast to Dolby B on cassette recorders. If this is missing during playback, the highs are emphasized and there is of course more noise. But with the earlier mono cassette recorders with handles, this was actually better.

Another advantage of c4 is its level independence; with High-Com you have to pay close attention to the level.