Compression: Only the best practices from a quality-conscious Viennese Radio engineer

Bob Katz Leave a Comment

From: Florian Camerer

My comments are: Congratulations!!
I just read Bob Katz’s article concerning Compression in Mastering and I find it one of the most comprehensive and informative sources on the subject around!!

In broadcasting (I am a sound engineer for the Austrian Broadcasting Corporation ORF) we have similar problems: programmes with a high percentage of spoken word (e.g. news etc.) and commercials make our lives very difficult, because they are sometimes heavily compressed to the uppermost level. In the transmission chain we have at least two or three additional peak-limiters which make themselves prominently recognizable in many cases. Also, there existed the unwritten rule in drama and documentary that dialog or commentary should be at peak-level (measured with VU-metering!!), because otherwise it would sound weak after the news or a longer commercial-block. When I started in television I soon rejected this “rule” in favor of more dynamics also in documentaries. I simply refuse to sacrifice any of the carefully crafted dynamics during the transmission. It takes some time to convince directors, but there are some tricks:

First I try to sit in the master control room 30 minutes before “my” program is being transmitted.

I would then – depending on the program – gradually lower the level modestly (to say a figure – 3 dB e.g.when it¥s news), and then, immediately before my program starts, I would raise the level back to the original! That’s sort of guerilla tactics but that is something that I have almost got used to – being an audio-partisan… If you know the guys from master control well, this is possible!! (In the past we had a dedicated person supervising overall audio quality and consistency of level in master control – today we – of course – have automation, and one single person must handle everything; the more high-techy we get, the more low-techy the audio-quality seems to be – speaking of bradcasting!!).

If you are not able to attend your transmission in master control, then you can do something if there is some sort of signation before your program. Try to get hold of it during post-pro and cut it to your program. Then lower the level of the signation on purpose, so that the consumer at home has to raise the volume to experience his familiar sensations.

(Hopefully, the person in master control doesn’t spoil your efforts by raising the level of the signation and sending all the rest into the transmission peak-limiter!!) You then have a similar average dialog or commentary-level as the news-program, but your transients, your explosions, gun shots or musical climaxes have all the headroom and naturalness they deserve!

I usually set my average commentary-level up to 5 or 6 dB lower than 0 dBU rel. That doesn’t seem to be very much, but dynamics in television is a bit more restricted than e.g. dedicated listening to classical music. Initially directors complained “Why do I have to turn up the volume control when I hear our program?” but now they more or less understand my arguments – by the way, I wouldn’t do it the other way. Fight overcompression!!!!!

I also agree with Mr.Katz 100 percent on the general reluctance of using compressors as an automatic means of solving flaws. In the days of moving faders, I almost all of the time am my own, human compressor, I do very careful gain-riding (at the end of words etc.) and together with slight compression when recording (commentary e.g.) it pays off for a natural, open-sounding voice.

Light at the end of the tunnel will be the meta-data capabilities in AC3-authoring, where the producer, better the mastering engineer can provide a set of compression settings like car, living room and “audiophile” room (no compression at all) leaving the choice to the consumer depending on the surroundings he’s in. That can also mean changing eq-settings for listening during the day and at 2 o’clock in the morning – the ominous “loudness” function…

I apologize for my overly long writing – I can get pretty upset when listening to current practices in television and radio…

Anyway, thank you very much for the wonderful resource – it should be read by everyone involved in audio.

Some points I would love to read your comments on: EQ, compatibility (mono-stereo-surround, tube revival, audio restoration;

All the best from Vienna,


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