I read a lot of criticism about Optimod and that people can 'hear' it working. But what is it exactly? What do you hear? How different is it from a sound engineer altering the faders ?
Curious.
Curious.
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Resurrection ManOriginally posted by Resurrection Man View Post
There has been a lot of discussion about Optimod, as you say. Basically it's an automatic device which reduces the dynamic range of the programme source, thus risking defeating the efforts of the mixer who balanced the sound in the first place, whether it was a commercial engineer or a BBC employee. All transmitted sound has to be produced between relatively narrow dynamic parameters, and background noise can become a problem. The idea behind Optimod when it was first introduced was that it would benefit car radio listeners during the so called "drive time" but now it seems to be universally applied.
It's worth remembering that radio and television transmitters have dynamic limiters to prevent excessive modulation, but these only operate if the overall prescribed range is exceeded.
What do you hear? Well, try listening to a broadcast of a disc that you already know well, say an overture which starts quietly and ends with a bang. As the final crescendo begins you will notice that the orchestral punch disappears, as the ending is subjectively no louder than the quiet strings at the beginning. You'll notice this disconcerting effect less on the small radio in the kitchen, but on a wide range system it's alarmingly obvious. Personally I find it less distracting on instrumental and chamber music, but it's still there.
A good sound engineer has a great advantage over Optimod, he or she can predict what is going to happen next and make adjustments accordingly. Human aural memory is not very good, so
by making small changes in dynamics during a performance or a recording it's possible to do a little dynamic cheating in a much more subtle way than an automatic device can achieve. There is no way yet to completely capture the huge dynamics of a modern symphony orchestra without compromise, but hands and ears can do a better job than a robot. -
Many thanks, Ferretfancy, for the explanation. It is as I suspected although I'd not quite picked up on the fact that it could defeat the sound engineer.
There is no way yet to completely capture the huge dynamics of a modern symphony orchestra without compromise, but hands and ears can do a better job than a robot. I totally agree especially after having my ears 'bent' on Saturday night at the RAH! There was a delightful spoof article about this written by a George Izzard O'Veering in Wireless World who went back to first principles to recreate the dynamic range in his sitting room.Comment
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Ferret has done a good job in describing what Optimod does. I think that another thread here [Limiting distortion] has shown what it looks like in action.Originally posted by Resurrection Man View Post
The machine is a digital processing engine that can be programmed to do what you require and so it can be harsh or soft in its effect. Whilst Ferret is right that a degree of dynamic range compression [NOT to be confused with compression as in MP3 etc] is required to contain the real world in a living room and that all radio stations use compression to help car and portable listeners, one would have thought that R3 of all stations would tailor its settings more appropriately to the music that the station transmits, expecially when it is live. I think they are set too strongly but that is a peronal preference. When you have recently experienced real life dynamics and are then confronted with compressed sound then it stands out rather well how poor reproduced sound actually is. At the best of times live concerts knock HiFi into a cocked hat!!Comment
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