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loudness / stream audio level

Posted: 23 Aug 2014 09:23
by Michiel Bouwmeester
Hello fellow PF users (and guests)

We spend a lot of time in setting up our stations but what surprises me that there is almost no information on how to properly setup the level of the streams.
There are massive discussions for radio and tv and of course in the music industry.. we all know the "loudness wars" but streaming is lost it seams.
This post is meant as a starting point for new stations, and may be some discussion for the older ones :D

What we wanted for our station:

- Always reasonable sound level so that the listeners does not need to turn up and down the volume all the time.
- Have some compression and stereo expansion to give the sound some "radio" feeling but nothing near so much as real "fm" stations.
- Protect the stream from overload
- Have some sort of reference to keep an eye on our stream

Our solutions:
Of course we needed to measure things. We are using the free Loudness meter Orban Page. It is a free tool that does a superb job.
We used winamp to play a 0dbfs pink noise file. While playing this we adjust the output of winamp to show -6dBfs on the PPM meter of the Orban loudness meter.
This will be our reference. We now tune in to our stream with this winamp player, not touching the volume again.

In ProppFrexx we use Stereo Tool. We have a very mild setting there. If any body wants to I can send you our settings file. We have adjusted the compression and autogain to our needs. Of course this is very personal but when tuning this keep an eye on the Orban meter, the 3 top meters show the (relative) loudness. You want to aim an ITU shorttherm level of around -22dB ~ -18dB (or -2dB ~ +2dB if you have set the scale to relative)
While adjusting keep an eye on the PPM meter also, it needs to peak at -6dBfs, no more.

This will take some time but if you respect the meter you will get a nice balance sound, and not that screaming dead compressed sound.
We are sounding a big bit softer then our "fm" partners do on there streams: For us that is ok, we don't like that sound.
If you want you can use this setup also to get the last possible db of loudness out of your stream... it is all up to you :)

Take a listen to our stream and let me know what you think! Universe Radio