Stereo Tool

Bug report: When closing ST and opening it again with BS412 enabled, you get silence.

Temporary workaround: Before closing ST, disable BS412. Then after restarting ST, enable BS412 again.

What's the point behind BS412 being mandatory at Europe anyway? Lower volume at FM transmission doesn't mean more noisy signal?

http://www.itu.int/dms_pubrec/itu-r/rec ... !PDF-E.pdf

Hmm after reading some more, it's probably not the answer to your question.
Anyway maybe it's usable.

Hmmm, after reading the document, I think that I got the point behind it. BS412 is supposed to protect broadcasters from some kinds of interference. But, in my opinion, reducing the broadcast volume also reduces the SNR and the effective range of the signal. Maybe BS412 is a good solution for interference, but it must be applied with a transmitter power increase to compensate the loss of range.

Most people don't seem to be too happy with it. After implementing this thing, I can tell you that it has some serious drawbacks. Mainly the the limiting is based on RMS level instead of some ITU-1770 like level, which causes big issues for both loud lows and loud highs.

If I choose 1-band RMS levelling for the input AGC and turn pre-emphasis off, the output of Stereo Tool is already nearly constant and the BS412 limiter has to do nearly nothing. Of course that's not really an option...

There is one big advantage that most BS412-compliant stations have: No or nearly no clipping. So compared to the horribly clipped (often with quite bad clippers) Dutch stations, the German stations usually sound great - but insanely quiet.

True, but we can always make same quiet preset, which can bring lot of room for dynamics, without BS412. Of course it might be not compile to BS412 papers. But it can sound even better.

I guess, as someone in North America, I just don't quite understand why there is the need for this. Is the band really that congested in Europe that these limits have to be put in place? How about transmitter power or antenna lowering?

Arggggghhhh you mentioned Stacker. Now I will have nightmares all weekend long.

I will need to check on that BS412 thing. My first thought is that it doesn't make any sense what they say about the bandwidth. If you comply to Stokkenmasker that should be the reference on how much bandwidth you use.
I would like to see it on the spectrum analyser. Maybe if I have some time next week I can see what it looks like.

Here's a BS412 compliant preset, based on Bojcha's Neodymium preset. Most important changes are that I have turned Bass Boost off, and linked AGC band 1 stronger to band 2.

http://www.stereotool.com/download/BS41 ... 20edit.sts

I have tested it with over 2 hours of audio, and results so far look good:
- Only twice I have seen a drop of the black line below -0.5 dB (ignoring the separation between tracks here of course; and even then the deepest drop I see is to -1.3 dB).
- Compression (green/purple line) only very occasionally dips to -2 dB. So not much compression.
- Red line deepest dip is also to around -0.6 dB.

Of course it is now possible to create lots of new presets.

Screenshot: http://i.imgur.com/lz6sv.png

Ah, now I remember. I think I was at the university at the time. It's just that the number 6.22 didn't immediately ring a bell