What would be a proper -db level radio play

Hello,
 
Everytime I finish a project i like to see if new projects sound range is compatible with Radio Play. Both loud songs and soft songs will have different levels for -.db   
 
Thanks for you input.  
 
Matthew

As said you need to read up on Average RMS level.
 
Peak Level does not tell you how loud a song is.  A song with a lot of transients will overdrive your peak level but might still come out at a low average RMS reading.    There are a few other standards but generally Average RMS  of between -12 and -14 is the benchmark ( for Rock) . Classical music has a different reading than metal for sure but pop music is more or less in the middle ground.  
As said you need a tool to analyze your song. Example Wav Lab can do this. 
Sonar will need a plug in as mentioned isotope is a good one. 
And final proof is using your ears. These reading just put you much closer to the truth. 

Arg, I wrote out a whole long reply to this, which I've accidentally edited into the above, and now I can't get it back.

Ah! Managed to find it with use of the Firefox back button. Thanks Firefox. Here you go:
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This is all changing quite quickly, and I have recently ran into a serious problem with it, which I luckily got to fix for the final release.
 
Increasingly, both radio and online streaming are standardising around an LUFS measure (Loudness Units Full Scale, to give it its full name). So not peaks, and not RMS, though it has something in common with RMS. I'm not the right person to explain LUFS with any clarity, so go and look that up yourself.
 
Or don't. You don't really need to understand it. What you need is a decent LUFS meter plugin, and enough knowledge to read it. Ozone 8 does good LUFS metering.

You also need the awareness that the current landscape is: YouTube will turn your track up or down to play back at a level of -14 to -12 LUFS. I think Spotify and Apple Music are closer to the -14 end of that. And most radio broadcasters are falling in line, though generally even *lower*. The BBC target around -20 LUFS for most programming, though I think there's some leeway for music shows.
 
The net result of this is that the loudness wars are over. Really. There is now not only not a benefit to a really loud master. It's worse than that. A really loud master will get turned down overall, or compressed into oblivion. And it's not a subtle thing. You will know it when you hear it.
 
Except like that crazy japanese soldier they found in the mid 70s living on an island somewhere who thought WWII was still on, people are still slamming the masters. But on digital, your slammed master will just get turned down, and on radio, it will get compressed far beyond the point of ugliness.
 
I was struggling with this idea, as I'm so used to people asking for really hot masters, and -14 LUFS is not remotely hot. So I initially delivered a master of an album at about -10 LUFS. Which is still fairly quiet, in "slammed master" terms, and will barely touch a good mastering limiter.

One of the songs got a preview play on BBC radio before we sent the stuff off for duplication and it was *horrible*. The broadcast compressor audibly pumped all the life out of it. And we did a private youtube test, and youtube turned it down by a full -5dB. So we we made a way, way quieter master. One of the revised versions got on the radio a couple of days ago, and sounded great.

So like I say, the war is over, but there is a wrinkle. If you're not going to radio or the bigger streaming platforms, then you should note that Soundcloud and Bandcamp currently don't do any LUFS based volume management. So if your main platform is Soundcloud, slamming the master will make your track sound louder than other tracks. Whether that's worth having is a matter for your own judgement. But if you've got something that's going to actual radio, go and research current thinking about LUFS.

Yes, learn about LUFS. Youlean is a free loudness meter that works well https://youlean.co/youlean-loudness-meter/
 
You should literally master for each format you are going to, so depending on what you do, you could end up with several masters, one for CD, another for Spotify, another for radio etc.