Why were my audio files distorted when streamed on the radio?

January 20, 2020 8:08 AM

A friend who DJs at a college station played my music (.wav file) on the radio but it sounded clipped and distorted - what could have caused it?

The files were recorded and mastered using Logic. I'm somewhat newish to mastering, but the plugin chain was basically just very mild compression and then Limiter with a -0.1 ceiling. The gain meters were definitely not deep in the red while mastering nor did they sound distorted.

My theory, as I've understood from reading, is that -0.1 does not allow enough overhead which is required by certain codecs - so whatever adjustments were made in the college radio's streaming system pushed the song beyond 0.0 and distorted it, maybe...?

Spotify recommends "...keep it below -1 dB TP (True Peak) max..."

So did I misunderstand and should have mastered at -1dB rather than -0.1dB?

posted by deern the headlice to Technology (7 answers total)

When you play it using the method of your choice, does it sound ok? If so, it wasn't your mastering process. It's quite possible that the line level was pushed too hi on the board for whatever device they used to play the .wav at the studio.
posted by humboldt32 at 9:13 AM on January 20, 2020

But why would only my song be pushed too high on the board and no other songs were distorted? I asked my friend the DJ who said nothing was different about anything when my music was played.

I'm curious if they convert wavs to mp3s in their streaming system and some difference in the codecs (unfortunately this is technical info my friend doesn't have but perhaps I could email the station).
posted by deern the headlice at 9:26 AM on January 20, 2020

Oh wait, did you listen to it streaming or over the air? It is possible that it sounded fine over the air and in the studio, but it went through some kid’s godawful CS senior project black box from 10 years ago to actually make it to the internet, and that’s what’s messing things up.
posted by rockindata at 10:25 AM on January 20, 2020

Were they playing the wav through the same playback equipment as their other music (i.e. not through someone's smartphone)? That could also be the problem point.

In general about limiter levels, and without being an expert but an occasional dabbler, I try to compare the final output to .wavs with .wavs from CDs of similar music- using both my ears and the visual data in audio software.
posted by p3t3 at 2:22 PM on January 20, 2020

This is reason a million not to master your own stuff, although what you did isn't really "mastering" in any conventional sense; you just gain-adjusted your mix with a couple plugins.

It's going to be hard for anyone to postmortem without the files in front of us, but it is quite possible that your track was way too hot, based on your description of your approach.

You say the gain meters weren't deep in the red - if there's any red at all your track is too hot. A mastered CD track ends up around 0dBFS, but there's almost no point in trying to chase that pony yourself, and it will usually backfire. Leave yourself some headroom. It's digital. You can always turn it up.
posted by aspersioncast at 2:12 PM on January 21, 2020

"you just gain-adjusted your mix with a couple plugins."

I've spent a fair amount of time reading about mastering and spending $$$ on online classes for mastering and gain adjustment with some other plugins is literally what was taught.
posted by deern the headlice at 7:23 AM on January 22, 2020

Then you wasted some money? Plenty of people still pay money for mastering, and aside from a few who are being profoundly ripped off it's really not just to have some grizzled old engineer run their files through ozone.

At any rate, it's entirely possible what you did was fine and the problem was on their end, just trying to steer you toward possible culprits on your own.
posted by aspersioncast at 1:18 PM on January 23, 2020