Why do tracks sound different after upload?

I`ve noticed this a couple of times that certain tracks sound different after uploading them to the Loops. Seems especially true for keyboard-heavy tracks. They sound "thinner" and I get the impression that individual layers (I tend to stack multiple different keys, mixing them to a separate track before adding that track to the overall mix) somehow get lost or at least are much quieter that other layers.

As I use the same monitoring setup for recording and listening on Loops, I can only imagine that for some technical reason the dynamics and characteristics of a track are changed by the player embedded in Loops.

Anyone else come across this and does anyone have an idea how to compensate for this loss during mixing?

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A very good question. Once LittleWing wrote about the importance of dithering which could apply here. The reason is that according to https://www.wikiloops.com/knowledge/audio_filtetypes_formats.php all files here play as .mp3 ones, so if you upload a .wav file as your main mix (which I often do), it will be converted to an .mp3 by the internal Wikiloops processing.

Unfortunately, this part of the Knowledge Base isn't very detailed in what exactly is going on, maybe we should improve this?

So what you could try is to upload the same track once as a .wav (maybe 24 bits 48kHz or so), and one time as an .mp3 one (maybe with 192kBit/sec), and if that has less than 24 bits, then add some triangular dithering in the mastering process before exporting? Just a thought on how to further test this.

Or maybe Dick (Richard) and/or OliVBee (who does brilliant sounding mixes) can help further here? If we knew how audio is processed here internally (maybe with resampling to 16 bits or so?), then we could "target" our stuff for that?

Good topic!

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Hey,
the effect MySounds describes has been chased before.
All I can add to the hunt is the following bits of information:
Yes, any .wav files do get encoded into 192k mp3s, using a standard encoder with no special processing settings.
This is done so the track can be streamed and played back quickly, sending the wav files out to the browser would take forever on a mobile connection (and it would cost a lot more streaming server power, too), so that's why.

So, yes, if you have mixed and listened to your mix in wav quality first and then listen to it in 192k mp3, there surely is an audible difference due to the compressed format.

On to a few more details:
- If you upload your track as p.e. 320k mp3, it will not be converted and the original 320k mp3 will be streamed, too.
- you can open any of your audio files in your browser, too - just drag the file onto some tab and drop it. The player that appears there is technically identical to the one used on wikiloops (called HTML5 player, a common browser feature nowadays)- if your own mix sounds different when listening via the browser, then the issue might be on your end and as simple as "I have my browsers audio volume set -6dB lower than my DAW in the sound settings".
Depending on your sound setup, audio from browser may be treated different to audio from some installed software, be it by some "do not disturb" or "reduce volume when video call comes in" monitoring tool that may be interfering.

I'm not saying the effect is non-existent, all I can say I've never included anything to "enhance" or alter the audio.
All that happens on wikiloops with audio files is re-naming them and adding the tracks text details & logo to the mp3-tags (these tags rest outside of the audio data in a different segment of the file, so I do not believe that alters sound).
Plus of course the mentioned mp3 conversion needed if wav is the supplied format.

I guess one could mix towards sounding good in compressed format, and that might require a different sounding wav mix before conversion happens. Quite alike to people doing different mastering for vinyl and CD to make the most of the final result, but I'm not an expert who could give you a lot of pointers on that.

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Dick and Wolfgang,
thanks for the suggestions and explanations. And just to make it clear, I wasn't complaining as I'm pretty sure that the cause lies somewhere on my side. So I'm just trying to do a bit of analysis.

What bugs me most - and this is how I came to notice the problem in the first place - is that frequencies seem to play a role. I seem to be losing volume on the high frequencies and gaining volume on the lower ones, just as if the track was run through a multiband processor with peculiar settings.

I'll just keep on experimenting and having fun in the process:)

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My experience is that an uploaded mp3 file in the browser on Wikiloops sounds the same (as far as I can differentiate) as the mp3 file played locally in the browser.
In contrast to this, I would guess that the "native" mp3 player on the Hardware Device has an equalizer setup which differs from the equalizer setup in the browser mp3 player?

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You can create a band room and use it for a test room how it’s going to sound before uploading .That way no surprises.

I will always test upload to my private test room first and if okay then it goes live.

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Thank you all for hints and advice. I think I`ve solved at least part of the problem. On the audio interface there`s a mix button that controls the headphone/monitor output between playback and recording. With the settings I had, it seems that what I heard wasn`t identical to what was recorded and mixed.

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Quick (and hopefully final) update. The culprit seems to have been my audio interface. After switching back to my Roland Rubix, all tracks suddenly sounded like they should have in the first place. Don`t really understand the mechanics of why even the waveform was different to what I saw in the DAW, but it`s a toss up between my settings and malfunctioning hardware.

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Hi,

From what you describe i think there is a possibility that the media streamed by your browser could be routed to your motherboard audio chipset (if there's one available) while your DAW could be routed to your interface thus a noticeable difference. Might worth a check of your system audio preferences ?

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I have also noticed that when I listen to a MP3 track that I mixed on my DAW (Which is on a different computer.) on my main PC which I use for all internet related stuff, it sounds really fat and boomy. After I upload the MP3 to the Loops it sounds somewhat less boomy or the bass seems a bit subdued. JUst FYI... :)

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