Re: volume extremely low when combining many files

[Bob S <bsabiston@gmail.com>]

> When you say 'silence' do you mean no signal at all, so if you looked at
> it in a waveform editor there would be no waveform at all, or do you 
> just
> mean very quiet (ie a small waveform)?
> 
> What does the output of sox, with the  stat  and  stats   effects look
> like for these files?   If you trim out one of the sections that you 
> think
> is silent, what do stat & stats say about such a section?
> 
> What do stat & stats say about one of the result file's meant-to-be 
> silent
> sections?
> 
> Personally rather than trying to do the whole thing in one command, I'd
> suggest you try working in changing the level of just one or two of the
> small files, and examine them then with stat & stats.  Then look at the
> file you get if you mix those two files together, and see if you can see
> what levels are changing.
> 
> -- 
> Jeremy Nicoll - my opinions are my own


Thanks Jeremy.  

Well, I am using the ‘pad’ command to insert what I assume is absolute silence. 

I have not used stat & stats, I’ll have to read up on those.

Also, for this example, I am not even changing the volume of each individual sample/track.  Everything is at full volume.
So say for example I have 4 sound effects being assembled (when really it is 100 — if I actually just have 4 then this doesn’t happen).
Each effect is 1/4 of a second long and they are spaced along a two second gap. And say they are all actually the same sound:

/ sound 1/ ………………………………………………………………………………
…………………………/ sound 1/ ……………………………………………………
………………………………………………………/ sound 1/ ………………………
 …………………………………………………………………………….../ sound 1/

So in my first loop I assemble each of those four tracks, using ‘pad’ to place them at the correct position along the whole soundtrack.
Then in the second pass I mix them all together.  And for some reason all that padded silence is adding up to static noise.

I will do some more investigation and try the stats thing.  But theoretically ‘pad’ should just add absolute silence, right? Adding 100 tracks of
it together shouldn’t add up to noise, should it?

Thanks
Bob



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