[Ardour-Users] Destructive editing

[Rob Quin]

On Monday 02 November 2009 10:58:19 Jörn Nettingsmeier wrote:
> Paul Davis wrote:
> > On Sun, Nov 1, 2009 at 7:00 PM, Rob Quin <robquin at uklinux.net> wrote:
> >> If I just import the raw tracks into Ardour, it makes resampled 32bit
> >> copies.
> >
> > Turn off the "Copy files to session" toggle near the lower right
> > corner of the import dialog. As long as they are at the same sample
> > rate as the session - no copying, Ardour will just use the original
> > files.
> >
> > Alternatively, or additionally, change Ardour's default native disk
> > sample format to 16 bit (Options -> Audio File Format -> Sample Format
> > -> 16 bit).
>
> ouch! don't do that. in 2009, there is no excuse to work at 16bits any
> more, unless you're doing really lo-fi stuff, such as speech archiving etc.
> at every processing stage, you will get round-off errors (which is
> signal-dependent noise), and they quickly accumulate, so that the
> effective bit-rate will have degraded to well below 16bits by the time
> you hit the CD, which effectively means you can *not* deliver CD
> quality. with clever dithering, you can squeeze 17-18 bits of
> information in there, which means you should not work at less than 20,
> and that only if you don't have many processing stages.
>
> (of course, ardour's internal sample format will always be float, so the
>  processing degradation only happens when you bounce stuff - but that
> happens, i'm told :-D)

The originals are at 16 bit because that's the best that my field recorder 
will do. Till I have spare cash to invest in something better I'm stuck with 
that. I'm quite happy for Ardour to resample to 32bit (no sense losing 
further quality during the processing and mixdown).  I don't want Ardour to 
be working with my originals (they're my backup). It's the length of the 
files that I'm bothered about. I don't want the resampled file to be 20 
minutes long when the finished export is going to end up at 2 minutes.

Rob