How does Sonar uncompress m4a (Apple lossless) files when they are dragged into the track view? Is it internal code or a system codec?
 
Why do I want to know this? Sonar does this flawlessly (nulls with imported wav file) but another program I use doesn't.
 
Cheers, Peter.
 

Uncompressing m4a with ALAC-compression is always losless.
It should make no differnece if this is internal or system code.
Only AAC compression is not losless.

Thanks. Yes, that's what I'd expected but I seemed to be getting differences. Turns out it's probably the volume metadata tag that itunes adds to files. It's meant to help with volume normalization. It is always calculated and stored in the file when ripping CDs, but the effect can be turned off for playback within itunes. However I'm suspecting that Sonos software honors the tag and therefore changes the volume of the song (and not by a constant either!)
 
Cheers, Peter.
 

I believe SONAR relies on the Microsoft Media Foundation library (MF.DLL) for its MP4/M4A/ACC codec. That's about all I know about it, but it at least that gives you a search term to google. My guess would be that SONAR properly ignores any volume normalization hints.
 
Q: When you say the SONAR-generated file "nulls", what are you nulling it against? 

Original wav file ripped from CD nulls with m4a/ALAC rip using itunes when both are imported into Sonar.
 
The same wav file played through a Sonos Connect and recorded all digitally (i.e. no A/D or D/A) also nulls with the original wav file.
 
However, the m4a/ALAC played through a Sonos Connect and recorded digitally does not null. I originally wondered if the m4a->wav codec might be the issue (Sonos runs a version of Linux internally, so doesn't use the windows codec), but I now doubt it.
 
I think the issue is that Sonos (not Sonar) honors the volume normalization ITUNNORM metadata tag that itunes adds when ripping any file. Sonos docs don't mention using this tag for ALAC files, but I think this is what is happening. I've just figured out how to change the ITUNNORM tag to set the volume normalization to zero (not trivial, as it turns out), so I'll run some tests today.
 
Ultimately I'd like to play my music just as it is on the CD, not normalized (which includes limiting, so the sound is compressed somewhat). It is not really feasible to change the tags on all my ripped ALAC files. When I'm sure this is what is happening I'll need to talk to the Sonos developers.
 
Cheers, Peter.