Topic: MT Set @ 16 Bit with V3 @ 24 bit - Whoops?

[manleyf]

  Dumb ass move #274118A: Out with my new rig, SR77 > V3 > MT last night at the Pageant in STL for the UM show....and I accidentally ran the MT @ 16bit with the V3 outputing 24bit.  I corrected this when I noticed ofcourse.

So, not sure what to do with the show.  I feel rather obligated to upload the show as I was part of UM's new tapers-comp policy, and was graciously treated to a ticket for taping AND uploading the show to the archive.  I just want to make sure the quality on the portion that I ran the MT @ 16 bit is worth uploading.  See the funny thing is, at least with a quick listen on my studio monitoring system and heaphones, it sounds fine to my ears.

So, I'm looking for some blind opinions of my 2 samples.  Can you hear a problem with either, or does one sound better?

Also, does anyone happen to know how exactly the MT handles such a situation?  (I'm naively, secretly hoping that the MT doesn't adversely alter the data in anyway in this scenario, that is, no dither applied by the MT, maybe the file is just marked as 16 bit, but maybe its not, etc...) 

So, please have a listen to these short samples.  They are in no specific order, have a listen please and let me know what you think I should do with the show:

http://separatereality.org/download/UM/

Thanks,
Manley

[Patrick]

The MT will just truncate the extra 8 bits.  No harm done, you just don't have a 24 bit show anymore, but the 16 bit versions are fine. 

[manleyf]

So when the MT truncates to 16 bit, there's no noticeable loss in audio quality (assuming I'm going to dither the 24bit files down to 16 bit as I've done with the samples)?  That is, after dithering the 24 bit set down to 16, etc, will it all sound just as good?

Did you happen to notice a difference in the samples?  Did one sound better than the other?

[Patrick]

So when the MT truncates to 16 bit, there's no noticeable loss in audio quality (assuming I'm going to dither the 24bit files down to 16 bit as I've done with the samples)?  That is, after dithering the 24 bit set down to 16, etc, will it all sound just as good?

Did you happen to notice a difference in the samples?  Did one sound better than the other?

There is no loss in audio quality other than the typical differences b/t 24 and 16bit files.  Basically, there are no added artifacts, or anything else that would sound different than running the v3 at 16 bit. 

Next time why don't you set you MT S/PDIF in to "auto" so that way it will accept whatever bit rate it is being fed.

I am in a library right now so I'll download the files when I get back home 

[anhisr]

The Bit rate is set to 16 or 24 bit.  There is no auto for that. 

[Patrick]

The Bit rate is set to 16 or 24 bit.  There is no auto for that. 

I don't have a MT (and have really only messed with one for a few mintues) but I thought I saw in the menu an option for auto bit rate.  Maybe that was just sampling rate?  Sorry. 

[anhisr]

sampling rate has an auto selection

[Brian Skalinder]

There is no loss in audio quality other than the typical differences b/t 24 and 16bit files.  Basically, there are no added artifacts, or anything else that would sound different than running the v3 at 16 bit.

Some people hear differences between native and/or properly dithered 16-bit and truncated 16-bit sources, others don't.  But in the latter case, that doesn't mean the sources don't suffer a loss of audio quality.  They do.  A 24-bit source truncated to 16-bit is not the same as a native 16-bit source or 24-bit source properly dithered to 16-bit, due to greater quantization errors / distortion in the truncated source v. the native or properly dithered source.

[manleyf]

Some people hear differences between native and/or properly dithered 16-bit and truncated 16-bit sources, others don't.  But in the latter case, that doesn't mean the sources don't suffer a loss of audio quality.  They do.  A 24-bit source truncated to 16-bit is not the same as a native 16-bit source or 24-bit source properly dithered to 16-bit, due to greater quantization errors / distortion in the truncated source v. the native or properly dithered source.

I absolutely agree and knew it was not a desirable situation.  What I'm wondering is if anyone can tell the difference in my two samples.  I hoping that no one can of course....

[Brian Skalinder]

I absolutely agree and knew it was not a desirable situation.  What I'm wondering is if anyone can tell the difference in my two samples.  I hoping that no one can of course....

Don't sweat it.  Some people may hear the difference, some may not.  It is what it is at this point.  I'd dither to 16-bit (looks like you've already done so), make a note of what happened in the info file, and seed.  People can decide whether they want to listen or not based on the info file and their own ears.

[Patrick]

There is no loss in audio quality other than the typical differences b/t 24 and 16bit files.  Basically, there are no added artifacts, or anything else that would sound different than running the v3 at 16 bit.

Some people hear differences between native and/or properly dithered 16-bit and truncated 16-bit sources, others don't.  But in the latter case, that doesn't mean the sources don't suffer a loss of audio quality.  They do.  A 24-bit source truncated to 16-bit is not the same as a native 16-bit source or 24-bit source properly dithered to 16-bit, due to greater quantization errors / distortion in the truncated source v. the native or properly dithered source.

Yeah, all this is right.  What I was basically trying to say is that the truncated files are playable, and are perfectly fine for circulating.  Sure there may be sound differences, but the truncated files and the content within them is not lost or damaged.

[manleyf]

I'd dither to 16-bit (looks like you've already done so)...

Actually, I didn't dither it as it opened in SF at 16/48.  So you think I should go ahead and apply 16bit dither?  Might as well I guess...

[Brian Skalinder]

I'd dither to 16-bit (looks like you've already done so)...

Actually, I didn't dither it as it opened in SF at 16/48.  So you think I should go ahead and apply 16bit dither?  Might as well I guess...

I recall reading an article indicating that dithering truncated sources will help minimize the quantization error, but can't seem to find it again.  If most of the file is properly dithered 16-bit (from the V3), I wouldn't worry about it.

[danlynch]

I assume the opposite situation is not desireable, but also not particularly noticeable either.  I had the Apogee set for 16/44 (don't ask), and the MT set for 24 bit.  The recording time was consistent with with a 24 bit (44.1)  recording, and that's what it opened as in Soundforge.  I ended up dithering down to 16 bit since that's really all the Apogee had given the MT.

[manleyf]

I assume the opposite situation is not desireable, but also not particularly noticeable either.  I had the Apogee set for 16/44 (don't ask), and the MT set for 24 bit.  The recording time was consistent with with a 24 bit (44.1)  recording, and that's what it opened as in Soundforge.  I ended up dithering down to 16 bit since that's really all the Apogee had given the MT.

In that case, I'm pretty sure that you should not apply any dither when converting the bitrate to 16bit.  In soundforge, just change the bit rate as you did, but choose Dither: None, Noise Shaping: Off.

The reason I say this is that the MiniMe has already dithered the signal down to 16bit for you, and I believe the MT really only captured 16 bits. 

I'm not absolutely 100% positive, but I don't believe the MT would fill or create the additional bits of info if they did not really exist, but the file was marked as 24bit.

Odds are that you probably won't be able to tell a difference between the undithered version and the dithered version.